Optimization of the simultaneous determination of imatinib and its major metabolite, CGP74588, in human plasma by a rapid HPLC method using D-optimal experimental design

A novel fluorescent probe based imprinted polymer-coated magnetite for the detection of imatinib leukemia anti-cancer drug traces in human plasma samples

Myeloid leukemia is a chronic cancer, which associated with abnormal BCR-ABL tyrosine kinase activity. Imatinib (IMB) acts as a tyrosine kinase inhibitor and averts tumor growth in cancer cells by controlling cell division, so it is urgent to develop an effective assay to detect and monitor its IMB concentration. Therefore, an innovative fluorescent biomimetic sensor is a promising sensing material that constructed for the efficient recognition of IMB and displays excellent selectivity and sensitivity stemming from molecularly imprinted polymer@Fe3O4 (MIP@Fe3O4). The detection strategy depends on the recognition of IMB molecules at the imprinted sites in the presence of coexisting molecules, which are then transferred to the fluorescence signal. The synthesized MIP@Fe3O4 was characterized using Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Furthermore, computational studies of the band gap (EHOMO-ELUMO) of the monomers, IMB, and their complexes were performed. These results confirmed that the copolymer is the most appropriate and has high stability (Binding energy; 0.004 x 10-19 KJ) and low reactivity. A comprehensive linear response over IMB concentrations from 5 × 10-6 mol/L to 8 × 10-4 mol/L with a low detection limit of 9.3 × 10-7 mol/L was achieved. Furthermore, the proposed technique displayed long-term stability (over 2 months), high intermediate precision (RSD<2.1 %), good reproducibility (RSD <1.9 %), and outstanding selectivity toward IMB over analogous molecules with similar chemical and spatial structure (no interference by 100 to 150-fold of the competitors). Owing to these merits, the proposed fluorescence sensor was utilized to detect IMB in drug tablets and human plasma, and satisfactory results (99.3-100.4 %) were obtained. Thus, the synthesized fluorescence sensor is a promising platform for IMB sensing in various applications.

Evaluation of separation performance for eggshell-based reversed-phase HPLC columns by controlling particle size and application in quantitative therapeutic drug monitoring

Eggshell-based reversed-phase packing materials were applied to an analytical column for high-performance liquid chromatography. Commercially available eggshell powder was classified by a cyclone system to obtain three types of particles with different diameters (arithmetic mean ± standard deviation: 4.3 ± 3.8, 5.6 ± 3.3, and 9.5 ± 5.5 μm). Sedimentation separation removed tiny particles from each sample, resulting in particles with arithmetic means of 6.6 ± 5.5, 7.3 ± 4.5, and 10.2 ± 5.0 μm, respectively. The unclassified particles and three particle types treated with sedimentation separation were subsequently packed into analytical columns (150 mm × 4.6 mm I.D.), and their separation efficiencies were evaluated by comparing their height equivalent to a theoretical plate (HETP). The column without sedimentation separation exhibited the highest HETP, whereas the columns with sedimentation separation showed better separation efficiency and lower back pressure. The column with the best separation efficiency was applied for the separation of 10 alkylbenzenes and 5 steroids, and all peaks were observed with complete separation (peak resolution: R_S > 1.5). Finally, the column was used for quantitative analysis of voriconazole, an azole antifungal agent, and imatinib, a first-generation molecularly targeted drug for cancer treatment, in spiked whole blood. Excellent accuracy (99.1-102.8%) and precision (0.6-1.9%) were observed for the spiked drugs and long-term stability (>3000 column volumes of mobile phase flow) indicated good applicability of the developed eggshell-based column as an analytical column for routine analyses of therapeutic drugs in blood.

Turn-off fluorescence of nitrogen and sulfur carbon quantum dots as effective fluorescent probes for determination of imatinib. Application to biological fluids

Nitrogen and sulfur carbon quantum dots(N,S-CQDs) as effective fluorescent nanoprobes were synthesized through one-step-hydrothermal method using thiosemicarbazide (as nitrogen and sulfur source) and citric acid (as carbon source). The highly fluorescent N,S-CQDs were subjected to various characterization techniques. The fluorescence of the synthesized N,S-CQDs is characterized by maximum fluorescence emission at 415 nm after excitation at 345 nm and a high quantum yield of 0.58. The native N,S-CQDs fluorescence is quantitatively quenched upon addition of imatinib (IMA), so they are used for its spectrofluorimetric determination in its pharmaceutical formulations and biological fluids. Under optimal conditions, N,S-CQDs exhibited a "turn-off" fluorescence response to IMA over the range of 1.0 to 15.0 µg/mL with a limit of quantification of 0.42 µg/mL and a lower detection limit of 0.14 µg/mL. Stern-Volmer equation was used to study the mechanism of quenching and it was found to occur through static quenching mechanism. The method was extended to the in-vitro determination of the drug in spiked human urine and plasma samples and the percent recoveries were satisfactory.

