RESUMO
OBJECTIVE: The primary objective was to test the comparability of the pharmacokinetics of beclomethasone dipropionate (BDP) delivered from a pressurized extrafine solution formulation in two inhalation devices in children with asthma. One inhaler was actuated using the press and breathe (P&B) technique and the other was breath-actuated (AH); both inhalers used HFA-134a as propellant. METHODS: Eighteen children aged between 9 years and 12 years entered and completed the study; written informed consent was obtained from all patients and their legal guardians. Each patient received, according to a randomized three-period crossover design, 200 microg BDP as four inhalations from 50 microg/actuation P&B, 200 microg BDP as four inhalations from 50 microg/actuation AH, and 400 microg BDP as four inhalations from 100 microg/actuation AH. Each patient was instructed on the proper use of each device once, at the screening visit. Patients self-administered all inhalations at the same time of day during the study without further coaching. Blood samples were collected for 24 h during each period to assay for the presence of BDP and metabolites. The log-transformed pharmacokinetic data were compared using a confidence-interval approach. RESULTS: Almost all the BDP-derived material in the plasma was the active metabolite beclomethasone 17-monopropionate; pharmacokinetic analyses were only performed for this metabolite. The ratios each of the pharmacokinetic parameters maximum plasma concentration (C(max)) and area under the plasma concentration-time curve (AUC), between the AH and P&B inhaler devices, were 0.94 and 1.1, respectively, and the corresponding 95% confidence intervals demonstrated comparability of the devices. Dose proportionality of C(max) and AUC between the 200-microg and 400-microg doses was similarly shown. About twice as many inhalation errors occurred during the P&B administration as during the AH periods, but the incidence was still low and did not result in any change in pharmacokinetics. CONCLUSION: The rate and extent of drug absorption was comparable from the P&B and AH inhaler devices in children with asthma. Dose proportionality was also observed.