Lung deposition of budesonide from the novel dry powder inhaler Airmax™

Abstract

The deposition of budesonide at fast (60 1 min-1) and slow (30 1 min-1) inspiratory flow rates from Air-max™, a new multi-dose dry powder inhaler, was compared with that from Turbuhaler® and a standard pressurized metered dose inhaler (pMDI). Twelve patients with mild to moderate asthma took part in a five-way randomized cross-over study, and inhaled a single nominal dose of 200 μg budesonide, labelled with 99mTc, on each study day. Deposition was determined by gamma scintigraphy. At the fast flow rate, Airmax™ and Turbuhaler® deposited 25.8 ± 6.5% (mean ± SD) and 29.8 ± 6.9%, respectively, of the delivered dose in the whole lung (P = 0.080). At the slow flow rate, Airmax™ deposited 28.3 ± 5.6%, Turbuhaler® 22.7 ± 5.6% and pMDI 12.1 ± 3.4%. Using data on emitted doses determined in vitro, it was estimated that Airmax™ deposited 53.1 ± 13.3 μg and 43.6 ± 8.6 μg budesonide in the lungs at 60 1 min-1 and 30 1 min-1 respectively, whilst Turbuhaler® deposited 48.3 ± 11.2 μg at 60 1 min-1 and 24.2 ± 6.0 μg at 30 1 min-1. In conclusion, lung deposition of budesonide from Airmax™ was comparable to that of Turbuhaler® at a high flow rate but was markedly superior to Turbuhaler® and pMDI at a lower flow rate. Unlike Turbuhaler®, Airmax™ performs with relative flow-rate independence. © 2002 Elsevier Science Ltd.