HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD FOR THE DETERMINATION OF THE MAJOR QUININE METABOLITE, 3-HYDROXYQUININE, IN PLASMA AND URINE

The determination of 3-hydroxyquinine in urine and plasma samples is d escribed. Extraction was performed using a mixture of toluene-butanol (75.25, v/v), followed by back-extraction into the mobile phase, which consisted of 0.1 M phosphate buffer, acetonitrile, tetrahydrofuran an d triethylamine. A reversed-phase liquid chromatography system with fl uorescence detection and a CT-sil C-18 column were used. The within-as say coefficient of variation of the method was 2% at the higher concen tration values in plasma, 2.95 mu M, 4% at 227 nM and 9% at the lower limit of quantitation, 4.5 nM. In urine, the coefficient of variation was 11% at the lower concentration, 227 nM and was 3% at 56.8 mu M. Th e between-assay coefficient of variation was 4% at the low concentrati on (5.1 nM) in plasma, 2% at 276.8 nM and 3% at 1.97 mu M In urine, th e between assay coefficient of variation was 4% at 204.6 nM, 3% at 5.1 2 mu M and 2% at 56.8 mu M. (C) 1998 Elsevier Science B.V.