Lipid-based microemulsion gel for the topical delivery of methotrexate: an optimized, rheologically acceptable formulation with conducive dermatokinetics.

In the present study, we have formulated a methotrexate (MTX)-loaded microemulsion topical gel employing quality-by-design optimization. The optimized lipid-based microemulsion was incorporated into a 2% carbopol gel. The prepared formulation was characterized for micromeritics, surface charge, surface morphology, conductivity studies, rheology studies, texture analysis/spreadability, drug entrapment, and drug loading studies. The formulation was further evaluated for drug release and release kinetics, cytotoxicity assays, drug permeation and drug retention studies, and dermatokinetics. The developed nanosystem was not only rheologically acceptable but also offered substantial drug entrapment and loading. From drug release studies, it was observed that the nanogel showed higher drug release at pH 5.0 compared to plain MTX, plain gel, and plain microemulsion. The developed system with improved dermatokinetics, nanometric size, higher drug loading, and enhanced efficacy towards A314 squamous epithelial cells offers a huge promise in the topical delivery of methotrexate.

Cellular pharmacokinetic of methotrexate and its modulation by folylpolyglutamate synthetase and γ-glutamyl hydrolase in tumor cells.

BACKGROUND AND PURPOSE: Clinical studies showed that prolonged infusion of methotrexate (MTX) leads to more severe adverse reactions than short infusion of MTX at the same dose. We hypothesized that it is the saturation of folate polyglutamate synthetase (FPGS) at high MTX concentration that limits the intracellular synthesis rate of methotrexate polyglutamate (MTX-PG). Due to a similar accumulation rate, a longer infusion duration may increase the concentration of MTX-PG and, result in more serious adverse reactions. In this study, we validated this hypothesis. EXPERIMENTAL APPROACH: A549, BEL-7402 and MHCC97H cell lines were treated with MTX at gradient concentrations. Liquid chromatograph-mass spectrometer (UPLC-MS/MS) was used to quantify the intracellular concentration of MTX-PG and the abundance of FPGS and γ-glutamyl hydrolase (GGH). High quality data were used to fit the cell pharmacokinetic model. KEY RESULTS: Both cell growth inhibition rate and intracellular MTX-PG concentration showed a nonlinear relationship with MTX concentration. The parameter Vmax in the model, which represents the synthesis rate of MTX-PG, showed a strong correlation with the abundance of intracellular FPGS. CONCLUSION AND IMPLICATIONS: According to the model fitting results, it was confirmed that the abundance of FPGS is a decisive factor limiting the synthesis rate of MTX-PG. The proposed hypothesis was verified in this study. In addition, based on the intracellular metabolism, a reasonable explanation was provided for the correlation between the severity of adverse reactions of MTX and infusion time. This study provides a new strategy for the individualized treatment and prediction of efficacy/side effects of MTX.

Synergistically engineered nanotransethosomes for co-delivery of methotrexate and baicalin for enhanced transdermal delivery against rheumatoid arthritis: formulation, characterisation and in vivo pharmacodynamic evaluation.

