Abstracts:

International Society

for Aerosols

in Medicine

23rd ISAM Congress

Boise, Idaho

May 22–26, 2021

Abstracts: 23rd ISAM Congress

01. Effective Removal of Exhaled Virus Using a Viral Filter on the Aerogen Ultra Nebuliser System

Ronan MacLoughlin,1,2,3 Mary Joyce,1 and Daniel O'Toole4

1Aerogen, IDA Business Park, Dangan, Galway, Ireland.

2School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons, Dublin, Ireland.

3School of Pharmacy and Pharmaceutical Sciences, Trinity College, Dublin, Ireland.

4School of Medicine, National University of Ireland Galway, Galway, Ireland.

Introduction: In response to the ongoing COVID‐19 pandemic, expert consensus suggests that connection of a filter to nebulisers has the potential to mitigate the risk of bystander exposure to patient‐derived bioaerosol. Here we assess the feasibility of removing exhaled virus using a viral filter and determine its effect on nebuliser performance.

Materials and Methods: Simulated exhaled breath, containing Adenovirus (Ad5‐GFP) as a tracer bioaerosol was generated during normal adult breathing (15BPM, Vt 500mL, I:E 1:1). At ∼100nm, Ad5‐GFP is similar size to SARS‐CoV‐2. Two viral filters (303EU; Vyaire, US) were connected to the mouthpiece of the Aerogen Ultra (Aerogen, Galway, Ireland). The primary filter was used to capture exhaled aerosol, the secondary to assess if virus escaped from the primary filter. Inhaled dose was assessed using salbutamol (2.5mL of 2.5mg/mL). No supplemental oxygen was used. QPCR was used to determine presence of viral plasmid on the filter. UV spectrophotometry was used to quantify salbutamol. Testing was completed in triplicate.

Results: For all tests, virus was detected on the primary filter with none detected on the secondary filter. Inhaled dose was recorded as 65.22 ± 1.2 % versus 65.98 ± 2.01 % (p > 0.05), unfiltered and filtered, respectively.

Conclusion: Connection of a viral filter was seen to effectively remove virus from the simulated exhaled breath, with the use of the filter not having a significant effect on nebuliser performance.

02. Differential Inflammatory and Toxic Effects in Vitro of Wood Smoke and Traffic‐Related Particulate Matter from Sydney, Australia

Baoming Wang,1,2 Hui Chen,1 Dia Xenaki,2 Jiayan Liao,3 Christine Cowie,2,4,5 and Brian G. Oliver1,2

1School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia.

2Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.

3Institute for Biomedical Materials and Devices, Faculty of Science, University of Technology Sydney, New South Wales, Australia.

4South West Sydney Clinical School, University of New South Wales, Liverpool, New South Wales, Australia.

5Ingham Institute of Applied Medical Research, Liverpool, New South Wales, Australia.

Background: PM2.5 generated by traffic or burning wood is pro‐inflammatory and induces various adverse health outcomes in humans. In Australia, the main anthropogenic contributors to particulate matter (PM) air pollution are wood combustion heaters, on‐road vehicles, and coal‐fired power stations. However, the relative toxicity of these local sources has not to date been investigated.

Method: PM2.5 was collected on filters from the same sampling site in Liverpool, Sydney. According to the positive matrix factorization and collection season, filters were representative of either day with high traffic‐related air pollution (TRAP), wood smoke, or both TRAP and woodsmoke (mixed air pollution). The elemental composition of the PM was assessed by accelerator‐based ion beam analysis techniques (i.e. PIXE & PIGE) and size by Dynamic Light Scattering. Toxicity and inflammation were assessed in‐vitro in human bronchial epithelial cells by measuring interleukin‐6 (IL‐6), interleukin‐8 (IL‐8) release, and MTT.

Results: Mixed air pollution (TRAP/wood smoke) PM had more nanometre‐sized PM than the other two groups. The mixed air pollution PM was the most toxic, whereas the PM from woodsmoke induced greater IL‐6 release than TRAP PM. There was no difference in the induction of IL‐8 between the three sources of PM.

03. Respirator Filtration Efficiency Before and After Decontamination by Moist Heat Incubation: Particle Size Dependence

Solbee Seo, Conor A. Ruzycki, Bailey Johnson, Hui Wang, Reinhard Vehring, Dan Romanyk, Warren H. Finlay, and Andrew R. Martin

Department of Mechanical Engineering, Faculty of Engineering, University of Alberta, Edmonton, Canada.

The decontamination and reuse of respirators have been proposed to mitigate the shortage of N95 or similar high‐efficiency respirators during pandemics. The NIOSH respirator filtration efficiency (FE) test protocol defined in 42 CFR Part 84 Subpart K has been used to verify if decontamination procedures can maintain a minimum FE above 95% for some respirators. However, the defined size range of sodium chloride test aerosol is limited and may not include the most penetrating particle size for all respirators. Here, FE was measured for N95 and KN95 respirators before and after ten decontamination cycles by moist heat incubation (MHI). A custom‐designed setup was used to determine the size‐specific FE for particle aerodynamic diameters between 0.07 and 1.97 μm. For two of the three respirators tested, FE was not reduced at any size after ten cycles of MHI. For the third respirator, FE was below 95% before MHI cycles and decreased to 81% after MHI cycles. The most penetrating particle size for this respirator was outside the range defined in NIOSH protocol and further increased after MHI cycles. From this study, it is recommended that a wider test particle range, including particle sizes up to the micrometer size range, should be used when testing the FE of respirators and facemasks used during pandemics. The risk of disregarding respirator performance at larger sizes is notable in the context of filtering infectious aerosols where infectious load increases with size.

04. Modulation of Allergic Airways Disease Employing Bio‐Mimetic Nanocarriers with TLR Agonists

Scalise, Melanie,1,2 Ferrié, Céline,1,2 Mutlu, Seyran,1,2 Amacker, Mario,1,3 Wotzkow, Carlos,2 Steiner, Selina,2 von Garnier, Christophe,4 and Blank, Fabian1,2

1Respiratory Medicine, Bern University Hospital, Bern, Switzerland.

2Department of BioMedical Research (DBMR), University of Bern, Bern, Switzerland

3Mymetics SA, Vaud, Switzerland.

4Pneumology Division, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.

Allergic asthma is characterized by airway hyperresponsiveness due to a maladaptive Th2/Th9/Th17 immune response against innocuous environmental substances. Current treatments only manage to reduce the symptoms but do not alter the natural course of the disease. We aim to design and characterise the effects of bio‐mimetic nanoparticles in a mouse model of experimental allergic inflammatory airways disease (EAIAD) to skew the immune response towards Th1 polarization. We established a reproducible EAIAD mouse model showing eosinophilia and enhanced IgE titre, ready to treat allergic response with liposomes/virosomes conjugated with OVA and a TLR7/8 agonist, followed by monitoring specific immune effects. Immune cells in different lung compartments (flow cytometry), as well as lung function (Flexivent SystemTM) and IgE titre (ELISA) were monitored before and after treatment. Lung function data revealed that treatment with OVA‐liposomes rescued animals from impaired lung function, such as enhanced airway resistance, reduced forced expiratory volume in 0.1 second, reduced peak expiratory flow, enhanced IgE levels in serum. Flow cytometry analysis of pulmonary immune cells following treatment is in progress. Our results show that virosomes/liposomes ameliorate hallmarks of allergic airways disease. Bio‐mimetic nanoparticles employed as carriers for antigen and adjuvant show great potential as future therapeutic approaches for re‐programming allergic airways disease.

05. Real‐time Resistance Monitoring of Human Lung Epithelial Tissue Models for Predictive Aerosol Research

Bedia Begum Karakocak,1 Gowsinth Gunasingam,1 Silvia Angeloni,2 Adrian Auderset,3 Alke Petri‐Fink,1 and Barbara Rothen‐Rutishauser1

1BioNanomaterials Group, Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland.

2SiMPLInext SA, Rue Fritz‐Oppliger 18, 2504 Biel/Bienne, Switzerland.

3Switzerland Innovation Park Biel/Bienne, Aarbergstrasse 46, 2503 Biel/Bienne, Switzerland.

Numerous lung cell models have been described to simulate the human lung tissue barrier for studying the interactions of aerosolized materials with cells. These in vitro models are typically assembled on semi‐permeable inserts consisting of two‐chamber compartments. The readiness of such cell models for transport studies and drug efficacy tests is typically assessed with transepithelial/endothelial resistance (TEER) measurements of tight junctions along with permeability assays. In this study, we will present a smart silicon nitride microporous permeable insert [SiMPLI] combined with single‐frequency impedance measurements to assess resistance values of selected cells in a non‐invasive digital platform. We validated the system using human alveolar epithelial type II (A549) cell line and compared cell growth, TEER, and permeability of fluorescein isothiocyanate with cells grown on polyethylene terephthalate (PET) inserts to SiMPLI. The preliminary results showed that with SiMPLI inserts, the standard error among the technical replicates was significantly lower than the measurements obtained on conventional PET inserts. Finally, a human alveolar 3D model composed of A549 and EA.hy926 cells, along with two types of immune cells: human monocyte‐derived macrophages and dendritic cells, will be assembled simulating the lung tissue barrier. We demonstrated the superiority of the SiMPLI system as a reliable platform for real‐time monitoring of resistance in human lung cell models.

06. Model‐Based Investigation of Infectious Aerosol Generation by Non‐Invasive Supplemental Oxygen Delivery Devices in Use with Covid‐19 Patients

Nathaneal A. Park,1 Paul S. Soma,1 Jhaymie Cappiello,2 Kamrouz Ghadimi,2 and Gary L. Glish1

1University of North Carolina at Chapel Hill.

2Duke Medical School.

The COVID‐19 pandemic, caused by the virus SARS‐cov‐2, has been serious global health crisis. A common symptom in patients with severe cases of COVID‐19 is dangerously low blood oxygen levels. Treatment of low blood oxygen requires supplementary oxygen delivery using external means, including noninvasive nasal cannulae, rebreathing masks, and non‐ invasive ventilators (NIV devices), and in severe cases anesthesia and invasive intubation with ventilation. Though effective, invasive intubation is dangerous due in part to the application of anesthetic, and intubated patient outcomes tend to be poor. NIV devices would thus be preferable when patients exhibit only modest symptoms. However, unknowns still exist surrounding whether or not NIV oxygen delivery methods produce potentially infectious virus‐containing aerosols. Invasive ventilation involving intubation is a completely closed system and is treated as aerosol‐free and less likely to spread infection. Thus, the choice of whether to prioritize the health of patients or healthcare workers has been a dilemma. Current work has explored the possibility that dangerous amounts of aerosol are produced by noninvasive oxygen delivery devices via a mannequin simulating a patient by detecting aerosol under various parameters. Preliminary data shows the efficacy of this mannequin model as well as evidence that noninvasive ventilation may produce more aerosol than nasal cannulae or a control.

07. No Evidence that Electrostatic Charge Near High Voltage Power Lines Increases the Deposition of Inhaled Ultrafine Environmental Particles in Human Lungs

M. Biddiscombe,1 J. Matthews,2 M. Wright,2 S. Meah,1 R. Underwood,1 P. Barnes,1 D. Shallcross,2 and O. Usmani1

1Imperial College London and Royal Brompton Hospital, London, United Kingdom.

2University of Bristol, Bristol, United Kingdom.

Background: Aerosol particles that are inhaled from the environmental air, (natural and industrial sources) may result in the deposition of potentially harmful particulate substances in the human airways. The mainly combustion‐generated submicron (1 μm) and “ultrafine” (100 nm) fractions of particles are increasingly implicated as a risk to health because of their higher number and surface area per unit mass, and their deeper lung penetration. Data showing an increase in adult and childhood leukaemia risk near to high‐voltage overhead power lines (HVPL) but beyond the range of the direct effects of electric or magnetic fields have been reported. One explanation is corona ions emitted by the power lines electrostatically charge ultrafine particles of air pollution through contact with them. This process may therefore increase the deposition fraction of charged particles relative to neutral particles in the lungs. Increased knowledge of the behaviour of charged particles in the airways is therefore crucial to the understanding of their potential impact on human health. This is the first study to clearly examine the effects of electric charge, of the same order of magnitude found near to HVPLs, on carbonaceous particulates smaller than 300 nm in the human lungs.

Aim: Our hypothesis for this investigation was that particles with excess electric charge have a higher likelihood of human lung deposition than 'non‐charged ' particles.

Methods: We developed and characterized a system for the generation and delivery of TechnegasTM (Cyclomedica) particles, labelled with the radionuclide Technetium‐99m (99mTc) to investigate the lung deposition of positively (CP) and neutrally charged (CN) 100nm particles. Eight healthy, non‐smoking participants (five females and three males; mean age, 33 yrs.) with normal spirometry (mean FEV1, 91.9% predicted) participated in the study. The primary outcome measure was penetration index (PI), a measure of aerosol lung deposition and penetration relative to an inert radioactive gas Krypton‐81m (81mKr). The particle number deposition efficiency (DFp) was also measured.

Results: PI and DFp were indistinguishable for charged and uncharged particles (Table). This implies that the mechanism of electrostatically enhanced deposition did not measurably influence particle lung deposition in adults. These results are contrary to the corona ion hypothesis.

Conclusion: The study found no evidence that charge leads to increased lung deposition in 100 nm particles suggesting that corona ions from HVPL may not be an important contributing factor influencing adult and childhood leukaemia risk.

08. A Pneumocyte‐Like Monoclonal Cell Line to Reliably Model the Human Air‐Blood Barrier in Vitro

Patrick Carius,1,2 Klaus Urbschat,3 Nicole Schneider‐Daum,1 and Claus‐Michael Lehr1,2

1Helmholtz‐Institute for Pharmaceutical Research Saarland (HIPS), Department of Drug Delivery (DDEL), Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany.

2Biopharmaceutics and Pharmaceutical Technology, Saarland University, Department of Pharmacy, 66123 Saarbrücken, Germany.

3Section of Thoracic Surgery of the Saar lung center, SHG clinics Völklingen, Saarbrücken, Germany.

Given the delicate features of the respiratory region of the human lung, mimicking the air‐blood barrier with cell‐based in Vitro models of alveolar epithelial cells is a demanding task. Ensuring standardization and reliability of such models is recognized by the research community as an important task to generate more predictive alveolar tissue models in the future. We here report the development and characterization of a novel sub clone of the human alveolar epithelium lentivirus immortalized (hAELVi) cell line, with enhanced physiological and morphological characteristics. The sub clone was established via a single‐cell printing method and systematically compared in Vitro to primary human alveolar epithelial cells (hAEpCs) as well as to the parent hAELVi cell line with electrophysiological, morphological and cell biological techniques. After 14 days of culture, the monoclonal cell line showed high transepithelial electrical resistance (TEER) of ∼3000 Ω*cm2and a potential difference (PD) of ∼30 mV under air‐liquid interface (ALI) conditions while simultaneously preserving monolayer‐like morphology confirmed via computational image analysis of confocal microscopic data. RNA‐sequencing analysis further showed similar expression of type 1 and type 2 pneumocyte specific transcripts between hAEpCs and the monoclonal cell line. The stability of the cell line in terms of physiological as well as morphological properties could be confirmed for more than 20 consecutive passages.

09. An Easy Access Microfluidic Model for Testing Aerosolized Drugs on Pulmonary Epithelia

Patrick Carius,1,2 Aurélie Dubois, Morvarid Ajdarirad,2 Arbel Artzy‐Schnirman,3 Josué Sznitman,3 Nicole Schneider‐Daum,1and Claus‐Michael Lehr1,2

1Helmholtz‐Institute for Pharmaceutical Research Saarland (HIPS), Department of Drug Delivery (DDEL), Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany.