Design of experiments for development and optimization of a liquid chromatography coupled to tandem mass spectrometry bioanalytical assay

Design of experiments (DoE) is a valuable tool for the optimization of quantitative bioanalytical methods utilizing liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Liquid chromatography mass spectrometry (LC-MS) is composed of several processes, including, liquid introduction and analyte ionization. The goal is to transfer analytes from atmospheric pressure to vacuum and maintain conditions that are compatible for both LC and MS. These processes involve many experimental factors which need to be simultaneously optimized to obtain maximum sensitivity and resolution at minimum retention time. In this tutorial, the basic concepts of DoE will be explained with focus on practical use of DoE. Three case studies optimized with DoE for liquid chromatography tandem mass spectrometry (LC-MS/MS) quantitative assays will then be presented.

Experimental design in HPLC separation of pharmaceuticals

Design of Experiments (DoE) is an indispensable tool in contemporary drug analysis as it simultaneously balances a number of chromatographic parameters to ensure optimal separation in High Pressure Liquid Chromatography (HPLC). This manuscript briefly outlines the theoretical background of the DOE and provides step-by-step instruction for its implementation in HPLC pharmaceutical practice. It particularly discusses the classification of various design types and their possibilities to rationalize the different stages of HPLC method development workflow, such as the selection of the most influential factors, factors optimization and assessment of the method robustness. Additionally, the application of the DOE-based Analytical Quality by Design (AQbD) concept in the LC method development has been summarized. Recent achievements in the use of DOE in the development of stability-indicating LC and hyphenated LC-MS methods have also been briefly reported. Performing of Quantitative structure retention relationship (QSRR) study enhanced with DOE-based data collection was recomended as a future perspective in description of retention in HPLC system.

Simultaneous quantification of imatinib and its main metabolite N-demethyl-imatinib in human plasma by liquid chromatography-tandem mass spectrometry and its application to therapeutic drug monitoring in patients with gastrointestinal stromal tumor

The aim of this study was to improve and validate a more stable and less time-consuming method based on liquid chromatography and tandem mass spectrometry (LC- MS/MS) for the quantitative measurement of imatinib and its metabolite N-demethyl-imatinib (NDI) in human plasma. Separation of analytes was performed on a Waters XTerra RP₁₈ column (50 × 2.1 mm i.d., 3.5 μm) with a mobile phase consisting of methanol-acetonitrile-water (65:20:15, v/v/v) with 0.05% formic acid at a flow-rate of 0.2 mL/min. The Quattro MicroTM triple quadruple mass spectrometer was operated in the multiple-reaction-monitoring mode via positive electrospray ionization interface using the transitions m/z 494.0 → 394.0 for imatinib, m/z 479.6 → 394.0 for NDI and m/z 488.2 → 394.0 for IS. The method was linear over 0.01-10 μg/mL for imatinib and NDI. The intra- and inter-day precisions were all <15% in terms of relative standard deviation, and the accuracy was within ±15% in terms of relative error for both imatinib and NDI. The lower limit of quantification was identifiable and reproducible at 10 ng/mL. The method was sensitive, specific and less time-consuming and it was successfully applied in gastrointestinal stromal tumor patients treated with imatinib.

Antineoplastic drugs and their analysis: a state of the art review

We provide an overview of the analytical methods available for the quantification of antineoplastic drugs in pharmaceutical formulations, biological and environmental samples.

