Harmonisation of Sterility Assessment for Autologous Serum Eyedrops in Switzerland

Although inexpensive and fast, ABC, widely used internationally for sterility assessment of ASED, had to be rejected, as none of the laboratories with a Swissmedic licence for sterility testing of finished medicinal products offer an ABC system. In addition, as an alternative method according to Ph. Eur. it would have required complex and expensive validation of the method with proof of accuracy, specificity, limit of detection, robustness, suitability and equivalence to the pharmacopoeia method. As part of the suitability assessment of the DI, serum was found to inhibit the growth of Pseudomonas aeruginosa. DI requires appropriate neutralisation of the antimicrobial activity of the serum prior to sterility testing, which is not possible and therefore DI was not considered suitable. The most expensive and time-consuming method, MF, was selected. Suitability tests were performed in triplicate for Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Clostridium sporogenes, Candida albicans and Aspergillus brasiliensis. MF was deemed suitable for the detection of bacterial and fungal strains, with antimicrobial activity of the product eliminated under the test conditions.