The Role of Binders in the Prevention of Capping within a Tablet

Abstract

The role of a dry or wet binder in the prevention of capping within a tablet was evaluated by considering the binding strength of compacts and the residual die wall pressure during compression.Capping of bucetin tablets was not prevented by adding dried colloidal silica, which increased the binding strength and the residual pressure. However, the addition of dried low-substituted hydroxypropyl cellulose, which increased the binding strength but decreased the residual pressure, prevented the capping.The effect of addition methods of a low viscosity grade of hydroxypropyl cellulose and α-starch was also investigated for bucetin and ascorbic acid tablets. The compacts showed the greatest binding strength when the binders were added in a wet state. However, the residual die wall pressure did not depend on the addition method. These results suggest that the addition of a binder in the wet method is effective for the prevention of the capping.