Development and validation of liquid chromatography method for the separation of valdecoxib and its SC-77852 impurity

A reversed-phase liquid chromatography method has been developed for the separation of valdecoxib and impurity SC-77852. The best results were achieved using a mobile phase-methanol: 1% water solution TEA (52 : 48 v/v), pH 7.35 (adjusted with 85% orthophosphoric acid), column temperature 24 degrees C. Separation was carried out on XTerra (TM) RP18 (150mm x 4,6 mm), particle size 5 mu m, flow rate 1ml/min, using detection on 220 nm. The method was statistically validated for its selectivity, linearity, precision (repeatability), and robustness. Quantitation and detection limits were determined for both valdecoxib and SC-77852. Method robustness was further evaluated by performing full factorial design experiment. Validated method was used for assay of valdecoxib and SC-77852 in Bextra (R) film-coated tablets.