Determination of 7-hydroxycoumarin and its glucuronide and sulphate conjugates in liver slice incubates by capillary zone electrophoresis

The simultaneous detection of the phase I metabolite of coumarin, 7-hydroxycoumarin, and the two phase II metabolites, 7-hydroxycoumarin-glucuronide and 7-hydroxycoumarin-sulphate by capillary electrophoresis with UV detection using liver slice incubations was investigated. Separation was carried out on an untreated fused silica capillary with detection at 320 nm. Separation was achieved in under 6 min with a total run time of 8 min. Both phase two metabolites were produced following an in vitro incubation of liver slices in Krebs-Hanseleit buffer with 100 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 sulphate and 6.17 mu M (1 mu g ml)(-1) for 7-hydroxycoumarin. Mean inter- and intra-assay results are presented for all three analytes, respectively. (C) 1998 Elsevier Science B.V. All rights reserved.