Liquid chromatographic determination of diclofenac in human synovial fluid.

A simple, rapid and sensitive HPLC method for the determination of diclofenac in synovial fluid is described. Special attention was paid to the procedure of sample preparation since gel formation may sometimes occur in synovial samples. With a one-step extraction procedure good and reproducible recovery of diclofenac was obtained. A subsequent HPLC assay was adjusted so as to achieve adequate sensitivity and precision needed for analysis of true samples. The results obtained by the described procedure proved the method to be suitable for monitoring concentrations of diclofenac in synovial fluid.