A validated LC-MS/MS method for rapid determination of methotrexate in human saliva and its application to an excretion evaluation study

Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) methods for the therapeutic drug monitoring of cytotoxic anticancer drugs: An update

In the era of precision medicine, there is increasing evidence that conventional cytotoxic agents may be suitable candidates for therapeutic drug monitoring (TDM)- guided drug dosage adjustments and patient's tailored personalization of non-selective chemotherapies. To that end, many liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) assays have been developed for the quantification of conventional cytotoxic anticancer chemotherapies, that have been comprehensively and critically reviewed. The use of stable isotopically labelled internal standards (IS) of cytotoxic drugs was strikingly uncommon, accounting for only 48 % of the methods found, although their use could possible to suitably circumvent patients' samples matrix effects variability. Furthermore, this approach would increase the reliability of cytotoxic drug quantification in highly multi-mediated cancer patients with complex fluctuating pathophysiological and clinical conditions. LC-MS/MS assays can accommodate multiplexed analyses of cytotoxic drugs with optimal selectivity and specificity as well as short analytical times and, when using stable-isotopically labelled IS for quantification, provide concentrations measurements with a high degree of certainty. However, there are still organisational, pharmacological, and medical constraints to tackle before TDM of cytotoxic drugs can be more largely adopted in the clinics for contributing to our ever-lasting quest to improve cancer treatment outcomes.

Toxicological Aspects of Methotrexate Intoxication: Concentrations in Postmortem Biological Samples and Autopsy Findings

The aim of this study was the establishment of a UHPLC-QqQ-MS/MS method to determine methotrexate in postmortem biological samples and quantify the postmortem distribution of methotrexate in a case of fatal intoxication of this drug. A volume of 100 μL or 100 mg of postmortem specimens was precipitated with 400 μL of cold methanol and then analyzed using UHPLC-QqQ-MS/MS. The validation parameters of the method were as follows: limit of quantification: 0.1−1.0 ng/mL or ng/g, coefficient of determination: >0.998 (R2), matrix effect, intra- and inter-day accuracies and precisions: not greater than 13.6%, 14.8% and 17.4%, respectively. The recoveries were: 89.0−113.6%. The postmortem distribution studies revealed methotrexate concentrations as follows: blood—7.2 ng/mL, vitreous humor—0.8 ng/mL, liver—43.7 ng/g, kidney—20.6 ng/g, bone marrow—29.9 ng/g, lumbar vertebra—20.0 ng/g. The highest concentrations of methotrexate after poisoning were found in the tissues with the most rapidly dividing cells. The method described is simple, precise and selective. Methotrexate concentrations can be routinely determined in postmortem specimens. Determination of methotrexate in the postmortem biological material is possible after a few days of intensive treatment.

Comparison of LC-MS3 and LC-MRM strategy for quantification of methotrexate in human plasma and its application in therapeutic drug monitoring

A simple, highly selective and high throughput liquid chromatography tandem mass spectrometry cubed (LC/MS³) method was developed and validated for quantification of methotrexate in human plasma. The MS³ detection is a scanning mode of QTrap MS systems or ion trap MS systems. After simple protein precipitation with methanol, methotrexate and methotrexate-d₃ were separated on an Agilent Poroshell 120 SB-C18 column (4.6 × 50 mm, 2.7 µm) using isocratic elution with a mobile phase consisting of 60% 0.1% formic acid in water and 40% 0.1% formic acid in acetonitrile. The flow rate is 0.8 mL/min. MS³ detection in positive ion mode used the MRM³ transitions at m/z 455.2→308.2→175.1 for quantification of methotrexate and m/z 458.2→311.2→175.1 for quantification of methotrexate-d₃. The total run time was only 3 min for each sample. The LC/MS³ assay was linear in the concentration range 10-3000 ng/mL(R² ≥ 0.995) and the intra- and inter-day accuracies were< 3.72% and precisions were< 7.78% at all concentrations. The absolute recoveries (%) and matrix effect (%) for methotrexate in human plasma were between 92.6 and 114.3. The novelty of the presented methodology is the MS³ technique resulting in enhanced selectivity and sensitivity. The application of this LC-MS³ method was successfully completed on 46 human plasma samples and the quantitative results of identical human plasma samples were compared with another LC-MRM based method. Passing-Bablok regression coefficients demonstrated that there is no significant difference between the LC-MS³ method and LC-MRM method. Bland-Altman plots showed a concordant results, supporting the developed LC-MS³ method is a reliable and accurate assay for determination of methotrexate in human plasma. This work is also a proof of concept for using LC-MS³ technique to determination of chemicals in biological samples.

