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Direct determination of phosphorylated intracellular anabolites of stavudine (d4T) by liquid chromatography/tandem mass spectrometry
Author(s) -
Pruvost Alain,
Becher François,
Bardouille Patrick,
Guerrero Catherine,
Cremi Christophe,
Delfraissy JeanFrançois,
Goujard Cécile,
Grassi Jacques,
Benech Henri
Publication year - 2001
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.384
Subject(s) - chemistry , chromatography , selected reaction monitoring , stavudine , tandem mass spectrometry , liquid chromatography–mass spectrometry , electrospray , mass spectrometry , reverse transcriptase inhibitor , electrospray ionization , reverse transcriptase , biochemistry , human immunodeficiency virus (hiv) , viral load , polymerase chain reaction , virology , antiretroviral therapy , gene , biology
Abstract The objective was to develop and validate a routine assay for active intracellular anabolites of stavudine (d4T), a nucleoside reverse transcriptase inhibitor in human PBMC, applicable to pharmacokinetic studies and treatment monitoring. This was achieved using liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS), which theoretically allies optimum sensitivity, specificity and high sample throughput. After cellular lysis in a Tris/methanol buffer, the extract spiked with 2 [H 8 ]‐ATP (internal standard) is directly injected into the LC/MS/MS system. Phosphorylated metabolites of d4T as well as deoxythymidine‐triphosphate, the competitor on the reverse transcriptase, are separated from d4T on a reverse‐phase microbore column with ion pairing. The detection is performed in the multiple reaction monitoring (MRM) mode after drug ionisation in negative mode electrospray. The limit of quantitation for d4T‐TP was 138 fmol per 7 mL blood (9.8 fmol per 10 6 cells) and CV% for repeatability and intermediate precision were lower than 15%. Stability of compounds was checked before and during the process of isolation of PBMC. Cellular samples from several d4T‐treated patients were successfully analysed using this method and d4T‐triphosphate and deoxythymidine triphosphate were recovered. In conclusion, we have developed and validated a routine LC/MS/MS method that allows the simultaneous determination of mono‐, di‐ and triphosphorylated anabolites of d4T in PBMC as well as the natural corresponding triphosphate in one analysis. For the first time, the chain terminator ratio (d4T‐TP/dT‐TP) could be directly measured. This method can be used simply and routinely on more than 35 samples per day. Extension to other nucleoside analogues is under development. Copyright © 2001 John Wiley & Sons, Ltd.