Simultaneous determination of sulfamethoxazole and its metabolite n4-acetylsulfamethoxazole in urine using derivative spectrophotometry

ABSTRACT

A simple, rapid and accurate first-derivative spectrophotometric method was described for the simultaneous determination of sulfamethoxazole and its metabolite N4-acetylsulfamethoxazole in urine. The metabolite N4-acetylsulfamethoxazole was determined by measuring the trough amplitude at gamma 242 nm, while the free acid [sulfamethoxazole] was determined from the peak amplitude at gamma 272 nm after correction. Analysis of mixtures containing variable concentrations of both compounds gave recovery percentages of 96.4 and 96.3, respectively. The described method was successfully utilized for the determination of the cumulative amounts of sulfamethoxazole and its metabolite in urine following an oral dose of 400 mg sulfamethoxazole to a human male volunteer