Factors influencing the in vitro dissolution rates of pMDI aerosols

Employing in vitro dissolution studies of pressurized metered dose inhalers (pMDIs) is crucial for assessing release of drugs from pMDIs and their subsequent availability for systemic absorption. Utilization of in vitro dissolution systems yields valuable data for decision-making, enabling the prediction of drug pharmacokinetics during the initial phases of drug development and optimization. This data facilitates more precise forecasts of in vivo drug behavior, helping avoid expensive failures in late stages of development.

At present, there are no established regulatory mandates or standardized procedures for conducting in vitro dissolution testing of pMDI products. Therefore, it is imperative to select or develop a dissolution testing methodology that is tailored to the specific attributes of the pMDI formulation. This article outlines factors that could influence in vitro dissolution of pMDI aerosols, offering guidance for optimizing formulation design by selecting appropriate APIs and excipients, as well as enhancing the manufacturing process. It also suggests directions for developing robust dissolution technologies to assess batch consistency.