Simultaneous determination of a novel anticancer drug, TAS-103, and its N-demethylated metabolite in monkey plasma by...

A simple and rapid method for the analysis of a novel anticancer drug, TAS-103, and its metabolite demethyl-TAS-103 in monkey plasma has been developed. This method is based on high-performance liquid chromatography with visible detection at 460 nm after solid-phase extraction with a Sep-Pak Vac PS-2 cartridge. The extraction recoveries of each compound, including the internal standard TAS-1-1018, were from 88 to 102%. The quantitation limit of each compound was 5.0 ng/ml in 0.5 ml of plasma. The coefficients of variation for each compound ranged from 0.9 to 4.9%, and relative errors for each compound ranged from -3.8 to 4.6%. Both compounds in monkey plasma were stable at -80 degrees C for 39 days and the extracts were stable at ambient temperature for 24 h. This method has been demonstrated to be useful for the pharmacokinetic study of TAS-103 in monkey plasma after intravenous administration.