An LC-MS/MS method for rapid and sensitive high-throughput simultaneous determination of various protein kinase inhibitors in human plasma

Development of a green high-performance liquid chromatography method for tofacitinib quantification in pharmaceutical formulations and degradation studies

A new high-performance liquid chromatography (HPLC) method was applied for the quantification of the active substance of tofacitinib. Analysis was performed on a Chromasil 100 C18 (100.0 × 4.0 mm, 3.5 μm) stationary phase. The mobile phase consisted of acetonitrile:0.2% phosphoric acid in water (12:88, v/v). The prepared sample (20.0 μL) was injected into the system. A detection wavelength of 285.0 nm was chosen for the compound, and the flow rate was 0.8 mL/min. The experiment was completed in 5.0 min. The analysis temperature was set to 40.0°C. The method was evaluated using green chemistry. The method was validated according to the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines. For linearity studies calibration curves were constructed in the range of 10.0-200.0 μg/mL. The recovery values were calculated at 97.66% and 105.68%. The method developed for the analysis of the active substance had a short analysis time and was cost-effective. It is an environmentally friendly method due to the mobile phase content used. The technique can be used in laboratory analysis and bioequivalence experiments.

Pharmacokinetics of Afatinib after Intravenous and Oral Administrations in Rats Using Validated UPLC MS/MS Assay

Afatinib is designated as the first-line management therapy for patients with advanced non-small cell lung cancer, and metastatic head and neck cancer. LC coupled to MS/MS can be utilised in therapeutic drug monitoring to ensure optimal use of Afatinib with the reduction of its possible adverse reactions. The aim of this investigation was to determine the pharmacokinetics of Afatinib in rats after single IV (2 mg/kg) and oral (8 mg/kg) doses. Therefore, a selective, sensitive and precise UPLC MS/MS assay thru electrospray ionisation basis with positive ionisation approach was established to measure Afatinib concentrations in the rat. The precision and accuracy of the developed assay method in the concentration range of 10-1000 ng/ml show no significant difference among inter- and-intra-day analysis (P > 0.05). Linearity was detected over the studied range with correlation coefficient, r > 0.995 (n = 6/day). The pharmacokinetics of Afatinib in the rat after a single IV dose showed a mean terminal half-life of 4.6 ± 0.97 h, and a mean clearance 480 ± 80 ml/h/kg. After PO administration, a short absorption phase with a mean Tmax of 1.3 ± 0.6 h with the highest concentration of 513.9 ± 281.1 ng/ml, and the lowest concentration detected after 24 h was 18.8 ± 10.7 ng/ml.

Pharmacokinetics of Anti-rheumatic Drugs Methotrexate and Tofacitinib with its Metabolite M9 in Rats by UPLC-MS/MS

BACKGROUND

Tofacitinib is an oral JAK inhibitor for the treatment of rheumatoid arthritis (RA). The clinical efficacy and safety of an administered tofacitinib, either monotherapy or in combination with conventional synthetic disease-modifying anti-rheumatic drugs, mainly methotrexate (MTX), have been evaluated. The high plasma concentration with delayed medicine clearance may affect the liver and/or kidney functions. In this study, an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC- MS/MS) method for the quantitative analysis of methotrexate, tofacitinib, and metabolite M9 in plasma of Sprague Dawley (SD) rats was developed, and its effectiveness was validated as well.

METHODS

Methotrexate, tofacitinib, M9 and fedratinib (internal standard, IS) were separated by gradient elution. The chromatography was performed on an Acquity BEH C18 (2.1 mm × 50 mm, 1.7 μm) column with the mobile phases of acetonitrile and 0.1% formic acid aqueous solution with different proportions at the flow rate of 0.30 mL/min. In the positive ionization mode, the analyzes were detected using a Xevo TQ-S triple quadrupole tandem mass spectrometer, with the following mass transition pairs: m/z 313.12 → 148.97 for tofacitinib, m/z 329.10 → 165.00 for M9 and m/z 455.12 → 308.05 for methotrexate.

RESULTS

The obtained results manifested good calibration linearity over the ranges of tofacitinib at 0.1-100 ng/mL, M9 at 0.05-100 ng/mL, and methotrexate at 0.05-100 ng/mL. The lower limit of quantifications (LLOQs) of methotrexate, tofacitinib and M9 were 0.05 ng/mL, 0.1 ng/mL and 0.05 ng/mL, respectively. Intra-day and inter-day accuracy values were confirmed with a range of -6.3% to 12.7%, while intra-day and inter-- day precision values were ≤14.4%. Additionally, recoveries were greater than 86.5% for each compound without significant matrix effects.

CONCLUSION

The currently established analytical method exhibited great potential for the evaluation of plasma concentrations of methotrexate, tofacitinib and M9 simultaneously, greatly reducing the detection time, which would serve as a supplementary role in formulating dose decisions to achieve personalized treatment, identify drugs that cause adverse reactions and finally, to assess drug-drug interactions on clinical studies.

