In vitro characterization of various factor VIII concentrates
Yoshioka, A.; Shima, M.; Nishino, M.; Yoshikawa, N.; Fukui, H.
Arzneimittel-Forschung 37(7): 753-756
1987
ISSN/ISBN: 0004-4172 PMID: 3118888 Document Number: 295937
The in vitro properties of 5 heat-treated Factor VII (F VIII) concentrates were studied and compared with those of conventional non heat-treated concentrates with special reference to F VIII/von Willebrand Factor(vWF) activities. The heat-treated F VIII concentrates were found to contain about 25 U/ml of F VIII:C as indicated on the label, 59.5-103.3 U/ml of F VIII:Ag, 20.0-74.0 U/ml of ristocetin cofactor activity (RDof), and 67.3-96.0 U/ml of vWF:Ag. The F VIII/vWF activities in the heat-treated concentrates were almost the same as those in the 6 non heat-treated concentrates. The antihemophilic factor (AHF)-cryoprecipitate contained 2.3 U/ml of F VIII:C which was roughly equivalent to the amount of F VIII:Ag. In addition, it contained 7.3 U/ml of RCof which was equivalent to the amount of vWF:Ag. The ratio of F VIII:Ag to F VIII:C in the F VIII concentrates ranged from 2.5 to 4.4. The ratio of vWF:Ag to RCof in the concentrates ranged from 1.1 to 4.8. There were, however, no significant differences in F VIII/vWF activities between the heat-treated and the non heat-treated F VIII concentrates with two exceptions. These findings suggest that the inactivation of the biological activities of F VIII and RCof, and/or the denaturation of both the F VIII:C protein and the vWF protein antigen occurred during the production procedure, while the heat-treatment did not lead to further changes in F VIII/vWF. In Haemate the content of RCof was characteristically high and the ratio vWF:Ag/RCof was low, and, in addition, there was no difference between the heat-treated and the non heat-treated preparation. The F VIII/vWF in Haemate consisted not only of small but also intermediate and some of the large multimers, whereas in the other F VIII concentrates (with one exception) only small multimers of F VIII/vWF could be demonstrated.