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.
Hirst
R H
RH
Pharmaceutical Profiles, Ruddington, Nottingham, UK.
Newman
S R
SR
Clark
D A
DA
Hertog
M G L
MG
D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000188:drug therapy*; D001993:Bronchodilator Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D019819:Budesonide / Q000008:administration & dosage* / Q000493:pharmacokinetics; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009330:Nebulizers and Vaporizers / Q000592:standards; D011208:Powders; D011877:Radionuclide Imaging; D013667:Technetium
D001993:Bronchodilator Agents; D011208:Powders; D019819:Budesonide; D013667:Technetium