In situ Analytical Quality Control of chemotherapeutic solutions in infusion bags by Raman spectroscopy

Analytical Quality Control (AQC) in centralised preparation units of oncology centers is a common procedure relying on the identification and quantification of the prepared chemotherapeutic solutions for safe intravenous administration to patients. Although the use of Raman spectroscopy for AQC has gained much interest, in most applications it remains coupled to a flow injection analyser (FIA) requiring withdrawal of the solution for analysis. In addition to current needs for more rapid and cost-effective analysis, the risk of exposure of clinical staff to the toxic molecules during daily handling is a serious concern to address. Raman spectroscopic analysis, for instance by Confocal Raman Microscopy (CRM), could enable direct analysis (non-invasive) for AQC directly in infusion bags. In this study, 3 anticancer drugs, methotrexate (MTX), 5-fluorouracil (5-FU) and gemcitabine (GEM) have been selected to highlight the potential of CRM for withdrawal free analysis. Solutions corresponding to the clinical range of each drug were prepared in 5% glucose and data was collected from infusion bags placed under the Raman microscope. Firstly, 100% discrimination has been obtained by Partial Least Squares Discriminant Analysis (PLS-DA) confirming that the identification of drugs can be performed. Secondly, using Partial Least Squares Regression (PLSR), quantitative analysis was performed with mean % error of predicted concentrations of respectively 3.31%, 5.54% and 8.60% for MTX, 5-FU and GEM. These results are in accordance with the 15% acceptance criteria used for the current clinical standard technique, FIA, and the Limits of Detection for all drugs were determined to be substantially lower than the administered range, thus highlighting the potential of confocal Raman spectroscopy for direct analysis of chemotherapeutic solutions.

Tissue-Engineered Bone Tumor as a Reproducible Human in Vitro Model for Studies of Anticancer Drugs

Studies of anticancer therapies in traditional cell culture models can demonstrate efficacy of direct-acting compounds but lack the 3-dimensional arrangement of the tumor cells and their tissue-specific microenvironments, both of which are important modulators of treatment effects in vivo. Bone cells reside in complex environments that regulate their fate and function. A bioengineered human bone-tumor model has been shown to provide a microphysiological niche for studies of cancer cell behavior. Here, we demonstrate successful transfer between 2 laboratories and utility of this model in efficacy studies using well-established chemotherapeutic agents. The bioengineered human bone-tumor model consisted of Ewing sarcoma (RD-ES) cancer cell aggregates infused into tissue-engineered bone that was grown from human mesenchymal stem cell-derived differentiated into osteoblasts within mineralized bone scaffolds. The tumor model was maintained in culture for over 5 weeks and subjected to clinically relevant doses of linsitinib, doxorubicin, cisplatin, methotrexate, vincristine, dexamethasone, or MAP (methotrexate, doxorubicin, and cisplatin combination). Drug administration cycles were designed to mimic clinical treatment regimens. The bioengineered tumors were evaluated days to weeks after the cessation of treatment to monitor the potential for relapse, using bioengineered bone and ES cell monolayers as controls. Drug binding to the scaffolds and media proteins and gene expression were also evaluated. We show that a bioengineered human bone tumor can be used as a microphysiological model for preclinical studies of anticancer drugs. We found that anticancer efficacy was achieved at concentrations approximating the human Cmax, in contrast to traditional ES cell monolayers. These studies show that the bone-tumor model can be successfully transferred between laboratories and has predictive power in preclinical studies. The effects of drugs on the bone tumors and healthy bone were studied in parallel, in support of the utility of this model for identification of new therapeutic targets.

