RESUMO
STUDY OBJECTIVE: To compare in vitro aerosol deposition from a beclomethasone dipropionate metered-dose inhaler (MDI) containing hydrofluoroalkane propellant with that of the MDI in combination with two common valved holding chambers (VHCs) to evaluate how these VHCs affect the respirable dose of beclomethasone dipropionate. DESIGN: In vitro aerosol deposition study. SETTING: University research center. DEVICES: Beclomethasone dipropionate hydrofluoroalkane MDI alone, the MDI with OptiChamber VHC, and the MDI with AeroChamber-Plus VHC. INTERVENTION: The respirable dose (1-5-microm aerosol particles) of beclomethasone dipropionate was determined by sampling 10 80-microg actuations from five runs with each configuration (MDI alone, MDI with OptiChamber, and MDI with AeroChamber-Plus), using a well-established in vitro cascade impactor method. MEASUREMENTS AND MAIN RESULTS: Beclomethasone dipropionate aerosol was washed from the impactor with 50% methanol and quantified by means of high-performance liquid chromatography. Differences among outcomes were determined by using analysis of variance. Mean beclomethasone dipropionate respirable dose from AeroChamber-Plus (27.2 +/- 10.0 microg/actuation) was not significantly different (p>0.05) from that of the MDI alone (29.0 +/- 7.0 microg/actuation). OptiChamber respirable dose (12.8 +/- 6.0 microg/actuation) was less than half that produced by either the AeroChamber-Plus or the MDI alone (p=0.013). CONCLUSIONS: The OptiChamber and AeroChamber-Plus VHCs do not demonstrate equivalent in vitro performance when used with a beclomethasone dipropionate MDI that contains hydrofluoroalkane propellant. The respirable dose of beclomethasone dipropionate aerosol from the hydrofluoroalkane MDI was decreased by only 6% when the MDI was mated to an AeroChamber-Plus VHC and by 56% when used with an OptiChamber VHC.