Progress of in vitro factor VIII coagulant activity from 0 to 8 hours after reconstitution

ABSTRACT

BACKGROUND: Continuous infusion of factor VIII (FVIII) is a more cost-effective method for treating hemophilia A than intermittent bolus injection. However, there is currently no specific data in Korea about the progress of in vitro FVIII coagulant activity (FVIIIC) after reconstitution from its lyophilized form. METHODS: Three commercial FVIII concentrate products (two recombinant FVIII and one plasma-derived) were used. In vitro FVIIIC was measured at 0, 2, 4, 6, and 8 hours following reconstitution in both the indoor light-exposed and light-shielded groups. RESULTS: For the three drugs, in vitro FVIIIC decreased over the 8 hours following reconstitution (P<0.001). The decline of FVIIIC was linear (P<0.001). In vitro FVIIIC for the indoor light-exposed groups was 95.3+/-1.9% and 90.6+/-2.5% after 4 and 8 hours following reconstitution, respectively, compared to baseline activity. In the light-shielded group, FVIIIC was 95.4+/-1.1% and 90.9+/-1.7% of the baseline activity after 4 and 8 hours, respectively. There was no statistical difference between FVIIIC in the indoor light-exposed and light-shielded groups (P=0.849). CONCLUSION: In vitro FVIIIC decreased after reconstitution, but activity was maintained at over 90% of the baseline value during 8 hours. Exposure to indoor light did not accelerate the loss of FVIIIC over the experimental time. This result indicates that CI with FVIII is available in 8-hour intervals, with no indoor light-exposure precautions needed.