title: 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 (FVIII:C) after reconstitution from its lyophilized form.
  
  
  METHODS
  Three commercial FVIII concentrate products (two recombinant FVIII and one plasma-derived) were used. In vitro FVIII:C 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 FVIII:C decreased over the 8 hours following reconstitution (P<0.001). The decline of FVIII:C was linear (P<0.001). In vitro FVIII:C 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, FVIII:C 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 FVIII:C in the indoor light-exposed and light-shielded groups (P=0.849).
  
  
  CONCLUSIONS
  In vitro FVIII:C 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 FVIII:C over the experimental time. This result indicates that CI with FVIII is available in 8-hour intervals, with no indoor light-exposure precautions needed.
authors.affiliation: Department of Pediatrics, Keimyung University Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea.
authors.forename: Ye Jee
authors.initials: YJ
authors.lastname: Shim
authors.affiliation: Department of Pediatrics, Kyungpook National University Hospital, Kyungpook National University School of Medicine, Daegu, Korea.
authors.forename: Kun Soo
authors.initials: KS
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, Incheon Medical Center Beakryung Hospital, Incheon, Korea.
authors.forename: Uk Hyun
authors.initials: UH
authors.lastname: Kim
authors.affiliation: Division of Pediatric Hematology/Oncology, Asan Medical Center Children's Hospital, Department of Pediatrics, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Jin Kyung
authors.initials: JK
authors.lastname: Suh
authors.affiliation: Green Cross Laboratories, Yongin, Korea.
authors.forename: Sae Yun
authors.initials: SY
authors.lastname: Baik
authors.affiliation: Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea.
authors.forename: Shin Young
authors.initials: SY
authors.lastname: Hyun
keywords: Continuous infusion; Factor VIII; Hemophilia A