EVALUATION OF SOME PARAMETERS INFLUENCING THE DRUG-DELIVERY FROM A DRY POWDER INHALATION DEVICE USING AN IN-VITRO MODEL OF THE HORSE AIRWAYS

The aim of this study was to determine the effect of breathing pattern , air humidity and position of the device on the delivery of an aeroso l generated by a dry powder inhalation (DPI) device (Inhalator M(R)). The in vitro inhalation study was performed using the cascade impactio n method (Andersen Sampler) adapted to imitate nasal breathing. The am ount of ipratropium found in the device, the artificial upper airways and the six stages of the Andersen Sampler was measured using high pre cision liquid chromatography. Stage 1 of the Andersen Sampler was cons idered to be the respirable fraction and stages 2 to 6 to be the non-r espirable fraction. Tt was concluded that the theoretical respirable f raction of ipratropium obtained after DPI through Inhalator M(R) was i nfluenced by relative air humidity, air flow and the position of the d evice, whereas the number of successive inspirations and the duration of inspiration did not affect this fraction of the drug.