2Biopharmaceutics and Pharmaceutical Technology, Saarland University, Department of Pharmacy, Saarbrücken, Germany.

3Department of Biomedical Engineering, Technion, Israel Institute of Technology, Haifa, Israel.

Microfluidic lung‐on‐chips are micron‐sized, biomimetic devices that allow the in vitro culture of lung specific cell types under physiological stimuli like perfusion or air liquid interface (ALI) conditions. In an effort to combine the advantages of well‐based filter supports, like the traditional Transwell®, with the virtues of microfluidic perfusion, we here present a versatile microfluidic platform to assess barrier permeability of and aerosol deposition on ALI grown pulmonary epithelial cells. The microfluidic platform was specifically designed to be produced and implemented by biopharmaceutical and cell biological laboratories without specific expertise in microfabrication methods and without the need to buy expensive additional equipment. In a proof‐of‐concept study, Calu‐3 cells cultured under liquid covered conditions (LCC) inside the platform showed similar development of transepithelial electrical resistance (TEER) over a period of 14 days as cells cultured on a traditional Transwell®. Fluorescein sodium was nebulized by the use of an Aerogen® Solo nebulizer connected to a customized deposition chamber onto Calu‐3 cells cultured under ALI conditions. Molecular transport of fluorescein sodium was investigated under dynamic flow as well as under static transport conditions. By making the building instructions for the platform as well as all needed accessories for reproducing the experiments described here publicly accessible, we encourage the concept of open science.

10. A Universal Approach for Inhalation Exposure Assessment for Bystanders During Inhalation of Therapeutic Aerosols

K. Schwarz1 and R. Dhand2

1Division of Chemical Safety and Toxicology, Fraunhofer Institute for Toxicology and Experimental Medicine, 30625 Hannover, Germany.

2Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, Tennessee, USA.

The risk of unintended inhalation of therapeutic aerosols is a topic of interest in the healthcare area. However, only a few studies have characterized the risk of bystander exposure during administration of inhalation therapies so far. More comprehensive research that allows for a better understanding of influencing factors and recommendations for healthcare workers and other bystanders is of importance. Therefore, an approach providing estimates of inhalation exposure towards therapeutic aerosols has been established based on the determination of the aerosol release potential, i.e. the aerosol source strength, in combination with exposure modelling. The source strength for the release of inhalable aerosols is quantified in control measurements carried out under representative conditions. These data are used as input parameters in a newly developed deterministic exposure model to predict spatial and temporal inhalation exposure concentration profile in indoor environments. The model considers the main relevant mechanisms ‐ dispersion, evaporation, sedimentation and removal by air exchange. Comparison of the results obtained from the control measurements and the model calculations with data measured in the field show good agreement. In conclusion a practical and easy‐to‐use approach allowing for the assessment of exposure to bystanders as well as analysis of potential influencing parameters during administration of inhalation therapies has been successfully developed.

11. Oxidative Stress Damage in Human Pulmonary Cells Following Titanium Dioxide Particulate Exposure

Jordan A. Hoops1 and Timothy M. Brenza1,2

1Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology.

2Program of Biomedical Engineering, South Dakota School of Mines and Technology.

Fine particulate matter (PM2.5) is a major health concern, impacting the respiratory system through impaired lung function, infection, cancer, and contributing to 4.2 million deaths globally in 2016. Exposure to particulate matter causes oxidative stress through the direct introduction of exogenous ROS and compounds that drive free radical reactions, or indirectly through the recruitment and activation of inflammatory cells which release free radicals. Titanium dioxide nanoparticles are widely used in industrial and consumer products including paints, plastics, pharmaceuticals, cosmetics, and food products and contribute to PM2.5. TiO2 nanoparticle toxicity has been studied extensively in dermal models, however, respiratory effects and oxidative damage pathways remain a concern. The goal of this work was to characterize the oxidative stress response of human pulmonary cell line A549 to titanium dioxide nanoparticles by chemokine production, apoptosis progression, and ratio of reduced and oxidized glutathione. Next, an antioxidant formulation was developed to prevent oxidative stress damage to the pulmonary cells when exposed to TiO2.

12. Respiratory Hazards from Biomass Cooking in the Shiselweni Region of Eswatini

Melinda Neumann,1Kuo‐Pin Yu,1, 2 Wen‐Chi Pan,1,2 and Shih‐Chun Candice Lung3

1International Health Program, National Yang Ming Chiao Tung University.

2Institute of Environmental and Occupational Health Sciences, National Yang Ming Chiao Tung University.

3Research Center for Environmental Changes, Academia Sinica.

Smoke emission from biomass fuels is an important source of indoor air pollution, which contains pollutants that are detrimental to health. In Eswatini, 62.3% of the households still rely on solid fuel for cooking, especially wood (61.8%). However, a quantitative exposure assessment study is not available in Eswatini. Therefore, this study aims to monitor carbon monoxide (CO) and carbon dioxide (CO2) concentration during cooking hours and to assess cancer and non‐cancer risk from the exposure of particulate bound polycyclic aromatic hydrocarbons (PAHs) during cooking hours for cooking personnel in households cooking indoor using biomass fuel in the Shiselweni region. Real‐time monitoring of CO and CO2and sampling of particulate matter was conducted in seventeen kitchens during cooking hours in the Shiselweni region among homesteads using different cooking methods: biomass in open fire, biomass stove, liquid petroleum gas stove and electric stove. Concentrations of particulate matter with aerodynamic diameter smaller than 2.5 μm (PM2.5) and 10 μm (PM10), and CO were reported to exceed the indoor exposure guideline in homesteads using biomass fuel. Moreover, from the evaluation of particulate PAHs intake concentration; biomass fuel users were reported to have a high risk of cancer (incremental lifetime cancer risk >10−5) and embryo or fatal survival (hazard quotient >1) from particulate PAHs exposure.

13. Acute Effect of E‐Cigarette (EC) Inhalation on Mucociliary Clearance (MC) in EC Users

William D. Bennett, Phillip W. Clapp, Kirby L. Zeman, Jihong Wu, Brian Ring, and Ilona Jaspers

Center for Environmental Medicine, Asthma, and Lung Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.

Introduction: Recent studies show e‐cigarette (EC) users have increased rates of chronic bronchitic symptoms that may be associated with depressed mucociliary clearance (MC). However, little is known about the acute or chronic effects of EC inhalation on in‐vivo MC.

Methods: In Vivo MC was measured in young adult vapers (n = 5 males, mean age = 21) following controlled inhalation of a radiolabelled (Tc99m‐sulfur collloid) aerosol (9.5 um MMAD at a slow 0.08 L/sec inhalation flow rate). Whole‐lung clearance was measured over a 90‐min period post‐radioaerosol inhalation for baseline MC and associated with periodic vaping over the first 60 minutes of MC measurements. A controlled vaping challenge was administered at 10 min intervals and consisted of 1 puff every 30 sec for 5min from a 4th generation box mod EC containing unflavored e‐liquid (65% propylene glycol/35% vegetable glycerine, 3mg/ml nicotine).

Results: Compared to baseline, whole lung average clearance (%) over the 90 min of MC measures was enhanced after EC challenge, 15 (±14) vs. 27 (±17) respectively (P < 0.05 by Wilcoxon signed‐rank test).

Conclusions: Acute enhancement of in Vivo MC following EC challenge is contrary to recent in Vitro studies showing slowed or no change in ciliary beat and mucus transport. However, our findings are consistent with an acute increase in fluid volume to the bronchial airway surface, similar to what is seen with inhaled hydration therapies such as hypertonic saline. Supported by NIH R01HL139369.

14. 3D Immunocompetent in Vitro Lung Models Provide Mechanistic Understanding for Inhaled Safety Assessments

Martin, A.,1,2 Hoffman, E.,2 Perez‐Diaz, N,2 Mahendran, R.,1 Saeed, A.,2 and Hutter, V.1,2

1Centre for Topical Drug Delivery and Toxicology, University of Hertfordshire, Hatfield, Herts, United Kingdom.

2ImmuONE Ltd, Science Building, College Lane, Hatfield, Herts, United Kingdom.

The fate of inhaled particles and ability to predict interactions that determine lung health largely remain unknown. It is well established that alveolar macrophages are the first line of defense against inhaled particulates in the respiratory airways. One third of inhaled medicines fail in pre‐clinical in Vivo studies due to the presence of abnormal alveolar macrophage morphology. However, it is unclear if these alveolar macrophage responses affect health and their relevance to humans. The aim of this work was to establish a robust human in vitro, 3D immunocompetent model of the alveolus to evaluate the responses of alveolar macrophages and to ascertain if this could provide a more accurate and mechanistic‐driven prediction of inhaled safety assessment. A 3D immunocompetent model of the alveolus (ImmuLUNGTM) was constructed and optimized such that it maintained functionality and viability of both epithelial and immune cell types for over 3 weeks. High‐content image analysis was used to assess detailed morphological and health descriptors of individual alveolar macrophage‐like cells within the model after exposure to a panel of inhaled medicines and control compounds. Phenotype profiling of cell responses was highly reproducible and allowed detailed mechanistic insight into the degree of adversity of the response. This approach has provided new insights to the mechanistic understanding of the fate of inhaled substances in human lungs to support toxicity assessment.

15. Quantification of Exhaled Particles for the Identification of Airborne Infection Risks in SARS‐CoV2 and Assessment of Protective Measures

Katharina Schwarz,1 Wolfgang Koch,1 Florian Fiedler,1 Horst Windt,1 Nadja Struß,1 and Jens Hohlfeld1,2,3

1Fraunhofer Institute for Toxicology and Experimental Medicine, 30625 Hannover, Germany.

2Department of Respiratory Medicine, Hannover Medical School, Hannover, Germany.

3Member of the German Center for Lung Research (DZL‐BREATH), Hannover, Germany.

Research is being conducted to assess and reduce the risk of infection by viruses transmitted via aerosols in enclosed spaces. This includes the development of simulation‐based methods requiring the input of exhaled droplet characteristics. Though a number of studies are available for different respiratory activities, there is a lack in data regarding the assessment of the complete size spectrum relevant for aerosol transmission as well as on aerosol release data during realistic use of masks. Therefore a new set–up has been established allowing for the quantitative collection and analysis of respiratory aerosols over a wide size range from 0.1 ‐ ∼ 80 μm under realistic conditions as well as under use of masks. Exhaled particle flux, size distribution and breathing patterns are determined for normal tidal breathing, speaking, coughing and singing in healthy volunteers (n = 30) by means of two laser particle spectrometers (PMT Lasair III‐110, Lighthouse Boulder Counter). This allows for a quantitative assessment of the particles relevant of the airborne transmission and the determination of the efficacy of medicinal and community masks regarding particle retention under realistic conditions. Based on these data and in combination with exposure simulations, the relevance and efficacy of active protective measures (masks, mouth‐nose cover) and passive protective measures (ventilation, air disinfection) can be derived and classified, especially for sensitive areas such as healthcare.

16. Cannabidiol (CBD) in e‐Cigarette Liquid Adducts to Cellular Proteins Induces Inflammation and Impairs Cilia Motility in Bronchial Epithelial Cells

C.A. Love,1 H.H. Kim,2 N.A. Porter,2 I. Jaspers1, and P.W. Clapp1

1University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.

2Vanderbilt University, Nashville, Tennessee, USA.

Use of e‐cigarettes with cannabidiol (CBD), a hemp‐derived non‐psychoactive cannabinoid, has increased in recent years. CBD can readily oxidize to reactive electrophile species. However, little is known about the health effects of CBD vaping. Here, we investigate whether CBD and vaped CBD aerosols can adduct cellular proteins and alter airway epithelial barrier integrity, inflammatory markers, and cilia motility. Differentiated primary human bronchial epithelial cells (hBECs) were exposed to diluted CBD e‐liquid or vaped aerosols using a JUUL device. Electrophilic protein modifications were assessed in hBECs and a model peptide using alkynyl‐tagged CBD followed by “click” chemistry to isolate tagged proteins. Adducts were confirmed by streptavidin blot and mass spectrometry. Exposed hBECs were further evaluated for changes in transepithelial electrical resistance (TEER), cilia beat frequency (CBF), and proinflammatory cytokine (IL‐6 and IL‐8) secretion. Vaped CBD aerosols, but not e‐liquid, formed adducts with hBEC proteins. Model peptide analysis further identified covalent modifications of cysteine residues. While only vaped CBD aerosols reduced TEER, both CBD e‐liquid and aerosols increased IL‐8 secretion and had no effect on IL‐6. At higher doses, CBD e‐liquid significantly suppressed CBF for one hour following exposure. These data demonstrate that electrophiles in vaped CBD aerosols can adduct cellular proteins and disrupt essential respiratory innate defenses.

17. SARS‐CoV2 Transmission by Aerosol in Syrian Hamsters

Adam Werts,1 Jason Cox,1 Hammad Irshad,1 and Philip J. Kuehl1

1Lovelace Biomedical, Albuquerque, New Mexico, USA.

The global SARS‐CoV2 pandemic has brought many aerosol transmission questions to the forefront of respiratory research. While methods for non‐clinical transmission have been characterized for flu little is known with SARS‐CoV2. Therefore, a non‐clinical model was developed in the Syrian hamster, a well characterized system for studying SARS‐CoV‐2. The standard method to challenge the hamster is with intranasal installation, which results signs of disease similar to clinical cases . The disease progresses over 5 ‐8 days and includes body weight loss, increase in lung weight (due to edema and cellular infiltrates), and viral load (measured via nasal swabs and lung tissue with PCR and TCID50). In order to establish a model of aerosol transmission systems were developed with one directional air flow chamber where an infected (index) animal is housed upstream of recipient (naïve) animals, separated by a connection chamber. Animals are completely separated from contact and the system design also prevents transmission from fomites such as bedding, feed, and excreta. During exposures, aerosols in the connection chamber were monitored via filter samples (glass fiber (GF/A) for total concentration, membrane (PES for mRNA) and with all glass impingers. PCR analysis of the aerosols showed that one infected hamster can generate an aerosol concentration of SARS‐CoV2 was ∼940 viral genomes per liter of air. Through aerosol transmission, naïve hamsters became infected with SARS‐CoV‐2, lost weight, had pulmonary inflammation, and importantly showed viral replication in the lungs. With additional confirmation testing this model will be appropriate for the evaluation of vaccines, and prophylactic and therapeutic interventions to prevent SARS‐CoV2 transmission.

18. Respiratory Function in Apoe− Mice Following Controlled Exposure to Wildland Fire Smoke

Jacqueline Matz,1 Matthew Eden,1 Priya Garg,2 Michael J. Gollner,2 Chiara Bellini,1 and Jessica M. Oakes1

1Department of Bioengineering, Northeastern University, Boston, Massachusetts, USA.

2Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California, USA.

