Pharmacokinetics of chlorofluorocarbon and hydrofluoroalkane metered-dose inhaler formulations of beclomethasone dipropionate.

AIMS: To compare the pharmacokinetic profile of Beclazone (beclomethasone dipropionate) in its chlorofluorocarbon (CFC)-based and CFC-free formulations.

METHODS: Ten healthy adults received a single 1,000 microg nominal dose (ex-valve) of beclomethasone dipropionate from a CFC inhaler (BEC-CFC) or from a CFC-free inhaler containing hydrofluoroalkane (HFA)-134a (BEC-HFA) in an open-label, randomized, two-way, crossover study. Blood samples were collected predose and over 12 h after inhalation. Comparisons were made of maximum plasma concentration of beclomethasone 17-monopropionate (17-BMP) (Cmax), and area under the plasma concentration vs time curve (AUC).

RESULTS: The tmax was significantly (P<0.05) earlier with BEC-HFA and plasma levels were significantly higher following administration of BEC-HFA than BEC-CFC. Geometric mean values for AUC were 1.5 fold greater (90% CI 1.3-1.9) and for Cmax were 1.9 fold greater (90% CI 1.6-2.6) following BEC-HFA than BEC-CFC.

CONCLUSIONS: Our data in healthy volunteers would not be consistent with the manufacturers' recommendation for a microgram equivalent (1:1) nominal dose switch between these HFA and CFC formulations. Further well designed trials are required in asthmatic patients to properly define their respective dose-response relationships for antiasthmatic and systemic adverse effects.