Novel method for fast trabectedin quantification using hydrophilic interaction liquid chromatography and tandem mass spectrometry for human pharmacokinetic studies

Few time-consuming bioanalytical methods are currently available for trabectedin quantification in clinical investigations. Here we present a novel, fast and sensitive method for trabectedin determination in human plasma based on hydrophilic interaction liquid chromatography and tandem mass spectrometry (HILIC-MS/MS). Plasma samples are treated with acetonitrile–0.1 % formic acid and the solvent extract is directly injected into an Acquity BEH Amide column (2.1 × 100 mm, 1.7 μm) operating in HILIC mode at 0.2 mL/min with 80:20 acetonitrile–0.1 % formic acid in water. The analyte is separated by an organic solvent gradient and quantified by an Agilent Ultivo triple quadrupole mass spectrometer operating in multiple reaction monitoring (MRM) mode. The quantitative MRM transitions were m/z 762→234 and m/z 765→234 for trabectedin and its d₃-labeled derivative, respectively. The lower limit of quantification (LLOQ) was 0.01 ng/mL and the assay was linear up to 2.5 ng/mL. The intra- and inter-day relative error ranged from 1.19 % to 8.52 %, while the relative standard deviation was less than 12.35 %. The method was used to determine the pharmacokinetic profiles of trabectedin in 26 patients with soft tissue sarcoma, showing that this new HILIC-MS/MS method is suitable for use in clinical research.