Imatinib metabolite profiling in parallel to imatinib quantification in plasma of treated patients using liquid chromatography–mass spectrometry

Abstract

Besides affecting the systemic bioavailability of the parent drug, drug metabolizing enzymes (DMEs) may produce bioactive and/or toxic metabolites of clinical interest. We have investigated the capability to analyze simultaneously the parent drug and newly identified metabolites in patients' plasma by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The anticancer drug, imatinib, was chosen as a model drug because it has opened a new area in cancer therapy and is given orally and chronically. In addition, resistance and rare but sometimes severe side effects have been reported with this therapy. The quantification of imatinib and the profiling of its metabolites in plasma were established following three steps: (1) set-up of a generic sample extraction and LC-MS/MS conditions, (2) metabolite identification by LC-MS/MS using either in vitro incubations performed with human liver microsomes (HLMs) or patient plasma samples, (3) the simultaneous determination of plasma levels of imatinib and 14 metabolites in the plasma samples of 38 patients. Partial or cross method validation has been done and revealed that precise determinations of metabolite levels can be performed whereas pure standards are not available. Preliminary results indicate that the disposition of imatinib and its metabolites is related to interindividual variables and that outlier metabolite profiles can be revealed. This article underscores that, in addition to usual therapeutic drug monitoring (TDM), LC-MS/MS methods can simultaneously record a complete drug metabolic profile enabling various correlation studies of clinical interest.

Drug interactions with the tyrosine kinase inhibitors imatinib, dasatinib, and nilotinib

“…7 TKIs are extensively metabolized by cytochrome P450 enzymes (CYP), whose activities are characterized by a large degree of interindividual variability. 8 Some TKIs are also substrates or inhibitors of the drug transporters P-glycoprotein (Pgp; coded by ABCB1) Breast Cancer Resistance Protein (BCRP; ABCG2) and the organic cation transporter 1 (hOCT1; SLC22A1). [9][10][11][12][13] A standard regimen can therefore produce very different circulating and cell concentration profiles from one patient to another, thus favoring the selection of resistant cellular clones by subtherapeutic drug exposure or the occurrence of toxicity in case of overexposure.…”

Relationship of imatinib-free plasma levels and target genotype with efficacy and tolerability

“…Hostdependent mechanisms of resistance have also been incriminated, including modulation of imatinib binding to a 1 -acid glycoprotein (AGP) in plasma (Gambacorti-Passerini et al, 2000;GambacortiPasserini et al, 2003;Larghero et al, 2003) and/or possibly enhanced drug metabolism (Rochat et al, 2008). Finally, nonadherence to imatinib dosage regimen may also play a role in resistance (Tsang et al, 2006).…”

Rapid Determination of Imatinib in Human Plasma by Liquid Chromatography-Tandem Mass Spectrometry: Application to a Pharmacokinetic Study

“…[3][4][5][6][7][8][9][10][11][12] Several papers reported the employment of solid-phase extraction (SPE) procedure 6,11 or liquid-liquid extraction (LLE) technique 7,8 to develop more sensitive quantitative method by the selective extraction and enrichment of imatinib from plasma. On the other hand, protein precipitation has also been described for simple sample preparation.…”

“…[3][4][5]9,10,12 In most case, reversedphase liquid chromatography (RPLC) has been applied to separation of imatinib due to its non-polarity although hydrophilic interaction liquid chromatography (HILIC) served as an alternative technique to RPLC by Hsieh et al 9 The aim of this study was to develop an efficient LC-MS/ MS method, which exhibited improved performance in terms of sensitivity, robustness, run time and sample preparation, to determine imatinib in human plasma. The LC-MS/MS methods, described by the previous studies, [3][4][5][6][7][8][9][10][11][12] had some limitations of time consumption, cost and method complexity due to high volume requirement of plasma sample by low dilution factor (4 to 11), relatively long run time (3 to 12 min) and complex extraction methods such as solid-phase extraction and liquid-liquid extraction. Unlike the previous studies, our method achieved protein precipitation for extraction, high dilution factor of plasma (14.4), retention time of 1.3 min and high-throughput analyses of real samples (n = 1101) that resulted in high sensitivity, simplicity of sample preparation, short run time and good robustness.…”