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

1. The metabolism and urinary excretion of 2-chloro-4-trifluoromethylaniline has been studied in the rat using F-19-NMR spectroscopy and directly coupled HPLC-NMR-MS methods. The compound was dosed to three male Sprague-Dawley rats (50 mg kg(-1) 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 rite 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 coupled HPLC-NMR-MS and F-19-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.