SPECTROPHOTOMETRIC DETERMINATION OF TRIMETHOPRIM BY OXIDATION IN DRUGFORMULATIONS

A spectrophotometric determination of trimethoprim is described based on the reaction of its amine group with persulfate which acts as a str ong oxidizing agent in alkaline media. The reaction produces a stable yellow colored compound after heating in a boiling water bath for 30 m in. At lambda(max) 355 nm, Beer's law is obeyed in the concentration r ange 10-60 mu g ml(-1) with a molar absorptivity of 2.7 x 10(3) 1 mol( -1)cm(-1). The method is applied to formulations with sulfamethoxazole .