Simultaneous spectrophotometric determination of diazepam and propranolol hydrochloride in tablets

The present manuscript describe simple, sensitive, rapid, accurate, precise and economical Qabsorbanceratio method for the simultaneous determination of diazepam and propranololhydrochloride in combined tablet dosage form. Absorbance ratio method uses the ratio ofabsorbances at two selected wavelengths, one which is an isoabsorptive point and other being the _-max of one of the two components. Diazepam and propranolol hydrochloride show anisoabsorptive point at 235 nm in 0.05 M methanolic sulphuric acid. The second wavelength usedis 215 nm, which is the _-max of propranolol hydrochloride in 0.05 M methanolic sulphuric acid.The linearity was obtained in the concentration range of 1-20 μg/ml for both diazepam andpropranolol hydrochloride. The concentrations of the drugs were determined by using ratio ofabsorbances at isoabsorptive point and at the _-max of propranolol hydrochloride. The methodwas successfully applied to pharmaceutical dosage form because no interference from the tabletexcipients was found. The results of analysis have been validated statistically and by recoverystudies. Keywords: Diazepam, Propranolol hydrochloride, Absorbance ratio method, Spectrophotometric, Tablet, Validation.