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AssigneeCentral Blood Laboratories Authority
InventorLowell Winkelman
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Efficient precipitation and removal of the proteins fibrinogen and fibronectin from blood plasma fractions, expecially cryoprecipitate, while leaving high yields of blood coagulation factor VIII in the supernatant. This is achieved by the addition of at least 0.15 mg, preferably 0.3-0.9 mg, of a sulphated polysaccharide, especially heparin, per ml of buffered plasma fraction solution while maintaining the temperature of the solution during fibrinogen/fibronectin removal at more than 15.degree. C., preferably 20.degree.-35.degree. C. Lyophilised factor VIII preparation prepared from the factor VIII-rich supernatant product of the invention are suitable for heat treatment at, for example, 70.degree. C. for 24 hours to inactivate blood-born viruses without significant generation of insoluble denatured protein by-products.
A method of preparing a FVIII-containing preparation which includes the steps of precipitating fibrinogen and fibronectin from a buffered solution of FVIII-containing blood plasma fraction by the dissolution of a SPS, and removing the precipitate from the FVIII-containing supernatant, characterised in that the amount of SPS added to the plasma fraction is at least 0.15 mg of SPS per ml of the buffered solution and further characterised in that the temperature of the buffered solution during the precipitation and removal of the fibrinogen and fibronectin is maintained at more than 15.degree. C.
A method of preparing a FVIII-containing preparation having an enhanced specific activity of FVIII, comprising the steps of precipitating fibrinogen and fibronectin from a buffered solution of cryoprecipitate at pH 6 to 8 by the dissolution of a SPS, removing the precipitate from the FVIII-containing supernatant, precipitating FVIII from the supernatant with a protein precipitant in the presence of salts, re-dissolving the FVIII precipitate, and converting the redissolved FVIII into a form which can be stored, characterised in that the amount of SPS added to the cryoprecipitate is at least 0.15 mg of SPS per ml of the buffered solution and further characterised in that the temperature of the buffered solution during the precipitation and removal of the fibrinogen and fibronectin is maintained at more than 15.degree. C.
Dependencies are inferred from the claim text.