Abstract
Since the mixing of many kinds of granules is necessary for the manufacture of solid dosage forms, the determination of their mixing limit is very important. Equations to calculate the theoretical mixing degree were obtained by Lacey and Stange for homogenous particles and for particles with a grain size distribution in binary systems. However, it became clear that the theoretical values thus obtained are very different from the experimental ones for the mixing of two kinds of granules with different grain size distributions. Hence, by assuming space filling with target granules of small size and by utilizing the experimental mixing values, new equations were obtained. The resulting theoretical values were in fair agreement with the experimental ones. Thus, it is considered that the mixing degree was affected not only by variation based on the random arrangements of particles, but also by the grain size distributions of the target particles in the mixing of granules with different grain sizes.
