Method development for determination of imatinib and its major metabolite, N-desmethyl imatinib, in biological and environmental samples by SA-SHS-LPME and HPLC.

A salting-out-assisted switchable hydrophilicity solvent-based liquid phase microextraction (SA-SHS-LPME) was developed for the separation and determination of trace amounts of imatinib and N-desmethyl imatinib in biological and environmental samples by HPLC-UV. Triethylamine as a hydrophobic compound and protonated triethylamine carbonate as a hydrophilic one were switched by the addition or elimination of CO2 . The use of NaOH resulted in the elimination of CO2 from the sample solution, which led to the conversion of P-TEA-C into triethylamine (TEA) and as a result, the analytes was extracted and entered the TEA phase. The salting out was performed to speed up the formation of the TEA in the shape of fine droplets in the specimen solution. Furthermore, the impact of several momentous factors that influence the recovery of the extraction was investigated. Under the optimum conditions, the limit of detection and limit of quantification were obtained in ranges of 0.03-0.05 and 0.1-0.15 µg L-1 for imatinib and 0.04-0.06 and 0.13-0.20 µg L-1 for N-desmethyl imatinib, respectively. The preconcentration factor was 250. Inter- and intraday precision (RSD, n = 5) was <5%. In the case of imatinib and N-desmethyl imatinib in biological and environmental specimens, a range of 97.0-102% was obtained as the recovery.

Thermosensitive molecularly imprinted poly(1-vinyl-2-pyrrolidone/methyl methacrylate/N-vinylcaprolactam) for selective extraction of imatinib mesylate in human biological fluid.

The efficiency of a molecularly imprinted polymer as a selective packing material for the solid-phase extraction of imatinib mesylate sorption was investigated. The molecularly imprinted polymer was prepared using N,N'-methylenebisacrylamide as a cross-linker agent, N-vinylcaprolactam as a thermo-sensitive monomer, 1-vinyl-2-pyrrolidone and methyl methacrylate as functional monomers, azobisisobutyronitrile as an initiator and imatinib mesylate as a template. The drug-imprinted polymer was identified by Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis, and scanning electron microscopy. It was found that this polymer can be used for determination of trace levels of imatinib mesylate with a recovery percentage that could reach over 90%. Furthermore, the synthesized molecularly imprinted polymer indicated higher selectivity towards imatinib mesylate than other compounds. From isotherm study, the equilibrium adsorption data of imatinib mesylate by imprinted polymer were analyzed by Langmuir, Freundlich, and Temkin isotherm models. The developed method was used for determination of imatinib mesylate in human fluid samples by high performance liquid chromatography with excellent results.

Rapid ionic liquid-supported nano-hybrid composite reinforced hollow-fiber electromembrane extraction followed by field-amplified sample injection-capillary electrophoresis: An effective approach for extraction and quantification of Imatinib mesylate in human plasma.

The focus of this study is development of a new, convenient, rapid and sensitive electromembrane extraction approach (based on an ionic liquid-supported MWCNTs/ZnO reinforced hollow fiber, for the first time) as an off-line sample clean-up/preconcentration method coupled with capillary electrophoresis (CE-UV) using field-amplified sample injection (FASI) for quantification of Imatinib mesylate in human plasma. The nano-hybrid sorbent, coated by 1-octyl-3-methylimidazolium bromide ionic liquid ([OMIm]Br) in this research, was prepared by a feasible basic catalyzed sol-gel method. Then, it was immobilized (supported by capillary forces and sonication) in pores of a segment of a polypropylene hollow fiber membrane as the extraction unit after dispersing in 2-nitrophenyl octyl ether (NPOE) solvent and subsequently served as the supported liquid membrane (SLM) composition. Significant variables affecting the proposed method were evaluated and optimized to achieve the maximum extraction performance. Optimal conditions were obtained by NPOE with 4mgmL-1 nano-sorbent as the SLM composition, 105V as the driving force, pH 2 and 1.8 of the donor and acceptor phases, respectively, an extraction time of 15min and an agitation rate of 800rpm. The developed method was validated according to FDA guidelines. Regarding the validation results, the method is proved to be linear (R2=0.998) over concentrations ranging from 25 to 1500ngmL-1 (LOD=6.24ngmL-1). The mean RSD values for intra- and inter-day precision studies were 6.83 and 7.71%, respectively and the mean recoveries ranged between 98 and 106%. Finally, the validated method was successfully applied for sensitive, selective and rapid determination of Imatinib in patient's plasma samples.

