This study describes the development and validation for the simultaneous estimation of rupatadine and montelukast by the Þ rst-order derivative UV spectroscopy method. The quantiÞ cation was achieved by the Þ rstorder derivative spectroscopy method at 273.46 nm and 297.27 nm over the concentration range of 5-25 µg/ ml for estimation of rupatadine and montelukast in a combined tablet formulation. Procedure does not require prior separation of components from the sample. Rupatadine and montelukast were determined at 15 µg/ml with a mean recovery of 99.59 + 0.225 and 99.21 + 0.76, respectively. Calibration curves were linear with a correlation coefÞ cient of 0.9994 and 0.9992 for rupatadine and montelukast, respectively. The relative standard deviation was found to be <2.0%. The present result shows that the proposed method can be successfully used for simultaneous determination of the drug content in marketed formulations.
Key words: Combination tablet, Þ rst-order derivative spectroscopy, montelukast, rupatadine.
