The effect of starch type, concentration and distribution on the penetration and disruption of tablets by water

The effect of starch type, and its concentration and distribution, on the pore structure of tablets of aspirin and magnesium carbonate has been measured using air permeability and liquid penetration techniques. The addition of starch had no significant effect on the pore structure of the dry tablet but caused disruption and alteration of this structure when penetrated by water. When each starch was incorporated into the granules in wet massing the rate of disruption decreased in the order potato, maranta, wheat, corn, waxy corn and rice; but a more complicated pattern was produced when the starch was added to the granules as a pre-dried powder. Maximum breakup efficiency of magnesium carbonate tablets was produced when 10 % potato starch was incorporated internally and the tablet compacted to a porosity of 28 %.