Determination of montelukast by new spectrophotometric method using bromocresol green

Simple, sensitive and accurate spectrophotometric method has been developed for the determination of Montelukast Sodium in raw and tablets formulation. The method is based on the formation of yellow ion-pair complex between Montelukast Sodium and Bromocresol green in Dichloromethane medium. The absorption maximum of the complex was found to be at 405 nm. Different parameters affecting the reaction such as: effect of solvents, reagent concentration, correlation ratio, etc. were carefully studied and optimized. The formed complex was quantified spectrophotometrically at absorption maximum. Linearity range was 2–19 μg/mL, regression analysis showed a good correlation coefficient R² = 0.9998. The limit of detection (LOD) and limit of quantification (LOQ) were to be 0.50 μg/mL and 1.51 μg/mL. The developed methods could be successfully applied to pharmaceutical formulations. The proposed method is simple, direct, sensitive and do not require any extraction process. Thus, this method could be readily applicable for the quality control and routine analysis.