Sensitive determination of methotrexate in plasma of children with acute leukemia using double-solvent supramolecular systemas a novel extractant for dispersive liquid-liquid microextraction

Methotrexate, as a folate antagonist, is one of the first anti-neoplasm drugs offered and is still used as an effective drug in the treatment of various malignancies. Methotrexate has a narrow treatment index and is associated with numerous side effects.In thisresearch, for the first time a double-solvent supramolecular system (DSS) was developed as an extractant without disperser solvent for dispersive liquid-liquid microextraction (DLLME). DSS - DLLME was applied to the extraction of methotrexate in plasma of children with acute leukemiaprior to itsdetermination by high-performance liquid chromatography-ultraviolet detection (HPLC - UV). In the present method, two long normal chain alcohols are mixed in a particular ratio, and then it is injected into the sample solution, which is on the magnetic stirrer. In this case, the mixture of the two alcohol changes to new supramolecular aggregate. This new supermolecule is used as an extractant, which has a higher extraction power than any of its components alone. Under the optimum conditions, the calibration graph was linear in the rage of 0.1-150 µg L^-1 with detection limit of 0.03 µg L^-1. Relative standard deviations (RSDs) including intra-day and inter-day of method based on7 replicate determinations of 100.0 µg L^-1of methotrexate were 2.6% and 4.8%,respectively. The results proved that DSS - DLLME is a sensitive, very simple, inexpensive, environmental friendly, rapid and efficient method for the preconcentration of trace amount of drugs in biological samples.

Dispersive Micro-Solid Phase Extraction for Sensitive Determination of Methotrexate from Human Saliva Followed by Spectrophotometric Method

For biological assessing of hospital personnel occupationally exposed to antineoplastic drugs, highly sensitive and accurate methods are required. Methotrexate (MTX) is an anticancer agent that is widely used in a variety of human cancers. For the first time, dispersive-micro solid phase extraction (D-µ-SPE) has been applied for determination of low levels of MTX in saliva samples. The method is based on rapid extraction of MTX using graphene oxide adsorbent. The sample preparation time is decreased by the fact that the adsorbent dispersed in the sample solution and extraction equilibrium can be reached very fast. This significant feature which obtained with this method is of key interest for routine trace laboratory analysis. The influence of different variables on D-µ-SPE was investigated. Under optimum conditions, the calibration graph was linear over the range of 10-1000 ng/ml. The relative standard deviations are better than 9.0%. The proposed method was successfully applied for the determination of MTX in patient samples.

Analytical methodologies for determination of methotrexate and its metabolites in pharmaceutical, biological and environmental samples

Methotrexate (MTX) is a folate antagonist drug used for several diseases, such as cancers, various malignancies, rheumatoid arthritis (RA) and inflammatory bowel disease. Due to its structural features, including the presence of two carboxylic acid groups and its low native fluorescence, there are some challenges to develop analytical methods for its determination. MTX is metabolized to 7-hydroxymethotrexate (7-OH-MTX), 2,4-diamino-N10-methylpteroic acid (DAMPA), and the active MTX polyglutamates (MTXPGs) in the liver, intestine, and red blood cells (RBCs), respectively. Additionally, the drug has a narrow therapeutic range; hence, its therapeutic drug monitoring (TDM) is necessary to regulate the pharmacokinetics of the drug and to decrease the risk of toxicity. Due to environmental toxicity of MTX; its sensitive, fast and low cost determination in workplace environments is of great interest. A large number of methodologies including high performance liquid chromatography equipped with UV-visible, fluorescence, or electrochemical detection, liquid chromatography-mass spectroscopy, capillary electrophoresis, UV-visible spectrophotometry, and electrochemical methods have been developed for the quantitation of MTX and its metabolites in pharmaceutical, biological, and environmental samples. This paper will attempt to review several published methodologies and the instrumental conditions, which have been applied to measure MTX and its metabolites within the last decade.

