Metabolism of sudoxicam by the rat, dog, and monkey.

Sudoxicam, N-(2-thiazolyl)-4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxamide 1, 1-dioxide, was prepared in radiolabeled form and administered to rats, dogs, and monkeys. Urine contained approximately 60, 25, and 49% of the label given to rats, dogs, and monkeys, respectively; the remainder was cleared via feces. In addition to some unchanged drug, urine from all species examined contained two major metabolites. These were identified from their mass spectra as the thiohydantoic acid and thiourea resulting from scission of the thiazole ring of sudoxicam.