DIRECT COLUMN LIQUID-CHROMATOGRAPHIC ENANTIOMER SEPARATION OF THE COUMARIN ANTICOAGULANTS PHENPROCOUMON, WARFARIN, ACENOCOUMAROL AND METABOLITES ON AN ALPHA-1-ACID GLYCOPROTEIN CHIRAL STATIONARY-PHASE

The enantiomers of the racemic coumarin anticoagulants phenprocoumon (PH) and metabolites (4'-, 6-, 7- and 8-hydroxy-PH), warfarin (WA) and metabolites (6-, 7-hydroxy-WA and the two diastereomeric WA alcohols) and acenocoumarol were resolved by column liquid chromatography using an immobilized alpha1-acid glycoprotein stationary phase; elution was performed using a phosphate buffer and isopropanol gradient with and without dimethyloctylamine as modifier, and detection by ultraviolet or fluorescence. The advantages of this method are: the procedure is simple and fast and does not require pre-column derivatization; the configuration of the enantiomers can be assigned by comparison with a reference sample with already known absolute configuration; the optical purities of these compounds can be analysed with high sensitivity; the method can be applied to the determination of the enantiomers in biological samples.