Abstract
The urinary metabolites of carbamazepine (CBZ) in epileptic patients receiving long-term drug treatment have been characterized by LC/MS. CBZ-10,11-epoxide (9.6–15.0 μg/ml),trans-10,11-dihydrodiol-CBZ (273.0–400.00 μg/ml), and CBZ (2.4–3.8 μg/ml) were measured by HPLC. The secondaryN-glucuronide of CBZ, four phenolicO-glucuronides (including those of 2- and 3-OH-CBZ), two additional OH-CBZ O-glucuronides, and theN-glucuronide of CBZ-10,11-epoxide constituted the products of either direct conjugation or preliminary monoxygenation. Derivatives of these monoxygenated compounds, which were characterized asO-glucuronides, were represented by dihydroxylated (catechol) CBZ and its putative O-methyl metabolite and by 10,11-dihydrodiol-CBZ. 10,11-Dihydro-10-OH-CBZO-glucuronide, a metabolite thought to be excreted only by uremic subjects, was not found. More complicated biotransformations of the 10,11-ene moiety were revealed by two carbinol products of azepine ring contraction: 9-OH-methyl-10-carbamoyl acridan and an hydroxylated derivative thereof, which were excreted as O-glucuronides. No polar sulfur-containing metabolites that might serve as indicators of reactive intermediate formation were found in human urine.
Footnotes
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Send reprint requests to: Dr. B. K. Park, Department of Pharmacology and Therapeutics, University of Liverpool, P.O. Box 147, Liverpool L69 3BX, UK.
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This study was supported by the Epilepsy Research Foundation (to M.P.) and by Glaxo Group Research. B.K.P. is a Wellcome Principal Research Fellow. The LC/MS system was purchased with a grant from the Wellcome Trust.
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↵2 J. L. Maggs, unpublished observation.
- Abbreviations used are::
- CBZ
- carbamazepine (5H-dibenz[b,f]azepine-5-carboxamide)
- DHD
- dihydrodiol
- CBZ-E
- carbamazepine-10,11-epoxide
- ESP
- electrospray
- SIM
- selected ion monitoring
- CID
- collision-induced decomposition
- OH
- hydroxy
- 9-HM-10-CA
- 9-hydroxymethyl-10-carbamoyl acridan
- Q1 and Q2
- 1st and 2nd quadrupoles
- Received March 25, 1996.
- Accepted December 5, 1996.
- The American Society for Pharmacology and Experimental Therapeutics
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