INDIRECT SPECTROPHOTOMETRIC DETERMINATION OF BENZYLPENICILLIN AND CLOXACILLIN IN PHARMACEUTICAL PREPARATIONS

An indirect spectrophotometric method for the determination of benzylp enicillin and cloxacillin is based on extraction of iodine produced by reduction of potassium iodate in acidic medium, where hydrolytic clea vage of a beta-lactam is achieved with sodium hydroxide. Beer's law is obeyed within the concentration ranges 0.04-0.8 mg ml(-1) benzylpenic illin and 0.02-0.5 mg ml(-1) cloxacillin. The precision, accuracy of t he method and the effect of foreign substances were studied. The resul ts have been statistically compared with those using the ammonium vana date method. An oxidation mechanism is proposed.