Impact of holding position during inhalation on drug release from a reservoir-, blister- and capsule-type dry powder inhaler.

Objective: To determine whether drug release may be impaired by tilting some dry powder inhalers (DPIs).

Methods: Using an inhalation simulator, we measured drug release from Turbuhaler® (TBH), Diskus® (DKS) and Breezhaler® (BZH) at several peak inhaled flow rates (PIFs) while the DPIs were held at level and tilted (80°). Drug release was then measured from all three DPIs at 0, 30, 60 and 90° of tilt, and capsule rotation was also recorded.