SIMULTANEOUS ESTIMATION OF RABEPRAZOLE SODIUM AND CINITAPRIDE HYDROGEN TARTRATE IN COMBINED PHARMACEUTICAL FORMULATION

Three simple, rapid, precise and accurate spectrophotometric methods have been developed for simultaneous analysis of Cinitapride Hydrogen Tartrate (CNT) and Rabeprazole Sodium (RAB) in their combined dosage form. Method A, Simultaneous equation method (Vierodt’s method) applies measurement of absorptivities at two wavelengths, 265.6 nm (λ_max of Cinitapride Hydrogen Tartrate) and 282.6 nm, (λ_max of Rabeprazole Sodium) in zero order spectra. The concentrations can be calculated from the derived equations. Method B, Q-Absorbance equation method. It involves formation of Q-absorbance equation at 279.00 nm (isoabsorptive point) and 265.60 nm (λ_max of Cinitapride Hydrogen Tartrate) in zero order spectra. Method C, Zero crossing first derivative spectrophotometry involves measurement of absorbance at 246.30 nm (for Cinitapride Hydrogen Tartrate) and 304.00 nm (for Rabeprazole Sodium) in first derivative spectra. Developed methods were validated according to ICH guidelines. The calibration graph follows Beer’s law in the range of 4.0 to 20.0 μg/ml for Cinitapride Hydrogen Tartrate and 4.0 to 20.0 μg/ml for Rabeprazole Sodium in water as a solvent with R square value greater than 0.999. Accuracy of all methods was determined by recovery studies and showed % recovery between 98 to 102%. Intraday and inter day precision was checked for all methods and mean %RSD was found to be less than 2 for all the methods. The methods were successfully applied for estimation of Cinitapride Hydrogen Tartrate and Rabeprazole Sodium in marketed formulation.