Determination of a novel antiangiogenic agent KR-31831 in rat plasma by liquid chromatography-tandem mass spectrometry

A liquid chromatography-tandem mass spectrometric (LC/MS/MS) method was developed for the determination of a new anti-angiogenic drug KR-31831 in rat plasma. KR-31831 and internal standard, KR-31543 were extracted from rat plasma with dichloromethane at basic pH. A reverse-phase LC separation was performed on Luna C8 column with the mixture of acetonitrile-ammonium formate (10 mM, pH 4.5) (67: 33, v/v) as mobile phase. The detection of analytes was performed using an electrospray ionization tandem mass spectrometry in the multiple-reaction-monitoring mode. The standard curve was linear (r = 0.999) over the concentration range of 1.0-500 ng/mL. The coefficient of variation of intra- and inter-assay ranged from 0.8-3.9% and 1.4-3.9%, respectively. The recoveries of KR-31831 ranged from 80.9% to 86.7%, with that of KR-31543, (internal standard) being 99.2 +/- 2.7%. The lower limits of quantification for KR-31831 was 1.0 ng/mL using 100 muL plasma sample. This method was applied to the pharmacokinetic study of KR-31831 in rats.