Abstract

The unique properties and characteristics of pressurized metered-dose inhaler (pMDI) formulations stem from the physicochemical properties of the hydrofluoroalkane (HFA) propellants. The limited number of excipients used in marketed pMDIs products adds to the complexity of development. In addition to the challenges for formulators, these systems require specialized analytical chemists, regulatory scientists, and pMDI manufacturing expertise. These challenges highlight the importance of understanding HFA formulations across multiple disciplines. Thus, influence of formulation variables must be appreciated for both formulation design and understanding product performance.