Quantitative studies on the urinary metabolic fate of 2-chloro-4-trifluoromethylaniline in the rat using 19F-NMR spectroscopy and directly coupled HPLCNMR-MS

Abstract

1. The metabolism and urinary excretion of 2-chloro-4-trifluoromethylaniline has been studied in the rat using F-NMR spectroscopy and directly coupled HPLC-NMRMS methods. The compound was dosed to three male Sprague-Dawley rats (50 mg kg i.p.) and urine collected over 0-8, 8-24 and 24-48 h post-dosing. 2. A total urinary recovery of 56.3 2.2% of the dose was achieved up to 48 h after dosing. The major metabolite in the urine was identified as 2-amino-3-chloro-5- trifluoromethylphenylsulphate accounting for a total of 33.5 2.2% of the dose. 3. Further metabolites detected and characterized included 2-chloro-4-trifluoromethylphenylhydroxylamine glucuronide (13.2 0.5% of the dose), 2-amino-3- chloro-5-trifluoromethylphenylglucuronide (3.8 0.4% of the dose) and 2-chloro-4- trifluoromethylaniline- N -glucuronide (3.6 0.1% of the dose). Several minor metabolites were also found and identified, including 2-chloro-4-trifluoromethylphenylsulphamate, which together accounted for 2.1 0.4% of the dose. 4. Directly coupledHPLC-NMR-MS and F-NMR spectroscopy is shown to provide an efficient approach for the unequivocal and rapid determination of the quantitative urinary metabolic fate and excretion balance of a fluorinated xenobiotic without the necessity for specific radiolabelling.