Latest advances in the development of dry powder inhalers.

The current market for dry powder inhalers (DPIs) has over 20 devices in present use and at least another 30 under development. Clinicians recognize that DPIs are a suitable alternative to pressurized metered dose inhalers (pMDIs) for some patients but the relative performance of devices is often unclear. The problem is compounded by the need to reformulate pMDIs with new propellants, introducing further products to the market with associated variations in performance. This article reviews the DPIs currently available, the driving forces governing new designs, and the claimed advantages of DPIs in the development pipeline.