Simultaneous Spectrophotometric Estimation of Thiocolchicoside and Diclofenac Potassium in Combined Capsule Dosage Form

Two simple, rapid, accurate and economical analytical methods have been developed for the simultaneous estimation of Thiocolchicoside and Diclofenac potassium in combined capsule dosage form. First method is based on the determination of Q-value and Second method is based on simultaneous equation method. Thiocolchicoside has absorbance maxima at 259 nm and Diclofenac potassium has absorbance maxima at 271 nm in distilled water and phosphate. The absorption ratio (Q-value) was determined at 264 nm (Iso-absorptivity point) and 259 nm (_max of Thiocolchicoside Both the drugs obey Beer's law in the concentration ranges employed for these methods. Both the methods were found to be simple, rapid, and accurate and can be adopted in routine analysis of drugs in formulations. The accuracy and reproducibility of the proposed method was statistically validated by recovery studies.