title: Characterization of mephenytoin metabolites in human urine by gas chromatography and mass spectrometry.
abstract: Metabolites of mephenytoin (5-ethyl-3-methyl-5-phenylhydantoin) were characterized in human urine following chromatography on XAD-2 resin, permethylation, and combined gas chromatography and mass spectrometry. Four glucuronide metabolites previously unidentified in man were characterized as their permethylated derivatives by chemical-ionization and electron-impact mass spectrometry. These metabolites included 5-ethyl-5-(hydroxyphenyl)-3-methylhydantoin O-glucuronide; 5-hydroxyethyl-3-methyl-5-phenyl-hydantoin 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.
mesh_terms: D000328:Adult; D001711:Biotransformation; D002849:Chromatography, Gas; D005965:Glucuronates / Q000302:isolation & purification / Q000652:urine; D006801:Humans; D006827:Hydantoins / Q000652:urine*; D008297:Male; D013058:Mass Spectrometry; D008617:Mephenytoin / Q000652:urine*
chemical_list: D005965:Glucuronates; D006827:Hydantoins; D008617:Mephenytoin