The use of a starch obtained from Dioscorea abyssinica in tablet formulations .1. The native starch as a binder and disintegrant

Some physico-chemical properties of Dioscorea starch (obtained from Ethiopian plant Dioscorea abyssinica) were investigated. The results were related to its binding and disintegrating abilities in tablet formulations and compared to those of maize starch. Dioscorea starch was found to have greater amylose content, larger particle size, higher moisture sorption property and mucilage viscosity than that of maize starch. Formulation studies on lactose monohydrate and dicalcium phosphate dihydrate tablets containing Dioscorea starch as a binder and disintegrant were conducted. Tablet crushing strengths, friabilities, disintegration times and porosities were measured and compared with the values of those tablets made with maize starch. The results show that Dioscorea starch has practically similar binding ability to that of maize starch, although tablets prepared with it exhibited somewhat lower crushing strength and higher porosity. Its disintegrating efficiency depended on the formulations. As compared to maize starch it exhibited faster disintegration time in lactose tablets but longer disintegration times in dicalcium phosphate tablets. The disintegration times were influenced by the amount of the disintegrant, the level of compression force and the rate of water uptake by the tablets.