Introduction to Suppository Testing

The suppository is a more common and accepted dosage form in Europe than in the USA. This probably explains why pharmacopoeial references to specific test methods relating to suppositories and associated dosage forms are in the main confined to the European Pharmacopoeia.

Hydrophilic suppositories are made from a water soluble base such as polyethylene glycol which dissolves in the rectal or vaginal fluids. The rate of drug release (dissolution) of such suppositories can be measured using the standard paddle, basket or flow through methods described in USP Chapter <711> and Ph. Eur. 2.9.3.

Lipophilic suppositories, on the other hand, are made from a greasy base, such as cocoa butter, which melts at body temperature. Various methods have been described to measure the rate of drug release (dissolution) from lipophilic suppositories including a modified basket method, a paddle method using a sinker and a modified flow through cell with dual chambers described in Ph. Eur. 2.9.42.

In addition, the European Pharmacopoeia 7th Edition makes reference to two other technical procedures relating to the disintegration and softening times of suppositories, namely:

2.9.2 Disintegration of suppositories and pessaries
2.9.22 Softening time determination of lipophilic
suppositories

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