Kinetics of R and S warfarin enantiomers

A method is reported for simultaneous measurement of the kinetics of R and S warfarin enantiomers. Pure pentadeuterated R and S enantiomers were each combined with unlabeled enantiomers to form “pseudo”-racemic mixtures which were given (0.75 mg/kg) to 5 healthy subjects. Plasma R and S enanliomer levels were measured by gas chromatography–mass spectrometry. Elimination half-lifes (t½s) and volumes of distribution (Vds) of the enantiomers were not altered by the presence of the other. Clinical Pharmacology and Therapeutics (1980) 28, 99–105; doi:10.1038/clpt.1980.137