Simultaneous estimation of Montelukast sodium and Bambuterol hydrochloride in tablets by spectrophotometry.

Two simple, rapid, accurate and precise methods have been developed for simultaneous estimation of Montelukast sodium and Bambuterol hydrochloride from tablet dosage form. In the first method, the first derivative spectrum was determined. Montelukast sodium showed zero crossing point at 209.5 nm and Bambuterol hydrochloride showed zero crossing point at 238.5 nm. The dA/dlambda was measured at 209.5 nm for Bambuterol hydrochloride and 238.5 nm for Montelukast sodium and calibration curves were plotted as dA/dlambda versus concentration respectively. Quantitative determination of Montelukast sodium and Bambuterol hydrochloride in tablets was carried out using calibration curve by interpolation method. In the second method, Multicomponent mode of analysis was used and the measurement of absorbances at two wavelengths, 283.6 nm (lambda-max of MKST) and 211.8 nm (working wavelength selected for BHC) in 95% methanol, was carried out. These methods were validated statistically as per ICH guidelines. The recovery studies confirm the accuracy of the proposed method.