title: Development of large-scale fractionation methods. VI. An improved method for preparation of antihemophilic factor.
abstract: To increase purity and potency of the antihemophilic factor (AHF) concentrate prepared by the American Red Cross method, the following modifications were introduced: (1) 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 degrees C. Factor VIII loss in this step was negligible. (2) AHF was then recovered from the cold-insoluble portion of the cryo by extraction at 21 degrees C with the same buffer. To increase the AHF concentration, this second 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 30-fold concentrated and 40- to 50-fold purified over plasma at a recovery of about 250 factor VIII units per liter of plasma. The final product was readily soluble, clear and almost colorless upon reconstitution.
mesh_terms: D000327:Adsorption; D005591:Chemical Fractionation / Q000379:methods; D055598:Chemical Phenomena; D002621:Chemistry; D003080:Cold Temperature; D004591:Electrophoresis, Polyacrylamide Gel; D005169:Factor VIII / Q000302:isolation & purification* / Q000592:standards; D006801:Humans; D011309:Preservation, Biological; D012995:Solubility
chemical_list: D005169:Factor VIII