SIMULTANEOUS ESTIMATION OF ERDOSTEINE, GUAIPHENESIN AND TERBUTALINE SULPHATE IN SYRUP FORMULATION BY TWO UV SPECTROPHOTOMETRIC METHODS

Two simple, rapid and economic UV spectrophotometric methods, namely successive ratio derivative and double divisor ratio spectra methods, have been developed for the simultaneous estimation of ternary mixtures of erdosteine, guaiphenesin and terbutaline sulphate without preceding separation steps. Method I is based on successive derivative of ratio spectra in two steps, whereas method II is based on convolution of double divisor ratio spectra, obtained by dividing the absorption spectrum of the ternary mixture by a standard spectrum of two of the three compounds in the mixture. All the drugs exhibited good linearity over the reported concentration range with acceptable correlation coefficient. The methods were validated according to ICH guidelines for the evaluation of accuracy, precision, sensitivity. The obtained relative standard deviation i.e. less than 2%, demonstrated that the proposed methods were accurate and precise and can be employed for routine analysis in quality control laboratories, eliminating the need of prior separation of the pharmaceutical mixtures.