Increasing global temperatures are leading to an increase in the number and size of wildland fires, exacerbating the occupation risk for wildland fire fighters (WLFF). Currently there are no respiratory protection requirements for WLFF. Epidemiological studies have shown that WLFF have increased rates of COPD, but a causative link between long‐term smoke exposure and negative health outcomes has not been shown. To accomplish our goal of quantifying the respiratory response following smoke exposure, we exposed male Apoe− mice to either Douglas Fir smoke or lab air for 8 weeks (5 days/week, 2 hrs/day). Smoldering conditions were created, and particulate matter (PM) concentrations were chosen, to model a career WLFF. The PM concentration was 22.1 ± 7.1 mg/m3 and the particle count median diameter was CMD = 110.2 ±4.6 nm with a GSD = 1.47 ± 0.01. Exposure conditions were verified with blood COHb levels, smoke exposed = 11.11 ±1.86 % for CO = 119 ±38 ppm, air exposed = 2.04 ± 0.93 % for CO = 0 ppm. There was a decrease in respiratory resistance (Rrs) in smoke exposed mice (0.57 ± 0.08 cmH20/ml) compared to controls (0.75 ± 0.13 cmH20/ml). There was also an increase in respiratory compliance (Crs) in smoke exposed (0.041 ± 0.006 ml/cmH2O) compared to control (0.033 ± 0.009 ml/cmH2O) mice. These results suggest adverse lung remodeling following prolonged exposure to wildland fire smoke, demonstrating that respiratory personal protective equipment (PPE) may be necessary for WLFFs.

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23. NO ABSTRACT

24. Preclinical Comparative Study of Aerosol Deposition Cartography in the Respiratory Tract Under Mechanical Ventilation: Impact of Humidification and Nebulizer Position

Yoann Montigaud,1 Quentin Georges,2 Lara Leclerc,1 Anthony Clotagatide,3Aurore Louf‐Durier,2 Jérémie Pourchez,1 Nathalie Prévôt,3,4 and Sophie Périnel2,4

1Intensive care unit G, CHU Saint‐Etienne, Saint‐Etienne, F‐42055, France.

2Mines Saint‐Etienne, Univ Lyon, Univ Jean Monnet, INSERM, U 1059 Sainbiose, Centre CIS, F ‐ 42023 Saint‐Etienne France.

3Nuclear medicine unit, CHU Saint‐Etienne, Saint‐Etienne, F‐42055, France.

4INSERM U1059 Sainbiose, Université Jean Monnet, Saint‐Etienne, F‐42023, France.

Nebulization is widely used in intensive care units, but efficiency remains relatively poor and aerosol deposition is impacted by numerous factors. Consequently, we used a preclinical ex vivo respiratory model to study regional aerosol deposition under MV and assess the impact of humidification and vibrating mesh nebulizer position. Under controlled volumetric ventilation, aerosols were performed with a vibrating mesh nebulizer (Aerogen Solo, Aerogen Ltd, Ireland) with or without humidification. The nebulizer was placed next to the ventilator or between endotracheal tube (ETT) and the Y piece adapter or 15 cm before this latter one. A quantitative 99mTc‐DTPA scintigraphic study was then performed to determine nebulized fraction and deposited fractions on each part of the system. The mean nebulized dose was higher than 95% of nominal dose. The respiratory tract deposited fraction of the nebulized dose varied considerably: 18 ± 4% without humidification next to ventilator, and for humidified ventilator circuit, 25 ± 3% prior the humidifier, 43 ± 11% between ETT and Y piece adapter and 57 ± 8% upstream the Y piece adapter. Moreover, the aerosol distribution varied equally in the repartition between tracheal and pulmonary deposition. Nowadays, mesh nebulizers allow an increase in nebulized dose under MV. Consequently, determining factors as humidification and nebulizer position could have a higher impact on the delivered dose in the respiratory tract.

25. A Breathing Lung‐on‐Chip Model to Mimic Inhalation of Toxic Aerosolized Compounds and Nanoparticles

Arunima Sengupta,1 Nuria Roldan,2 Janick Stucki,2 Patrick Weindl,3 Tobias Krebs,3 Oliver Wisser,3 Nina Hobi,2 and Olivier. T. Guenat1

1ARTORG Organs‐on‐Chip Technologies, University of Bern, Switzerland.

2AlveoliX AG, Swiss Organs‐on‐Chip Innovation, Switzerland.

3Vitrocell Systems GmbH, Germany.

Inhalation is a major route for exposure where the pulmonary epithelium serves as the portal of entry to the systemic circuit for airborne toxicants. Inhalation studies in animals present species‐specific variations and makes it difficult to draw conclusions in human. Hence, current research efforts have been focused to develop alternative, biologically‐relevant in vitro models. In this quest, we have utilized microfluidic devices to recreate a breathing alveolar in vitro model to study toxicity. To this end, we have used human lung epithelial cells with the AXLung‐on‐Chip System (AlveoliX). We subjected the cells to cyclical stretch and air‐liquid interface (ALI) on the chip. To recreate occupational inhalation of nanoparticles and toxic compounds, we exposed the lung epithelial barrier to varying doses of ZnO nanoparticles and PHMG (CAS 89697‐78‐9) using the Vitrocell cloud‐12 exposure system. Our results demonstrated a stable barrier formation in the cells over time represented by distinct tight junction protein expression and gradual increase in transepithelial electrical resistance (TEER). Aerosolized ZnO nanoparticles caused significant toxicity in stretched cells compared to cells in static conditions. Furthermore, decreased barrier integrity was observed with PHMG exposure with cells in cyclical stretch and ALI conditions with respect to cells in static submerged conditions respectively. In summary, our findings demonstrate the relevance of reproducing key physiological conditions like cyclic stretch and ALI for in vitro toxicity studies. Together with the potential for including patient‐derived cell complexity, this lung‐on‐chip is a promising alternative tool to study animal‐based inhalation toxicity. *The Project ID E! 12977‐AIM4DoC is co‐funded by Innosuisse–Swiss Innovation Agency and the European Union Eureka Eurostars Program.

26. Early Detection of Lung Abnormalities in Asymptomatic e‐Cigarette Vapers Using THC Products

Chantal Darquenne,1 Ann R. Elliott,1 A.S. Kizhakke Puliyakote,2 Laura E. Crotty Alexander,1 and Rebecca J. Theilmann2.

Departments of Medicine1 and Radiology,2 University of California, San Diego, California, USA.

With the legalization of marijuana for recreational use and the popular “vaping” trend providing a delivery system for high levels of tetrahydrocannabinol (THC), there is a pressing need to assess the potential health risks to the respiratory system associated with cannabis use. Multiple breath washout (MBW) and lung diffusing capacity (DLCO) were acquired in 14 e‐cigarette users (13 with normal spirometry: 8M/5F, age: 19‐24 yr, FEV1: 82‐121%pred, FEV1/FVC: 0.76‐0.92, one with abnormal spirometry: 1M, 23yr, FEV1: 51%pred, FEV1/FVC: 0.57) and a vaping history of at least 2 year (range: 2‐5 years, median: 4 year). Eleven of the subjects also used THC (smoking and/or vaping). Two main MBW indices were calculated: the lung clearance index (LCI), an overall index of ventilation heterogeneity and the alveolar mixing efficiency (AME), an index linked to peripheral lung structure. Three of the nicotine/THC users showed abnormal values for LCI and AME with two of them also showing abnormal DLCO values suggesting gas exchange impairment in addition to airway dysfunction. Overall, there was a trend for an increase in LCI (p = 0.1) and a significant decrease in AME (p = 0.03) in nicotine/THC users when compared to e‐cig vapers that do not inhale THC. There was no significant difference in DLCO between groups. These preliminary data strongly suggest a detrimental effect of THC on lung structure and function even in subjects with normal spirometry. This work was supported by grant 1R01HL135496 from NHLBI (NIH).

27. Inclusion of an Aerosol Dispersion Model in the Multiple Path Particle Dosimetry (MPPD) Model Improves Predictions of Aerosol Deposition

Bahman Asgharian,1 Owen Price,1 Andrew P. Kuprat,2 Sean Colby,2 Rajesh K. Singh,2 Richard A. Corley,3 and Chantal Darquenne4

1Applied Research Associates, Inc., Arlington Division, Raleigh, North Carolina, USA.

2Pacific Northwest Natl Lab, Richland, Washington, USA.

3Greek Creek Toxicokinetics Consulting, LLC, Boise, Idaho, USA.

4Department of Medicine, University of California, San Diego, California, USA.

Because of the complexity of the respiratory tract geometry and mechanics, computationally efficient whole‐airway deposition predictions are mainly based on 1D models. Comparison of model predictions by the Multiple‐Path Particle Dosimetry Model (MPPD v3.04, ARA, 2016) in the integrated PD01/Yeh & Schum lung geometry with recent measurements (Darquenne et al., 2016) showed underpredictions for the deposition of 1 μm and 3 μm inhaled particles. The discrepancy may be due to particle dispersion by alveolar mixing in the deep lung during inhalation which was not modeled. Hence, a dispersion model was developed and included in MPPD by assuming each alveolated airway to consist of a core region (duct), with axial convective flow through, that is surrounded by an outer shell region (alveoli). The core and shell regions exchanged particles during inhalation and exhalation mainly by convective flow. Transport models were solved in these two regions of the alveolar airways to calculate particle concentration and deposition in each airway. Model predictions indicated that a noticeable fraction of suspended particles was present in the deep lung following the end of a breathing cycle. Predictions of particle retained in the lung (deposition and suspension) from the MPPD‐dispersion model were higher than in the original MPPD model and showed reasonable agreement with measurements. This work was supported by grant 1U01ES028669 from NIEHS (NIH).

28. Computational Projection of Virion Transmission Rates to the Lower Airway from the Initial SARS‐CoV‐2 Infection at the Nasopharynx

Saikat Basu,1 Natasha S Hochberg,2,3,4 Brent A Senior,5 Diane Joseph‐McCarthy,6,7 and Arijit Chakravarty8

1Department of Mechanical Engineering, South Dakota State University, Brookings, South Dakota, USA.

2Section of Infectious Diseases, Department of Medicine, Boston University, Boston, Massachusetts, USA.

3Boston University School of Public Health, Boston, Massachusetts, USA.

4Boston Medical Center, Boston University, Boston, Massachusetts, USA.

5Department of Otolaryngology/Head and Neck Surgery, University of North Carolina, Chapel Hill, North Carolina, USA.

6Department of Biomedical Engineering, Boston University, Boston, Massachusetts, USA.

7Bioengineering Technology and Entrepreneurship Center, Boston University, Boston, Massachusetts, USA.

8Fractal Therapeutics, Cambridge, Massachusetts, USA.

While the nasopharynx stands out as the dominant initial infection site for SARS‐CoV‐2, the physiological mechanism launching the lower airway infection is still not well‐understood. Based on the speed of infection progress, it is thought that the nasopharynx acts as the seeding zone for subsequent contamination of the lower airway via aspiration of virus‐laden boluses of nasopharyngeal fluids. We examine the plausibility of this transport process through computational fluid mechanics models of steady and forced breathing in five tomographic airway reconstructions, thereby quantifying the nasopharyngeal liquid volume transmitted to the lower airspace in each aspiration. Our model predicts 2‐4 aspirations during an 8‐hour sleep cycle, consistent with prior experimental data. Extending the numerical trends on aspiration volume to earlier records on aspiration frequency indicates a total aspirated nasopharyngeal liquid volume of 0.3–0.76 ml/day. Using sputum viral loads for hospitalized COVID‐19 patients, we then estimate the number of virions transmitted daily to the lungs via nasopharyngeal liquid boluses. For peak sputum viral load, the number is 7.1 × 108–1.8 × 109 virions/day, well in excess of the estimated minimum infectious dose for SARS‐CoV‐2. These findings provide a mechanism for the progression of SARS‐CoV‐2 infection of the nasopharynx to the COVID‐19 disease within a patient, and point to dysphagia as one of the potential underlying risk factors for adverse outcomes.

29. NO ABSTRACT

30. Effect of API Polydispersity on PBPK Model Simulations of Intranasal Corticosteroid Sprays

Jeffry Schroeter,1 Morgan Rose,1 Julia Kimbell,2 Steven Chopski,3 and Ross Walenga3

1Applied Research Associates, Raleigh, North Carolina, USA.

2University of North Carolina, Chapel Hill, North Carolina, USA.

3Division of Quantitative Methods and Modeling, Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA.

Intranasal corticosteroid sprays are used to treat symptoms associated with rhinitis. Active pharmaceutical ingredient (API) particle size in suspension nasal sprays is a key attribute affecting dissolution rate, absorption through the nasal epithelium, local and systemic bioavailability. Recent studies using Raman spectrometry have shown that API particle sizes are polydisperse and range in size from 1‐15 μm. A physiologically‐based pharmacokinetic (PBPK) model was previously developed to simulate the absorption and bioavailability of deposited drug particles from suspension nasal sprays. Key elements of the PBPK model included nasal spray deposition estimates, dissolution, diffusion through nasal epithelium, mucociliary clearance, glucocorticoid receptor binding, plasma protein binding, and liver metabolism. In this study, the PBPK model was modified to simulate polydisperse API size distributions using particle size data from spectrometry studies. Simulations were conducted for fluticasone propionate (FP) and budesonide (Bd) nasal sprays. Simulation results for Bd predicted faster clearance from the nasal mucosa and lower plasma concentrations for polydisperse particles (blood maximum concentration (Cmax) = 5 ng/ml) compared to equivalent monodisperse sizes (blood Cmax = 15 ng/ml). The effect of polydispersity was less pronounced for FP (blood Cmax∼0.1 ng/ml for both cases), showing that solubility and particle size play major roles in bioavailability of intranasal sprays. Funding was provided by contract 75F40119C10079 from the Department of Health and Human Services (DHHS), U.S. Food and Drug Administration. Views expressed here do not reflect the official policies of the DHHS; nor does mention of trade names, commercial practices or organizations imply endorsement by the U.S. Government.

31. Modeling the Human Air‐Blood‐Barrier on a Breathing‐Lung‐on‐Chip in Health and Disease

Clémentine Richter,1,2,4 Alberto Hidalgo,1,4 Patrick Carius,1,2,4 Nuria Roldan,3,4 Janick Stucki,3,4 Nina Hobi,3,4 Nicole Schneider‐Daum,1,4 and Claus‐Michael Lehr1,2 4

1Helmholtz Institute for Pharmaceutical Research Saarland, Helmholtz Center for Infection Research, 66123 Saarbrücken, Germany.

2Department of Pharmacy, Saarland University, 66123 Saarbrücken, Germany.

3AlveoliX AG, Swiss Organ‐on‐chip Innovation, 3010 Bern, Switzerland.

4Member of the AiM4DoC project (Advanced Inhalation Model for Drug Discovery on Chip) founded by the Eureka EurostarsTM program (Project ID E! 12977 ‐ AIM4DoC).

The human air‐blood‐barrier is the largest epithelium in direct contact with air, making it a significant way of entry for pathogens and pharmaceutical agents. In the context of drug development and pulmonary disease modeling, there is a rising need for alternative methods to animal testing, mainly due to poor pathobiological transferability from animal to human, cost and ethical issues. However, traditional in vitro models lack complex dynamical environment and cellular diversity. We aim to develop an advanced in vitro model of a human alveolus based on the emerging organ‐on‐chip technology. We use the AX12 lung‐on‐chip system developed by AlveoliX AG, which allows for physiological stretch and aerosol exposure within the Vitrocell® cloud system, to model alveolar inflammation and anti‐inflammatory drug administration. To generate an in vitro human model of the alveolus, we co‐culture alveolar epithelial cells (hAELVi) with monocyte‐derived macrophages (THP‐1). To induce and treat inflammation, the co‐cultures are subjected to lipopolysaccharide and the anti‐inflammatory drug Budesonide in static and breathing conditions. Subsequent cytokine release was analysed by FACS, and transepithelial electrical resistance and paracellular permeability was measured to monitor barrier integrity. First results indicate that the intensity of inflammatory response seems to be dependent on the breathing motion, highlighting the importance of dynamics in modeling the air‐blood‐barrier.

