Inhaled Aerosol Deposition Across Idealized and Patient-Derived Nasal Cavities in Variable Breathing Conditions

• Jaclin Patterson, Chemical Engineering, University of Delaware

• Catherine Fromen, Chemical and Biomolecular Engineering, University of Delaware

Inhaled therapeutics present an optimal delivery route for respiratory illness by harnessing the high surface area and vasculature of respiratory tissue in the nose and lungs allowing for quick and efficient absorption. Currently aerosols are not largely prescribed due to difficulty in precisely targeted regional delivery from lack of depositional mapping of the airways in current literature. To eliminate this issue, more accurate models are needed to determine how therapeutics move throughout and deposit within the airways. The nasal cavity and the aerosol deposition patterns therein are of particular interest due to complexities of both structure and mucosal coating, as well as its proximity to the brain. To address this gap, my work focuses on validating benchtop models and mucosal coatings to accurately predict regional nasal deposition under various breathing conditions.

To map regional deposition within the nasal cavity, two models were developed and assessed under various breathing conditions with a fluorescent tracer solution, Rhodamine B. An idealized open-source model published by the EPA, derived from computational simulations, was first printed and validated against published clinical data. Different patient factors were investigated, such as insertion angles, and breathing vs. breath hold conditions. Next, a patient model was developed using a CT scan of a healthy individual’s nasal cavity and also validated. Both models were then coated in a thin layer of an in-house synthetic mucus gel which was characterized to have similar rheological properties to human nasal mucus. Deposition was mapped once again under breathing and optimized insertion angle conditions. We hypothesize that this coating allows for more realistic deposition patterns as it mimics that seen in a normal airway, possibly causing particles to stick earlier in the pathway. These validated models show the impact of mucosal coatings on airway models and address the gap in preclinical aerosol testing.