DETERMINATION OF 7-HYDROXYCOUMARIN AND ITS GLUCURONIDE AND SULFATE CONJUGATES IN LIVER SLICE INCUBATES BY CAPILLARY-ZONE-ELECTROPHORESIS

The simultaneous detection of the phase I metabolite of coumarin, 7-hy droxycoumarin, and the two phase II metabolites, 7-hydroxycoumarin-glu curonide and 7-hydroxycoumarin-sulphate by capillary electrophoresis w ith UV detection using liver slice incubations was investigated. Separ ation was carried out on an untreated fused silica capillary with dete ction at 320 nm. Separation was achieved in under 6 min with a total r un time of 8 min. Both phase two metabolites were produced following a n in vitro incubation of liver slices in Krebs-Hanseleit buffer with 1 00 mu M 7-hydroxycoumarin. Limits of detection were 5.52 mu M (2 mu g ml(-1)) for the glucuronide, 2.21 mu M (0.5 mu g ml(-1)) for the sulph ate and 6.17 mu M (1 mu g ml)(-1) for 7-hydroxycoumarin. Mean inter- a nd intra-assay results are presented for all three analytes, respectiv ely. (C) 1998 Elsevier Science B.V. All rights reserved.