Dissolution Profiles of Nalidixic Acid Powders Having Weibull Particle Size Distribution

Abstract

General equations were derived describing the exact dissolution profile and particle number reduction rate for powders of Weibull particle size distribution under sink conditions. Several nalidixic acid (NA) powders of Weibull distribution, having mean diameter (μ), smallest diameter (r₀), and largest diameter (R₀) values of 400, 0, and 1000μm respectively, were prepared by varying the parameters of the Weibull distribution. By means of dissolution tests of these powders, the effects of size distribution and truncation of powders, having the same mean diameters were investigated. The results of the dissolution tests were consistent with those obtained in computer simulations, so that the derived equations were assumed to be reasonable. The dissolution rate of powders of Weibull distribution, having the same mean diameter, increased as the size distribution became narrower. Upper-end truncation had more effect on the dissolution profile of the powders than lower-end truncation.