In vitro effect of a holding chamber on the mouth-throat deposition of QVAR (hydrofluoroalkane-beclomethasone dipropionate).
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.
Rahmatalla
Muhib F
MF
Aerosol Research Laboratory of Alberta, Department of Mechanical Engineering, Edmonton, Canada.
Zuberbuhler
Peter C
PC
Lange
Carlos F
CF
Finlay
Warren H
WH
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
D000336:Aerosols; D018927:Anti-Asthmatic Agents; D001507:Beclomethasone