Background: Rheumatoid arthritis (RA) is a systemic autoimmune disease that significantly impacts the quality of life of those affected. Owing to the complex pathophysiology of RA, it is not possible for any singular treatment to entirely impede the progression of the disease. Hence, the current study aimed to adopt a holistic and synergistic approach towards the management of RA by means of a co-delivery strategy involving methotrexate (MTH), a conventional slow-acting anti-rheumatic drug, and baicalin (BCN), a bioactive phytochemical using a transethosomal (TRS) gel formulation.Purpose: The present study aims to evaluate the potential benefits of administering MTH and BCN in nanoparticulate form, which may lead to improved stability and solubility, as well as enhanced penetration into the arthritic tissues of interest.Methods and results: The MTH-BCN-TRS that were synthesised exhibited small particle size of 151.3 nm and polydispersity index of 0.125, as well as a favourable zeta potential of -32.22 mV. Additional assessments were conducted, including a pharmacokinetic analysis, TEM, skin permeation analysis and confocal microscopy. According to the Confocal laser scanning microscopy (CLSM) study, the formulated MTH-BCN-TRS gel exhibited superior MTH and BCN permeation through the skin layers when compared to the MTH-BCN suspension gel. The MTT experiment on Raw 264.7 and SW982 cell lines revealed a considerable reduction (p < .05) in the IC50 value of the MTH-BCN-TRS formulation (9.2 mM and 43.2 mM, respectively) in comparison to the drug suspension. According to the findings of the in vivo study, it was found that the MTH-BCN-TRS gel exhibits significantly promising anti-arthritic properties when compared to the conventional diclofenac gel. This was demonstrated through histopathological studies and radiographic analysis. Furthermore, skin irritation investigation on Wistar albino rats confirmed that the formulated MTH-BCN-TRS is a safe option for topical treatment on the skin. The present study has confirmed that the formulated TRS vesicles are a valuable carrier for the transdermal delivery of MTH and BCN, which may be used for the management of rheumatoid arthritis.

Validation of UV-Vis spectrophotometric and colorimetric methods to quantify methotrexate in plasma and rat skin tissue: Application to in vitro release, ex vivo and in vivo studies from dissolving microarray patch loaded pH-sensitive nanoparticle.

This research transformed MTX into smart nanoparticles that respond to the acidic conditions present in inflammation. These nanoparticles were then incorporated into a patch that dissolves over time, aiding their penetration. A method using UV-Vis spectrophotometry was validated to support the development of this new delivery system. This method was used to measure the quantity of MTX in the prepared patches in various scenarios: in laboratory solutions with pH 7.4 and pH 5.0, in skin tissue, and plasma. This validation was conducted in laboratory studies, tissue samples, and live subjects, adhering to established guidelines. The resulting calibration curve displayed a linear relationship (correlation coefficient 0.999) across these scenarios. The lowest quantity of MTX that could be accurately detected was 0.6 µg/mL in pH 7.4 solutions, 1.46 µg/mL in pH 5.0 solutions, 1.11 µg/mL in skin tissue, and 1.48 µg/mL in plasma. This validated method exhibited precision and accuracy and was not influenced by dilution effects. The method was effectively used to measure MTX levels in the developed patch in controlled lab settings and biological systems (in vitro, ex vivo, and in vivo). This showed consistent drug content in the patches, controlled release patterns over 24 h, and pharmacokinetic profiles spanning 48 h. However, additional analytical approaches were necessary for quantifying MTX in studies focused on the drug's effects on the body's functions.

Population pharmacokinetic analyses of methotrexate in pediatric patients: a systematic review.

BACKGROUND AND OBJECTIVES: Methotrexate is widely utilized in the chemotherapy of malignant tumors and autoimmune diseases in the pediatric population, but dosing can be challenging. Several population pharmacokinetic models were developed to characterize factors influencing variability and improve individualization of dosing regimens. However, significant covariates included varied across studies. The primary objective of this review was to summarize and discuss population pharmacokinetic models of methotrexate and covariates that influence pharmacokinetic variability in pediatric patients. METHODS: Systematic searches were conducted in the PubMed and EMBASE databases from inception to 7 July 2023. Reporting Quality was evaluated based on a checklist with 31 items. The characteristics of studies and information for model construction and validation were extracted, summarized, and discussed. RESULTS: Eighteen studies (four prospective studies and fourteen retrospective studies with sample sizes of 14 to 772 patients and 2.7 to 93.1 samples per patient) were included in this study. Two-compartment models were the commonly used structural models for methotrexate, and the clearance range of methotrexate ranged from 2.32 to 19.03 L/h (median: 6.86 L/h). Body size and renal function were found to significantly affect the clearance of methotrexate for pediatric patients. There were limited reports on the role of other covariates, such as gene polymorphisms and co-medications, in the pharmacokinetic parameters of methotrexate pediatric patients. Internal and external evaluations were used to assess the performance of the population pharmacokinetic models. CONCLUSION: A more rigorous external evaluation needs to be performed before routine clinical use to select the appropriate PopPK model. Further research is necessary to incorporate larger cohorts or pool analyses in specific susceptible pediatric populations to improve the understanding of predicted exposure profiles and covariate identification.

