optimization of mobile phase of high performance liquid chromatography using full factorial design for simultaneous estimation of thiocolchicoside and dexketoprofen trometamol in tablets

the present study was aimed to develop and validate a high performace liquid chromatography method for determination of thiocolchicoside and dexketoprofen trometamol in combined dosage form. the proposed hplc method utilizes an agilent eclipse c-8 column (5 µm, 250×4.6 mm) at ambient temperature. a 23 full factorial design was performed for optimization of mobile phase for separation of two drugs. for the factorial design, the dependent variables chosen were % of acetonitrile, % of 0.1% o-phosphoric acid and ph. the optimum mobile phase consisted of acetonitrile: 0.1% o-phosphoric acid in water (41.9:58.1; ph 2.6). the flow rate was kept 1 ml/min with uv detection at 254 nm. the run time was found to be 1.41 min and 7.58 min for thiocolchicoside and dexketoprofen trometamol, respectively. the method was validated as per ich guidelines. the calibration plots were linear in the range of 1-5 μg/ml with r2=0.998 for thiocolchicoside and 6-30 μg/ml with r2 = 0.995 for dexketoprofen trometamol. the % recovery values were found to be 98.52 ± 1.21 and 98.16 ± 1.45 for thiocolchicoside and dexketoprofen trometamol, respectively. the minimum detectable and minimum quantifiable amounts were found to be 0.11 and 0.35 μg/ml, respectively for thiocolchicoside and 1.41 and 4.38 μg/ml, respectively for dexketoprofen trometamol. the developed method could be utilized successfully in simultaneously analyzing the drugs in bulk as well as combined dosage form.