Identification of the major urinary metabolites of acrylonitrile in the rat

The metabolism of acrylonitrile (AN) in rats was studied in conjunction with toxicological and pharmacokinetic studies to help assess the potential hazard of exposure to AN in the workplace. Rats were administered 30 mg/kg [1-14C] AN or [2,3-14C] AN orally. Radiolabeled metabolites excreted in the urine during the first 16 h were separated by ion-exclusion liquid chromatography and identified (after derivatization) by gas chromatography-infrared spectroscopy and/or gas chromatography-mass spectrometry. Two major urinary metabolites were identified as thiocyanate and N-acetyl-S-(2-cyanoethyl)cysteine. A third was tentatively identified as 4-acetyl-3-carboxy-5-cyanotetrahydro-1,4-2H-thiazine. AN was not detected in the urine. One possible scheme for the AN metabolic pathways is proposed.