Development and validation of a multiplex HPLC-MS/MS assay for the monitoring of JAK inhibitors in patient plasma

Janus kinase inhibitors (JAKi) are oral small molecules used in the treatment of a broad spectrum of autoimmune and myeloproliferative diseases. JAKi exhibit significant intra- and inter-individual pharmacokinetic variabilities, due to fluctuations in compliance with oral treatments and their metabolism essentially driven by cytochrome P450 enzymes. Intrinsically, JAKi have dose-response relationship and narrow therapeutic index: therapeutic drug monitoring (TDM) is expected to optimize and adapt their dosage regimen in order to resolve problems of efficacy and tolerance linked to dose and safety. A sensitive analytical method using multiplex high-performance liquid-chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) was developed and validated for the simultaneous quantification in plasma of the 6 major currently used JAKi, namely abrocitinib, baricitinib, fedratinib, ruxolitinib, tofacitinib, and upadacitinib. Plasma samples are subjected to protein precipitation with MeOH, using stable isotopically labelled internal standards. The separation of JAKi in supernatants diluted 1:1 with ultrapure H2O was performed using a C18 column Xselect HSS T3 2.5 µm, 2.1x150 mm using a mobile phase composed of formic acid (FA) 0.2% and acetonitrile (+FA 0.1%) in gradient mode. The analytical run time for the multiplex assay was 7 min. JAKi drugs were monitored by electrospray ionization in the positive mode followed by triple-stage quadrupole MS/MS analysis. The method was validated according to SFSTP and ICH guidelines over the clinically relevant concentration ranges (0.5-200 ng/mL for abrocitinib, baricitinib and upadacitinib; 1-400 ng/mL for tofacitinib; 0.5-400 ng/mL for ruxolitinib, and 10-800 ng/mL for fedratinib). This multiplex HPLC-MS/MS assay achieved good performances in term of trueness (91.1-113.5%), repeatability (3.0-9.9%), and intermediate precision (4.5-11.3%). We developed and validated a highly sensitive method for the multiplex quantification of the JAKi abrocitinib, baricitinib, fedratinib, ruxolitinib, tofacitinib, and upadacitinib in human plasma. The method will be applied for prospective clinical pharmacokinetic studies to determine whether TDM programs for JAKi based on residual drug concentrations can be recommended using disease-specific therapeutic ranges.

Simultaneous quantification of donafenib, sorafenib, and their N-oxide metabolites in rat plasma using a HPLC-MS/MS method

Donafenib and sorafenib are small molecule chemotherapy drugs for the management of hepatocellular carcinoma, with donafenib being a deuterated derivative of sorafenib. To date, a high liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method that quantify donafenib, sorafenib, and their main metabolites has not yet been developed. The objective of this study was to establish a HPLC-MS/MS method for the simultaneous detection of donafenib, donafenib-N-oxide, sorafenib, and sorafenib-N-oxide and for the pharmacokinetic studies in rat. The extraction of all analytes was achieved by simple protein precipitation utilizing acetonitrile. The Waters XBridge C18 column (2.1 × 100 mm, 3.5 µm) was selected, and the analytes could be efficiently separated and quantitated during a 2.8 min gradient elution procedure. The method was linear within the predefined quantification ranges and provided acceptable precision (%CV < 9.4%), reproducible extraction recovery (99.4%-111.5%), and low matrix effect (88.1%-98.6%). The hemolysis effect did not interfere with the quantification of all analytes, and similar results were obtained by changing the anticoagulant K2-EDTA to heparin or sodium citrate. Plasma pharmacokinetics revealed that the values of t1/2, Cmax, and AUC0-t of donafenib were 1.4-, 6.2-, and 3.1-fold higher than those of sorafenib, respectively. In conclusion, the proposed bioassay was successfully applied to pharmacokinetic studies in rat after administration of donafenib and sorafenib. Our work not only improves the bioanalytical method for determining the plasma concentrations of donafenib, sorafenib, and their N-oxide metabolites, but also provides a scientific reference for clinical pharmacokinetic studies.

Quantitation of Cabozantinib in Human Plasma by LC-MS/MS

To support a phase III randomized trial of the multi-targeted tyrosine kinase inhibitor cabozantinib in neuroendocrine tumors, we developed a high-performance liquid chromatography mass spectrometry method to quantitate cabozantinib in 50 μL of human plasma. After acetonitrile protein precipitation, chromatographic separation was achieved with a Phenomenex synergy polar reverse phase (4 μm, 2 × 50 mm) column and a gradient of 0.1% formic acid in acetonitrile and 0.1% formic acid in water over a 5-min run time. Detection was performed on a Quattromicro quadrupole mass spectrometer with electrospray, positive-mode ionization. The assay was linear over the concentration range 50-5000 ng/mL and proved to be accurate (103.4-105.4%) and precise (<5.0%CV). Hemolysis (10% RBC) and use of heparin as anticoagulant did not impact quantitation. Recovery from plasma varied between 103.0-107.7% and matrix effect was -47.5 to -41.3%. Plasma freeze-thaw stability (97.7-104.9%), stability for 3 months at -80°C (103.4-111.4%), and stability for 4 h at room temperature (100.1-104.9%) were all acceptable. Incurred sample reanalysis of (N = 64) passed: 100% samples within 20% difference, -0.7% median difference and 1.1% median absolute difference. External validation showed a bias of less than 1.1%. This assay will help further define the clinical pharmacokinetics of cabozantinib.

