Determination of two major metabolites of the novel anti-tumour agent 5,6-dimethylxanthenone-4-acetic acid in hepatic microsomal incubations by high-performance liquid chromatography with fluorescence detection

High-performance liquid chromatographic methods have been developed and val idated for the glucuronidated and oxidative metabolites of the novel anti-t umour agent 5,6-dimethylxanthenone-4-acetic acid (DMXAA), produced in human liver microsomal incubations. Calibration curves for DMXAA acyl glucuronid e (DMXAA-Glu) and 6-hydroxymethyl-5-methylxanthenone-4-acetic acid (6-OH-MX AA) were constructed over the concentration ranges of 0.25 to 20 and 0.5 to 40 mu M, respectively. Assay performance was determined by intra- and inte r-day accuracy and precision of quality control (QC) samples. The differenc e between the theoretical and measured concentration, and the coefficient o f variation, were less than 15% at low QC concentrations, and less than 10% at medium and high QC concentrations for both analytes. The methods presen ted good accuracy, precision and sensitivity for use in kinetic studies of the glucuronidated and oxidative metabolites of DMXAA in human liver micros omes. (C) 1999 Elsevier Science B.V. All rights reserved.