3/4 March 2020
In the current version 29.2 of Pharmeuropa the European Directorate for the Quality of Medicines & Health Care (EDQM) published a revision of chapter 5.1.8. Microbiological Quality of Herbal Medicinal Products for Oral Use and Extracts Used in their Preparation. One sentence was added to indicate that medicinal products containing live yeasts or bacteria (live biotherapeutic products, LBP) are not within the scope of the chapter.
For these products, separate monographs were developed. Namely in chapter 2.6.36 and 2.6.38 the methods for enumeration and specified microorganisms are described while the acceptance criteria are specified in the general monograph Live Biotherapeutic Products (3053).
The chapter 2.6.36 and 2.6.38 are pendant to chapter 2.6.12 and 2.6.13, i.e. they describe the general method to be used to enumerate mesophilic bacteria and yeast/molds that may grow under aerobic conditions and tests for specified microorganisms. For both chapters, several links to chapter 2.6.12/13 are given, e.g. the media to be used for testing of LBP are the same as the ones described in chapter 2.6.13. As methods only the plate count or most-probable-number (MPN) are recommended. Several details on the choice of method, test strain preparations, negative control or growth promotion of the media are described, and at least some of this information can be helpful for laboratories performing tests according to 2.6.12/13. As for 2.6.12/2.6.13 the most important part is to show the suitability of the testing method in the presence of the LBP which is the most challenging part. Here the chapters indicate to use e.g. antibiotics or specific growth media to inhibit or limit growth of the LBP microorganism. It is explicitly mentioned that if none of the procedure described can be demonstrated to be satisfactory, an alternative procedure must be developed.
If inhibition occurs during the suitability test separate paragraphs describe how to proceed. Here the Ph. Eur. clearly states that such an adaption must be appropriately validated. Specific methods for LBP containing lactic bacteria, Bacillus clausii, B. cereus, Saccharomyces cerevisiae, Escherichia coli, Enterococcus species, yeast or molds are described. Very helpful is the decision tree on how to proceed to establish a suitable method of testing in both chapters.