The oropharyngeal and lung deposition patterns of a fusafungine MDI spray delivered by HFA 134a propellant or by CFC 12 propellant

Abstract We report for the first time the deposition pattern in the respiratory tract of a metered dose inhaler formulated with hydrofluoroalkane (HFA) 134a, in comparison with an inhaler containing chlorofluorocarbon (CFC) 12. The inhalers delivered 125 μg fusafungine per metered dose, and deposition was assessed using the non-invasive technique of gamma scintigraphy. Preliminary in vitro validation studies showed that the 99m Tc tracer acted as a good marker for the distribution of fusafungine. The in vivo study was carried out in 10 healthy volunteers who each inhaled a single dose of radiolabelled fusafungine on two occasions. The majority of the dose from the HFA 134a and CFC 12 fusafungine formulations was deposited in the oropharynx (mean 65.7 and 64.3%, respectively), with an average of only 2.4 and 3.2% deposited in the lungs. It was concluded that the deposition pattern for the new fusafungine formulation with HFA 134a propellant is similar to that of the existing formulation containing CFC 12.