In vivo evaluation of the new multiple dose powder inhaler and the Rotahaler using the gamma scintigraphy.

Deposition of 99mTc-labelled particles of disodium cromoglycate in the respiratory tract was evaluated after inhalation from two dry powder inhalers. The inhalers tested were a new multiple dose powder device (Chiesi Farmaceutici) and the Rotahaler powder device (Glaxo). Fractional deposition in the whole lung area, the upper respiratory passages and the stomach, as well as in the inhaler, was measured using a gamma camera. Ten healthy volunteers participated in the inhalation test. The mean, whole lung deposition of the inhaled disodium cromoglycate particles was about 9 per cent of the dose for the both devices. The deposition patterns of the inhaled drug doses in the lung area given by the devices were, however, clearly different. The Chiesi powder inhaler was more efficient in dispersing the drug particles into the therapeutically important alveolar regions of the lungs. The fraction of the dose retained in the inhaler was significantly higher for the Rotahaler than for the Chiesi powder device. On the other hand, the deposition in the upper passages was somewhat larger for the Chiesi device than for the Rotahaler. According to the deposition results of this study, a new multiple dose powder inhaler can be useful in inhalation therapy.