Influence of particle size and patient dosing technique on lung deposition of HFA-beclomethasone from a metered dose inhaler.
The objective of this study was to determine the lung delivery of HFA-134a-beclomethasone dipropionate (HFA-BDP) from a breath-activated inhaler (QVAR Autohaler) compared with proper and improper press and breathe (QVAR P&B) metered dose inhaler (MDI) technique. The hypothesis was that that the smaller particles of BDP from HFA-BDP would stay suspended longer in the inspiratory air of patients and thus reduce the deleterious effects of inhaler discoordination. The study was an open label, four period, cross-over design. Asthmatic patients (n = 7) with a history of asthma symptoms, an FEV-1 of >70% of predicted normal, and a history of reversibility to a beta-agonist of >or=12% were utilized. BDP was radiolabeled with technetium-99m and delivered from the QVAR Autohaler or QVAR P&B device in patients trained to reproducibly utilize coordinated and discoordinated P&B MDI technique. Patients using Autohaler MDI exhibited 60% lung deposition of BDP. Patients using coordinated technique with the P&B MDI exhibited 59% lung deposition. Patients trained to consistently actuate the P&B MDI before inhaling exhibited 37% lung deposition. Patients trained to consistently actuate the P&B MDI late in the inspiration (i.e., 1.5 sec into a 3-sec inspiration) exhibited 50% lung deposition. In conclusion, the breath-activated Autohaler automatically provided optimal BDP lung deposition of 60%. Patients with good P&B MDI technique also received optimal lung deposition of 59%. The degree of lung deposition was decreased as patients demonstrated poor inhaler technique. However patients with poor technique still received a large lung dose of BDP (i.e., >or=37%) compared with lung deposition values of 4-7% for CFC-BDP MDIs previously published and confirmed in this study.
Leach
Chet L
CL
3M Pharmaceuticals, St. Paul, Minnesota, USA. cleach@lrri.org
Davidson
Patricia J
PJ
Hasselquist
Bruce E
BE
Boudreau
Robert J
RJ
D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000336:Aerosols; D001249:Asthma / Q000188:drug therapy*; D001507:Beclomethasone / Q000008:administration & dosage* / Q000493:pharmacokinetics; D018592:Cross-Over Studies; D016503:Drug Delivery Systems / Q000379:methods*; D005260:Female; D006801:Humans; D008168:Lung / Q000378:metabolism*; D008297:Male; D036501:Metered Dose Inhalers; D008875:Middle Aged; D010316:Particle Size; D012588:Scintillation Counting; D013667:Technetium
D000336:Aerosols; D013667:Technetium; D001507:Beclomethasone