SIMULTANEOUS DETERMINATION OF A NOVEL ANTICANCER DRUG, TAS-103, AND ITS N-DEMETHYLATED METABOLITE IN MONKEY PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY USING SOLID-PHASE EXTRACTION

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 bee n developed. This method is based on high-performance liquid chromatog raphy with visible detection at 460 nm after solid-phase extraction wi th a Sep-Pak Vac PS-2 cartridge. The extraction recoveries of each com pound, including the internal standard TAS-1-018, were from 88 to 102% . The quantitation limit of each compound was 5.0 ng/ml in 0.5 ml of p lasma. 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 3 9 days and the extracts were stable at ambient temperature for 24 h. T his method has been demonstrated to be useful for the pharmacokinetic study of TAS-103 in monkey plasma after intravenous administration.