title: In vitro effect of a holding chamber on the mouth-throat deposition of QVAR (hydrofluoroalkane-beclomethasone dipropionate).
abstract: Experimental work has been conducted on the effect of an add-on holding chamber (Aerochamber) on the characteristics of deposition in a mouth-throat model using 100-microg hydrofluoroalkane-beclomethazone dipropionate (QVAR) metered dose inhalers at inhalation flow rates of 28.3, 60, and 90 L/min. A filter or cascade impactor downstream of the mouth-throat collected aerosol not depositing. The results emphasize the important well documented effect of a valved holding chamber (VHC), in reducing drug deposition in the mouth-throat. This reduction is largest (24% of nominal dose) at the lowest flow rate tested, becoming insignificant at 60 L/min. Total amount of drug delivered distal to the mouth-throat increases with flow rate both with and without a holding chamber, increasing from 42% to 69% of the nominal dose without a VHC as the inspiratory flow rate increases from 28.3 to 90 L/min. The effect of the holding chamber on post mouth-throat delivery was small, reaching significance only at the highest flow rate (90 L/min), where an increase by 8% of the nominal dose was observed. No significant effect on MMAD of beclomethasone-dipropionate occurred when the holding chamber was used. An argument based on the interaction between induced turbulence and particle inertia is used to shed light on the above observations.
authors.affiliation: Aerosol Research Laboratory of Alberta, Department of Mechanical Engineering, Edmonton, Canada.
authors.forename: Muhib F
authors.initials: MF
authors.lastname: Rahmatalla
authors.forename: Peter C
authors.initials: PC
authors.lastname: Zuberbuhler
authors.forename: Carlos F
authors.initials: CF
authors.lastname: Lange
authors.forename: Warren H
authors.initials: WH
authors.lastname: Finlay
mesh_terms: D000336:Aerosols / Q000008:administration & dosage*; D000704:Analysis of Variance; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage*; D001507:Beclomethasone / Q000008:administration & dosage*; D004867:Equipment Design; D066298:In Vitro Techniques; D009055:Mouth; D009330:Nebulizers and Vaporizers; D010614:Pharynx
chemical_list: D000336:Aerosols; D018927:Anti-Asthmatic Agents; D001507:Beclomethasone