Development of novel univariate and multivariate validated chemometric methods for the analysis of dasatinib, sorafenib, and vandetanib in pure form, dosage forms and biological fluids

New precise, responsive and selective univariate and multivariate chemometric spectrophotometric methods were developed and validated for determination of vandetanib (VTB), dasatinib (DTB), and sorafenib (SFB) in pure form, tablets, spiked human (plasma and urine). Determination of these drugs is essential because of their therapeutic benefits. These methods included double divisor ratio spectra derivative univariate method and chemometric multivariate method including partial least-squares (PLS) and principal component regression (PCR). A novel univariate method was developed for the estimation of these drugs. This method depends on the UV-Spectrophotometric data for simultaneous analysis of a ternary overlapped mixture. The Double divisor ratio spectra derivative absorption minima at 358.4 nm was used for quantification of VTB, absorption maxima at 300.3 nm for quantification of DTB and absorption maxima at 259.8 nm for quantification of SFB. This method shown a linearity in the extent of 2-9 μg/mL for VTB and DTB and over the concentration range of 3-9 μg/mL SFB within correlation coefficient (r2) of 0.9999. This method was successfully applied to pure form, tablet dosage form, spiked human (urine and plasma). Chemometric PLS and PCR models were found to be linear in the range of 2-9, 2-9, and 3-9 μg/mL for VTB, DTB and SFB, respectively. These models were estimated using eighteen mixtures as calibration set and seven mixtures as validation set. In the original data, the minimum root mean square error of prediction (RMSEP) was 0.11, 0.09 and 0.09 for VTB, DTB and SFB by PLS and 0.05, 0.04 and 0.03 by PCR while in the derivative data, the RMSEP was 0.09, 0.10 and 0.09 by PLS and 0.06, 0.06 and 0.03, by PCR for VTB, DTB and SFB, respectively. These methods were applied for the determination of the drugs in pure form and dosage form. Updating PLS model permitted the determination of the VTB, DTB and SFB in spiked human urine, plasma and drug-dissolution test of their tablet.

Simple and efficient spectroscopic-based univariate sequential methods for simultaneous quantitative analysis of vandetanib, dasatinib, and sorafenib in pharmaceutical preparations and biological fluids

Six sequential spectrophotometric-based univariate methods were developed and validated for the simultaneous estimation of three novel anticancer drugs vandetanib (VAN), dasatinib (DAS), and sorafenib (SOR) in a mixture, without the requirement for separation. These methods are novel, simple, precise, and accurate. Different steps including zero crossing, ratio-based, and/or derivative spectra were utilized to develop these analytical methods, namely, ratio difference spectrophotometric method, constant center method, successive derivative ratio method, isoabsorptive method, mean centering of the ratio spectra method, and derivative ratio spectrum-zero crossing method. The calibration curve linearity was ranged from 2 to 9, 2-9, and 3-9 μgmL^-1 for VAN, DAS, and SOR, respectively. These established methods were applied for the quantification of the three selected drugs in different biological fluids (spiked human plasma and urine) and pharmaceutical preparations. The aforementioned methods were established for the concurrent estimation of ternary and binary mixtures to enhance the signal-to-noise ratio. The results did not statistically differ from the other reported methods, indicating no significant difference in accuracy and precision at p = 0.05.

LC-MS/MS Estimation of Rociletinib Levels in Human Liver Microsomes: Application to Metabolic Stability Estimation

BACKGROUND

Rociletinib (CO-1686; RLC) is a new, small molecule that is orally administered to inhibit mutant-selective covalent inhibitor of most epidermal growth factor receptor (EGFR)-mutated forms, including T790M, L858R, and exon 19 deletions, but not exon 20 insertions. Non-small-cell lung cancer (NSCLC) with a gene mutation that encodes EGFR is sensitive to approved EGFR inhibitors, but usually resistance develops, which is frequently mediated by T790M EGFR mutation. RLC is an EGFR inhibitor found to be active in preclinical models of EGFR-mutated NSCLC with or without T790M.

METHODS

In silico drug metabolism prediction of RLC was executed with the aid of the WhichP450 module (StarDrop software package) to verify its metabolic liability. Second, a fast, accurate, and competent LC-MS/MS assay was developed for RLC quantification to determine its metabolic stability. RLC and bosutinib (BOS) (internal standard; IS) were separated using an isocratic elution system with a C18 column (reversed stationary phase).

