Sterility testing of difficult-to-filter and growth-inhibiting samples.

摘要

An important question for many companies in the pharmaceutical industry is whether to use membrane filtration or direct inoculation of liquid culture when developing new sterility testing methods. USP <71> recommends membrane filtration as the preferred method for sterility applications whenever the nature of the product permits. Filtration methods have the advantage of allowing large sample volumes to be tested for meeting USP requirements and recommendations. Also, for products with antimicrobial activity, filtration allows rinsing and thus the removal of the inhibitory characteristics of the product. While membrane filtration is often straightforward, some sample types can be challenging. These include difficult-to-filter viscous oils, water-in-oil emulsions and fatty base ointments as well as samples containing substances that inhibit microbial growth. High-density cell cultures can also prove problematic. However, membrane filtration can be made to work for most such products perfectly well.