Characterization of mephenytoin metabolites in human urine by gas chromatography and mass spectrometry
Lynn, R.K.; Bauer, J.E.; Gordon, W.P.; Smith, R.G.; Griffin, D.; Thompson, R.M.; Jenkins, R.; Gerber, N.
Drug Metabolism and Disposition the Biological Fate of Chemicals 7(3): 138-144
1979
ISSN/ISBN: 0090-9556 PMID: 38083 Document Number: 153729
Metabolities of mephenytoin (5-ethyl-3-methyl-5-phenylhydantoin) were characterized in human urine after chromatography on XAD-2 resin, permethylation and combined gas chromatography and mass spectrometry. Glucuronide metabolites(4) previously unidentified in man were characterized as their permethylated derivatives by chemical-ionization and electron-impact mass spectrometry. The metabolities included 5-ethyl-5-(hydroxyphenyl)-3-methylhydantoin O-glucuronide, 5-hydroxyethyl-3-methyl-5-phenylhydantoin O-glucuronide, 5-ethyl-5-(hydroxymethoxyphenyl)-3-methylhydantoin O-glucuronide and a metabolite tentatively identified as 5-ethyl-5-phenylhydantoin N3-glucuronide in which both N-demethylation and glucuronide conjugation of the hydantoin ring have occurred. Mephenytoin, N-demethylmephenytoin, 5-ethyl-5-(hydroxyphenyl)-3-methylhydantoin and 5-ethyl-5-(hydroxymethoxyphenyl)-3-methylhydantoin were characterized in extracts of enzymatically hydrolyzed urine.