Anti-warfarin antibody preparation and its characterization for radioimmunoassay

Abstract

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.

Electrical Properties of Cr–N Films Deposited by Sputtering: Application to Cryogenic Temperature Sensors

“…The intensity of XRD peaks for Cr-N films deposited under various substrate temperatures (T S : RT to 400 C) decreased as the substrate temperature increased. 12) It is possible that nitrogen was released from Cr-N films at high substrate temperatures. The kinetic energy of sputtered particles increases as the sputtering total pressure decreases.…”

A Flow-through Sensing Device with Fluorometric Transduction for the Determination of Warfarin by Using an Anion-Exchanger Gel Combined with an FIA System

“…[10][11][12] However, these methods are still timeconsuming and a derivatization step is necessary. Other techniques such as radioimmunoassay 13 have also been employed.…”