Mucositis oral como efecto adverso al uso del metotrexato en el tratamiento de la artritis reumatoide: una revisión sistematizada de casos / Oral mucositis as an adverse effect of the use of methotrexate in the treatment of rheumatoid arthritis: a systematized review of cases

Introducción: el metotrexato se usa ampliamente para el tratamiento de una variedad de enfermedades neoplásicas y autoinmunes. Sin embargo, como todo fármaco, su eficacia viene marcada por cierto grado de toxicidad debido a la farmacocinética del medicamento. El metotrexato se creó como un fármaco anticancerígeno; sin embargo, se ha convertido en el tratamiento de elección contra la artritis reumatoide. Principalmente, el metotrexato causa inflamación de las mucosas epiteliales. La mayoría de los efectos secundarios del metotrexato se pueden detectar de forma temprana y son reversibles. La mucositis del tracto alimentario es el principal efecto secundario de la quimioterapia contra el cáncer. Se le conoce colectivamente como lesión de la mucosa inducida por quimioterapia, afecta todo el canal alimentario desde la boca hasta el ano, ocasionando la mucositis oral y la mucositis intestinal. Material y métodos: se buscaron casos clínicos en los que se reporte mucositis causada por metotrexato en tratamiento de artritis reumatoide. Se empleó un diagrama de flujo, PRISMA modificado para la búsqueda de artículos. Finalmente, se cotejó que los casos clínicos cumplieran con los fundamentos de la CARE guide, para manejar una correcta estructura y bajo riesgo a sesgo. Conclusiones: una correcta anamnesis y exploración clínica oral es lo más importante de la medicina oral. Es relevante indagar sobre las enfermedades que presentan los pacientes, así como la historia de medicamentos que se administren, especialmente en pacientes mayores, con mayores padecimientos de enfermedades sistémicas (AU)

Introduction: methotrexate is widely used for the treatment of a variety of neoplastic and autoimmune diseases. However, like all drugs its efficacy is marked by a certain degree of toxicity due to the pharmacokinetics of the drug. Methotrexate was developed as an anticancer drug, however, it has become the treatment of choice for rheumatoid arthritis. Methotrexate primarily causes inflammation of the epithelial mucous membranes. Most of the side effects of methotrexate can be detected early and are reversible. Mucositis of the alimentary tract is the main side effect of cancer chemotherapy. It is collectively known as chemotherapy-induced mucosal injury, affecting the entire alimentary canal from the mouth to the anus, where oral mucositis and intestinal mucositis are both common. Material and methods: we searched for clinical cases reporting mucositis caused by methotrexate in the treatment of rheumatoid arthritis, using a modified PRISMA flowchart to search for articles. Finally, the clinical cases were checked for compliance with the fundamentals of the CARE guide, in order to manage a correct approach to oral medicine. It is important to inquire about the diseases the patients present, as well as the history of medications administered, especially in older patients, with more systemic disease conditions, structure, and low risk of bias. Conclusion: a correct anamnesis and oral clinical examination is the most important aspect of oral medicine. It is important to inquire about the diseases that the patients present, as well as the history of medications that are administered, especially in older patients with major systemic diseases (AU)

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.

GENETIC PREDICTORS OF TOXIC EFFECTS OF METHOTREXATE IN CANCER PATIENTS.

