Oral administration of factor VIII concentrate preparation in von Willebrand's disease.

We investigated on how to effectively administer orally factor VIII preparation to two patients with von Willebrand's disease as volunteers, and the following results were obtained: Bleeding time and aPTT were shortened, but no change of PT was observed. Factor VIII:C increased slightly, but no significant increase was observed in factor VIIIC:Ag. The recovery of factor VIII:C was 19-40%. Factor VIIIR:Ag increased slightly, but no changes of factor VIIIR:RCo were observed. In the Ristocetin induced platelet aggregation (1.5 mg/ml of ristocetin), the collected aggregation abilities were not clear. The factor VIII concentrate preparations, entrapped with liposome, were absorbed from the intestines.