Investigating Drug Loading on Stainless-Steel Mesh Filters used for Estimating Regional Lung Deposition
Alexander Huang1, Scott Tavernini1, Dino J. Farina2, Warren H. Finlay1, Andrew R. Martin1
1Aerosol Research Lab of Alberta, University of Alberta, 116 St & 85 Ave, Edmonton, T6G 2R3, Canada
2Proveris Scientific Corporation, 2 Cabot Rd, Hudson, MA 01749, United States
Summary
Our group has recently developed a filter-based apparatus (FBA) for in vitro estimation of regional lung deposition for dry powder and pressurized metered dose inhalers. The FBA utilizes a set of specialized stainless-steel mesh filters, positioned downstream of a mouth-throat airway model (Alberta Idealized Throat, AIT), to collect and separate the tracheobronchial fraction of the lung dose. The work presented here evaluated potential loading effects of repeated actuations of inhalers through the apparatus on the filtration efficiency of the mesh filters. Varying doses of a fluticasone propionate dry powder inhaler (DPI) were actuated through the in vitro assembly while using realistic breathing profiles. Scanning electron microscopy (SEM) provided a qualitative assessment of active pharmaceutical ingredient (API) and carrier particle deposition onto the filters with increased loading, while ultraviolet (UV) spectroscopy provided a quantitative analysis of the amount of API collected on the filters. The mass of API collected on the filters, normalized by number of actuations, was unchanged between 2, 5, and 7 repeated actuations. This study therefore demonstrated the robustness of the FBA and its potential to contribute to in vitro evaluation of orally inhaled drug products (OIDPs).