Method of obtaining intermediate purity factor VIII

Abstract

A method of obtaining Factor VIII which comprises (a) adding heparin to freshly obtained blood plasma collected into a calcium chelating anticoagulant or collecting blood plasma by plasma pheresis using heparin and a calcium chelating anticoagulant; (b) freezing the plasma; (c) resolubilizing the plasma; (d) isolating a cryoprecipitate from the plasma; (e) resolubilizing the cryoprecipiate; (f) adding a citrate saline heparin buffer to the resolubilized cryoprecipitate; (g) incubating the buffered, resolubilized cryoprecipitate at a temperature of from about 0.degree. to about 10.degree. C. for a time in excess of about one hour, whereby Factor VIII present in the cryoprecipitate is insolubilized using heparin precipitable cold insoluble globulin and the resulting Factor VIII rich precipitate also includes cold insoluble globulin; (h) separating the Factor VIII rich precipitate; and (i) isolating Factor VIII therefrom. The introduction of the cold insoluble globulin (CIg) step to Factor VIII production results in markedly increased yields of Factor VIII in the cryoprecipitate and, as well, in the cold-insoluble globulin obtained from the cryoprecipitate. Using this procedure, 81% of the Factor VIII is recovered in the cryoprecipitate. The cold-insoluble globulin contains 62% of the starting Factor VIII activity. A final recovery of 666 units per liter of starting plasma is therefore obtained and the amount of protein is reduced to less than 1%. In addition, the procedure can be carried out in blood donor centers, although it is also envisaged to be useful in larger scale recovery of Factor VIII procedures.

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