Simple, precise and economical spectrophotometric method has been developed for the simultaneous estimation of Montelukast sodium (MON) and Fexofenadine HCL (FEX) in combined tablet dosage form. This study describes the development and validation for the simultaneous estimation of Montelukast(MON) and Fexofenadine HCL (FEX) by the Ratio derivative UV spectroscopy method. Methanol is used as solvent. The amplitudes at 288.17nm and 289.12nm of the first derivative of ratio spectra were selected to determine MON and FEX, respectively. Beer's law is obeyed in the concentration range of 2–10 μg/mL and 24–120 μg/mL for Montelukast sodium and Fexofenadine HCL, respectively by both the methods. The % assay in commercial formulation was found to be 93.08% for MON and 98.91% for FEX by the proposed method. The method was validated with respect to linearity, precision and accuracy. Recovery was found in the range of 98.12–99.96% for MON and 99.12–99.97% for FEX by ratio derivative method. The relative standard deviation was found to be <2.0%. The present result shows that the proposed method can be successfully used for simultaneous estimation of the drug content in marketed formulations.
Montelukast sodium, Fexofenadine HCL, Ratio Spectra Derivative Spectrophotometry
