Physical aspects of wet granulation III. effect of wet granulation on granule porosity

Abstract

The porosity of granules produced by wet granulation has been studied using mercury porosimetry. Granule pore size distribution appears to be bimodal, with a population of micropores and macropores. Pore surface area varies with kneading time, going through a maxima at a point where physical properties such as flow and bulk density also exhibit a maxima. True granule density displays a direct relationship to rate of flow. The information in general supports the postulate that equilibrium microporous granules are formed first in the wet granulation process, followed by consolidation with subsequent formation of microporous twins and agglomerates.