The Relevance of Mass Spectrometry Analysis for Personalized Medicine through Its Successful Application in Cancer "Omics"

Mass spectrometry (MS) is an essential analytical technology on which the emerging omics domains; such as genomics; transcriptomics; proteomics and metabolomics; are based. This quantifiable technique allows for the identification of thousands of proteins from cell culture; bodily fluids or tissue using either global or targeted strategies; or detection of biologically active metabolites in ultra amounts. The routine performance of MS technology in the oncological field provides a better understanding of human diseases in terms of pathophysiology; prevention; diagnosis and treatment; as well as development of new biomarkers; drugs targets and therapies. In this review; we argue that the recent; successful advances in MS technologies towards cancer omics studies provides a strong rationale for its implementation in biomedicine as a whole.

A novel mixed hemimicelles dispersive micro-solid phase extraction using ionic liquid functionalized magnetic graphene oxide/polypyrrole for extraction and pre-concentration of methotrexate from urine samples followed by the spectrophotometric method

Methotrexate (MTX) is an anticancer drug that is widely used in a variety of cancers including primary central nervous system lymphoma. It is also administrated in the treatment of some autoimmune diseases. A simple, accurate, sensitive, and precise mixed hemimicelles dispersive micro-solid phase extraction was proposed for MTX quantification in human urine samples. MTX was quantified by spectrophotometer after dispersive micro-solid phase extraction using ionic liquid functionalized magnetic graphene oxide/polypyrrole. Interactions of adsorbent and MTX were modeled by molecular docking and the interaction energy was predicted to be -8.35 kcal/mol. A larger absolute value of binding energy represents larger adsorption strength, indicating that graphene oxide nanosheets could perform higher adsorption strength toward MTX. The concentrations of MTX were proportional to analytical response in amounts ranging from 10 to 1000 ng/mL with a good correlation (R² = 0.99). Inter- and intra-day precisions and accuracies were within the acceptable limit according to FDA guideline (15% for biological determination). The recoveries were ranging from 89 to 93% and the method was specific for routine analysis of MTX. This protocol was applied to the urine of two patients under MTX therapy received an intravenous administration of 1 mg/kg/dose of MTX with acute lymphoblastic leukemia. The accuracy of the method was confirmed by HPLC measurements.

A Review on Liquid Chromatography-Tandem Mass Spectrometry Methods for Rapid Quantification of Oncology Drugs

In the last decade, the tremendous improvement in the sensitivity and also affordability of liquid chromatography-tandem mass spectrometry (LC-MS/MS) has revolutionized its application in pharmaceutical analysis, resulting in widespread employment of LC-MS/MS in determining pharmaceutical compounds, including anticancer drugs in pharmaceutical research and also industries. Currently, LC-MS/MS has been widely used to quantify small molecule oncology drugs in various biological matrices to support preclinical and clinical pharmacokinetic studies in R&D of oncology drugs. This mini-review article will describe the state-of-the-art LC-MS/MS and its application in rapid quantification of small molecule anticancer drugs. In addition, efforts have also been made in this review to address several key aspects in the development of rapid LC-MS/MS methods, including sample preparation, chromatographic separation, and matrix effect evaluation.

UPLC-MS/MS Analysis of Methotrexate in Human Plasma and Comparison with the Fluorescence Polarization Immunoassay

Methotrexate (MTX) plasma concentration is routinely monitored to guide the dosage regimen of rescue drugs. This study aims to develop and validate an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for plasma MTX analysis, and to establish its agreement with the fluorescence polarization immunoassay (FPIA) in patients with high-dose MTX therapy. Separation was achieved by gradient elution with methanol and water (0.05% formic acid) at 40°C with a run time of 3 min. The intra- and inter-day inaccuracy and imprecision of the UPLC-MS/MS method were -4.25 to 3.1 and less than 7.63%, respectively. The IS-normalized recovery and matrix effect were 87.05 to 92.81 and 124.43 to 134.57%. The correlation coefficients between UPLC-MS/MS and FPIA were greater than 0.98. The UPLC-MS/MS method was in agreement with the FPIA at high levels of MTX (1.0 - 100 μmol/L), but not at low levels (0.01 - 1.0 μmol/L). Further studies are warranted to confirm these results.

