Improved virus safety and purity of a chromatographically produced factor IX concentrate by nanofiltration

A virus removal system based on tangential flow filtration was introduced into a Factor IX production process. Beside the intended virus reduction potency of filter membranes, an additional purification effect could be achieved. This purification effect was evaluated in detail by means of sodium dodecyl sulphate-polyacrylamide gel electrophoresis and size-exclusion HPLC. High-molecular-mass impurities were retained by the membrane, thus increasing the specific activity of the product.