THE FEASIBILITY OF USING CONCENTRATES CONTAINING FACTOR-IX FOR CONTINUOUS-INFUSION

We have investigated the feasibility of continuous infusion of undilut ed factor IX (FIX) over several days using minipumps. The stabilities of seven different reconstituted FIX products were substantially bette r than those declared by the manufacturers. Several concentrates maint ained factor activities above 80% of baseline for the entire period of 4 weeks at 4-8 degrees C as did one product at 20-23 degrees C. At 37 degrees C the latter concentrate was stable for at least 1 week. The stability seemed to correlate with the purity of the product. Analysis of two prothrombin complex concentrates by gel electrophoresis demons trated degradation of prothrombin to prethrombin-1 and fragment 1 at 3 7 degrees C and in one of the concentrates also at 20-23 degrees C. In two FIX concentrates the corresponding analysis did not reveal any de gradation. Four patients were treated with continuous infusion with a pure FIX concentrate (Mononine(TM), Armour) after surgery or for serio us haemorrhage (two each) with good haemostatic effect, an initial pro gressive decrease of the FIX clearance, and no side-effects. Continuou s infusion with FIX, using a minipump and undiluted reconstituted fact or, is therefore feasible and effective, and can be conveniently prepa red for several days at a time. Pure FIX products are more stable and probably safer for this purpose.