The objective of this investigation was to evaluate the USP dissolution apparatus. The test drug products used were two brands of chlorpromazine HC1 tablets which had been previously evaluated clinically. On the basis of the dissolution characteristics obtained with these and several other products, it was concluded that (a) simulated gastric fluid was the media of choice for tablets containing chlorpromazine HC1, (b) the geometry of the dissolution vessel had no significant effect on dissolution characteristics, (c) a ten mesh basket be substituted for the 40 mesh basket now specified by the USP, (d) the depth of the basket in the media should be 3 cm. rather than the 2 cm. now specified, (e) the pH effect of the media should be studied carefully before setting specifications for a drug product, (f) that the basket should be inserted into the media while rotating in order to prevent variations in dissolution characteristics, (g) the method is reproducible under standardized conditions, and (h) the method is as good or better than three other dissolution methods described in the literature. This abstract represents the true contents of the thesis submitted. / Pharmaceutical Sciences, Faculty of / Graduate