The chemical compatibility of the different membrane materials and of the most frequently used product ingredients is known and published by filter suppliers. If compatibility with a particular ingredient is unknown or doubtful, specific tests can reveal structural changes to the membrane, the effects on integrity test values, or the potential impact on a membrane’s bacterial retention. Process-specific filter validation allows identification of potential effects on the final product, such as by verifying the concentration of the ingredients in the first vials.
In general, binding tests are performed to ensure that the filter membranes do not remove any valuable components from the end product (e.g., the protein). Extractable and leachable tests of the filter membrane ensure the end product is not contaminated with the filter material. A chemical compatibility test is crucial to meet the requirements of organic solvents, or certain pH conditions. Furthermore, flow-rate tests are important for filtering fluids with high viscosity.