Spectrophotometric determination of etamsylate in pharmaceuticals using ferric chloride based on complex formation reactions

Abstract

The present study describes two simple and selective spectrophotometric methods for the rapid determination of etamsylate (ETM) in bulk and in capsule formulations. The methods are based on the oxidation of ETM with ferric chloride in neutral medium and subsequent chelation of the resulting iron(II) with 1,10-phenanthroline (Phen) (method A) and with 2,2?-bipyridyl (Bipy) (method B). The resulting red colored chromogens are measured at 510 and 520 nm, in method A and B, respectively. In both methods, the absorbance is found to increase linearly with increasing ETM concentration. Beer?s law is obeyed over the ranges 0.5-10 and 0.8-16 ?g/ml for method A and B, respectively. The calculated molar absorptivity values are 2.17?104 and 1.65?104 l/mol/cm for method A and B, respectively, and the corresponding sandell sensitivities are 0.012 and 0.016 ?g/cm2. Intra-day and inter-day precision and accuracy of the methods were established according to ICH guidelines. The proposed methods were applied to determine ETM in dosage forms and the results were statistically compared with that of an official BP method.