RESULTS

The developed LC-MS/MS analytical method showed linearity of 5-500 ng/mL with r2 ≥ 0.9998 in the human liver microsomes (HLMs) matrix. A limit of quantification of 4.6 ng/mL revealed the sensitivity of the analytical method, while the acquired inter- and intra-day accuracy and precision values below 4.63% inferred the method reproducibility. RLC metabolic stability estimation was calculated using intrinsic clearance (20.15 µL/min/mg) and in vitro half-life (34.39 min) values.

CONCLUSION

RLC exhibited a moderate extraction ratio indicative of good bioavailability. The developed analytical method herein is the first LC-MS/MS assay for RLC metabolic stability.

Chromatographic bioanalytical assays for targeted covalent kinase inhibitors and their metabolites

Deriving from targeted kinase inhibitors (TKIs), targeted covalent kinase inhibitors (TCKIs) are a new class of TKIs that are covalently bound to their target residue of kinase receptors. Currently, there are many new TCKIs under clinical development besides afatinib, ibrutinib, osimertinib, neratinib, acalabrutinib, dacomitinib, and zanubrutinib that are already approved by the FDA. Subsequently, there is an increasing demand for bioanalytical methods to qualitatively and quantitively investigate those compounds, leading to a number of papers reporting the development, validation, and use of bioanalytical methods for TCKIs. Most publications describe the technological set up of analytical methods that allow quantification of TCKIs in various biomatrices such as plasma, cerebrospinal fluid, urine, tissue, and liver microsomes. In addition, the identification of metabolites and biotransformation pathways of new TCKIs has gained more interest in recent years. We provide an overview of bioanalytical methods of this new class of TCKIs. The included issues are sample pretreatment, chromatographic separation, detection, and method validation. In the scope of bioanalysis of TCKIs, protein precipitation is mostly applied to treat the biological matrices sample. Liquid chromatographic in reversed-phase mode (RPLC) and mass detection with triple quadrupole (QqQ) are the most often utilized separation and quantitative detection modes, respectively. There may be a possibility of increased use of the high-resolution mass spectrometry (HRMS) for qualitative investigation purposes in the future. We also found that US FDA and EMA guidelines are the most common guidelines employed as validation framework for the bioanalytical methods of TCKIs.

Characterization of Stable and Reactive Metabolites of the Anticancer Drug, Ensartinib, in Human Liver Microsomes Using LC-MS/MS: An in silico and Practical Bioactivation Approach

BACKGROUND

Ensartinib (ESB) is a novel anaplastic lymphoma kinase inhibitor (ALK) with additional activity against Abelson murine leukemia (ABL), met proto-oncogene (MET), receptor tyrosine kinase (AXL), and v-ros UR2 sarcoma virus oncogene homolog 1 (ROS1) and is considered a safer alternative for other ALK inhibitors. ESB chemical structure contains a dichloro-fluorophenyl ring and cyclic tertiary amine rings (piperazine) that can be bioactivated generating reactive intermediates.

METHODS

In vitro metabolic study of ESB with human liver microsomes (HLMs) was performed and the hypothesis of generating reactive intermediates during metabolism was tested utilizing trapping agents to capture and stabilize reactive intermediates to facilitate their LC-MS/MS detection. Reduced glutathione (GSH) and potassium cyanide (KCN) were utilized as trapping agents for quinone methide and iminium intermediates, respectively.

RESULTS

Four in vitro ESB phase I metabolites were characterized. Three reactive intermediates including one epoxide and one iminium intermediates were characterized. ESB bioactivation is proposed to occur through unexpected metabolic pathways. The piperazine ring was bioactivated through iminium ions intermediates generation, while the dichloro-phenyl group was bioactivated through a special mechanism that was revealed by LC-MS/MS.

CONCLUSION

These findings lay the foundations for additional work on ESB toxicity. Substituents to the bioactive centers (piperazine ring), either for blocking or isosteric replacement, would likely block or interrupt hydroxylation reaction that will end the bioactivation sequence.

LC-MS/MS Estimation of the Anti-Cancer Agent Tandutinib Levels in Human Liver Microsomes: Metabolic Stability Evaluation Assay

PURPOSE

Tandutinib (MLN518 or CT 53518) (TND) is a novel, oral, small-molecule inhibitor of type III receptor tyrosine kinases utilized for the treatment of acute myeloid leukemia (AML).

MATERIALS AND METHODS

In silico prediction of hepatic drug metabolism for TND was determined using the StarDrop® WhichP450™ module to confirm its metabolic liability. Second, an efficient and accurate LC-MS/MS method was established for TND quantification to evaluate metabolic stability. TND and entrectinib (ENC) (internal standard; IS) were resolved using an isocratic elution system with a reversed stationary phase (C8 column).

