• epothilone D analog;
  • ultra-performance liquid chromatography–tandem mass spectrometry;
  • human plasma


A novel ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS-MS) method has been established for the determination of a newly synthesized epothilone D analog (AV-EPO-106) in human plasma. The plasma samples were prepared by liquid–liquid extraction with cold tert-butyl methyl ether. The chromatographic separation was achieved within 5 min on a C18 column with water–methanol (10:90, v/v) as mobile phase at a flow-rate of 0.8 mL/min. Mass transition of m/z 568.2 to 386.1 was measured for AV-EPO-106 in positive atmospheric pressure chemical ionization mode. A detailed validation of the method was performed as per the USFDA guidelines. For AV-EPO-106 at the concentrations of 1.0, 5.0 and 10.0 µg/mL in human plasma, the absolute extraction recoveries were 86.17, 85.24 and 85.69%, respectively. The linear quantification range of the method was 0.10–20.0 µg/mL in human plasma with linear correlation coefficients greater than 0.999. The intra-day and inter-day accuracy for AV-EPO-106 at the levels of 1.0, 5.0 and 10.0 µg/mL in human plasma fell in the ranges of 98.25–100.47 and 94.19–97.25%, and the intra- and inter-day precision were in the ranges of 4.75–6.30% and 8.89–10.45%, respectively. The method was successfully applied to quantify AV-EPO-106 in human plasma to determine the half-life of this compound in human plasma. Copyright © 2008 John Wiley & Sons, Ltd.