32. PET Imaging for Optimization of Intranasal Insulin in Nonhuman Primates

K.R. Smith,1,4 J. Fan,2‐4 G.A. Marriner,5 J. Gerdes,6 R. Kessler,2 and K. Zinn1,2,4

Departments of 1Biomedical Engineering, 2Radiology, and 3Chemistry, Michigan State University, East Lansing, Michigan, USA.

4Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, Michigan, USA.

5Molecular Imaging Department, Charles River Laboratories, Mattawan, Michigan, USA.

6Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, Montana, USA.

Intranasal insulin has been shown to improve cognitive performance in adults with dementia. However, the fate of insulin remains unknown following dosing and clinical results report varied efficacy, be it due to administration device design or technique, undesirable transport kinetics, or formulation characteristics. We developed a proof‐of‐concept method for assessing intranasal 18F‐insulin delivery to the brain via PET that can be used for optimization in the clinic. We fitted the Omron MicroAir nebulizer with 3D‐printed accessories to deliver high specific activity 18F‐insulin aerosol to Rhesus macaques (n = 1M, 1F) with 0.1 or 2 LPM airflow. Following delivery, subjects underwent 120 minutes of dynamic PET followed by CT and MRI. 18F‐insulin aerosol delivered with 0.1 LPM airflow resulted in 0.28% delivery of the starting dose to the subject, impaction in the medial ethmoturbinate, and no brain uptake over 120 minutes. 18F‐insulin delivered with 2 LPM airflow increased dose delivery 100‐fold and achieved 0.01% brain uptake with aerosol impaction in the nasal vestibule. Brain uptake peaked 2 minutes into the scan. Due to the site of aerosol deposition and rapid brain uptake, the mechanism of intranasal insulin delivery to the brain was not clear. Future experiments will focus on improving direct delivery to the brain via deposition at the olfactory epithelium and investigate the impact of formulation on transfer kinetics. This work is supported by NIH R21 1R21AG054960‐01.

33. The Effect of Physical Spray Parameters on Regional Deposition of Nasal Sprays

Madison Dyson,1 Jihong Wu,1 Guilherme J.M. Garcia,3 Julia S. Kimbell,2 Jeffrey D. Schroeter,4 and William D. Bennett1

1Center for Environmental Medicine, Asthma, and Lung Biology.

2Department of Otolaryngology/Head and Neck Surgery.

3University of North Carolina, Chapel Hill, North Carolina, USA; Department of Biomedical Engineering, Medical College of Wisconsin.

4Applied Research Associates, Raleigh, North Carolina, USA.

Introduction: The efficacy of nasal sprays to treat the nasal passages is limited by their ability to deliver drug beyond the nasal valve (%Pen). To determine characteristics that may affect %Pen, experiments were performed on 3D‐printed nasal replicas derived from CT scans. A patient specific nozzle positioning tool was designed to aim the spray bottle at a 45o angle with respect to the nasal floor. The head was tilted forward at an angle of 22.5o. The nasal replica had a soft anterior nose to allow insertion of the spray bottle.

Methods: Experiments were performed by a single operator in triplicate on both the left and right sides of six models. For each day of testing, the radioisotope Tc‐99m was mixed into a bottle of Nasacort, which was placed within a hand actuation monitor to track the actuation travel velocity and actuation force. Following each spray actuation, a 3‐min static 2D gamma camera image was acquired with and without the soft anterior nose. Image processing was performed to quantify %Pen as activity without the soft nose divided by total deposited activity.

Results: There was a negative correlation between %Pen (50 ± 13%) and actuation travel velocity (31 ± 8 mm/s) (R = ‐0.34, p < 0.05) but no correlation with the actuation force (44 ± 3N).

Conclusion: At a relatively constant force applied to the nasal spray nozzle, %Pen increases with decreasing actuation travel velocity, likely due to less inertial impaction in the nasal valve. Funding was provided by contract 75F40119C10079 from the Department of Health and Human Services (DHHS), U.S. Food and Drug Administration. Views expressed here do not reflect the official policies of the DHHS; nor does mention of trade names, commercial practices or organizations imply endorsement by the U.S. Government

34. Development of a Novel in Vitro Integrated Dissolution and Permeability Methodology for Orally Inhaled and Nasal Drug Products

Robert Price and Jagdeep Shur

Nanopharm an Aptar Pharma Company, Cavendish House, Hazell Drive, Newport, NP10 8FY.

For orally inhaled and nasal drug products, the FDA has introduced the concept of structural equivalence (Q3) for local acting products that are qualitatively (Q1) and quantitatively (Q2) the same as the reference listed drug products (RLD). The structural differences in the arrangement of matter and state of aggregation within the formulated and aerosolized forms of orally inhaled and nasal drug products (OINDPs) is dependent on physicochemical properties of the formulation. In vitro dissolution and/or in Vitro release testing are an important Q3 in Vitro tool for OINDPs). While an in Vitro release test is not expected to directly correlate with, or be predictive of, in vivo bioequivalence, the measurement of the in Vitro release rate (IVRR) can provide a comparative test of the local rate of release of the active drug between test and RLD batches. We have developed a bespoke in Vitro release test (IVRT) system to measure the release rate of the impactor stage mass (ISM) of an aerosolized product, using Nanopharm's Unidose aerosol dose collection apparatus. We have used the IVRT system to measure the in Vitro release rate of beclomethasone dipropionate from a Fostair 100/6 solution MDI and a Fostair 100/6 NEXThaler DPI. For equivalent ISM doses, the in Vitro release rate of beclomethasone in both products were similar. Our new IVRT system is therefore able to discriminate between dissolution/permeation properties of the ISM dose of OINDPs

35. Real‐Time in Vitro Assessment of Aerosol Delivery During Mechanical Ventilation

Michael McPeck,1 Janice A. Lee,1 Ann D. Cuccia,2 and Gerald C Smaldone1

1Pulmonary Mechanics and Aerosol Research Laboratory, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Stony Brook University Medical Center, Stony Brook, New York, USA.

2Respiratory Care Program, School of Health Technology and Management, Stony Brook University, Stony Brook, New York, USA.

Background:In Vitro assessment of inhaled drug delivery during mechanical ventilation has been shown to predict in Vivodelivery. A new method for assessing factors determining real‐time aerosol delivery is described.

Methods: A breath‐enhanced jet nebulizer (BEJN) operated in a ventilator/heated humidifier system was continuously infused with 99m‐Tc/saline for 90 min by a pump. A shielded gamma ratemeter was oriented to count radioaerosol accumulating on an Inhaled Mass (IM) filter at the airway opening of a test lung. Gamma counts taken at 2‐5 min intervals were expressed as % syringe activity/min infused into the BEJN over 90 min. All circuit parts were measured and imaged by gamma camera to determine Mass Balance.

Results: Ratemeter IM% of syringe charge/hr by linear regression = 0.6362 + 0.1291x (x = run time, min), R2 0.999. Mass Balance (basis: dose infused in 90 min): IM % 39.2%, BEJN residual 35.5%, sum of circuit parts including humidifier 23.4%; total recovery = 98.1%. Review and analysis of circuit part images identified sites of increased deposition due to entrance/exit effects and turbulence.

Conclusion: Real‐time ratemeter measurement with gamma camera imaging provides operational feedback during the testing procedure and yields a detailed analysis of the parameters influencing drug delivery during mechanical ventilation. This method of analysis facilitates assessment of device function and influence of circuit parameters on drug delivery.

36. Modeling Interaction of Particle Size and Breathing Characteristics, and Their Optimization for Maximum Lung Regional Deposition

Hyunhong James Min, Stephen Payne, and Eleanor Stride

University of Oxford, United Kingdom.

Background: Regional targeting in the lung is expected to improve efficacy and minimize side‐effects. in silico and in vivo studies have studied effect of particle size and breathing characteristics individually. However, the interaction of particle size and breathing characteristics are not fully understood, and their optimized values have not been studied.

Method: In this study a DoE‐approach metamodel is used on in silico multiple‐path bolus particle deposition model to study interaction of particle size (0.1 – 6μm), inspiratory flow rate (6 – 120L/min) and tidal volume (100 – 3000mL), and followingly, optimized parameter values are found for maximum regional deposition in conducting airways (large, small and whole) and acini. Particle lung residence time is fixed at 10 seconds.

Results: For large conducting airways, deposition is primarily impaction driven, hence large particles (5‐6μm) at high flow rate (90‐120L/min) are favorable. For small and whole conducting airways, large particles (4‐6 μm) at low tidal volume (100mL) and low flow rate (<15L/min) are advantageous. Low tidal volume increases particle residence time in small conducting airways during pause‐phase, and heavy particles increases sedimentation‐efficiency. For acini, small particles (0.1μm) with deep breath (>2300mL) maximizes deposition. Small particle increases diffusion efficiency and deep breath increases particle penetration into deeper lungs, which, combined, increases acini deposition

37. Optimization of Particle Characteristics for Use in Deposition Studies to Inform Computational Modeling to Improve Emphysema Treatment

Margaret Bourlon and Lucila Garcia‐Contreras

College of Pharmacy, University of Oklahoma Health Sciences Center. Oklahoma City, Oklahoma, USA.

Emphysema is mainly treated with DPIs, but the efficacy of treatment is decreased by the large fraction of drug deposited in the mouth‐throat region. Treatment efficacy can be improved by evaluating the factors influencing powder deposition using computational fluid dynamics models.

Aim: Prepare microparticles in optimum size and distribution to be radiolabeled for use in deposition studies with rats. Data generated in this study will be used in modeling experiments for humans.

Methods: The spray‐drying conditions were optimized to obtain particles in suitable size and distribution: feed concentration (0.25‐0.35%) and flow rate (3‐7.5ml/min), N2 flow rate (600‐742L/h), and aspiration rate (50‐100%). Geometric diameter (Dg) of the particles was determined from SEM images and volume diameter (Dv) by laser diffraction.

Results: The optimized particles had Dg = 2.3μm, Dv = 5.1μm, and GSD <2. The similarity between Dg and Dv indicated the particles were slightly aggregated but this would not significantly affect the interpretation of deposition studies. Based on Dg and using a direct administration method, 2% of the radiolabeled particles would deposit in the trachea of rats, 4% in the bronchi, 29% in the bronchioles, and 64% in the alveoli.

Conclusion: The prepared microparticles are suitable for use in studies enhancing powder deposition in rat alveoli. However, the particle size would need to be modified to be used in modeling experiments for humans.

38. Throat Deposition Variations with Pediatric Airway Development in Silico

Emily L. Kolewe,1 Jenna W. Briddell,2 Yu Feng,3 and Catherine A. Fromen1

1Chemical and Biomolecular Engineering Department, University of Delaware, Newark, Delaware, USA.

2Department of Surgery, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, USA.

3School of Chemical Engineering, Oklahoma State University, Stillwater, Oklahoma, USA.

Rationale: A lack of large subject sample sizes has been repeatedly identified as a limitation of pediatric airway development research. The purpose of this study is to create an in silico database of pediatric deposition patterns to inform therapeutic development, provide fundamental deposition data, and be a platform for future work targeting upper airways.

Methods: Materialise mimics was used to convert CT scans of 10 out of 60 available healthy pediatric subjects' scans. A k‐omega SST model was implemented using ANSYS Fluent with a mouth inlet flow rate of 15 Lpm, trachea outlet pressure of 0 gauge pressure, and trapped wall boundary conditions. Particle accretion of varying diameters from 100 nm‐10 μm and density of 1 kg/m3 was reported as 3D coordinates of particle deposition location and analyzed to determine the number of depositing particles as a function of distance along the medial axis path of the airway.

Results: To date, our results indicate that the area of highest deposition is at a position near the smallest diameter of the trachea. Notably, this location is developing for the age range being investigated and thus the anatomical structure is varying as well. Future investigation into the anatomical structure of each subject is required.

Conclusions: Our model predicts the deposition of aerosols in pediatric subjects to be related to airway diameter, however this diameter is developing with age and thus relates to varying anatomical structures. The identification of anatomical variations influencing deposition will inform the development of therapeutics for pediatric patients. Additionally, this provides a platform for future work targeting the glottis of patients with Juvenile Onset Recurrent Respiratory Papillomatosis.

39. Image‐Based Aerosol Deposition Modeling in Asthma Subjects

Kamran Poorbahrami,1 Katie Carey,3 Andrew Hahn,3 Sean Fain,2,3,4 and Jessica M. Oakes5

1Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts, USA.

2Departments of Biomedical Engineering, 3Medical Physics, and 4Radiology, University of Wisconsin‐Madison, Wisconsin, USA.

5Department of Bioengineering, Northeastern University, Boston, Massachusetts, USA.

The goal of asthma treatment is to maintain asthma control and limit the number of hospitalization visits. Key advances in severe asthma treatment may be accomplished by integrating medical image data with computational fluid‐particle dynamics simulations, providing novel insights into dosimetry and structural/functional relationships. To understand the interplay of particle dose, disease severity, airway morphometry, and segmental ventilation levels from hyperpolarized gas magnetic resonance imaging (MRI), we performed patient‐specific in‐silico modelling on 26 patients (10 mild/moderate, 16 severe). Four ventilation levels measured from MRI (high, moderate, low, and defected) are included. For 3μm diameter particles, deposition in the central airways is significantly different between mild/moderate and severe asthmatic subjects (3.8% ± 1.5%, 8.9% ± 9.6%, p = 0.007). Computational endpoints show significant differences between severity groups (central resistances, p = 0.02; total resistances, p = 0.007; ventilation levels, p = 0.009) while spirometry tests (e.g., FEV1) are not significantly different (p = 0.16). We observe high variability in particle dosimetry between subjects (mild/moderate ranged from 1.8% to 5.8% and severe ranged from 2.6% to 41.6%), likely due to central vs peripheral airway remodeling. This variability highlights the importance of integrating structure/function imaging with computer simulations to improve inhaled medication treatment in asthma.

40. Assessment of Mouthpiece‐Mediated Aerosol Delivery During Low Flow Nasal Oxygen Therapy in a Spontaneously Breathing Adult

Barry Murphy,1 Mary Joyce,1 James B. Fink,2 and Ronan MacLoughlin1

1Aerogen, Galway Business Park, Dangan, Galway, Ireland.

2Aerogen Pharma Corporation, 1660 S. Amphlett Blvd., Suite 360, San Mateo, California, USA.

Introduction: Patients presenting with hypoxia and requiring oxygen supplementation are often treated with low flow oxygen therapy in combination with mouthpiece‐mediated aerosol delivery. This study assesses' aerosol delivery via mouthpiece to spontaneously breathing adult patients during concurrent low flow nasal oxygen therapy.

Method: 2000 μg Salbutamol (GSK, Ireland) was aerosolized using a vibrating mesh nebuliser (VMN) with an aerosol chamber (Aerogen Solo & Ultra, Aerogen, Ireland). Low flow oxygen therapy was delivered at rates of 0, 2 & 5 LPM using a nasal cannula positioned on an anatomically correct 3D printed adult head model. A breathing simulator (IngMar Medical, US) was used to generate a standard adult breathing pattern (Vt 500mL, 15 BPM, ratio 1:1). The mass of drug captured on a filter placed distal to the trachea was quantified using UV spectroscopy at 276 nm.

Results: The tracheal dose (%) for aerosol delivery during low flow oxygen rates of 0, 2 & 5 LPM resulted in 29.83 ± 0.96 %, 29.76 ± 1.06 % and 25.91 ± 1.35 % respectively. Statistical significance detected between 0 and 5 LPM (p = 0.0004) and 2 & 5 LPM (p = 00005). Significance was determined as p value ≤0.05.

