Development of Large‐Scale Fractionation Methods

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Abstract
A modification of the method of Johnson for the preparation of clinical factor VIII concentrates is described by which a concentrate may consistently be obtained from 100‐liter plasma volumes at a potency of 10 factor VIII units/ml or greater and a specific activity of 0.3 factor VIII units/mg protein (18 to 20‐fold purification over plasma) with a final recovery close to 40% of the actual factor VIII activity of the starting plasma; these potency and purity values exceed the minimum requirements of the Division of Biologics Standards of the National Institutes of Health.The major changes that were introduced were: (a) an accelerated cryoprecipitation step to minimize the risk of pyrogen formation; (b) the elimination of ethanol to avoid coprecipitation of nonspecific proteins, thereby improving the purity of the final concentrate; (c) the reduction of the tris extraction volume to obtain a higher final factor VIII potency and smaller volumes for lyophilization; (d) the control of pH during the Al (OH)3 adsorption step to improve the purity and filtrability of the concentrate; (e) the removal of the Al (OH)3 precipitate by a foamless centrifugation technique to minimize denaturation of the factor VIII in the supernatant; and (f) the use of new clarification media to facilitate the final sterile filtration step.