A simple, accurate, and reproducible UV spectrophotometric and HPLC method for simultaneous estimation of thiocolchicoside (THC) and aceclofenac (ACE) in combined tablet dosage form have been developed. The first developed method is Area under curve method, wavelength range selected are 264.5-254.5 nm for thiocolchicoside and 279.0-269.0 nm for aceclofenac respectively. Linearity was observed in concentration range of 4-36 μg/ml for thiocolchicoside as well as for aceclofenac. Second developed method is RP- HPLC method using Thermo C18 column (4.6 mm i.d. × 250 mm) and acetonitrile: water: 0.025M pot. dihydrogen orthophosphate buffer (pH adjusted to 3.0 with orthophosphoric acid) in the ratio of 70:10:20 % v/v/v as mobile phase. For HPLC method, linearity was observed in concentration range of 1-6 μg/ml for thiocolchicoside and 25-150 μg/ml for aceclofenac. Results of analysis were validated statistically and by recovery studies