Conclusion: Increasing nasal low flow oxygen flow rates resulted in a decrease in tracheal dose. However, results indicate that mouthpiece‐mediated aerosol delivery during low flow oxygen therapy delivers large doses and is a viable option for patients requiring oxygen supplementation.

41. NO ABSTRACT

42. NO ABSTRACT

43. NO ABSTRACT

44. NO ABSTRACT

45. Modeling Regional Deposition and Pharmacokinetics for Inhaled Prodrug Treprostinil Palmitil

Andrew R. Martin,1 Vladimir S. Malinin,2 David Cipolla,2 and Warren H. Finlay1

1Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada.

2Insmed Inc., Bridgewater, New Jersey, USA.

A compartmental disposition model was developed for treprostinil palmitil (TP), a treprostinil prodrug, Incorporating prediction of regional lung deposition, conversion to free treprostinil, mucociliary clearance, and absorption. For TP formulated as a nebulized suspension, the model was used to estimate regional masses of prodrug and free drug in the lungs, as well as plasma treprostinil concentrations, over time following aerosol administration to healthy adults. Regional lung deposition and airway surface liquid properties were calculated using previously established models. Rate constants for the compartmental model were established based on published pharmacokinetic (PK) data for treprostinil sodium via intravenous infusion or via inhalation, as well as on data for nebulized TP. Model predictions agreed well with PK data for nebulized TP. For a healthy adult lung model, drug depositing in the tracheo‐bronchial airways was removed from the lungs in approximately 6 hr. Drug depositing in the alveolar region remained in the lungs up to 24 hr. At the 24 hr time point, approximately 90% of prodrug initially depositing in the alveolar region had converted and been absorbed. Treprostinil plasma AUC from 0 to 24 hr was related to alveolar deposition of TP. In contrast, plasma Cmax, occurring between 0.8 and 1.45 hr after inhalation, was most closely correlated with total lung deposition. Overall, systemic exposure was influenced by alveolar, but not tracheo‐bronchial, deposition.

46. EGylation Prolongs the Half‐Life of Alpha1‐Antitrypsin

Xiao Liu,1 Mireille Dumoulin,2 and Rita Vanbever1

1Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium. 2Center For Protein Engineering, University of Liège, Liège, Belgium.

Intravenous infusion of alpha1‐antitrypsin (AAT) to AAT deficient patients with respiratory disease allows only 2 % of the dose to reach the lung. Inhaled AAT is rapidly cleared from the lung, resulting in limited efficacy. PEGylation of AAT might improve its stability and prolong its half‐life. Native human AAT was purified from Pulmolast® and conjugated to linear 30 kDa, linear 40 kDa and 2‐armed 40 kDa polyethylene glycol (PEG) – maleimide (PEGmal) by thiol PEGylation. The mono‐PEGylated AAT was purified and characterized for its activity and stability in long‐term storage, or to physical stresses and proteolysis. The PEG‐AAT conjugate which was stable in storage and presented preserved activity, improved resistance to proteolysis was selected to perform the in vivo pharmacokinetic (PK) study. AAT or PEG‐AAT was administrated by intravenous injection (IV) or intratracheal instillation (IT). The protein and PEG content in bronchoalveolar lavage (BAL), lung homogenates and plasma were quantified by ELISA. All PEG‐AAT conjugates (linear PEGmal30k‐AAT, linearPEGmal40k‐AAT, and 2‐armed PEGmal40k‐AAT) showed unaltered biological activity as native AAT. 2‐armed PEGmal40k‐AAT was used for in vivo PK study. The results show that PEGylation a) increases eight‐fold the serum half‐life of AAT following IV and slows down AAT penetration in the lungs; b) increases two‐fold the half‐life of AAT in the lungs following IT.

47. Bedaquiline‐Loaded Liposome Dry Powders for Treating Pulmonary Mycobacterial Infections

Huck, Benedikt,1,2 Durairaj, T.,1 Schwarzkopf, K,3 Besecke, K.,4 Furch, M.,4 Gieseler, R.,4 Hosza, C.,4 Waldow, F.,5 Schwudke, D.,5 Loretz, B.,1 and Lehr, C.M.1,2

1Helmholtz‐Institute for Pharmaceutical Research Saarland (HIPS) and Helmholtz Centre for Infection Research (HZI), Department of Drug Delivery, Saarbrücken, Germany.

2University of Saarland, Department of Pharmacy, Saarbrücken, Germany.

3Klinikum Saarbrücken, Department of Anesthesia and Intensive Care, Saarbrücken, Germany.

4Rodos Biotarget GmbH, Hannover, Germany.

5Research Center Borstel, Leibniz Lung Center, Germany.

Introduction: Drug resistance of M. tuberculosis is an emerging healthcare issue. Systemic oral delivery of antibiotics requires high doses and several months of treatment, which is associated with high costs, reduced patient's compliance and severe side effects. In the ANTI‐TB consortium, a novel treatment strategy is developed based on inhalable nanopharmaceuticals loaded with antimycobacterial compounds against multidrug‐resistant tuberculosis.

Methods: Dry powders were developed by spray drying of Bedaquiline (BDQ)‐loaded liposomes. Aerodynamic properties were analyzed using next generation impactor. Microscopic studies comprised SEM, confocal and correlative microscopy and Cryo‐TEM. BDQ recovery was measured by LC‐MS2. Liposome release and barrier interaction with pulmonary mucus were studied by DLS and particle tracking. Antimicrobial activity was tested on M. abscessus (MA) after dry powder aerosol deposition.

Results: Dry powder aerosols with >70% fine particle fraction and >80% drug recovery were developed by optimizing lactose and leucine concentrations. Microscopy showed liposome distribution in the powder and confirmed integrity upon release. Particle tracking revealed high mobility and fast release of liposomes in pulmonary mucus. Growth reduction of MA achieved after dry powder aerosol deposition was equal to BDQ‐liposomes as with same dose.

Conclusion: We have developed a liposomal dry powder formulation that holds promise for pulmonary antimycobacterial therapy.

Acknowledgment: The ANTI‐TB project is funded by the Federal ministry of education and research (grant#: 16GW0167).

48. Hepatocyte Growth Factor Transfected T Cells as a Potential Therapeutic Option in a Bleomycin Injured Murine Lung Model

Mutlu, Seyran,1,2 Fytianos, Kleanthis,1,2 Ferrié, Céline,1,2 Wotzkow, Carlos,2 Steiner, Selina,2 Tschirren, Anna‐Barbara,1,2Gazdhar, Amiq,1,2 and Blank, Fabian1,2

1Department of Pulmonary Medicine, University Hospital Bern Switzerland.

2 Department of BioMedical Research (DBMR), University of Bern, Bern, Switzerland.

Introduction: Idiopathic pulmonary fibrosis (IPF) is a lethal disease where aberrant wound repair pathways lead to the loss of alveolar epithelial (AE) integrity. The role of lung immune cells is still not yet well understood. We and others reported the beneficial effect of the hepatocyte growth factor (HGF) towards AE recovery. Here, we test if adoptive transfer (AT) of HGF expressing T cells may induce AE repair by restoring immune cell homeostasis in a murine bleomycin injured lung (BIL) model.

Methods: Seven, 10 and 14 days following bleomycin instillation (1.52U/kg), single cell suspensions of lung parenchyma (LP) and bronchoalveolar lavage fluid (BALF) were analyzed by flow cytometry. Seven days after bleomycin instillation, AT of 5x105 HGF‐transfected CD3+ T cells was done and mice were sacrificed 7 days after administration. BALF HGF level was screened by ELISA and lung collagen content was measured.

Results: Increased frequencies of Tregs and CD8+T cells were found in LP after HGF transfected T cell administration compared to BIL mice. Lung HGF content increased after HGF transfected T cells treatment. Lung collagen content was significantly reduced compared to BIL mice.

Conclusion: AT therapy showed clear alteration of T cell subsets frequencies during the course of BIL. Elevated HGF in the lung together with decrease of collagen content, after AT, indicate a promising role of this treatment in restoration of disrupted lung homeostasis.

49. Mechanism of Aerosol Droplet Generation Affects Biological Activity of Mycobacterium Virus D29

Nicholas B. Carrigy,1,2 Sasha E. Larsen,3 Philip Kuehl,4 Melissa Harrison,5 Rachel Y. Chang,6 Sharon S.Y. Leung,6,7 Zaritza Petrova,8,9 Welkin H. Pope,8 Warwick J. Britton,10 Hak‐Kim Chan,6 Graham Hatfull,8 Dominic Sauvageau,5 Warren H. Finlay,1Rhea N. Coler,3,11and Reinhard Vehring1

1Department of Mechanical Engineering, University of Alberta, Edmonton, Canada.

2Current address: Inhalation Product Development, AstraZeneca, South San Francisco, California, USA.

3Seattle Children's Research Institute, Seattle, Washington, USA.

4Lovelace Biomedical, Albuquerque, New Mexico, USA.

5Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Canada.

6School of Pharmacy, University of Sydney, Sydney, Australia.

7Current address: School of Pharmacy, Chinese University of Hong Kong, Hong Kong.

8Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.

9Current address: Department of Pharmacology, Yale University, New Haven, Connecticut, USA.

10Centenary Institute of Cancer Medicine and Cell Biology, and Sydney Medical School, University of Sydney, Sydney, Australia.

11Department of Global Health, University of Washington, Seattle, Washington, USA.

Biological inactivation may occur during the droplet generation process in aerosol delivery devices. The extent of inactivation is important to measure prior to in vivo studies as it can impact treatment times and outcomes. Indeed, past clinical trials have failed because the biological activity is lower than expected upon delivery. In this study, Siphoviridaemycobacteriophage D29, a virus active against multidrug‐resistant Mycobacterium tuberculosis, is aerosolized with 3 different inhalation devices utilizing different droplet generation mechanisms: 1) jet nebulizer; 2) vibrating mesh nebulizer; 3) soft mist inhaler. The biological inactivation is measured by comparing the activity following aerosolization onto a filter relative to the activity prior to aerosolization. Subsequently, the inhaled dose is estimated and a suitable inhalation device selected for an in Vivo study that demonstrates the prophylactic efficacy of D29 against M. tuberculosis. Statistical modelling predicts that sufficient protective efficacy would only be achieved with the vibrating mesh nebulizer considering factors such as the dose required, aerosol delivery rate, initial titer used in this study, and measured inactivation level.

50. Development of a Spray‐Dried Inhalable Dry Powder Presentation of a Tuberculosis Vaccine Candidate with Demonstrated Long‐Term Physical Stability at High Temperatures for Use in Developing Countries

Mellissa Gomez,1 Joseph McCollum,2 Hui Wang,1 Mani Ordoubadi,1 Nicholas B. Carrigy,1 David Barona,1 Shital Bachchhav,1Chester Jar,1 Isobel Tetreau,1 Michelle Archer,2 Alana Gerhardt,2 Chris Press,2 Ryan M. Kramer,2 Christopher B. Fox,2 and Reinhard Vehring3

1Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada.

2Infectious Disease Research Institute, Seattle, Washington, USA.

Two key issues hindering the ability to safely and effectively distribute vaccines in the developing world are the cold chain maintenance required by many vaccines and the problems associated with needle delivery. One method of bypassing these issues is the development of a thermostable dry powder vaccine that can be administered via the pulmonary route as an aerosol. Our work focuses on developing a dry powder presentation of ID93+GLA‐SE—an adjuvanted subunit Tuberculosis vaccine candidate—that is suitable for inhalation. Trehalose was utilized as a stabilizing excipient. Formulation development established trileucine as an effective dispersibility enhancing agent compatible with the vaccine candidate. ID93+GLA‐SE and the excipient system were spray dried and the resulting powder was placed on a stability study. Results found that particle morphology was maintained after storage at temperatures up to 40 °C for a year. Similarly, high emitted dose (>95%) and lung dose (32‐38%) as measured in vitro was preserved for one year at temperatures up to 40 °C. The chemical stability of the adjuvant system was maintained at storage temperatures up to 25 °C for as long as one year, with >80% component retention and <50% emulsion size change. After three months of storage at 40 °C the spray‐dried inhalable product retained 50% of the antigen, whereas the antigen in a liquid product could not be detected after one month of storage at 37 °C.

51. Bronchodilator Delivery via High‐Flow Nasal Cannula: A Randomized Controlled Trial to Compare the Effects of Gas Flow Rates

Jie Li,1 Yibing Chen,2 Stephan Ehrmann,3 Jie Wu,2 Lixin Xie,2 and James B Fink1,4

1Department of Cardiopulmonary Sciences, Division of Respiratory Care, Rush University Medical Center, Chicago, Illinois, USA.

2Department of Respiratory and Critical Care Medicine, Pulmonary Function Test Lab, People's Liberation Army General Hospital, Beijing, China.

3CHRU Tours, Médecine Intensive Réanimation, CIC INSERM 1415, CRICS‐TriggerSEP research network, Tours, France; and INSERM, Centre d'étude des pathologies respiratoires, U1100, Université de Tours, Tours, France.

4Aerogen Pharma Corp, San Mateo, California, USA.

Introduction:In Vitro studies report that the ratio of high‐flow nasal cannula (HFNC) gas flow to patient inspiratory flow (GF:IF) is crucial in trans‐nasal aerosol delivery. This RCT was designed to explore the effective dose of inhaled bronchodilator via HFNC and to validate the role of GF:IF ratio in reducing dosing requirements.

Methods: Patients with a history of COPD or asthma and documented positive response to inhaled bronchodilators in a pulmonary function lab were recruited. Subjects were randomized to receive inhalation at gas flow ratio/settings of : GF:IF = 0.5, GF:IF = 1.0, or GF = 50L/min. Subjects were assigned to inhale saline (control) followed by salbutamol via HFNC with an escalating dose sequence (0.5mg, 1.0mg, 2.0mg and 4.0mg). Spirometry was performed at baseline and after each inhalation.

Results: Seventy‐five subjects (49 asthma and 26 COPD) were enrolled. Using the criteria of post‐bronchodilator FEV1 returning to screening post‐bronchodilator FEV1 with salbutamol, a higher percentage of subjects receiving GF:IF = 0.5 met the criteria at a cumulative dose of 1.5mg, than those receiving GF:IF = 1.0, and GF = 50L/min (64% vs 29% vs 27%, respectively, p = 0.011). Similarly at 3.5mg (88% vs 54% vs 46%, respectively, p = 0.005). The effective dose at GF:IF = 0.5 was 1.5mg while for GF = 50L/min it was 3.5mg.

Conclusion: Dose response to salbutamol via HFNC was greater when administered with gas flow set at 50% of patient inspiratory flow, than with higher gas flow rates.

52. The Impacts of High‐flow Nasal Cannula Device, Nebulizer Type and Its Placement on Trans‐Nasal Aerosol Drug Delivery

Jie Li,1 Lucas Williams,1 and James B Fink1,2

1Department of Cardiopulmonary Sciences, Division of Respiratory Care, Rush University Medical Center, Chicago, Illinois, USA.

2Aerogen Pharma Corp, San Mateo, California, USA.

Introduction: High‐flow nasal cannula (HFNC) has been used to deliver aerosol. However, the effects of different HFNC devices, nebulizer types and placements on aerosol deposition remain largely unknown.

Methods: An adult manikin was used, with a collection filter connecting the manikin's trachea and the breathing simulator. Comparisons included: 1)Devices: OptiflowTM vs. Airvo 2TM with AirSpiralTM vs. 900PT501 circuits; 2)vibrating mesh nebulizer (VMN) vs. small volume nebulizer (SVN); 3)nebulizer placed at the humidifier vs. close to patient. Quiet vs. distressed breathing with HFNC gas flows of 10,20,40 and 60L/min were used. 2.5mg of albuterol was used in each run (n = 3). Drug was eluted from the filter and assayed with UV spec (276 nm).

