Compounding Suppositories and Lozenges

Suppository Compounding

Suppositories are solid dosage forms designed for insertion into body cavities (rectal, vaginal, or urethral) where they melt or dissolve to deliver medication. Common bases include cocoa butter (melts at body temperature) and polyethylene glycol (PEG) bases that dissolve in body fluids.

The displacement factor is important when calculating how much base to remove to accommodate the active ingredient. If a mold holds 2 g of cocoa butter and the drug has a displacement factor of 1.5, each drug dose displaces 1.5 times its weight in base.

Lozenge and Troche Preparation

Lozenges (troches) are solid dosage forms that dissolve slowly in the mouth. They are commonly made with a PEG or sugar base. The active ingredient is mixed into the melted base, poured into molds, and allowed to harden.

Temperature control is critical: the base must be melted at the lowest effective temperature to avoid degrading heat-sensitive active ingredients. Proper mixing ensures uniform drug distribution throughout each lozenge.

Study These Topics

Specialized dosage forms appear on the PTCB exam. Review with flashcards and take practice exams.