A Quality by Design Approach to Microbial Retention Validation

Regulatory and manufacturing requirements exist for performance of product-specific microbial retention testing on sterilizing filters. The implementation of a Quality by Design approach to sterilizing filtration supports a paradigm that would obviate the need for product-specific testing for early-stage products that do not have the quantity of material required to perform such testing easily and efficiently. Process and product parameters were varied to determine their effect on microbial retention to define a design space. To minimize the burden of filter validation retention studies for early-stage (Phase 1) manufacturing, it is recommended that manufacturers perform a risk assessment to confirm their product and process conditions are within the established design space. For later stage product development prior to marketing authorization, product-specific filter validation testing is expected.