Anti-warfarin antibody preparation and its characterization for radioimmunoassay.
Anti-warfarin antiserum was prepared in rabbits by immunization with a synthesized warfarin antigen, 4'-azo-warfarin human serum albumin, which possesses two enantiomorphic haptenic sites of warfarin on the molecule. The antiserum recognized both R- and S-warfarin to the same degree, 50% cross reactivities of racemic warfarin, respectively. One of the warfarin metabolites, racemic warfarin alcohol, showed 1% cross reactivity, and R- or S-warfarin alcohol have half the reactivity of the racemic alcohol. Rabbit plasma warfarin levels were determined by radioimmunoassay using this antiserum and racemic [14C]warfarin and by fluorometric assay after isolation by thin layer chromatography. After a single administration of warfarin (2 mg kg-1 orally or 500 microgram kg-1 i.v.), the plasma levels determined by both assay methods showed a good correlation (r = 0.97, P less than 0.001, Y = 1.04-0.09). The results show that the radioimmunoassay can determine total plasma warfarin without interference of plasma metabolite. The applicability and limitation of the radioimmunoassay for pharmacokinetic study are discussed.
D000818:Animals; D000906:Antibodies; D003429:Cross Reactions; D006801:Humans; D011817:Rabbits / Q000276:immunology; D011863:Radioimmunoassay / Q000379:methods; D013237:Stereoisomerism; D013997:Time Factors; D014859:Warfarin / Q000032:analysis / Q000276:immunology*
D000906:Antibodies; D014859:Warfarin