INTRODUCTION: Use of high global warming potential propellants (e.g., HFA-134a) for pressurised metered-dose inhalers (pMDIs) is being phased down. Beclometasone dipropionate (BDP) is approved for the treatment of asthma in several countries via an HFA-134a propellant pMDI. This is being reformulated using the low global warming potential propellant HFA-152a. Two studies compared BDP pharmacokinetics delivered via pMDI using HFA-152a vs HFA-134a. METHODS: Both studies (N=71/study) were single-dose (four inhalations of BDP), randomised, double-blind, crossover (Study 1, four-way
Study 2, two-way), in healthy volunteers. In Study 1, subjects inhaled BDP via HFA-134a pMDI in two periods (200 μg/actuation in one period, 100 μg/actuation in the other) and HFA-152a pMDI in the other two (200 or 100 μg/actuation). In Study 2, subjects inhaled BDP 200 μg/actuation via HFA-134a or HFA-152a pMDI using a spacer device. pMDIs containing HFA-152a and HFA-134a were compared in terms of lung availability (BDP comparisons) and total systemic exposure (beclometasone-17-monopropionate comparisons [B17MP
active metabolite of BDP]), with bioequivalence concluded if the 90% confidence intervals (CIs) of the geometric mean ratios of maximum plasma concentration (C RESULTS: BDP C CONCLUSIONS: Overall, bioequivalence was confirmed of HFA-152a and HFA-134a for BDP 200 μg/actuation, with and without a spacer. Although bioequivalence of the two formulations cannot be formally concluded for BDP 100 μg, the minimal difference suggests the two formulations can be considered therapeutically equivalent.