The distribution of components in the different size fractions of granules prepared from binary mixtures.

Boric acid, sulphanilamide and citric acid have been mixed separately with lactose and then granulated by massing and screening. The granules have been fractionated by sieving and each fraction has been analysed for lactose content. The effect of premixing time, massing time, binder volume and ratio of components on the distribution of lactose between size fractions of granules prepared from lactose: boric acid mixtures has been investigated. Uneven distribution of lactose has been found for all blends examined. There is a premixing time and massing time that gives the optimum distribution of lactose for any given blend and binder volume. Increased binder volume in some cases improves granule uniformity. The proportion of lactose in the blend has a major effect on the distribution of this component in the granules, as does the particle size of the lactose. Granules prepared from blends of lactose with sulphanilamide and with citric acid were also examined for lactose distribution.