Biomedical Engineering Reference
In-Depth Information
processing of blood samples from patients receiving different single-drug or combined
regimens and for maximizing laboratory's resource utilization.
Thus, the development and validation of enhanced throughput methods with
simple extraction procedure followed by LC-MS/MS are of high interest for the
simultaneous analysis of every major anticancer-targeted agent [
130,
131
] , which in
the future may possibly be used also in combination therapy [
132
] .
In that context, an assay limited to the antileukemic drugs imatinib, dasatinib,
and nilotinib was proposed in 2009 implying plasma protein precipitation procedure
followed by reversed-phase chromatography. TKIs detection was made by an ESI
interface, coupled to positive SIM mode single quadrupole mass spectrometer [
133
] .
However, single quadrupole MS analysis is probably not sensitive enough for the
accurate quantification of very low plasma levels of dasatinib. In fact, the lower
limit of quantification for dasatinib reported in this study is 62.5 ng/ml, which cor-
responds to peak plasma concentrations rather than trough dasatinib levels [
134
]
(see Table
2
). This suggests that such an assay, because of the insufficient sensitivity
provided by a single quadrupole mass spectrometer, is of limited clinical usefulness
for a formal therapeutic monitoring of dasatinib.
At about the same time, our laboratory has reported the development and valida-
tion of an LC tandem MS assay for as much as six TKIs simultaneously. The pro-
posed LC-MS/MS method allows the simultaneous determination of clinically
relevant ranges of concentrations for the six major TKIs currently in use imatinib,
dasatinib, nilotinib, sunitinib, sorafenib, and lapatinib [
122
] . Plasma is puri fi ed by
acetonitrile protein precipitation followed by reversed-phase chromatographic sepa-
ration. Analyte quantification is performed by electrospray ionization-triple qua-
drupole mass spectrometry by selected reaction monitoring (SRM) detection using
the positive mode. This was the first broad-range LC-MS/MS assay covering the
major currently in-use TKIs.
Various methodologies have been proposed since then for multiple TKIs assays.
The measurement of the first three marketed TKIs gefitinib, erlotinib, and imatinib
was carried out by liquid-liquid extraction of human plasma, using hexane-ethyl
acetate (30:70, v/v) as extracting solvent. The reconstituted extracts in the organic
upper phase were subjected to reversed-phase HPLC and the TKIs were detected by
electrospray triple quadrupole mass spectrometry, operated in the positive mode
[
135
]. A multiplex analysis of TKIs used for the treatment of solid tumors, (gefitinib,
erlotinib, sunitinib, and sorafenib) was also proposed using plasma protein precipi-
tation with acetonitrile, supernatant injection into reversed-phase column, and TKIs
detection/quantification by a triple quadrupole mass spectrometer equipped with a
turbo-spray ionization operating in positive multi-reaction-monitoring-mode [
136
] .
Just recently, Götze et al. have published a multiplex assay for the determination of
erlotinib, imatinib, lapatinib, nilotinib, sorafenib, and sunitinib that was proposed
for routine clinical application [
137
]. Finally, an assay allowing the determination
of as much as nine TKIs simultaneously (imatinib, its metabolite, nilotinib, lapa-
tinib, erlotinib, sorafenib, dasatinib, axitinib, gefitinib, and sunitinib) has been
recently developed by Bouchet et al., using 96-well SPE plates and UPLC tandem
MS [
138
] .