RESULTS

The established LC-MS/MS method exhibited linearity (5-500 ng/mL) with r2 ≥0.9999 in the human liver microsomes matrix. The method sensitivity was indicated by the limit of quantification (3.8 ng/mL), and reproducibility was revealed by inter- and intraday precision and accuracy (below 10.5%). TND metabolic stability estimation was calculated using intrinsic clearance (22.03 µL/min/mg) and in vitro half-life (29.0 min) values.

CONCLUSION

TND exhibited a moderate extraction ratio indicative of good bioavailability. According to the literature, the approach developed in the present study is the first established LC-MS/MS method for assessing TND metabolic stability.

Quantification of cobimetinib, cabozantinib, dabrafenib, niraparib, olaparib, vemurafenib, regorafenib and its metabolite regorafenib M2 in human plasma by UPLC-MS/MS

A sensitive and selective ultra‐high performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method for the simultaneous determination of seven oral oncolytics (two PARP inhibitors, i.e. olaparib and niraparib, and five tyrosine kinase inhibitors, i.e. cobimetinib, cabozantinib, dabrafenib, vemurafenib and regorafenib, plus its active metabolite regorafenib M2) in EDTA plasma was developed and validated. Stable isotope‐labelled internal standards were used for each analyte. A simple protein precipitation method was performed with acetonitrile. The LC–MS/MS system consisted of an Acquity H‐Class UPLC system, coupled to a Xevo TQ‐S micro tandem mass spectrometer. The compounds were separated on a Waters CORTECS UPLC C18 column (2.1 × 50 mm, 1.6 μm particle size) and eluted with a gradient elution system. The ions were detected in the multiple reaction monitoring mode. The method was validated for cobimetinib, cabozantinib, dabrafenib, niraparib, olaparib, vemurafenib, regorafenib and regorafenib M2 over the ranges 6–1000, 100–5000, 10–4000, 200–2000, 200–20,000, 5000–100,000, 500–10,000 and 500–10,000 μg/L, respectively. Within‐day accuracy values for all analytes ranged from 86.8 to 115.0% with a precision of <10.4%. Between‐day accuracy values ranged between 89.7 and 111.9% with a between‐day precision of <7.4%. The developed method was successfully used for guiding therapy with therapeutic drug monitoring in cancer patients and clinical research programs in our laboratory.

Metabolic Stability Assessment of Larotrectinib Using Liquid Chromatography Tandem Mass Spectrometry

INTRODUCTION

Larotrectinib (VITRAKVI) is an orally potent tropomyosin receptor kinase (Trk) inhibitor that acts by competitive inhibition of all corresponding receptor kinases. It demonstrated a marked response rate (75%) and robust anticancer activity in Trk fusion-positive patients. This response is independent of cancer type, age and gender.

METHODS

In this study, an efficient and accurate LC-MS/MS analytical method was developed for Larotrectinib (LRB) quantification in addition to evaluation of its metabolic stability. LRB and lapatinib (LTP) (which is chosen as an internal standard; IS) were eluted utilizing an isocratic mobile phase with a reversed phase elution system (C18 column).

RESULTS AND DISCUSSION

The linearity range of the established method was 5-500 ng/mL (r 2 ≥ 0.9999) in the human liver microsomes (HLMs) matrix. Various parameters were calculated to validate the method sensitivity (limit of quantification was 5 ng/mL) and reproducibility (inter and intra-day accuracy and precision were below 3% in all samples) of our methodology. For evaluation of LRB metabolic stability in HLMs matrix, in vitro half-life (48.8 min) and intrinsic clearance (14.19 µL/min/mg) were computed.

CONCLUSION

Accordingly, we can conclude that LRB is a moderate extraction ratio drug when compared with other tyrosine kinase inhibitors (TKIs). According to our knowledge, the discussed procedure in this study is the first LC-MS/MS analytical method for evaluating LRB metabolic stability.

FDA- and EMA-Approved Tyrosine Kinase Inhibitors in Advanced EGFR-Mutated Non-Small Cell Lung Cancer: Safety, Tolerability, Plasma Concentration Monitoring, and Management

Non-small-cell lung cancer (NSCLC) is the most common form of primary lung cancer. The discovery of several oncogenic driver mutations in patients with NSCLC has allowed the development of personalized treatments based on these specific molecular alterations, in particular in the tyrosine kinase (TK) domain of the epidermal growth factor receptor (EGFR) gene. Gefitinib, erlotinib, afatinib, and osimertinib are TK inhibitors (TKIs) that specifically target EGFR and are currently approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) as first line treatment for sensitive EGFR-mutant patients. However, these four drugs are associated with severe adverse events (AEs) that can significantly impact patient health-related quality of life and patient monitoring. EGFR-TKIs are commonly used together with other types of medication that can substantially interact. Here, we review approaches used for the management of TKI-AEs in patients with advanced NSCLC to promote the benefits of treatments and minimize the risk of TKI treatment discontinuation. We also consider potential TKI–drug interactions and discuss the usefulness of plasma concentration monitoring TKIs based on chromatographic and mass spectrometry approaches to guide clinical decision-making. Adjusting the most appropriate therapeutic strategies and drug doses may improve the performance therapy and prognosis of patients with advanced EGFR-mutated NSCLC.