Results: Results: Inhaled dose with VMN via OptiflowTM, Airvo 2TM with two circuits in quiet breathing was 12.6%, 8.9% and 4.5%, respectively (p = .063), and higher for each in distressed breathing (16.8%, 13.5% and 9.9%, respectively (p = .012). During quiet breathing, delivery was greater with VMN placed at humidifier vs. close to patients (p = .008 for OptiflowTM, and p = .043 for Airvo 2TM with both circuits). VMN at humidifier was more efficient than SVN with both quiet (median 16.5% vs 8.4%, p = .003) and distressed breathing (p < .001).

Conclusion: During trans‐nasal aerosol delivery, OptiflowTM outperformed the Airvo2TM. VMN generated a higher inhaled dose than SVN, while inhaled dose was higher with nebulizer placed at humidifier than close to patient.

53. Empty Liposomal Formulation Reduces Lung Inflammation and Airway Hyperactivity in a Murine Model of Asthma

Varsha Komalla,1,3 Venkata Sita Rama Raju Allam,1,3 Philip Chi Lip Kwok,4 Brian. G. Oliver,2,3 Hui Chen,2 and Mehra Haghi1

1Graduate School of Health, University of Technology Sydney, Sydney, NSW, 2007, Australia.

2School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW 2007 Australia.

3Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, 2037, Australia.

4Sydney Pharmacy School, Faculty of Medicine and Health, University of Sydney, NSW 2006, Australia.

Introduction: Inhaled corticosteroids are the most effective therapy to control airway inflammation and asthma symptoms . Nevertheless, some patients with severe asthma respond poorly to steroids 3. Hence, there is a need for effective anti‐inflammatory therapies for treatment. Phospholipids, the structural component of liposomes have shown anti‐inflammatory properties, however these properties have not been demonstrated in liposomes. The aim of this study was to evaluate the potential of empty liposomes (UTS‐L) as an anti‐inflammatory treatment in asthma.

Methods: Liposomes were prepared by the thin film hydration and characterised in terms of size and poly dispersity index. Acute allergic inflammation was induced by sensitization and challenge of ovalbumin in C57BL/6 mice. For OVA+UTS‐L treated group, UTS‐L was injected every day from day 0. Twenty‐four hours after last aerosol challenge, lung function was performed and bronchoalveolar lavage fluid (BALF) was collected.

Results: The size of UTS‐L was 191 ± 7 nm with a polydispersity index of 0.28 ± 0.01. The OVA treated group exhibited a significant increase (P < 0.05) in eosinophil number compared to the PBS group, demonstrating the successful establishment of the allergic asthma in OVA challenged mice. In the OVA+UTS‐L group, there was a significant decrease (P < 0.05) in the eosinophil number compared to OVA‐group indicating a strong anti‐inflammatory effect of UTS‐L. Elastance (Ers) as a measure of airway hyperresponsiveness (AHR) was significantly higher (P < 0.01) in the OVA group, compared to the OVA‐UTS‐L group. The result of this study demonstrate that UTS‐L can significantly inhibit OVA‐induced airway inflammation in a murine model of asthma.

54. Pulmonary Surfactant and Drug Delivery: A Novel Approach to Transport the Anti‐Mycobacteria Drug Bedaquiline

Alberto Hidalgo,1 Annette Boese,1 Pascal Paul,1 Jesus Perez‐Gil,2,3 and Claus‐Michael Lehr1,4

1Helmholtz Institute for Pharmaceutical Research Saarland, Helmholtz Center for Infection, 66123 Saarbrücken, Germany.

2Department of Biochemistry and Molecular Biology, Faculty of Biology, Complutense University, 28040 Madrid, Spain.

3Research Institute “Hospital 12 de Octubre (imas12)”, 28041 Madrid, Spain.

4Department of Pharmacy, Saarland University, 66123 Saarbrücken, Germany.

Pulmonary surfactant (PS), a lipid‐protein material essential for the process of breathing, offers great opportunities in respiratory drug delivery. The interfacial properties and lipid composition of PS are ideal solutions to solubilize and transport hydrophobic drugs by surfing the respiratory surface, targeting alveoli and phagocytic cells: the so‐called interfacial delivery. Here, we propose the use of PS‐based formulations to solubilize and transport bedaquiline, a poorly water‐soluble and potent anti‐Mycobacteria drug approved for multidrug resistant tuberculosis, over the respiratory air‐liquid interface. A special in vitro setup, consisting of two different aqueous troughs exposed to air and connected by an interfacial bridge, was used to test the vehiculizing capacity of PS. Interestingly, measuring the appearance of the drug at the recipient trough by mass spectrometry, we confirmed that, in contrast with pure lipid systems, PS transports bedaquiline interfacially, with breathing‐like dynamics promoting the process. Moreover, we evaluated the synergistic antibiotic effects of PS‐based formulations compared to the drug alone or solubilized into surfactant lipid vesicles. To do so, we cultured Mycobacterium abscessus on the recipient trough, observing a prominent antibiotic effect of PS/Bedaquiline formulations. This highlights the potential of PS‐based formulations as efficient carriers for treating non‐tuberculous and tuberculous Mycobacteria respiratory infections.

55. Instability of Antibody during Aerosolization is Associated with Adverse Effects after Inhalation

Thomas Secher,1,2 Elsa Bodier‐Montagutelli,1,2,3,* Christelle Parent,1,2,* Laura Bouvart,1,2,4 Mélanie Cortès,1,2 Marion Ferreira,1,2,5 Otmar Schmid,6 Christophe Paget,1,2 Renaud Respaud,1,2,3 and Nathalie Heuzé‐Vourc'h1,2

1INSERM, Centre d'Etude des Pathologies Respiratoires, U1100, F‐37032 Tours, France.

2Université de Tours, F‐37032 Tours, France.

3CHRU de Tours, Service de Pharmacie, F‐37032 Tours, France.

4CHRU de Tours, Département de Médecine pédiatrique, F‐37032 Tours, France.

5CHRU de Tours, Département de Pneumologie et d'exploration respiratoire fonctionnelle, F‐37032 Tours, France.

6Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum München, 81377 Munich, Germany.

*Contributed equally to this work.

Aggregates are one of the major risk factor for undesired immunogenicity of therapeutic antibodies, which ultimately results in hazardous adverse effects. For inhaled Ab, one should consider the aggregation associated with the nebulization process. The aim of this study was to determine the impact of inhalation of nebulization‐dependent aggregated antibodies on the host immune system. Human and murine IgG were nebulized using a clinically‐relevant nebulizer. After analyzing their aggregation profile, we compared their immunogenic potency in vitro using a human monocyte‐derived dendritic cell (MoDC). Immunogenicity of nebulized murine IgG was also assessed in mice after pulmonary administration. We analyzed immune cells in the airway compartment, lung parenchyma and spleen.

Nebulization‐mediated aggregation of IgG was associated with an increased activation of MoDC characterized by production of cytokines and expression of co‐stimulatory markers. In mice, the airway administration of nebulization‐mediated aggregated IgG was associated with deleterious adverse effects including a profound and durable local and systemic immune cell death. Nebulization‐mediated aggregation is associated with pro‐inflammatory and cytotoxic processes. These crucial findings are essential for determining the optimal conditions for airway administration of biopharmaceuticals.

56. Advancement of an Infant Dry Powder Aerosol Delivery System: In VitroAnalysis of Air Source Effects

Connor Howe,1 Dale Farkas,1 Serena Bonasera,2 Mohammad Momin,2 Michael Hindle,2 and P. Worth Longest 1,2

1Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia, USA.

2Department of Pharmaceutics, Virginia Commonwealth University, Richmond, Virginia, USA.

A positive‐pressure dry powder inhaler (DPI) platform has been developed for infant nose‐to‐lung aerosol administration. The platform initially used a hand operated syringe as the air source, which may lead to performance variability. The objective of this study was to develop consistent automated air sources and investigate the effect of the air‐flow profiles and flow rate on aerosol delivery performance. Three unique air sources (Timer, Spring, Pneumatic) delivering 10 ml air volumes were tested across four unique air‐jet DPIs. DPIs were loaded with a test spray dried powder formulation and actuated 3 times per powder loading. Aerosolization metrics evaluated were emitted dose (ED) and mass median aerodynamic diameter (MMAD). The best performing air‐jet DPI was used to test each air source with a preterm (1600 g) infant nose‐throat model and tracheal filter. The three air sources were found to have no statistically significant difference in aerosol performance (based on MMAD and ED) except one case; Spring showed slight improvement over the Pneumatic in terms of MMAD. Each air source, when used with the best performing DPI, delivered about 35% of the loaded dose to the tracheal filter. Reducing the delivery flow rate from 4 to 1.7 LPM increased lung delivery efficiency to nearly 55%. The platform was not found to be sensitive to the tested air‐flow profiles which promotes versatility in operating environments, while lowering the flow rate increased lung delivery efficiency.

57. Designing Metal Organic Frameworks for Respiratory Delivery via Spray Drying: General Considerations with a Focus on Pulmonary Tuberculosis Treatment and Theragnostics

Ian E. Stewart,1 Ignacio Luz,2 Ninell P. Mortensen,2 and Anthony J. Hickley1

1Center for Engineered Systems, RTI International, Research Triangle Park, North Carolina, USA.

2Center for Analytical Chemistry and Pharmaceutics, RTI International, Research Triangle Park, North Carolina, USA.

Metal organic frameworks (MOFs) have garnered increased attention over the past 20 years. Due to their porosity, high surface area, and nearly limitless customization and tunability MOFs have been designed for applications ranging from gas storage and separation to catalysis to sensing to biomedical engineering. Within the latter category, MOFs offer an appealing function for drug delivery as they can be loaded with multiple therapeutic moieties tailored to target specific disorders with triggered and controlled release characteristics. However, there is an unmet need to assess their viability for pulmonary treatment via inhalation as most MOF drug delivery research has ignored this administration route. Targeting pulmonary diseases by delivering medication directly to the lungs attacks the primary site of infection rather than relying on systemic distribution. The advantage of this strategy is maximizing local lung concentrations of the drug. Here, MOF dry powder aerosols have been developed via spray drying as a potential therapy for drug resistant (DR) tuberculosis (TB). The CuPOA2 (pyrazinoate acid) MOFs can be tailored to exhibit a respirable mass median aerodynamic diameter (MMAD) of 2.6 μm and geometric standard deviation (GSD) 1.7. This method is repeated to manufacture Gd0.1Cu0.9(POA)2 MOFs for inhalable theragnostics. MOFs deserve consideration as a unique alternative for treating respiratory infections and require further biological safety and efficacy research.

58. Development of a Heated Dryer System (HDS) for High‐Efficiency Excipient Enhanced Growth (EEG) Delivery of Nebulized Medications during Oral Inhalation

Benjamin Spence,1 Mohammad Momin,2 P. Worth Longest,1,2 and Michael Hindle2

1Mechanical and Nuclear Engineering Department, Virginia Commonwealth University, Richmond, Virginia, USA.

2Pharmaceutics Department, Virginia Commonwealth University, Richmond, Virginia, USA.

Many available nebulizer‐based inhalation devices waste a large portion of the aerosolized drug leading to low and highly variable lung delivery efficiency. Three major factors contributing to low lung delivery are poorly timed aerosol production, device losses, and extrathoracic deposition. This study presents a new Heated Dryer System (HDS) for the production and oral administration of high dose aerosols, synchronized to naturally breathing human subjects, by drawing nebulized droplets through a streamlined mixing‐heating region. Experimental aerosol characterization at the device outlet indicated a MMAD of 1.04 μm, consistent with excipient enhanced growth aerosol delivery at a nebulization rate of 0.4 ml/min. Using realistic in vitro testing methods, electronically controlled nebulization during inhalation enabled approximately 80% of the nebulized dose to be deposited on a filter placed distal to a realistic adult mouth‐throat model. Lung delivery efficiency was found to be sensitive to nebulizer shutoff timing. Non‐optimal control schemes reduced filter dose to 60% of nebulized medication mainly due to fewer particles reaching the lung filter before exhalation. For best conditions, aerosol depositional losses within device and model during transport to the lungs were reduced to 15% nebulized dose. Continued development of the HDS will focus on further loss reduction and evaluation of human subject usability for extended delivery of high‐dose antibiotics and antivirals.

59. Pulmonary Delivery to Treat Animal Models of Infection to SARS‐COV‐2

Jake McDonald, Phil Kuehl, Adam Werts, Meghan Vermillion, and Hammad Irshad

Lovelace Biomedical, Albuquerque, New Mexico, USA.

In response to the global COVID‐19 pandemic an immediate need developed to establish relevant animal models that recapitulate the human disease for purposes of drug evaluation studies. Further, due to the respiratory nature of the disease pulmonary delivery evolved as a means of improving the efficiency and effectiveness of therapeutics, many of which were originally developed for non‐respiratory routes of administration. We will present data to present our (and others) approach to establish research models of SARS‐CoV‐2 challenged animals. African Green Nonhuman Primates are challenged by aerosol or intranasal/intratrachel administration. Evaluations for one week are performed to evaluate viral, immune, clinical and pathologic response. Transgenic mice and Syrian hamsters are challenged via intranasal administration, and evaluated up to three weeks after administration for the same endpoints. Interventions, including antivirals, antibodies, vaccines, xRNA approaches, are performed via a number of routes. We will present on examples of pulmonary administration, and the technical approach to administer drugs via aerosol within BSL3 containment for both nonhuman primates and rodents.

60. Formulation and in Vivo Efficacy of Monoclonal Antibody Spray Dried Dispersions: Local Treatment of Non‐Small Cell Lung Cancer with Bevacizumab

Philip J. Kuehl,1 Molly Adam,2 John Baumann,2 Julia Oddo,2 Amanda Pluntze,2 David Revelli,1 Lauren Switala,2 Kimberly Shepard,2 David Vodak,2 Yue Zhou,1 and Michael Banks3

1Lovelace Biomedical, Albuquerque, New Mexico, USA.

2Research and Development, Lonza Bend, Oregon, USA.

3Lonza Biologics, Portsmouth, New Hampshire, USA.

Non‐invasive strategies to deliver biologic APIs (proteins, peptides and antibodies) are of great interest for targeted delivery to the lung. However, development of inhaled formulations to deliver large, delicate molecules such as monoclonal antibodies (mAb) has remained a challenge. This work describes a platform for mAb pulmonary formulation via spray drying, using bevacizumab as a case study. Bevacizumab was spray dried in a custom lab‐scale two‐fluid nozzle with collection in a cyclone. Three formulations were developed/evaluated: 10/70/20, 20/60/20, and 40/40/20 bevacizumab/trehalose/L‐leucine (by weight). The final dry powder consists of two phases: crystalline L‐Leucine and amorphous trehalose/bevacizumab. The activity of the final formulations was confirmed with a reporter‐based assay for bioactivity determination of anti‐VEGF antibodies. Activity of all formulation was unchanged from the naïve bevacizumab. The 40% active formulation was evaluated in a nude rat model of lung cancer (Calu‐3 cell line). The in vivo study evaluated systemic delivery (15 mg/kg) and the DPI (1.5 mg/kg pulmonary deposited dose) in both a treatment and a maintenance phase of disease. The results showed that the DPI at a 10x lower dose had equivalent reduction in tumor burden within the treatment phase. Within the maintenance phase the DPI reduced tumor burden and increased survival. These results open new opportunities for platform delivery of mAb for targeted delivery in lung cancer.

