Chemical stability, extemporaneous

The risk due to instability is especially relevant for stock batches for extemporaneous products that are immediately administrated to a single patient at least physical stability and a short term chemical stability has to be guaranteed. 

Suppositories prepared as extemporaneous preparations following a non-standardised formula, having an unknown chemical or physical stability, should immediately be dispensed to the patient who gets a maximal usage period of 1 month only (see Sect. 22.7.2) if classified as semisolid preparation. If the patient only takes a suppository on demand a usage period of 1 month is very short and it may be justified to consider fiiem to be comparable to a dry dosage form with an arbitrarily chosen maximum usage period of 6 months. 

Extemporaneous preparations, with unknown or uncertain chemical or physical stability, carmot be kept on stock in the pharmacy. They have a maximum usage period according to Table 22.15, but this period is not more than 1 month for liquid and semisolid preparations, and not more than 6 months for dry forms. If the formula is similar to a standardised one, the maximum shelf life of that standardised formula can be used. 

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