Development of two different formats of heterogeneous fluorescence immunoassay for bioanalysis of afatinib by employing fluorescence plate reader and KinExA 3200 immunosensor

Afatinib (AFT) is a potent and highly selective drug used to treat various solid tumors including non-small cell lung cancer (NSCLC). To ensure safe and effective treatment of cancer patients with AFT, its plasma concentrations should be monitored. Thus, sensitive immunoassays are required for measuring AFT concentrations in plasma samples. In this study, two different formats of heterogeneous fluorescent immunoassays were developed and validated for AFT bioanalysis. These assays were microwell-based fluorescence immunoassay (FIA) using fluorescence plate reader and kinetic exclusion assay (KinExA) using KinExA 3200 immunosensor. Both FIA and KinExA were developed using the same reagents: mouse anti-AFT antibody, solid-phase immobilized AFT conjugated with bovine serum albumin protein (AFT-BSA), and goat anti-mouse IgG labelled with fluorescein isothiocyanate (FITC-IgG) for signal generation. The analytical performances of both assays were comparatively evaluated, and the results revealed that although both assays had comparable accuracies, KinExA was superior to FIA in terms of sensitivity and precisions. Moreover, both FIA and KinExA were better alternatives to the existing chromatographic methods for bioanalysis of AFT. The proposed FIA and KinExA are anticipated to effectively contribute in ensuring safe and effective treatment with AFT in clinical settings.

Liquid chromatography-tandem mass spectrometry metabolic profiling of nazartinib reveals the formation of unexpected reactive metabolites

Nazartinib (EGF816, NZB) is a promising third-generation human epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor. This novel irreversible mutant-selective EGFR inhibitor targets EGFR containing both the resistance mutation (T790M) and the activating mutations (L858R and Del19), while it does not affect wild-type EGFR. However, the metabolic pathway and bioactivation mechanisms of NZB are still unexplored. Thus, using liquid chromatography-tandem mass spectrometry, we screened for products of NZB metabolism formed in vitro by human liver microsomal preparations and investigated the formation of reactive intermediates using potassium cyanide as a nucleophile trap. Unexpectedly, the azepane ring was not bioactivated. Instead, the carbon atom between the aliphatic linear tertiary amine and electron-withdrawing system (butenoyl amide group) was bioactivated, generating iminium intermediates as reactive species. Six NZB phase I metabolites, formed by hydroxylation, oxidation and N-demethylation, were characterized. Moreover, two reactive iminium ions were characterized and their corresponding bioactivation mechanisms were proposed. Based on our results, we speculate that bioactivation of NZB can be blocked by small sterically hindering groups, isosteric replacement or a spacer. This approach might reduce the toxicity of NZB by avoiding the generation of reactive species.

Liquid chromatography-tandem mass spectrometry metabolic profiling of nazartinib reveals the formation of unexpected reactive metabolites

Nazartinib (EGF816, NZB) is a promising third-generation human epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor. This novel irreversible mutant-selective EGFR inhibitor targets EGFR containing both the resistance mutation (T790M) and the activating mutations (L858R and Del19), while it does not affect wild-type EGFR. However, the metabolic pathway and bioactivation mechanisms of NZB are still unexplored. Thus, using liquid chromatography-tandem mass spectrometry, we screened for products of NZB metabolism formed in vitro by human liver microsomal preparations and investigated the formation of reactive intermediates using potassium cyanide as a nucleophile trap. Unexpectedly, the azepane ring was not bioactivated. Instead, the carbon atom between the aliphatic linear tertiary amine and electron-withdrawing system (butenoyl amide group) was bioactivated, generating iminium intermediates as reactive species. Six NZB phase I metabolites, formed by hydroxylation, oxidation and N-demethylation, were characterized. Moreover, two reactive iminium ions were characterized and their corresponding bioactivation mechanisms were proposed. Based on our results, we speculate that bioactivation of NZB can be blocked by small sterically hindering groups, isosteric replacement or a spacer. This approach might reduce the toxicity of NZB by avoiding the generation of reactive species.

Novel spectrophotometric and factor-based multivariate calibration-prediction techniques for determination of two inhibitors of hepatitis C-virus and hepatocellular carcinoma in pure, human urine, and human plasma