61. A Novel Dry Powder Delivery Device for Pre‐Clinical Animal Dosing

G. Williams, J. Suman, and A. Fischer

Aptar Pharma, Nextbreath.

This work describes the development, use mode, comparison and in vitro testing of a novel dry powder delivery device that can be employed for nasal or pulmonary pre‐clinical dosing of aerosolized powders during small animal testing. The device consist of around six components including an air pump, dosing chamber (which can accommodate from 1 to 20mg of powder) and a stainless steel delivery cannula (0.27”). The powder‐dosing chamber can be manually filled and a precision air pump provides ∼200μl of air for the rapid insufflation of the aerosolized dose via the delivery cannula. The performance of the novel device was compared to current industry standards, e.g. Penn Century Insufflator™, with a favorable outcome. In vitro testing of the aerosolized powder revealed good performance characteristics including delivery efficiency of ∼91% (range ∼75 – 100%) and variability (RSD) of ∼4%.

62. Protein Stability and Bioactivity of Recombinant Interferon Gamma (rIFN g) After Aerosolization Using an i‐NEB‐MiniTM Nebulizer

Rohinton Toddywala,1 Vijay Shukla,1 and Gerald Smaldone2

1InspiRx Inc., Somerset, New Jersey, USA.

2SUNY, Stony Brook, New York, USA.

Background: Recombinant Interferon Gamma (rINF g) is an immunomodulatory pleiotropic cytokine with potential for treatment of respiratory diseases such as MDRTB, Pulmonary Fibrosis and SARS‐CoV‐2. The i‐NEB‐MiniTM is a SVN designed for small volumes of potent drugs (< 2 mL) and to aerosolize rINF g. Objectives: Determine amount aerosolized, protein stability and bioactivity of rINF g formulations using i‐NEB‐MiniTM. Methods: Two rINF g (200 mg/mL and 1 mg/mL) formulations were studied. i‐NEB‐MiniTM was driven using a commercial portable compressor and aerosolized using a 15 L/min vacuum. Total amount nebulized was determined using a UV280 assay. Protein stability and Bioactivity pre‐/post‐nebulization were determined using SDS‐PAGE and HLADR assay (compared to EP10 ref. std.) respectively.

Results: Total amount of rINF‐g aerosolized from a 1 mg/mL formulation using 3 devices was 1.28 ± 0.18 mg (61.66% ± 8.71%.) SDS PAGE showed no changes in molecular weight or detectable degradation compared to pre‐nebulized formulations and the EP Standard. The bioactivity pre‐ and post‐nebulization of a 200 mg/mL formulation was consistent with the EP standard suggesting that that nebulization did not affect biological activity of the protein.

Conclusions: Aerosol studies indicate that a clinically relevant and reproducible dose of rINF g can be delivered with i‐NEB‐MiniTM. SDS‐PAGE gels and bioactivity assay indicates that the rINF g remains stable and bioactive upon nebulization.

63. Simultaneous Delivery of Two Aerosols During Mechanical Ventilation

Ann D. Cuccia,1 Janice A. Lee,2 Michael McPeck,2 and Gerald C. Smaldone2

1Respiratory Care Program, School of Health Technology and Management, Stony Brook University, Stony Brook, New York, USA.

2Pulmonary Mechanics and Aerosol Research Laboratory, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Stony Brook University Medical Center, Stony Brook, New York, USA.

Background: Continuous nebulization of pulmonary vasodilators is an off‐label therapy for hypoxemia. Patients may require additional aerosol therapies such as bronchodilators and antibiotics. This study evaluates delivery of concurrent therapy of multiple medications during continuous nebulization without interruption or circuit disconnection.

Methods: One i‐AIRE dual‐port breath‐enhanced jet nebulizer (BEJN) and two Aerogen Solo vibrating mesh nebulizers (VMN) were installed on the dry side of the humidifier. VMN were stacked, one for infusion, the second for bolus drug delivery. The BEJN was powered by air at 3.5 L/min,50 PSIG. Radiolabeled saline was infused at 5 & 10 mL/hr with radiolabeled 3 mL and 6 mL bolus injections at 30 and 120 min respectively. Two breathing patterns (DC 0.13,0.34) were tested, infusion time was 4 hours. Inhaled Mass expressed as % of initial syringe activity (IM%/min) was monitored with a ratemeter and collected on a filter at the airway opening.

Results: IM %/hr during continuous infusion was linear and predictable, mean ± SD: 3.63 ± 2.02%, 3.54 ± 2.78% for BEJN and VMN respectively. VMN infusion stopped spontaneously 1 in 4 runs. Bolus delivery IM% mean ± SD: 22.17 ± 7.65%, 14.37 ± 10.62% for BEJN and VMN respectively.

Conclusion: Simultaneous continuous and bolus nebulization without circuit disconnection is possible for both jet and mesh technology. Monitoring of VMN devices may be necessary in case of spontaneous interruption of nebulization.

64. Aerosol Delivery from the Dry Side of a Heated Humidifier During Mechanical Ventilation

Janice A. Lee,1 Michael McPeck,1 Ann D. Cuccia,2 and Gerald C Smaldone1

1Pulmonary Mechanics and Aerosol Research Laboratory, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Stony Brook University Medical Center, Stony Brook, New York, USA.

2Respiratory Care Program, School of Health Technology and Management, Stony Brook University, Stony Brook, New York, USA.

Background: Permanent placement of a single‐patient‐use nebulizer on the wet/outlet side of the heated humidifier results in excess condensation in the inspiratory limb and nebulizer flooding. We tested an inline breath‐enhanced jet nebulizer (BEJN) compared to vibrating mesh nebulizer (VMN) on the humidifier dry/inlet side which does not disrupt heating.

Methods: Nebulizers were operated in vitro during mechanical ventilation with 2 duty cycle (DC) breathing patterns during continuous infusion (5 or 10 mL/hr) or bolus (3 or 6 mL) delivery of 99m‐Tc radiolabeled saline. Inhaled mass (IM) as a function of delivery time was measured by a real‐time ratemeter (μCi/min). Data was analyzed by multiple linear regression.

Results: During continuous infusion, IM increased linearly as a function of time for both nebulizer types. IM variability was attributable to DC (p < 0.0001, 35%) and infusion flow (p = 0.001, 32%), but independent of nebulizer technology (p = 0.381, 6%). During bolus treatments, IM increased linearly to plateau. IM variability was attributable to DC (p < 0.0001, 25%) and residual nebulizer volume (p < 0.0001, 19%), with VMN residual volume contributing 16% of the variability and BEJN 5%. IM variability was independent of bolus volume (p = 0.571, 10%). System losses were similar (BEJN: 32% residual in nebulizer; VMN: 34% in circuitry).

Conclusion: Aerosol delivery is similar for both nebulizer technologies; BEJN is more predictable during bolus infusion.

65. Targeted GATA3 Knockdown in Activated T Cells via Pulmonary siRNA Delivery as Novel Therapy for Allergic Asthma

Rima Kandil,1Domizia Baldassi,1 Yuran Xie,2 Aditi Metha,1 and Olivia Merkel1

1Department of Pharmacy, Pharmaceutical Technology and Biopharmacy, Ludwig‐Maximilians‐University, Butenandtstraße 5‐13, 81337 Munich, Germany.

2Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan, USA.

Asthma represents one of the most common chronic respiratory diseases worldwide. Despite great advances achieved in its treatment, it is still uncontrolled in 5‐10% of the patient population. In this view, an siRNA‐based therapy targeting the GATA3 transcription factor in activated T helper 2 (Th2) cells could represent a strategy to downregulate one of the main upstream factors involved in allergic asthma, thus keeping the inflammatory cascade typical for the disease under control. Th2 cells, however, are difficult‐to‐transfect. We have developed a nanocarrier for siRNA composed of low molecular weight polyethylenimine (PEI) as polycationic carrier, transferrin (Tf) as targeting ligand, and chemically protected melittin (Mel) as endosmolytic agent. These polyplexes showed optimal characteristics for pulmonary delivery as well as specific cellular uptake by activated primary T cells, whose activation protocol was carefully optimized. GATA3 knockdown by Tf‐Mel‐PEI/polyplexes was tested at the RNA level by qRT‐PCR. Moreover, the suppression of the downstream effects was confirmed by measuring the release of Th2 cytokines. In a following study, the formulation was investigated ex vivo on human precision‐cut lung slices (PCLS). Tf‐Mel‐PEI/siRNA polyplexes showed no toxic effect on the tissue and efficiently delivered siRNA. Finally, the ability of Tf‐Mel‐PEI/siRNA polyplexes to decrease Th2 cytokine secretion was assessed in human PCLS.

66. Aerosol Performance of the Pulmospray® Soft‐Mist Inhaler for Inhalation of High Amounts of Liquid Formulations

Bernhard Muellinger,1 Jody Bartholomew,2 and Wilbur de Kruij3

Resyca GmbH,1 Medspray B.V.,2 Resyca B.V.3

Liquid formulations are popular for drug delivery in inhalation products. Many compounds are available as liquid formulation and delivery devices as soft‐mist‐inhalers (SMI) or smart nebulizers have been employed to improve the delivery efficiency and usability. However, SMI are limited to small dosages and nebulizers require electricity, which is often not in‐line with the target treatment setting, were single use or energy independent on‐the‐go devices are required (e.g. COVID‐19, rescue). In this study, we assessed the aerosol performance of the mechanical and disposable Pulmospray inhaler, that is designed for application of a liquid volume of up to 1 mL. To assess the aerosol characteristics, cascade impaction testing (NGI) was performed (3 repetitions, 1 mL of 5.85% NaCl). Four device variants with different nozzle pore sizes were tested. The content sampled on impactor stages and the UIP was assessed by Conductivity. Mass Median Aerodynamic Diameter (MMAD) and the Geometric Standard Deviation (GSD) were calculated. The delivery rate was assessed by using a spray time of 10 sec per actuation. With pore sizes of 1.6, 1.7, 1.8 and 1.9 μm, MMAD was 5.12, 5.73, 5.90 and 6.70 μm, and GSD was 1.46, 1.49. 1.48, 1.56, respectively. The drug flow rate during actuation was 7.26, 8.17, 8.60, 11.25 μL/sec for the different pore sizes, respectively, which corresponds to an administration time for 1 mL between 1.5 to 2.3 min. Results from this study indicate that the Pulmospray allows a fast administration of 1 mL within ∼2 min. The combined results from narrow size distribution (GSD), the MMAD results (smaller pore size) and the built‐in flow limitation of the device allows efficient delivery to the lungs as indicated by other publications.

67. Assessing Airway Deposition of PureHale® Using a Cascade Impactor and Computational Fluid Particle Dynamics

Alexander Kolund, Timo Jung, Julien Storz, Degenhard Marx, Fotos Stylianou, and Stavros Kassinos

Aptar Radolfzell GmbH, Radolfzell, Germany: Computational Sciences Laboratory, University of Cyprus, Nicosia, Cyprus.

Aptar Pharma developed a portable, nebulizer‐like system for moistening the upper respiratory tract, now registered under the trademark PureHale®. The device generates a continuous fine mist with a mean droplet size of about 15 μm, optimized to reach the nasal cavity, throat and pharynx region with negligible deposition in the lower airways. A Bag‐on‐Valve system delivers the formulation. In combination with a newly developed nozzle technology, placed in the applicator, a continuous fine mist is generated with an output rate of around 1 ml per minute. Droplet size was determined using a laser diffraction method (Malvern Spraytec). Deposition of a fluorescein formulation was determined using a Next Generation Pharmaceutical Impactor with an Alberta idealized throat (Copley Scientific Limited) connected to a respirator. In addition, Computational Fluid Particle Dynamics was used to predict aerosol deposition in physiologically realistic upper airways during oral and nasal breathing with or without a facemask. High deposition rates in the upper airways was demonstrated in both test systems. Therefore, PureHale® as a portable, cordless and ready‐to‐use device is well suited for the moistening of the upper airways. The administration of an antiviral formulation to prevent or treat upper respiratory tract infections could be another field of use.

68. Sprayable, Thermoreversible Hydrogels for Treating Burn Wound Infections

Riannon Smith,1 Jackson Russo,2 Nicole Brogden,2 and Jennifer Fiegel1,2

1Department of Chemical and Biochemical Engineering, University of Iowa.

2Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa.

Chronic skin wound infections are an important health concern and current care, which includes rubbing antimicrobial creams onto the skin, is very painful. The goal of this research is to develop sprayable hydrogels to improve infection treatment in chronic wounds and to reduce application pain. We are developing thermoreversible polymers loaded with antibiotics and NSAIDs, which can be sprayed onto the skin as a liquid. As the polymer solution heats up upon contact with the skin, it transitions to a gel in the wound and can provide prolonged drug release. Poloxamer‐hyaluronic acid hydrogels loaded with diclofenac or ciprofloxacin were evaluated using rheological, antimicrobial, and spray analysis methods. Hydrogels with gelation temperatures between 21°C and 34°C gel at skin temperatures or below, and thus chosen for further analysis. Ciprofloxacin‐loaded hydrogels were evaluated with zone of inhibition studies, and the developed hydrogels have shown promising antimicrobial activity compared to silver sulfadiazine cream, a common topical treatment for burn wound infections. Spray pattern analysis showed that the type of nozzle and distance to a target largely influence the size and shape of the spray pattern. High speed imaging showed that the type of nozzle and formulation sprayed both significantly influenced spray plume development. These sprayable systems hold significant promise for improving the treatment of chronic wounds.

69. Utilizing Tunable, Acid‐Degradable UiO‐66 Metal‐Organic Framework (MOF) Nanoparticles for Pulmonary Drug Delivery

Zachary Stillman,1 Bader Jarai,1 Lucas Attia,1 Gerald Decker,2 Erich Bloch,2 and Catherine Fromen1

1University of Delaware Department of Chemical and Biomolecular Engineering.

2University of Delaware Department of Chemistry and Biochemistry.

Metal‐organic frameworks (MOFs) have risen in interest in recent years because of their high loading capacity and varied physical and chemical properties, giving the class of materials a wide range of applications including gas storage, catalysis, and, more recently, drug delivery (DD). MOFs, in particular MOF nanoparticles (NPs), have recently been used in DD applications because of their flexibility in design, though they have seldom been used for pulmonary delivery in particular. Herein, we report the first comprehensive evaluation of the MOF UiO‐66, a Zr‐based MOF with terephthalic acid ligands, for pulmonary drug delivery. For this evaluation, we have synthesized a suite of UiO‐66 NPs of constant NP size (100 nm) and varying missing linker defectiveness (extent of missing terephthalic acid linkers from 0% to 20%). The UiO‐66 NPs showed promising results in terms of their aerodynamic sizes, having aerodynamic diameters between 1 and 1.5 um as a dry powder, which is ideal for aerosol delivery, and also demonstrated high loading of cargo up to 0.2 mg cargo/mg UiO‐66. Not only that, but the UiO‐66 NPs were shown to be biocompatible both in vitro and in vivo when instilled orotracheally. Lastly, we determined that the UiO‐66 NPs were able to selectively release cargo in environments mimicking intracellular pH, while retaining cargo in extracellular pH environments. Accordingly, we believe that UiO‐66, and potentially other MOF NPs, show great promise for use in pulmonary DD.

70. Regulatory Decisions During COVID‐19: Efficient Nonclinical Inhalation Toxicology for a Clinical Program

Holli Cherevka,1 Philip J. Kuehl,2 and Laura Goldberg1

1Ampio Pharmaceuticals, Englewood, Colorado, USA.