An ultra-specific and sensitive sandwich ELISA for imatinib using two anti-imatinib antibodies.

The development of an immunoassay for a low-molecular-weight drug first requires the identification of specific antibodies that do not cross-react with the drug's metabolites. If two antibodies can simultaneously recognize the entire structure of the drug, we can then utilize them to establish an ultra-specific sandwich ELISA, free from interference due to the metabolic products of the drug. This paper reports an ultra-specific and sensitive sandwich ELISA for determination of the tyrosine kinase inhibitor imatinib using two anti-imatinib antibodies. The anti-imatinib antibodies were obtained by two partial structures of imatinib as haptens (2-(5-amino-2-methylanilino)-4-(3-pyridyl)pyrimidine and 4-{(4-methyl-1-piperazinyl)-methyl}-benzoate). Under optimized conditions, this sandwich ELISA shows a linear detection range from 64 pg mL-1 to 8 ng mL-1, and a limit of detection of approximately 64 pg mL-1 for 100-µL samples. The ELISA is specific to imatinib and while there was no cross-reactivity with the major metabolite N-desmethyl-imatinib, slight cross-reactivity was found with metabolite pyridine-N-oxide-imatinib. This assay demonstrated significantly lower cross-reactivity with metabolites than competitive ELISAs. Using this assay, drug levels were easily measured in rat blood after oral administration of imatinib via a single dose of 30 mg kg-1 or 100 mg kg-1. The levels in rat serum measured by this ELISA were comparable with those measured by HPLC, and there was a strong correlation between the values determined by the two methods (y = 0.983x + 0.081, R2 = 0.948). Thus, we have successfully developed the first specific and sensitive sandwich ELISA for imatinib using two anti-imatinib antibodies. This sandwich ELISA will be a valuable tool for therapeutic drug monitoring and pharmacokinetic studies of imatinib.

The metal-organic framework MIL-101(Cr) as efficient adsorbent in a vortex-assisted dispersive solid-phase extraction of imatinib mesylate in rat plasma coupled with ultra-performance liquid chromatography/mass spectrometry: Application to a pharmacokinetic study.

Metal-organic framework MIL-101(Cr) was successfully used as an efficient sorbent in a vortex-assisted dispersive solid-phase extraction (VA-DSPE) and applied for the determination and the pharmacokinetic of imatinib mesylate in rat plasma by UPLC-MS/MS. In the enrichment of imatinib from rat plasma, the analyte was efficiently adsorbed on MIL-101(Cr) and simply recovered by using initial mobile phase (0.1% formic acid-methanol (6:4 v/v)) as elution solvent. Meanwhile, the protein in the plasma samples was excluded from the porous structure of MIL-101(Cr), leading to direct extraction of drug molecule from protein-rich biological samples without any other pretreatment procedure. After being removed, the supernatant was filtered and directly injected into the UPLC-MS/MS for the analysis of the target. The experimental parameters, including nature of MOFs, amount of MIL-101(Cr), pH value of aqueous solution, extraction time, type and volume of elution solvent, were systematically optimized. After VA-DSPE, chromatographic separation was performed on an ACQUITY UPLC(®) BEH C18 column (2.1mm×100mm, 1.7µm) with a 3min gradient elution using 0.1% formic acid and methanol as mobile phase at a flow rate of 0.3mL/min. The detection was accomplished on a tandem mass spectrometer via an electrospray ionization (ESI) source by multiple reaction monitoring (MRM) in the positive ionization mode. The lower limit of quantification of 1ng/mL was achieved and the mean recovery of the analyte was higher than 81.2%. Moreover, computational simulation was primarily applied to predict the adsorption behavior and revealed the molecular interactions and free binding energies between MIL-101(Cr) and imatinib with the molecular modeling method, providing certain explanation of the adsorption mechanism. The originally established pretreatment and detection method has some merits, such as less solvent consumption, easy operation, higher sensitivity and lower matrix effect. And the MIL-101(Cr) exhibited a potential as an efficient sorbent in the enrichment of the analyte from complex biosamples.