Effects of inspirease holding chamber on the deposition of metered dose inhalation aerosols.

A modified cascade impaction method as well as a radiotracer technique has been used to assess the effects of the 700 ml collapsible holding chamber (InspirEase) on the in vitro and in vivo deposition of inhaled metered dose aerosols. The in vitro deposition of beclomethasone dipropionate 250 micrograms/dose aerosol administered either through the conventional aerosol actuator with the short plastic mouthpiece or through the InspirEase-device was evaluated with the modified cascade impactor which method imitated the human respiratory tract. For the in vivo study the disodium cromoglycate particles were labelled with pure gamma-radiator 99mTc using a coprecipitation technique based on spray drying. The deposition of the inhaled disodium cromoglycate particles in the human respiratory tract after administration of the drug doses from the devices tested was determined by means of gamma camera. InspirEase increased both in the in vitro and in vivo tests the fraction of the drug dose deposited into the therapeutically significant regions of the respiratory tract. In addition, the therapeutically insignificant fraction deposited in the upper passages and mouth clearly decreased. Thus using the InspirEase holding chamber not only a better lung penetration of the inhaled drug particles can be achieved but also the local side effects would be decreased.