Vaginal solutions preservation

Just as in enemas (see Sect. 11.9.6) chemical stability may be a problem in vaginal solutions. This caimotbe avoided by choosing a different pH or another solvent as with enemas. So the active substance should be inherently stable in water. For the microbiological stabiUty of non-sterile vaginal solutions which are often concentrates for multiple dosing, preservation may be necessary if the concentrate doesn t meet the test on preservation effectiveness (see Sect. 32.8). Methyl parahydroxybenzoate can be used as a preservative. 

Non-sterile but preserved vaginal solutions may have a shelf life of 3 years after preparatiOTi, if prepared according to a standard formula and chemically and physically stable. Once opened by the patient, such vaginal solutions can be assigned an in-use period of 6 months. A concentrate diluted by the patient should be kept only 24 h after dilution. A non-standardised preserved preparatirai should not be stored in the pharmacy because the maximal shelf Ufe of say 1 month, may be reasonably needed by the patient. A diluted concentrate may be kept for 24 h after dilution. Unpreserved n(Mi-sterile vaginal solutions may have a shelf life of maximal 2 weeks and they have to be stored in a refrigerator. 

Sterile vaginal solutions are packaged in a single-dose container that can be sterilised, for instance glass (preferably class I, eventually class II) or plastic (polypropylene). Preserved concentrates, intended to be diluted before use, are usually packaged in a container of glass (class III) or plastic (polypropylene, polyethylene) meant for multiple dosing. 

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