Factor VIII concentrate prepared from blood donors stimulated by intranasal administration of a vasopressin analogue.

With an interval of eight weeks between collections, blood was drawn twice from 120 blood donors. At one of the donations, 0.25 ml of synthetic vasopressin, (DDAVP, 1300 micrograms/ml), was administered intranasally 60 minutes prior to collection of the blood. No drug was given at the other donation. The yield of factor VIII clotting activity (VIII:C) and factor VIII antigen (VIIIR:Ag) was compared in blood drawn from the treated and untreated donors. To prevent degradation of VIII:C by fibrinolysis, tranexamic acid was added to the plasma from treated donors immediately after separation from the red blood cells. Plasma from treated donors and the derived Cohn fraction I-O contained approximately twice as much VIII:C as plasma and fraction I-O from untreated control donors. The concentration of VIIIR: Ag was also increased in fraction I-O made from plasma from treated donors, however to a lesser degree. The in vivo properties of factor VIII concentrates made from each group of donors were studied. Half-life in plasma and recovery of VIII:C were identical. Thus, intranasal synthetic vasopressin may be used to increase the yield of VIII:C in production of factor VIII concentrates.