Today, methotrexate (MTX) is used in combination with other medicines to treat a wide range of malignancies. Despite its proven high efficacy, MTX often causes serious side effects, which may result in the need to reduce the dose of MTX or discontinue the drug altogether. This, in turn, can provoke the development of MTX resistance and cancer progression. Predicting the risk of MTX-induced toxicity is currently difficult due to the variability of pharmacokinetics and pharmacodynamics in different patients, so the scientific literature is intensively searching for potential biomarkers. Based on the data available in the current literature, we analyzed the relationship between variants in the genes encoding the key components of MTX intracellular metabolism and the MTX-induced side effects and drug response. According to the results of our work, the most studied variants are those of the SLC19A1 gene, which encodes the reduced folate carrier protein 1, and the MTHFR gene, which encodes the enzyme methylenetetrahydrofolate reductase. Studies of the effect of methylation of the promoter regions of genes on the therapeutic effect of MTX are also very promising. In conclusion, the study of molecular genetic markers of MTX toxicity is extremely relevant and necessary because it can help to avoid the effect of multidrug resistance and improve the quality of life and survival of patients.

External Evaluation of Population Pharmacokinetic Models for High-Dose Methotrexate in Adult Patients with Hematological Tumors.

Currently, numerous population pharmacokinetic (popPK) models for methotrexate (MTX) have been published for estimating PK parameters and variability. However, it is unclear whether the accuracy of these models is sufficient for clinical application. The aim of this study is to evaluate published models and assess their predictive performance according to the standards of scientific research. A total of 237 samples from 74 adult patients who underwent high-dose MTX (HDMTX) treatment at Shanghai Changzheng Hospital were collected. The software package NONMEM was used to perform an external evaluation for each model, including prediction-based diagnosis, simulation-based diagnosis, and Bayesian forecasting. The simulation-based diagnosis includes normalized prediction distribution error (NPDE) and visual predictive check (VPC). Following screening, 7 candidate models suitable for external validation were identified for comparison. However, none of these models exhibited excellent predictive performance. Bayesian simulation results indicated that the prediction precision and accuracy of all models significantly improved when incorporating prior concentration information. The published popPK models for MTX exhibit significant differences in their predictive performance, and none of the models were able to accurately predict MTX concentrations in our data set. Therefore, before adopting any model in clinical practice, extensive evaluation should be conducted.

Population pharmacokinetics of methotrexate and 7-hydroxymethotrexate and delayed excretion in infants and young children with brain tumors.

PURPOSE: The objectives of this study were to develop a population pharmacokinetic model of methotrexate (MTX) and its primary metabolite 7-hydroxymethotrexate (7OHMTX) in children with brain tumors, to identify the sources of pharmacokinetic variability, and to assess whether MTX and 7OHMTX systemic exposures were related to toxicity. METHODS: Patients received 2.5 or 5 g/m2 MTX as a 24-hour infusion and serial samples were analyzed for MTX and 7OHMTX by an LC-MS/MS method. Pharmacokinetic parameters were estimated using nonlinear mixed-effects modeling. Demographics, laboratory values, and genetic polymorphisms were considered as potential covariates to explain the pharmacokinetic variability. Association between MTX and 7OHMTX systemic exposures and MTX-related toxicities were explored using random intercept logistic regression models. RESULTS: The population pharmacokinetics of MTX and 7OHMTX were adequately characterized using two-compartment models in 142 patients (median 1.91 y; age range 0.09 to 4.94 y) in 513 courses. The MTX and 7OHMTX population clearance values were 4.6 and 3.0 l/h/m2, respectively. Baseline body surface area and estimated glomerular filtration rate were significant covariates on both MTX and 7OHMTX plasma disposition. Pharmacogenetic genotypes were associated with MTX pharmacokinetic parameters but had only modest influence. No significant association was observed between MTX or 7OHMTX exposure and MTX-related toxicity. CONCLUSIONS: MTX and 7OHMTX plasma disposition were characterized for the first time in young children with brain tumors. No exposure-toxicity relationship was identified in this study, presumably due to aggressive clinical management which led to a low MTX-related toxicity rate.

A population pharmacokinetic model of methotrexate in Korean patients with haematologic malignancy.

