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

The deposition of budesonide at fast (60 l min(-1)) and slow (301 min(-1)) inspiratory flow rates from Airmax, 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 crossover study, and inhaled a single nominal dose of 200 microg 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 microg and 43.6+/-8-6 microg budesonide in the lungs at 60 l min(-1) and 30 l min(-1) respectively whilst Turbuhaler deposited 48.3+/-11.2 microg at 60 l min -and 24.2+/-6.0 microg at 30 l 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.