Surfactant effect on the dissolution of sulfanilamide granules

Polysorbate 80 incorporated in sulfanilamide granules was found to depress the dissolution of sulfanilamide. The largest decrease corresponded to the lowest concentration of surfactant used. Sulfanilamide granules formulated with either starch or microcrystalline cellulose also decreased the release of the drug. The effect of starch depressing sulfanilamide dissolution was greater with higher starch content in the granules. However, addition of polysorbate 80 improved the dissolution of sulfanilamide granules containing starch but not those with microcrystalline cellulose. This difference was found to be related to the ability of starch to swell and cause granule disintegration. The inclusion of polysorbate 80 in starch-containing granules produced softer and more densely packed granules which were more responsive to the swelling effect of starch.