Effect of intergranular versus intragranular cornstarch on tablet friability and in vitro dissolution

The effect of blending dry cornstarch versus wet granulation with the drug and other excipients on friability and in vitro dissolution of a ticlopidine hydrochloride tablet formulation was studied. The friability of the tablets was reduced by wet granulating cornstarch with the drug and other excipients compared with the dry blending. The dissolution rate and the tablet-to-tablet variability was improved by incorporating cornstarch in the wet-granulation stage. The lactose placebo tablets, which were wet granulated with either a binder solution or without a binder, also showed reduced tablet friability due to the incorporation of cornstarch in the wet-granulation step. Examination of the tablet cross sections under the scanning electron microscope indicated clumping of starch grains when starch was blended in the dry form. Starch grains were well embedded in the other materials of the tablet and not readily visible when starch was wet granulated with the other excipients. This results in better bonding, fewer weak points, and better homogeneity of the starch disintegrator within the tablet, which accounts for better friability and improved dissolution.