High-performance liquid chromatography/tandem mass spectrometry for the quantitative analysis of a novel taxane derivative (BAY59-8862) in biologicalsamples and characterisation of its metabolic profile in rat bile samples

A sensitive, specific, accurate and reproducible high-performance liquid ch romatography (HPLC) analytical method was developed and validated for the q uantification of the novel oral taxane analogue BAY59-8862 in mouse plasma and tissue samples. A fully automated solid-phase extraction procedure was applied to the plasma after internal standard (IS) addition, with only 0.2 mL volume of the sample loaded on a CN-Sep-pak cartridge. In the case of th e tissues a very simple acetonitrile extraction was used to recover BAY59-8 862 and its internal standard from liver. The procedure for the quantificat ion of BAY59-8862 and its IS (IDN5127) is based on high-performance liquid chromatography/ion spray-tandem mass spectrometry, operating in selected io n monitoring mode. The retention times of BAY and IS were 7.21 and 10.36 mi n, respectively. In both plasma and tissue specimens the assay was linear i n the range 50-5000 ng/mL (ng/g). The overall precision and accuracy were a ssessed on three different days. The results for plasma were within 6.1% (p recision) and between 99 and 112% (accuracy), and for the liver samples wit hin 7.3% and between 104 and 118%, respectively. The LOD was 5 ng/mL and 20 ng/g in the plasma and liver, respectively. In addition, the biliary excre tion of the compound in rats was studied. The study showed that an oxidativ e chemical reaction was the preferred metabolic pathway for biliary excreti on, and two sets of mono- and dihydroxylated metabolites were detected by L C/ISP-MS/MS experiments. With this method, BAY59-8862 pharmacokinetic was d etermined in mice. The combined results demonstrate that the methodology ca n be considered a valid approach to conduct pharmacokinetic and metabolic s tudies during preclinical and clinical investigations. Copyright (C) 2001 J ohn Wiley & Sons, Ltd.