Metabolism of tenoxicam in rats

Abstract
1. The structures of six metabolites of tenoxicam in rats (2mg/kg, orally), elucidated by physicochemical analyses or the reverse-isotope dilution method, were 5′-hydroxyten-oxicam (5% dose), 3-(methylsulphamoyl)-2-thiophenecarboxylic acid (9% dose), and the C-7 or C-8 O-glucuronide of tenoxicam (30% dose). 2. The mechanism of formation of N-methylthiophenesulphimide, a possible precursor of 3-(methylsulphamoyl)-2-thiophenecarboxylic acid from tenoxicam, is discussed.