M.Sc Thesis


M.Sc StudentAbu Ahmad Leen
SubjectTransport and Deposition of Excipient Enhanced Aerosols in
the Lungs of an Infant
DepartmentDepartment of Biomedical Engineering
Supervisor ASSOCIATE PROF. Josue Sznitman


Abstract

Among the most widely used approaches available for lung disease treatment, inhalation therapy is the preferred route for administration of pharmaceutical compounds to the lungs. Drug delivery can be done by administrating aerosols through oral or nasal inhalation. In most circumstances, oral inhalation is the main technique used for pharmaceutical aerosol delivery, while the nasal route is rarely considered. However, this route proves to be quite useful among children and infants since they are mainly nasal breathers. Usually, aerosols are delivered to pediatric patients less than 5 years of age through a face-mask interface. Delivery using facemasks is problematic due to facial depositional loss, aerosol loss through leaks, low lung delivery rates, and noncompliance by the young patient. In comparison, previous studies have shown that the use of cannula prongs for drug delivery in children and infants may significantly improve the delivery efficiency.

Recently, a controlled condensational growth approach has been proposed to improve the delivery efficiency. Using this approach, aerosols can experience a size increase during their journey through the respiratory tract. Techniques to produce the required size increase include enhanced condensational growth (ECG) and excipient enhanced growth (EEG). In this work, we use computational fluid dynamics (CFD) simulations to examine and evaluate aerosol deposition in different regions of a 3D CT-scan based nose-to-lungs anatomy of a 14-month-old infant, where the aerosols are delivered using cannula prongs to improve the delivery. In addition, we adopted the condensational growth approach (namely, EEG) for comparison and examined its influence on the delivery. Our findings reveal a narrow window of aerosol initial sizes where condensational growth may play a key-role in improving pulmonary drug delivery. Specifically, sub-micron aerosols which would usually be exhaled due to their small size, are identified as the best candidates for such application, where hygroscopic growth would allow them to cross to the micron range, thus yielding the highest delivery rates in the lungs.