A NEW RAPID AND SENSITIVE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY FOR DICLOFENAC IN HUMAN PLASMA

A new rapid and sensitive reversed-phase HPLC method for the routine a nalysis of diclofenac in human plasma is described. The method shows h igh selectivity, sensitivity, and reproducibility employing 4'-methoxy diclofenac as internal standard (IS) with W-detection at 282 nm. The c orrelation of peak area ratios (diclofenac/IS) versus diclofenac plasm a concentrations are linear between 5.0-2000 ng/ml with a detection li mit of 3 ng/ml. Intra- and interday precision studies yielded coeffici ents of variation < 6.2 % for all concentrations (range 20.0-1600 ng/m l). The method was applied for the assay of diclofenac in plasma of he althy volunteers after p.o. and rectal dosage of 50 mg diclofenac sodi um and was found to be highly suitable for routine analyses.