A NOVEL DRY POWDER AEROSOL DELIVERY SYSTEM FOR REAL-TIME MEASUREMENT OF THE INHALED DOSE TO LARGE ANIMALS (DOGS)

Pharmaceutical drugs can be administered by inhalation to experimental animals as a dry powder aerosol. In such experiments the aerosol is c ontinuously generated from a dry powder generator and inhaled by the e xperimental animal. The drug delivery system can be used to study the effects of drugs either locally, in the airways and lung, or systemica lly. With conventional methods, however, it has not been possible to m easure the inhaled mass and calculate the accumulated inhaled dose nor to perform the measurements in real time. The method evaluated here, called FIDO, was thus developed to more accurately estimate an inhaled dose than the methods used previously. To validate the feasibility of FIDO, it was compared with two conventional filter methods. Inhalatio n studies on five dogs were performed at three different aerosol conce ntrations corresponding to low, medium, and high inhaled doses. The do gs were exposed in a random manner four times at each dose level. in s eparate studies the generator performance along with the dog minute vo lume variation and their influence on the accuracy of FIDO was also in vestigated. A statistical evaluation of the results was done, comparin g the analytically determined mass on filter, from the dog studies, wi th the inhaled dose estimated by the two conventional filter methods a nd the inhaled dose measured by FIDO. For each method, the mean value, 95% confidence interval, and standard deviation was computed. The dat a obtained supports the hypothesis that FIDO seems to be more accurate in calculating the inhaled dose compared to the other two methods. (C ) 1997 American Association for Aerosol Research.