According to different process requirements, the requirements for interception capacity are divided into the following three levels:
• The most restrictive retention requirements are required for the filtered gas to come into contact with the critical surface of the final sterile product or related equipment. For example, compressed air filtration of aseptic filling machines, respirator of sterile raw liquid storage tanks and lyophilization equipment or vacuum removal filters for sterilization pots (cabinet). Gas filters for such applications should pass liquid microbial challenge experiments whose physical integrity testing needs to be associated with liquid microbial challenge experiments.
• Moderate requirements are that the filtered gas does not come into direct contact with the exposed surface of the sterile drug, including the handling of many intermediate steps and the aeration of the fermentation process. Gas filters for such applications should challenge experiments with aerosol microbes whose physical integrity needs to be correlated with aerosol microbial challenge experiments.
• It is the least demanding for applications that only require a reduction in microbial contamination levels. Because they are generally similar to the requirements for High Efficiency Particulate Air Filter (HEPA), such filters are typically challenged with dispersed aerosols to establish retention capabilities that are acceptable.www.inocofiltration.com