Author Archives: Yanglin Mok

Figure 1: Design and layout of Millidisk and Millipak barrier filters

Best Practices for Critical Sterile Filter Operation: A Case Study

A number of regulatory guidelines recommend preuse integrity testing of critical sterilizing liquid filters for aseptic processing (1–3). Before sterilization, a preuse test will confirm that a filter is installed properly and was not damaged during shipment or handling. Performing a preuse test after sterilization detects damage that may have occurred during the sterilization cycle. Testing after sterilization limits risk, so it is a practice applied based on risk assessment. Because it is perceived to reduce business loss risk, preuse…

Sterilizing-Grade Filter Sizing Based on Permeability

    Sterilizing filtration renders biotherapeutics free of biocontamination. In many cases, sterilizing-grade filters also reduce bioburden or facilitate closed or aseptic processing. They are used to filter active pharmaceutical ingredients (APIs), formulated bulk, cell culture media, buffer, additives, process intermediates, and so on. Such applications are often critical for ensuring a successful batch operations. Nonetheless, a significant amount of time and resources are typically not devoted to establishing filter sizing requirements for “simple” applications such as buffer filtration. Here,…