RP-HPLC estimation of paracetamol and valdecoxib in combined dosage form

A reverse phase high performance liquid chromatography method was developed for simultaneous estimation of paracetamol and valdecoxib in tablet formulation. The separation was achieved by Luna C 18 column and methanol: phosphate buffer pH 3.5 (60:40 v/v) as eluent, at a flow rate of 1.0 ml/min. Detection was carried out at 242 nm. Etoricoxib was used as an internal standard. The retention time of PAR and VAL was found to be 3.01 and 8.51 min, respectively. The method was validated for linearity, accuracy and precision. Linearity for paracetamol and valdecoxib were in the range 25-150 µg/ml and 1-6 µg/ml, respectively. The developed method was found to be accurate, precise, and selective for simultaneous estimation of paracetamol and valdecoxib in tablets.