Measuring methotrexate polyglutamates in red blood cells: a new LC-MS/MS-based method.

@article{Boer2013MeasuringMP,
  title={Measuring methotrexate polyglutamates in red blood cells: a new LC-MS/MS-based method.},
  author={Ethan den Boer and Roland J W Meesters and Bertrand D van Zelst and Theo M. Luider and Johanna M. W. Hazes and Sandra G. Heil and Robert de Jonge},
  journal={Analytical and bioanalytical chemistry},
  year={2013},
  volume={405 5},
  pages={1673-81}
}
The folate antagonist methotrexate (MTX) is the anchor drug in the treatment of rheumatoid arthritis. The therapeutic effects of MTX are attributed to the intracellular levels of MTX, present in the cell as polyglutamates (MTXPGn). We developed a new liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS)-based assay to separately quantitate MTXPGn in red blood cells using stable-isotope-labelled internal standards. Samples were analyzed by LC-ESI-MS/MS using a… CONTINUE READING