Impact of Capsule Selection on Formulation Stability in Dry Powder Inhalers (DPIs)

This article is an examination of differences between gelatin and HPMC capsules and their respective contributions to DPI formulations. Two-piece capsules have proven to be excellent containers to hold powder formulations for DPI applications. By treating the capsule as an excipient of the formulation itself, formulators can take advantage of the properties of various polymers to enhance and protect the formulation held inside.