DETERMINATION OF DICLOFENAC SODIUM IN HUMAN PLASMA BY REVERSED-PHASE LIQUID-CHROMATOGRAPHY

Following a detailed study, a simple, rapid and accurate reversed-phas e liquid chromatographic method has been developed for the determinati on of diclofenac sodium in human plasma. The sample is separated isocr atically within 7 min using an octadecyl-bonded silica column and a mo bile phase of methanol and sodium acetate buffer (68:32, v/v; pH 4.2). The compounds were quantitated using a ultraviolet detector operated at 274 MI which allowed determination of 0.10 - 2.50 mu g/ml of diclof enac sodium with high reproducibility. The limit of detection is 0.03 mu g/ml. Intra-day and inter-day coefficients of variation for assayin g the plasma sample containing 0.20 mu g/ml concentration of diclofena c sodium were 7.4% (n=9) and 7.6% (n=7), respectively, The extraction efficiency of diclofenac sodium were 91.3 - 93.2% for plasma. The meth od has been used to determine diclofenac sodium in the plasma samples from ten volunteers and provide data on the pharmacokinetics of the dr ug.