The granulation of ternary mixtures: the effect of the wettability of the powders.

Granules have been prepared by a standard method from ternary mixtures of lactose, boric acid and either sulphanilamide, heavy kaolin or salicylic acid, using an aqueous solution of polyvinylpyrrolidone as binder. The granules were examined for size distribution and for the work required to crush larger granules from each batch. For the same binder volume the mean granule sizes and resistance to crushing of the granules increased as the wettability of the third component increased. The detailed results are discussed in relation to powder wetting and the packing properties of powder mixtures.