title: Sensitive GLC procedure simultaneous determination of phenytoin and its major metabolite from plasma following single doses of phenytoin.
abstract: An improved GLC procedure was developed for the simultaneous determination of phenytoin and its metabolite, 5-(p-hydroxyphenyl)-5-phenylhydantoin, in plasma and urine following enzyme hydrolysis. After extraction, the drug, the metabolite, and the internal standard, 5-(p-methylphenyl)-5-phenylhydantoin, are measured by GLC with flame-ionization detection as their respective methyl derivatives following flash-heater methylation with trimethylanilinium hydroxide. The drug and metabolite give well-resolved symmetrical peaks on a phenyl methyl silicone column, and the method has a sensitivity of 150 ng/ml of phenytoin and 125 ng/ml of the metabolite. GLC-mass spectral evidence is presented for the formation and intact determination of methyl derivatives of the drug, its metabolite, and the internal standard.
mesh_terms: D000284:Administration, Oral; D002849:Chromatography, Gas; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008722:Methods; D008745:Methylation; D010672:Phenytoin / Q000008:administration & dosage / Q000097:blood*; D013997:Time Factors
chemical_list: D010672:Phenytoin