Routine therapeutic drug monitoring of tyrosine kinase inhibitors by HPLC-UV or LC-MS/MS methods

Analytical methods using high performance liquid chromatography coupled to ultraviolet detection (HPLC-UV) or liquid chromatography-tandem mass spectrometry (LC-MS/MS) have been reported for the quantification of oral tyrosine kinase inhibitors (TKIs) such as imatinib, nilotinib, and dasatinib in biological fluids. An LC-MS/MS method can simultaneously assay multiple TKIs and their metabolites with high sensitivity and selectivity for low plasma concentrations less than 1 ng/mL. For quantification of imatinib, nilotinib, and dasatinib, a limit of quantification (LOQ) of less than 10 ng/mL, 10 ng/mL, and 0.1 ng/mL, respectively, in the clinical setting is necessary. Because simpler and more cost-efficient methodology is desired for clinical analysis, plasma concentrations of imatinib and nilotinib (target trough concentrations of 1000 ng/mL and 800 ng/mL, respectively) could be assayed by an HPLC-UV method after comparison with results obtained from the standard LC-MS/MS method. However, in the quantification of dasatinib, the LC-MS/MS method that has high sensitivity and selectivity and is free from interference by endogenous impurities is superior to the HPLC-UV method. Highly precise analytical methods are needed for individualized treatment via dose adjustment of oral anticancer drugs, in particular those with low target plasma concentrations less than 10 ng/mL.

Population Pharmacokinetic Analysis of the Oral Absorption Process and Explaining Intra-Subject Variability in Plasma Exposures of Imatinib in Healthy Volunteers

BACKGROUND AND OBJECTIVE

Imatinib mesylate is presently the first-line treatment for chronic myeloid leukemia (CML). The aim of this study was to investigate the absorption and distribution kinetics of imatinib in healthy Iranian volunteers using nonlinear mixed effects modeling (NLMEM) to assess the overall, intra- and inter-subject variabilities in pharmacokinetic parameters after oral administration.

METHODS

This analysis was based on data from 24 healthy subjects who participated in a bioequivalence study after administering a single dose of 200 mg of each formulation. Imatinib concentrations were quantified using a validated liquid chromatography method. To simultaneously describe the imatinib pharmacokinetic profiles obtained with both formulations, a population pharmacokinetic model was applied to data using SAEM algorithm implemented in MONOLIX, whilst simulations were used by numerical solving of ordinary differential equations to calculate secondary parameters in individuals for bioequivalence studies.

RESULTS

According to goodness-of-fit criteria, a two-compartment open model with sequential zero- then first-order absorption and first-order elimination was used as the structural pharmacokinetic model. Inter-individual variability (IIV) was considered for all parameters. Typical population estimates (% IIV) were fraction of the drug absorbed with a zero-order kinetic (Fr) of 0.153 (47.9 %) in period (Tk0) of 0.714 h (47.4 %), first-order absorption rate constant (k a) of 0.94 h(-1)(31.2 %), oral clearance of 19 L/h (27.9 %), central volume of distribution (V c/F) of 139 L (21.5 %), apparent peripheral volume of distribution (V p/F) of 130 L (29.7 %) and the apparent inter-compartment clearance (Q/F) of 29.6 L/h (41.8 %). Body mass index (BMI) was the only covariate found to significantly affect V p /F. The coefficient of variation for intra-individual plasma exposure (AUC0-∞) was 27.8 %.

CONCLUSIONS

Analyses using NLMEM for imatinib exhibited absorption complexities such as two input rates and medium to high intra-individual variability in drug exposure.

Population pharmacokinetics of imatinib in Iranian patients with chronic-phase chronic myeloid leukemia

PURPOSE

We evaluated the population pharmacokinetics (PPK) and exposure-response relationship of imatinib mesylate in Iranian patients with chronic myeloid leukemia (CML).This study was designed to assess steady state (SS) imatinib trough concentrations (Cmin) and pharmacokinetics parameters of imatinib in patients with CML in chronic phase after at least 12-month treatment.

METHODS

Plasma concentrations from a randomized controlled trial consist of 61 patients who received oral imatinib at doses ranged between 300 and 800 mg in various dosing interval, which were quantified using a validated reversed-phase high-performance liquid chromatographic method with UV detection method on different occasions at SS and evaluated using PPK model.

RESULTS

A one-compartment model with zero-order absorption and a lag time was sufficient in describing the concentration-time profile. Inter-individual variability (IIV) was modeled for all parameters. Oral clearance (CL/F) and the volume of distribution (V/F) were estimated to 10.8 L/h with 30 % IIV and 265 L with 53 % IIV, respectively. Inter-occasion variability (IOV) was included in CL/F (17 %) and V/F (22 %).The proportional residual error of the model was 8 %.

CONCLUSIONS

Simulation analysis from individual parameters shows exposure to imatinib is highly variable among patients. Imatinib trough plasma levels <1,257 ng/mL were associated with lower rates of major molecular response. Because of the wide IIV compared with IOV with imatinib in our study, trough levels may play a role in investigating instances of suboptimal response.