Novel univariate and multivariate factor-based calibration-prediction techniques were validated for simultaneous ultraviolet spectrophotometric determination of ribavirin (RIV), daclatasvir (DAV), sofosbuvir (SOV), and sorafenib (SON) which are co-administered for treatment of hepatocellular carcinoma (HCC) that results from Hepatitis C-virus (HCV) infection in their commercial products and in biological fluids. Determination of these compounds is essential owing to their pharmacotherapeutic benefits. Due to spectral overlapping of RIV, DAV, SOV, and SON, univariate extended derivative ratio (EDR) method and multivariate partial least-squares (PLS) and principal component regression (PCR) methods were used for constructing the calibration curves. The extended derivative ratio (EDR) absorption maxima at 215 nm and minima at 310.5 nm was used for determination of RIV and DAV, respectively and absorption maxima at 240.3 nm and minima at 284.5 nm for determination of SOV and SON, respectively. The linearity was established over the range of 6-42 μg mL^-1, 4-16 μg mL^-1, 10-70 μg mL^-1, and 3-9 μg mL^-1 for RIV, DAV, SOV and SON with correlation coefficient (r2) of 0.9997, 0.9997, 0.9999 and 0.9997, respectively. This method was effectively applied to pure, pharmaceutical preparations and to spiked human urine and plasma. PLS and PCR models were established for the determination of the studied drugs in the range of 6-42, 4-16, 10-70 and 3-9 μg mL^-1 for RIV, DAV, SOV, and SON, respectively. Furthermore, updating the PLS model (PLS model update) were allowed for the determination of these drugs in spiked human urine, plasma and drug-dissolution test of their tablets. The obtained results were compared to official and reported method showing that there were no significant differences. The results of applying PLS and PCR models for evaluation of RIV, DAV, SOV, and SON in human urine samples as real samples were also encouraging. It is expected that the suitable features of the proposed method make it helpful for biological and clinical applications.

Validated LC-MS/MS assay for quantification of the newly approved tyrosine kinase inhibitor, dacomitinib, and application to investigating its metabolic stability

Dacomitinib (DMB) is a second-generation irreversible tyrosine kinase inhibitor (TKI) that is claimed to overcome the disadvantages of the resistance reported for first-line epidermal growth factor receptor (EGFR) TKIs. Towards the end of 2018, the US Food and Drug Administration approved DMB in the form of VIZIMPRO tablets. In the current study, a validated LC-MS/MS assay was established for DMB quantification in rat liver microsomes (RLMs) with application to the drug metabolic stability assessment. Chromatographic resolution of DMB and lapatinib (internal standard) was achieved using an isocratic mobile phase and a reversed-phase C18 column. The linearity of the established LC-MS/MS assay ranged from 2 to 500 ng/mL with r2 ≥ 0.9999. The limit of detection (LOD) and limit of quantification (LOQ) were 0.35 and 1.1 ng/mL, respectively. The precision and accuracy (both intra-day and inter-day) were 0.84-3.58% and 92.2-100.32%, respectively. The metabolic stability of DMB in the RLM matrix was estimated by calculating two parameters, in vitro t1/2 (0.97 mL/min/kg) and intrinsic clearance (157.5 min). Such values infer that DMB would be excreted very slowly from the human body, which might lead to possible bioaccumulation. To the best of our knowledge, this is the first method for DMB analysis in RLMs with metabolic stability estimation.

A simple liquid chromatography-tandem mass spectrometry method to accurately determine the novel third-generation EGFR-TKI naquotinib with its applicability to metabolic stability assessment

Naquotinib (ASP8273, NQT) is a novel third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKIs). NQT was found to be more effective than osimertinib against the EGFR L858R plus T790M mutation (L858R+T790M). A rapid resolution liquid chromatography (RRLC)-tandem mass spectrometry (MS/MS) method was developed and validated for NQT quantification and its metabolic stability was investigated. NQT and foretinib (FTB) as an internal standard (IS) were separated using a mobile phase under isocratic conditions with a C18 column (reversed phase system). The linearity of the analytical method ranged from 5 to 500 ng mL⁻¹ (coefficient of correlation [r²] ≥ 0.9999) in a human liver microsome (HLM) matrix. The limit of detection and limit of quantification were 0.78 and 2.36 ng mL⁻¹, respectively. The inter-day and intra-day accuracy and precision were −6.36 to 1.88 and 0.99 to 2.58%, respectively. The metabolic stability of NQT in the HLM matrix was calculated using the in vitro half-life (t_1/2, 67.96 min) and intrinsic clearance (Cl_int, 2.12 mL min⁻¹ kg⁻¹). NQT is considered to be a moderate extraction ratio drug that is moderately excreted from the human body compared with other related TKIs. This proposed methodology is thought to be the first method for assessing NQT concentration and its metabolic stability.

The first established LC-MS/MS method for NQT analysis. NQT was shown to be moderately excreted from the human body.

An Accurate and Effective Method for Measuring Osimertinib by UPLC-TOF-MS and Its Pharmacokinetic Study in Rats

Osimertinib, a new-generation inhibitor of the epidermal growth factor, has been used for the clinical treatment of advanced T790M mutation-positive tumors. In this research, an original analysis method was established for the quantification of osimertinib by ultra-performance liquid chromatography with time of flight mass spectrometry (UPLC-TOF-MS) in rat plasma. After protein precipitation with acetonitrile and sorafinib (internal standard, IS), they were chromatographed through a Waters XTerra MS C₁₈ column. The mobile phase was acetonitrile and water (including 0.1% ammonia). The relative standard deviation (RSD) of the intra- and inter-day results ranged from 5.38 to 9.76% and from 6.02 to 9.46%, respectively, and the extraction recovery and matrix effects were calculated to range from 84.31 to 96.14% and from 91.46 to 97.18%, respectively. The results illustrated that the analysis method had sufficient specificity, accuracy and precision. Meanwhile, the UPLC-TOF-MS method for osimertinib was successfully applied into the pharmacokinetics of SD rats.

