Author Archives: Priyabrata Pattnaik

Figure 1: General polysaccharide conjugate vaccine process (UF/DF = ultrafiltration/diafiltration)

Membrane-Based Clarification of Polysaccharide Vaccines

Polysaccharide vaccines are essential for protection against infectious diseases, which remain an alarming cause of mortality. The first glycoconjugate vaccine for use in humans — a Haemophilus influenzae type b (Hib) conjugate — was licensed in the United States in 1987. This vaccine successfully reduced the incidence of invasive Hib disease in childhood and led to the further development of conjugate vaccines designed to prevent infection by other encapsulated bacteria (1). Polysaccharides are relatively complex carbohydrates made up of many…

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…

Integrity Testing of Ultrafiltration Systems for Biopharmaceutical Applications

    Ultrafiltration (UF) is a membrane-based separation technology commonly used in the biopharmaceutical industry for concentration or diafiltration of protein solutions to remove low–molecular-weight (LMW) impurities or exchange buffers. The nominal MW limit of UF membranes ranges from 1,000 Da (1 kDa) to 1,000,000 Da (1,000 kDa). A target product is retained by the membrane while lower-MW solutes or impurities pass through (1). For a target product with a smaller MW than the impurities, separation is accomplished by allowing…