Reversed-phase chromatography of fenflumizole, a new potential anti-inflammatory agent, and its application in pharmacokinetic studies in rat, dog and man.

Two high-performance liquid chromatographic methods for quantitation of fenflumizole in biological fluids are described. Fenflumizole is a new agent with demonstrable anti-inflammatory properties in laboratory rodents. The major difference between the two methods lies in the utilization of fluorescence detection of the column eluate in assay II as compared to the less selective ultraviolet-visible detection used in assay I. Assay II appeared suitable for monitoring metabolites in addition to the parent compound. The quantitation limit of plasma fenflumizole was below 10 ng/ml for assay I and approximately 100 pg/ml for assay II. The reproducibility within a plasma concentration range of 50-150 ng/ml was below 7% (standard deviation) in both assays. Fenflumizole was found to be subject to photodecomposition. The impact of this on the analytical performance was evaluated and precautionary measures were assessed. The reliability of the analytical methods is examined and their applicability in in vivo studies conducted in rat, dog, and man.