[Pharmacology of a new sleep-inducer, a 1H-1,2,4-triazolyl benzophenone derivative, 450191-S (VIII). Examination and determination of metabolites in human plasma and urine].

Oral administration of 450191-S to humans at 4 mg/man led to the formation of the same plasma metabolites as those found in animals; i.e., M-1, M-2, M-A, M-3 and M-4. Unlike in animals, M-4 was the major metabolite in human plasma for 6 hr after dosing. 450191-S was not found in human plasma after administration of the commonly used dose of 450191-S (1-2 mg/man). The major human urinary metabolite was also M-4, and 44-68% of the dose was excreted as M-4 into 0-24 hr urine. The unchanged 450191-S excreted into the urine was scarcely detectable. Minor metabolites also seemed to be present in the urine, such as the 4OHM-3 conjugate, M-1 and its conjugate, M-2 and its conjugate, M-A and its conjugate, and M-3 and its conjugate. However, all of them together came to not more than 1% of the dose.