Identifying determinants of capsule emptying
Mark Sanders1 & Darragh Murnane1
1University of Hertfordshire, College Lane, Hatfield, AL10 9AB, UK
Summary
Single dose capsule inhalers are a popular dry powder delivery system, and a number of advantages for the patient and manufacturer; there is a positive reinforcement rattle sound that implies delivery. The ERS/ISAM Task Force report (1) explains that the dose from a capsule DPI is emitted slower than that of a reservoir or blister DPI and that therefore inhalation volume is an important parameter for patients using capsule inhalers. A UH project has investigated what other parameters may be relevant determinants of efficient capsule emptying and found that duration of inhalation, flow rate of inhalation, power generated and device resistance all make a contribution to capsule emptying.