STUDY OF COUMARIN METABOLISM BY HUMAN LIVER-MICROSOMES USING CAPILLARY ELECTROPHORESIS

A method for the rapid determination of 7-hydroxycoumarin, based on se paration by capillary electrophoresis (CE), with UV absorbance detecti on at 210 nn, was applied to a study of the metabolism of coumarin in human liver microsomes. The linear detection range for 7-hydroxycoumar in was 0-50 mu g/ml, while the limit of detection was 1 mu g/ml. Human liver microsomes from 5 patients were used in metabolic studies and t he profiles clearly indicated that there is inter-individual variabili ty in coumarin 7-hydroxylase activity. The CE method allowed the inves tigation of NADP(+)/NADPH cofactor reactions involved in coumarin meta bolism. The CE method was also compared to a liquid chromatographic me thod for the analysis of the metabolite and it was found that the resu lts did not differ but the CE method was more rapid and needed no samp le preparation. The very short time between sampling and analysis make s the method suitable for automated sample transfer and measurement.