In vivo metabolism and whole-blood clearance of n-nitrosomethylbenzylamine in the rat.

The pharmacokinetics and metabolism of N-nitrosomethyl-benzylamine, N-nitroso[methyl-14C]benzylamine, and N-nitrosomethyl[benzyl-7-14C]amine were studied in male Sprague-Dawley rats, and a major urinary metabolite was identified. N-Nitrosomethylbenzylamine (4.7 mg/kg body weight i.p.) was distributed throughout extracellular water and cleared from the whole blood by metabolism with a half-life of 66 min. Less than 1% of the administered dose of N-nitrosomethylbenzylamine (4.7 mg/kg i.p. or 3.3 mg/kg intragastric intubation) was excreted and expired as the parent compound. In the 24-hr period following injection of N-nitroso[methyl-14C1benzylamine (3.4 mg, 1 mCi/kg i.p.), 46% of the radioactivity administered was expired with a half-life of 2.1 hr. In contrast, 81% of the radioactivity from a dose of N-nitrosomethyl[benzyl-7-14C1amine (2.4 mg, 1 mCi/kg i.p.) was excreted in the urine with a half-life of 4.2 hr. Hippuric acid accounted for 80% of the radioactivity recovered in the urine.