2Lovelace Biomedical, Albuquerque, New Mexico, USA.

Background: The ISAM Networking groups identified that effective regulatory development of therapeutics is essential and critical during the COVID‐19 pandemic. Ampion is a novel biologic containing a blood‐derived cyclized peptide and small molecules that target pathways in the innate immune response characteristic of inflammatory disease, which provides treatment for respiratory distress due to COVID‐19. The FDA identified a need to assess the no‐observed adverse effect level (NOAEL) in animals with Ampion via inhalation as the intended route of administration. A study was designed with FDA feedback to assess the potential local toxicity to the lung and other respiratory tissues at a range of inhalation doses.

Methods: Rats were exposed to multiple doses of nebulized Ampion delivered via nose‐only inhalation daily over 5 days. Aerosol delivery was optimized to ensure exposure at a maximum feasible dose at least 10x higher than the planned human dose.

Results: Ampion was well tolerated for all exposure groups with no abnormal clinical signs, changes in lung function, hematology/chemistry, and no adverse findings during gross/detailed pathology. The NOAEL daily dose is equal to 15x higher than the proposed human adult nominal dose. Subsequently, the FDA awarded an active Investigational New Drug (ClinicalTrials.gov: NCT04606784).

Discussion: This program is an example of efficient development that is responsive to the COVID‐19 pandemic and FDA requirements.

71. Addition of Leucine to Trehalose‐Containing Microparticles Enhances Environmental Robustness against Moisture for Nasal Vaccination Applications

Zheng Wang, Hui Wang, and Reinhard Vehring

Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada.

Nasal dosage forms, e.g. nasal dry powder vaccines, have attracted increasing research interest due to their needle‐free administration and low storage and transportation requirements. High environmental robustness of dry powder vaccines is important to ensure efficacy is maintained when powders are exposed to humid environments during use. The purpose of this study was to investigate the environmental robustness of various two‐component particle systems when exposed to high humidity environments. Trehalose/leucine, trehalose/pullulan, and trehalose/trileucine particle systems, as well as pure trehalose particles, were prepared using monodisperse spray drying. Particle size, morphology, crystallinity and powder dispersibility of the two‐component particle systems were characterized and compared with those of the pure trehalose particles. The results show that trehalose/leucine formulations maintained a high emitted dose even after up to 60 min unprotected exposure to 90% relative humidity and 25°C, whereas almost no pure trehalose particles were emitted under these conditions. Protection for 10 min was achieved with as little as 10 % leucine in the formulation. In conclusion, leucine is an appropriate shell forming excipient to enhance the environmental robustness of nasal dry powder vaccines against moisture exposure.

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78. Optimization of Spray Drying for the Novel Inhalable Formulation of Ciprofloxacin Nanocrystals Within Liposomal Vesicles: Box‐Behnken Experimental Design

Isra Khatib,1 Michael Y.T. Chow,1 Juanfang Ruan,2 David Cipolla,3 and Hak‐Kim Chan1

1Advanced Drug Delivery Group, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, New South Wales, Australia.

2Electron Microscope Unit, Mark Wainwright Analytical Centre, The University of New South Wales, New South Wales, Australia.

3Insmed Corporation, Bridgewater, New Jersey, USA.

Production of novel inhalable formulation of ciprofloxacin (Cf) nanocrystals inside liposomes (CNL) by spray drying was optimized in this study. Method optimization was performed using the Box–Behnken design (BBD). The independent variables were the lyoprotectant (LP) type (sucrose, trehalose, or lactose), LP amount, inlet air drying temperature, and spray gas flow. Individual spray drying experiments were performed at various set points for each variable. Produced powders were characterized for the following dependent variables: liposome particle size, drug encapsulation efficiency (EE), zeta potential, and Cf nanocrystals (CNs) dimensions. Mathematical models were constructed via MATLAB and Expert‐Design software with ANOVA to determine the models' reliability and the significant factors. The results showed that CNL powders contained spherical to elliptical liposomal vesicles with elongated cylindrical CNs of an aspect ratio 4.0 ‐ 7.8. Liposomal particle sizes, drug EE, and zeta potential varied between 98 and 159 nm, 30 and 95% w/w, and ‐3.5 and ‐10.5 mV, respectively. The predicted and experimental values were in good agreement for all responses except the CNs dimensions. Sucrose and lactose were superior to trehalose as liposomal LPs during spray drying. LP amount significantly affected the characteristics of the CNL powders (p‐value <0.05). The optimum conditions which produced CNs with drug EE (90%) and a vesicle size of ∼125 nm were 57% w/w sucrose at 80 °C or lactose at 65 °C drying temperature and atomization of 742 L/hr. The optimized CNL powders of sucrose or lactose were prepared with 2% w/w magnesium stearate and/or 5% w/w isoleucine as aerosolization enhancers. These powders exhibited aerosol fine particle fraction (% wt. <5 μm) of 61.7% (sucrose) and 76.2% (lactose) when dispersed through Osmohaler® at a flow rate of 100 L/min. The formulation demonstrated extended Cf release from liposomes as 90% was released within 8 hours while the original liquid formulation released Cf within 2 hours. BBD has efficiently modeled the spray drying conditions for the generation of inhalable CNL powders with controlled drug release properties.

79. PEGylation of rhDNase Provides a Long‐Acting Version of the Mucolytic for Patients with Cystic Fibrosis that can Significantly Reduce Treatment Burden

Tobias Wilms,1 Sohaib Mahri,1 Aurélie Rondon,1 Cynthia Bosquillon,2 and Rita Vanbever1

1Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium.

2University of Nottingham, School of Pharmacy, Nottingham, United Kingdom.

Pulmozyme (rhDNase) is the mucolytic agent most commonly used for the symptomatic treatment of cystic fibrosis (CF). However, a time‐consuming and suboptimal administration of rhDNase is required daily as it is rapidly cleared from the lungs, thereby contributing to the high therapeutic burden of CF. We have developed a long‐acting PEGylated rhDNase that could be administrated on a weekly instead of daily basis. Conjugation of rhDNase to PEGs of different sizes was previously shown to significantly prolong the residence time of rhDNase in the lungs of mice after pulmonary delivery, while still preserving its full enzymatic activity. In the present study, the mechanisms promoting the extend lung retention of PEG‐rhDNase were investigated in more detail. These mechanistical studies showed that the increased retention of PEG‐rhDNase is mainly due to a decrease in transport across pulmonary epithelial cells as well as in uptake by alveolar macrophages. In addition, the biodistribution and elimination pathways of native and PEGylated rhDNase after intratracheal instillation was assessed. These studies did not only confirm the sustained pulmonary presence of PEG‐rhDNase, but also demonstrated that both intact native and PEGylated rhDNase are systemically absorbed, although the latter to a lesser extent. Moreover, catabolism, which occurred primarily in the lungs and secondarily systemically, followed by renal excretion of byproducts were the predominant elimination pathways. Catabolism was nevertheless more extensive for the native protein.

80. Realistic in Vitro Lung Delivery Testing of a Pediatric Positive‐Pressure Dry Powder Device with Excipient Enhanced Growth (EEG) Antibiotic Formulation

Dale Farkas,1 Karl Bass,1 Serena Bonasera,2 Michael Hindle,2 and P. Worth Longest1,2

1Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia, USA.

2Department of Pharmaceutics, Virginia Commonwealth University, Richmond, Virginia, USA.

The objective of this study was to develop a platform for active delivery of an excipient enhanced growth (EEG) formulation to pediatric patients by implementing an air‐jet dry powder inhaler (DPI) and nasal cannula interface with a 3D rod array structure. An active positive‐pressure DPI is ideal for use in children who may not be able to follow best practices for efficient lung delivery while using a conventional passive inhaler. The concept of EEG delivery requires an initial small aerosol size to allow the particles to pass through the restrictive extrathoracic passages, prior to aerosol size increase in the lungs. The air‐jet DPI with connected nasal cannula interface containing a 3D rod array produced an emitted dose (ED) of 76% and a mass median aerodynamic diameter (MMAD) of 1.7 μm with a preliminary EEG test powder. For lung delivery assessment, a pediatric nose‐throat (NT) and upper tracheobronchial (TB) airway model led to an aerosol growth chamber that simulated lung thermodynamic conditions and an approximate 2 sec exposure time, followed by a Next Generation Impactor (NGI). Approximately 70% of the loaded dose was delivered through the NT‐TB model and growth chamber while growing from 1.7 to 3.2 μm in aerodynamic size. In conclusion, this study demonstrates efficient aerosol delivery with a dry powder pediatric platform and the ability of the EEG approach to grow the aerosol to a size that will better deposit in the lungs.

81. Characterizing Nose‐to‐Lung Aerosol Delivery for Preterm Infants with Commercial and Novel Nasal Cannulas

Karl Bass,1 Robert M. DiBlasi,2 and P. Worth Longest1,3

1Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia, USA.

2Department of Respiratory Care, Seattle Children's Hospital, Seattle, Washington, USA.

3Department of Pharmaceutics, Virginia Commonwealth University, Richmond, Virginia, USA.

Appropriately sized medical aerosols delivered to preterm infants at relatively low flow rates are expected to efficiently traverse the natural filtration of the extrathoracic airways, due to low particle inertia and the associated reduction of impaction depositional losses. This approach to respiratory drug delivery provides a highly effective method of aerosolized surfactant delivery, which is administered to improve lung function of preterm infants on mechanical ventilation. This study aims to characterize extrathoracic aerosol losses with multiple flow rates and particle sizes in preterm infant models, which both include and neglect the laryngopharynx, by utilizing validated computational fluid dynamics models. The delivery systems considered include the flexible Hudson Size 2 cannula, which extends deep into the anterior region of the nasal cavity, and novel cannula designs that aim to maximize lung dose. Comparisons are also made between single prong cannulas, where the aerosol is only delivered to one nostril, and traditional dual prong cannulas. Results focus on the development of impaction parameter curves (where deposition fractions are plotted against the product of the flow rate and particle diameter squared) for all airway models and delivery systems considered. These curves establish optimal operating conditions for each delivery system and the best‐case method of aerosol administration that minimizes extrathoracic losses and maximizes available lung dose.

82. Is a Pressure Drop ≥10 cm H2O (1kPa) with Any Dry Powder Inhaler (DPI) a Reasonable Threshold Above Which a Patient Should Receive an Adequate Lung Dose? An Initial Clinically Relevant Laboratory Assessment

Mark Nagel,1 Jason Suggett,1 and Jolyon Mitchell2

1Trudell Medical International, London, Canada.

2Jolyon Mitchell Inhaler Consulting Services Inc., London, Canada.

Clark et al. have claimed, based on the negative pressure generated by the patient's inspiratory effort, a pressure drop ∼≥10 cm H2O with any DPI is a threshold above which an adequate lung dose should be received. We compared dose delivery using inspiratory flow profiles for 5 patients with varying severity of COPD, using a medium inspiratory flow resistance DPI (Turbuhaler*; 80μg budesonide/4.5μg formoterol), with a purpose‐constructed attachment to a pneumotachometer. Each inhalation profile was recreated (n = 3 replicates) via a breathing simulator coupled to the mouthpiece. The simulator was located distal to a microbial collection filter, positioned at the exit of a model adult oropharynx, to capture medication likely to have deposited at the carina and therefore potentially available for lung delivery. The maximum inspiratory pressures were 19.2, 11.5, 12.7, 33.3 and 101.8 cm H2O in the order patient A to E. Yet the corresponding mass/inhalation of budesonide and formoterol components (mean±SD) recovered from the model mimicking these inspiratory flow rate‐time profiles varied widely at 18.2 ± 0.8, 16.2 ± 1.5, 13.6 ± 3.3, 22.4 ± 2.2, 35.3 ± 1.4 μg budesonide and 0.7 ± 0.1, 0.8 ± 0.1, 0.7 ± 0.2, 1.1 ± 0.1, 1.8 ± 0.1 μg formoterol, also in the order patient A to E. These findings highlight the potential value in further discussion around what is an ‘adequate’ lung does and what other factors, in addition to pressure drop, may be involved.

83. A STELLA Simulation Model for in Vitro Dissolution Testing of Respirable Size Particles

Basanth Babu Eedara,1,2 Ian G. Tucker,1 and Shyamal C. Das1

1School of Pharmacy, University of Otago, 18 Frederick St, Dunedin 9054, New Zealand.

2Skaggs Pharmaceutical Sciences Center, The University of Arizona College of Pharmacy, Tucson, Arizona, USA.

In Vitro dissolution testing is a useful quality control tool to discriminate the formulations and to approximate the in vivodrug release profiles. This study aimed to construct a simple STELLA simulation model to predict the dissolution behavior of the respirable size inhaled dry powder particles in a small volume of mucus simulant (25 μL spread over 4.91 cm2 area i.e. ̴50 μm thick) and diffusion through a membrane. Using this model, the permeation (dissolution followed by diffusion through the membrane) of two anti‐tubercular drugs of differing solubilities, moxifloxacin (17.68 ± 0.85 mg mL−1) and ethionamide (0.46 ± 0.02 mg mL−1), from the respirable size particles and their diffusion from a solution were simulated. The simulated permeation profiles of moxifloxacin from solution and respirable size particles were similar, indicating fast dissolution of the particles. However, the simulated permeation profile of ethionamide from respirable size particles showed slower permeation compared to the solution indicating the slow dissolution of the respirable size particles of ethionamide. The sensitivity analysis suggested that increased mucus volume and membrane thickness decreased the permeation of drug. While this model was useful in predicting and distinguishing the dissolution behaviors of respirable size moxifloxacin and ethionamide, further improvement could be made using appropriate initial parameter values obtained by experiments.

84. Comparison of JUUL e‐Cigarette and Cigarette Exposure in Apoe− Mice Through Pharmacokinetics and Dosimetry Analysis

Matthew J. Eden,1,* Yasmeen M. Farra,1,* Jacqueline Matz,1 Jessica M. Oakes,1 and Chiara Bellini1

1Department of Bioengineering, Northeastern University, Boston, Massachusetts, USA.

*Authors contributed equally

For in Vivo exposure studies to effectively compare the chronic health effects of pod e‐cigs (e.g., JUUL) use with cigarettes (cig), it is important to equate circulating nicotine levels. Here, we investigate the pharmacokinetics of cotinine, nicotine's primary metabolite, in 7 groups of Apoe− mice exposed to JUUL aerosols (3% nicotine) or cig smoke. Cotinine data was collected for 4 exposure durations and an additional 3 groups were exposed for the maximum exposure time plus 30, 90, or 150 mins. The particle size distributions (PSD) of JUUL and cig were characterized with an EEPS 3090 (TSI) and used to model mouse airway deposition. We found that cotinine absorbed and cleared more rapidly from the blood of JUUL exposed mice, as quantified by the time to reach maximum concentration (JUUL: 14.5 min, cig: 50.4 min) and elimination half‐life (JUUL: 55.4 min, cig: 106 min). Particle counts followed lognormal distributions, with one (cig) or two (JUUL) modes. The primary mode for e‐cig aerosols is smaller (CMDJUUL = 116 ± 3.0 nm) but has larger dispersion (GSDJUUL = 1.70 ± 0.004) compared to cigarette smoke (CMDcig = 178 ± 0.001 nm; GSDcig = 1.41 ± 0.004). We predict that 31.4% and 27.7% of inhaled particulates deposit in the mouse airways for JUUL and cig, respectively. As deposited doses were similar, we expect the differences in uptake and distribution of nicotine to be attributed to differences in the aerosol bioavailability.