Simultaneous quantification of MTC-220 and its metabolites in beagle dog plasma by liquid chromatography-tandem mass spectrometry

A sensitive LC-ESI-MS/MS method for simultaneous determination of MTC-220 and its metabolites (paclitaxel and MDA-linker) in dog plasma has been developed and validated. After addition of docetaxel (internal standard), plasma samples containing MTC-220, paclitaxel and MDA-linker were prepared based on a simple protein precipitation by adding two volumes of acetonitrile. The separation was performed on a ZorbaxSB-C18 column (3.5 mu m, 2.1 mm x 100 mm) at a flow rate of 0.2 ml/min, using acetonitrile/water containing 0.1% formic acid (v/v) as mobile phase. The detection was performed on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization (ESI) by selected reaction monitoring (SRM). The MS/MS ion transit ions monitored were 1444.4 -> 623.8 for MTC-220, 876.4 -> 307.9 for paclitaxel, 631.2 -> 531.2 for MDA-linker and 830.2 -> 549.1 for the internal standard. Linear detection responses were obtained for MTC-220, paclitaxel and MDA-linker ranging from 10 to 5000, 5 to 2500 and 5 to 500 ng/ml, respectively. The lower limits of quantitation (LLOQs) for MTC-220, paclitaxel and MDA-linker were 10, 5 and 5 ng/ml, respectively. The intra-day and inter-day precisions (RSD, %) of the three analytes do not exceed 10.9% except for LLOQs (<= 17.50), and the accuracy (RE, %) were within +/- 17.5% for LLOQs and +/- 12.6% for the others. The average recoveries of three compounds were greater than 85.0%. The analytes were proved to be stable during all sample storage, preparation and analytic procedures. The validated method was successfully applied to pharmacokinetic studies of MTC-220 and its metabolites in beagle dogs after intravenous infusion of MTC-220 at 2.5 mg/kg.. (C) 2014 Elsevier B.V. All rights reserved.