The Pharmaceutics and Compounding Laboratory
Preparation of Suppositories

When the Density Factor is Not Known

When bases other than cocoa butter are used, or when the density factor for a drug in cocoa butter is not known, then the density factor can be estimated by calculation or experimentally determined by the double casting technique.

The weight of the blank suppository is easily determined. A portion of the suppository base is melted, poured into the suppository mold and allowed to congeal. The suppositories are removed from the mold, and the total weight of the suppositories is determined. The average weight of the blank suppository is determined by dividing the total weight by the number of suppositories.