Assessing Regional Extrathoracic Drug Deposition for Pressurized Metered-Dose Inhalers
Pressurized metered-dose inhalers (pMDIs) are widely used to deliver drugs to the lungs for treatment of respiratory diseases. However, targeting delivery of inhaled drugs to the lungs is not straightforward. The airways of the mouth and throat present a barrier through which inhaled particles must penetrate in order to reach their target sites in the lungs. Indeed, deposition of drug-containing particles emitted from inhalers in the mouth and throat is limits the lung dose that can be achieved from inhalers in current use, and in some cases can lead to undesirable side effects, including sore throat, altered voice quality, and oral infections.The proposed work will investigate regional patterns of deposition in the mouth and throat for particles delivered from pMDIs. Physical models of adult and child mouth and throat airways will be used for this purpose. Use of airway models helps to avoid early testing of new drug and device combination products in animals or humans, and allows drug developers to gain valuable feedback on innovative technologies. The influence of device and formulation parameters on regional mouth-throat deposition will be evaluated over a range of inhalation flow rates for both the adult and child airway geometries.