High performance liquid chromatographic determination of diclofenac sodium in plasma of the rat

A rapid and sensitive high performance liquid chromatographic method has been developed for the determination of diclofenac sodium in rat plasma. The assay was performed after liquid-liquid extraction with 1M orthophosphoric acid and a mixture of hexane:isopropyl alcohol. Chromatographi c separations were performed on C18 stationary phase with a mobile phase composed of acetonitrile: deionised water: orthophosphoric acid (45:54.5:0.5,v/v) as mobile phase with final pH of (3.5). Analytes were detected at wave leng th of 276nm. This method was validated for specificity and linearity with a correlation coefficient, r=0.99.