title: Identification of ninhydrin-positive caprolactam metabolites in the rat.
abstract: Caprolactam (2-oxohexamethylenimine) is metabolized in the rat partly to 4-hydroxycaprolactam or the corresponding free acid. The 4-hydroxy metabolite rearranges spontaneously in acidic aqueous medium to an equilibrium mixture of which 6-amino-gamma-caprolactone is the major component and 6-amino-4-hydroxyhexanoic acid is a minor component. Approximately 16% of the caprolactam ingested daily by rats fed a diet containing 3% caprolactam was excreted as the 4-hydroxy metabolite and a small amount was excreted as the non-hydroxylated acid, 6-aminohexanoic acid. The metabolites were isolated by ion-exchange chromatography and identified by gas chromatography-mass spectroscopy and infra-red and nuclear magnetic resonance spectroscopy.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001381:Azepines / Q000378:metabolism*; D001711:Biotransformation; D002209:Caprolactam / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D002855:Chromatography, Thin Layer; D008401:Gas Chromatography-Mass Spectrometry; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009555:Ninhydrin; D009904:Optical Rotation; D051381:Rats; D011919:Rats, Inbred Strains; D013053:Spectrophotometry
chemical_list: D000596:Amino Acids; D001381:Azepines; D002209:Caprolactam; D009555:Ninhydrin