Stability testing herbal preparations

If a herbal medicinal product contains combinations of several herbal substances or herbal preparations, and if it is not possible to determine the stability of each active substance, the stability of the medicinal product should be determined by appropriate fingerprint chromatograms, appropriate overall methods of assay and physical and sensory tests or other appropriate tests. The appropriateness of the tests shall be justified by the applicant. 

Assay In the case of herbal preparations with constituents of known therapeutic activity, assays of their content are required with details of the analytical procedure. Wherever possible, a specific, stability-indicating procedure should be included to determine the content of the herbal substance in the herbal preparation. In cases where use of a nonspecific assay is justified, other supporting analytical procedures should be used to achieve overall specificity. For example, where a UV/VIS spectrophotometric assay is used for anthraquinone glycosides, a combination of the assay and a suitable test for identification (e.g., fingerprint chromatography) can be used. In the case of herbal preparations where the constituents responsible for the therapeutic activity are not known, assays of marker substances or other justified determinations are required. The appropriateness of the choice of marker substance should be justified. 

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