Which Anticoagulant Unit Serves Better for Evaluation of in Vivo Potency of Whale Heparin, B. P. or U. S. P. Unit?

Abstract

The correspondence between the in vitro and in vivo anticoagulative activities of beef and whale heparins was studied using the assay methods of heparin described in the British Pharmacopoeia [B.P.] and the United States Pharmacopeia [USP]. The coagulation time was measured by the Lee-White method for 2 hr. after 0.5 mg/kg of either beef or whale heparin preparation was administered intravenously to dogs. B.P. unit of whale heparin and its in vivo potency in dogs were 1.4 times more potent than those of beef heparin, whereas U.S.P. units of whale and beef heparins were the same. Better correspondence was obtained between B.P unit and the in vivo test in dogs. The B.P. assay method may be better for the clinical evaluation than the U.S.P. assay method, when the whale lung or intestine is used instead of the ox lung as the source of heparin.