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Three methods of drying pharmaceutical granules have been investigated using tray, fluidized-bed and intra-red dryers. A comparative study of the dryers' thermal efficiency and drying time and their effects on granule and tablet properties is presented. Fluidized-bed and intra-red dryers were found to have a 2- to 5-fold advantage in thermal efficiency over tray dryers in granule drying with the fluidized bed dryer being the most efficient. The granules dried by these two dryers also produced of better physical properties (quality) than those of tray dryer, in the formulation of tablets of both soluble and insoluble organic medicinal substances.

The effect of temperature on the binding efficiency of yam starch and cassava starch pastes has been investigated. Starch pastes prepared at different temperatures were used to granulate lactose powder and the resulting granules and tablet properties were evaluated. Increased average granule size and decreased percentage fines were observed as the pasting temperature was increased upto a certain level and then there was a decrease in average size and increase in amount of fines as the pasting temperature was further increased. Granules prepared with yam starch pastes exhibited relatively lower amount of fines and larger average granule size. The corresponding tablets also showed higher crushing strength values and were less friable. Although the disintegration time of tablets was found to increase with the temperature of pasting of both the starches, no relationship between the pasting temperature and the crushing strength of tablets was observed. The release of amylose/amylopectin from starch grains, the amylopectin chain length and the amount of free molecular components as the pasting temperature increased are believed to be the factors contributing to the increased binding efficiency of the starch pastes.