The present study describes the development and validation of a simple, accurate, and cost-effective UV–visible spectrophotometric method for the simultaneous estimation of Tetrabenazine and Amlodipine besylate in bulk and pharmaceutical dosage forms. Comprehensive pre-formulation studies were performed to evaluate the physicochemical characteristics of both drugs, including organoleptic properties, solubility, pH, melting point, and spectral behavior. Methanol was selected as the solvent based on solubility studies. Distinct absorption maxima were observed at 285.0 nm for Tetrabenazine and 360.0 nm for Amlodipine besylate, with an overlapping wavelength at 299.5 nm enabling simultaneous estimation. The method showed linearity in the concentration range of 10–60 µg/mL for Tetrabenazine and 5–30 µg/mL for Amlodipine besylate, with correlation coefficients greater than 0.98. The developed method was validated in accordance with ICH guidelines, demonstrating satisfactory specificity, precision, accuracy, ruggedness, robustness, and sensitivity. Low limits of detection and quantification confirmed the suitability of the method for routine quality control analysis. Overall, the validated UV spectrophotometric method is reliable, economical, and appropriate for simultaneous estimation of Tetrabenazine and Amlodipine besylate in pharmaceutical formulations.
Shamshad Alam*1, Himanshu Mishra2, (Mon,) studied this question.