DIRECT HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF THE ENANTIOMERS OF ALFUZOSIN IN PLASMA ON A 2ND-GENERATION ALPHA-1-ACID GLYCOPROTEIN CHIRAL STATIONARY PHASE

A direct liquid chromatographic method was developed for the determination of the enantiomers of alfuzosin in human plasma, without derivatization, on a chiral α1-acid glycoprotein column. The influence of pH, of uncharged organic solvents and of a cationic modifier (tetrabutylammonium) of the mobile phase on retention and enantioselectivity was evaluated. The enantiomers and an internal standard, structurally related to alfuzosin, were extracted from plasma with dichloromethane-diethyl ether from alkaline solution, then separated with a mobile phase of 0.025 M phosphate buffer (pH 7.4) containing 0.025 M tetrabutylammonium bromide-acetonitrile (94:6, v/v). The limit of quantification for each isomer was 1 ng/ml. The method has been applied to the determination of the pharmacokinetic profile of alfuzosin enantiomers in healthy volunteers after intravenous administration of the racemate. © 1990.