Development of Large‐Scale Fractionation Methods

Abstract

To increase purity and potency of [human] antihemophilic facoptor (AHF) concentrate prepared by the American Red Cross method, the following modifications were introduced. A cold extraction step was incorporated to remove cold-soluble impurities. The cryoprecipitate (cryo) was extracted with 0.02 M Tris buffer, pH 7.0 (4 ml/g cryo) at 0.degree. C. Factor VIII loss in this step was negligible. AHF was then recovered from the cold-insoluble portion of the cryo by extraction at 21.degree. C with the same buffer. To increase the AHF concentration, this 2nd extraction step was carried out with a smaller buffer volume (2 ml instead of 3-4 ml/g cryo). The subsequent steps, deprothrombinization, filtration and lyophilization were essentially unchanged. To further increase factor VIII concentration, the dried AHF concentrate was reconstituted to 40 rather than 50% of the initial volume. AHF concentrate prepared on a large scale by this method was 20- to 3-fold concentrated and 40- to 50-fold purified over plasma at a recovery of about 250 factor VIII units/l of plasma. The final product was readily soluble, clear and almost colorless upon reconstitution.