Simultaneous stereoselective high-performance liquid chromatographic determination of 10-hydroxycarbazepine and its metabolite carbamazepine-10,11-trans-dihydrodiol in human urine

An enantioselective HPLC method for the simultaneous determination of the c oncentration of the enantiomers of the oxcarbazepine metabolites 10-hydroxy carbazepine (MHD) and carbamazepine-10,11-trans-dihydrodiol (DHD) in human urine is described. The method is based on extraction with tert.-butylmethy l ether-dichloromethane (2:1, v/v) under alkaline conditions, separation an d evaporation of the organic phase and dissolution of the residue in the mo bile phase. Enantiomers are resolved on a Diacel Chiralcel OD column (250 m mx4.6 mm I.D.) under isocratic conditions using as mobile phase n-hexane-et hanol-2-propanol (18:2:1, v/v/v) with addition of glacial acetic acid (0.1% ), The enantiomers are detected by UV at 215 nm. The method allows reliable determination of the MHD and DHD enantiomers in human urine with limits of quantification of 0.2 mg/l and 0.4 mg/l, respectively. (C) 2000 Elsevier S cience B.V. All rights reserved.