Preclinical testing of 5-amino-1-((1R,2S,3S,4R)-2,3-dihydroxy-4-methylcyclopentyl)-1H-imidazole-4-carboxamide: a potent protein kinase C-ι inhibitor as a potential prostate carcinoma therapeutic

Protein kinase C-iota (PKC-ι) is an oncogene overexpressed in many cancer cells including prostate, breast, ovarian, melanoma, and glioma. Previous in-vitro studies have shown that 5-amino-1-((1R,2S,3S,4R)-2,3-dihydroxy-4-methylcyclopentyl)-1H-imidazole-4-carboxamide (ICA-1s), a PKC-ι specific inhibitor, is effective against some cancer cell lines by decreasing cell growth and inducing apoptosis. To assess ICA-1s as a possible therapeutic, in-vivo studies using a murine model were performed. ICA-1s was tested for stability in blood serum and results demonstrated that ICA-1s was stable in human plasma at 25 and 37°C over a course of 2 h. Toxicity of ICA-1s was tested for both acute and subacute exposure. The acute exposure showed patient surviving after 48 h of doses ranging from 5 to 5000 mg/kg. Subacute tests exposed the patients to 14 days of treatment and were followed by serum and tissue collection. Aspartate aminotransferase, alkaline phosphatase, γ-glutamyl transpeptidase, troponin, and C-reactive protein serum levels were measured to assess organ function. ICA-1s in plasma serum was measured over the course of 24 h for both oral and intravenous treatments. Heart, liver, kidney, and brain tissues were analyzed for accumulation of ICA-1s. Finally, athymic nude mice were xenografted with DU-145 prostate cancer cells. After tumors reached ~0.2 cm², they were either treated with ICA-1s or left as control and measured for 30 days or until the tumor reached 2 cm². Results showed tumors in treated mice grew at almost half the rate as untreated tumors, showing a significant reduction in growth. In conclusion, ICA-1s is stable, shows low toxicity, and is a potential therapeutic for prostate carcinoma tumors.

Development and validation of an ELISA with high sensitivity for therapeutic monitoring of afatinib

AIM

To support the therapeutic drug monitoring of afatinib (AFT), an ELISA was required.

RESULTS

A hapten for AFT was prepared and linked to each of BSA and KLH proteins by diazotization/coupling reaction. A polyclonal antibody recognizing AFT with high affinity (IC₅₀ = 40 ng ml^-1) was generated and used in the development of a competitive ELISA for quantitation of AFT in plasma samples. The assay limit of detection was 2 ng ml^-1. The assay accuracy and precision were proved.

CONCLUSION

The assay is an appropriate alternative to the existing LC-MS/MS assays for AFT and it is anticipated to effectively contribute to the therapeutic drug monitoring of AFT in clinical settings.

Current state of bioanalytical chromatography in clinical analysis

Chromatographic methods have become popular in clinical analysis in both routine and research laboratories.

Online extraction of antihypertensive drugs and their metabolites from untreated human serum samples using restricted access carbon nanotubes in a column switching liquid chromatography system

A novel analytical method was developed to determine 5 antihypertensive drugs of different pharmacological classes (angiotensin-converting enzyme inhibitors, calcium channel blockers, α-2 adrenergic receptor agonists, angiotensin II receptor blockers, and aldosterone receptor antagonists) and some of their metabolites in human serum. The untreated samples were directly analyzed in a column switching system using an extraction column packed with restricted access carbon nanotubes (RACNTs) in an ultra-high performance liquid chromatography coupled to a mass spectrometer (UHPLC-MS/MS). The RACNTs column was able to exclude approximately 100% of proteins from the samples in 2.0min, maintaining the same performance for about 300 analytical cycles. The method was validated in accordance with Food and Drug Administration (FDA) guidelines, being linear for all the determined analytes in their respective analytical ranges (coefficients of determination higher than 0.99) with limits of detection (LODs) and quantification (LOQs) ranging from 0.09 to 10.85μgL^-1 and from 0.30 to 36.17μgL^-1, respectively. High recovery values (88-112%) were obtained as well as suitable results for inter and intra-assay accuracy and precision. The method provided an analytical frequency of 5 samples per hour, including the sample preparation and separation/detection steps. The validated method was successfully used to analyze human serum samples of patients undergoing treatment with antihypertensive drugs, being useful for pharmacometabolomic, pharmacogenomic, and pharmacokinetic studies.

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.