Simultaneous UV-Spectrophotometric determination of Thiocolchicoside and Diclofenac in Pharmaceutical formulation

A simple, specific, accurate, precise and reproducible method has been developed and validated for the simultaneous estimation of Thiocolchicoside and Diclofenac in pharmaceutical formulation by UV-Spectrophotometric method which includes Simultaneous Equation method (Method I), Absorbance Correction method (Method II). For development of Method I, wavelengths were selected 260.0 nm λmax for thiocholchicoside and 276.5 nm λmax for diclofenac sodium, while for Method II, 276.5 nm λmax for diclofenac sodium and 373.0 nm is isoabsorptive point of thiocholchicoside and diclofenac sodium. The two drugs follow Beer-Lambert’s law over the concentration range of 1-10 μg/mL for thiocholchicoside and 6.25-62.5 μg/mL for diclofenac sodium in both the methods. The percent recoveries of the drugs were found to be nearly 100 % representing the accuracy of both the methods. Validation of the proposed methods was carried out for its accuracy, precision, and ruggedness according to ICH guidelines. The proposed methods can be successfully applied in routine work for the determination of thiocholchicoside and diclofenac sodium in combined dosage form. Also the method II can be applied for estimation of thiocholchicoside even in presence of the diclofenac sodium in the formulation matrices without interference.