HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD FOR THE ROUTINE DETERMINATION OF DICLOFENAC AND ITS HYDROXY AND METHOXY METABOLITES FROM IN-VITRO SYSTEMS

A rapid and sensitive high-performance liquid chromatographic method i s presented for the determination of diclofenac and its hydroxylated a nd methoxylated metabolites. The procedure describes extraction of dic lofenac and its metabolites from acidified incubation medium into tert .-butylmethyl ether. Separation is achieved with a C18 reversed-phase column and quantification by UV detection at 280 nm. The method employ s an internal standard resulting in good accuracy and precision. The l imit of detection is 5 ng/ml for diclofenac and 10 ng/ml for its metab olites. One analysis requires no more than twelve minutes so that the assay is very suitable for the determination of a large number of samp les.