Saliva as a Future Field in Psoriasis Research

Psoriasis is a skin inflammatory disease characterized by an increased body of comorbidities, including parodontopathy. Despite the visibility of skin lesions, prognostic biomarkers, related to disease monitoring and therapeutic effectiveness, are still missing. Although several markers have been studied, none of them has been identified as an independent prognostic factor. This concise review aims to summarize the current knowledge and results in saliva research applied to psoriasis. Combination of different markers could improve the prognostic prediction in patients with psoriasis. Future studies are needed to implement research on salivary biomarkers and their prognostic/therapeutic effects in the management of patients with psoriasis.

Tenofovir Disoproxil Fumarate Is a New Substrate of ATP-Binding Cassette Subfamily C Member 11

Tenofovir disoproxil fumarate (TDF), a nucleotide reverse transcriptase inhibitor, after conversion to tenofovir (TFV), is mainly eliminated by glomerular filtration and active tubular secretion. The major adverse effect of tenofovir is nephrotoxicity; however, the exact mechanism remains poorly understood. In this study, the ATP-binding cassette subfamily C member 11 (ABCC11; multidrug resistance protein 8 [MRP8]) transporter, which is abundant in proximal tubular cells, was demonstrated to act as an efflux transporter of tenofovir. Real-time PCR (RT-PCR) and indirect immunofluorescence assays were used to determine MRP8 overexpression in a continuous cell line. Tenofovir accumulations were assessed by cytotoxicity, cellular transport, and vesicular uptake assays. Substrate specificity was confirmed using MK-571, an MRP-specific inhibitor, and methotrexate, which served as a known substrate. Intracellular and intravesicular concentrations of tenofovir were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The 50% cytotoxic concentration (CC₅₀) of TDF in MRP8-overexpressing cells was 4.78 times higher than that of parental cells. Transport assays also showed that the intracellular accumulation of tenofovir in MRP8-overexpressing cells was 55 times lower than that in parental cells and was partly reversed by MK-571. Similarly, an "inside-out" vesicular uptake assay, using Sf9 inverted membrane vesicles to allow measuring of accumulation of the substrates into the vesicles, demonstrated a higher intravesicular concentration of tenofovir in MRP8-overexpressing vesicles than in Sf9 insect control vesicles. These effects were effectively reversed by increasing concentrations of the specific inhibitor MK-571. In conclusion, tenofovir is a new substrate of the MRP8 transporter. An alteration in the activity of this efflux pump may increase the intracellular accumulation of tenofovir in proximal renal tubular cells.

Influence of pretreatment of piperazine ferulate on pharmacokinetic parameters of methotrexate in methotrexate-induced renal injury model rats by HPLC-MS

The present study was designed to investigate the influence of the pretreatment of piperazine ferulate on pharmacokinetic parameters of methotrexate in methotrexate-induced renal injury rats. A simple and efficient high performance liquid chromatography coupled with mass spectrometry (HPLC-MS) method was developed to determine methotrexate in rat plasma. Methotrexate and syringic acid (internal standard) were extracted from rat plasma samples by protein precipitation with acetonitrile. The analysis was performed on a CAPCELL PAK C₁₈ column (150 mm × 4.6 mm, 5 µm) with acetonitrile and 5 mmol/l ammonium acetate aqueous (10:90, v/v). The linear range was 5.0 × 10⁻² to 100.0 µg/ml for methotrexate. Other parameters were all within the acceptance criteria. The validated method was successfully applied the pharmacokinetic study of methotrexate between two methotrexate treated groups (with and without the pretreatment of piperazine ferulate). Compared with the methotrexate treated alone group, the pharmacokinetic parameters in the methotrexate with the pretreatment of piperazine ferulate group showed significantly lower MRT_(0-t), MRT_(0-∞) and T_1/2. Results suggested that methotrexate can be rapidly eliminated, cleared or metabolized in rat blood, which might be related to the pretreatment of piperazine ferulate. The method provided deeper insights into rational clinical use of methotrexate with the pretreatment of piperazine ferulate on cancer patients with renal dysfunction.