AIMS: This study was conducted to develop a population pharmacokinetic (PK) model of methotrexate in Korean patients with haematologic malignancy, identify factors affecting methotrexate PK, and propose an optimal dosage regimen for the Korean population. METHODS: Data were retrospectively collected from 188 patients with acute leukaemia or non-Hodgkin's lymphoma who were admitted to Severance Hospital during the period from November 2005 to January 2016. Using demographic factors and laboratory results as potential covariates for PK parameters, model development was performed using NONMEM and optimal dosing regimens were developed using the final PK model. RESULTS: A two-compartment model incorporating body weight via allometry best described the data, yielding typical parameter values of 25.09 L for central volume of distribution ( V 1 ), 17.65 L for peripheral volume of distribution ( V 2 ), 12.89 L/h for clearance (CL) and 0.655 L/h for inter-compartmental clearance in a 50 kg patient. Covariate analyses showed that, at the weight of 50 kg, CL decreased by 0.11 L/h for each 1-year increase in age above 14 years old and decreased 0.8-fold when serum creatinine level doubled, indicating the importance of age-specific dose individualization in methotrexate treatment. Volume of distribution at steady state derived from PK parameters (= V 1 + V 2 ) was 0.85 L/kg, which was similar to those in the Western or Chinese populations. Optimal doses simulated from the final model successfully produced the PK measures close to the target chosen. CONCLUSIONS: The population PK model and optimal dosage regimens developed in this study can be used as a basis to achieve precision dosing in Korean patients with haematologic malignancy.

A semimechanistic pharmacokinetic/pharmacodynamic model for alanine aminotransferase-based hepatotoxicity of methotrexate in paediatric patients with acute lymphoid leukaemia.

AIMS: Methotrexate (MTX) is recognized for its potential to induce hepatotoxicity, commonly manifested by elevated alanine aminotransferase (ALT) levels. However, the quantitative relationship between the pharmacokinetics (PK) of MTX and ALT-based hepatotoxicity remains unclear. This study aimed to develop a semimechanistic PK/pharmacodynamic (PD) model to characterize the MTX-induced hepatotoxicity based on ALT in paediatric patients with acute lymphoid leukaemia. METHODS: A retrospective study was conducted on paediatric patients who received high-dose (3-5 g/m2 ) MTX treatment. MTX concentrations were assessed at 24-h intervals until the concentration dropped below 0.1 µmol/L. ALT concentrations were measured both before and after MTX administration. A population PK model was initially developed, which was later connected to a semimechanistic hepatotoxicity model. RESULTS: The PK model was developed using 354 MTX concentrations obtained from 51 patients, while the PD model was constructed using 379 ALT concentrations collected from 48 patients. The optimal PK model for MTX consisted of a 2-compartment structure, where body surface area served as a covariate for clearance and central volume of distribution. An indirect response model coupled to a liver injury signal transduction model was developed to describe the dynamics of ALT after MTX administration. The drug effect was adequately described by a linear model, exhibiting considerable interoccasion variability for each treatment session. No significant covariates were identified to have an impact on the PD parameters. CONCLUSION: A semimechanistic model was developed to describe ALT-based hepatotoxicity of MTX, and it has the potential to serve as a valuable tool for characterizing drug-induced hepatotoxicity.

Multifunctional nanoparticles encapsulating methotrexate and curcumin for holistic management of rheumatoid arthritis: in-vitro and pre-clinical assessment.

PURPOSE: Bovine serum albumin (BSA) nanoparticles (BSA-MTX-CUR-NPs) encapsulating methotrexate (MTX) and curcumin (CUR) was developed with an aim to co-deliver the drugs at the inflamed joint so as to maximize the therapeutic efficacy and alleviate toxic side effects associated with MTX. METHODS: Nanoparticle albumin-bound technology was used to formulate nanoparticles, followed by characterization for its particle size, polydispersity index, encapsulation efficiency, zeta potential, surface morphology, in-vitro drug release and drug release kinetics. Further, we investigated the pharmacokinetics and pharmacodynamics of the developed nanoparticles in the adjuvant-induced arthritis model. RESULTS: BSA-MTX-CUR-NPs exhibited particle size of 163.05 ± 1.708 nm, polydispersity index of 0.195 ± 0.0024 and % encapsulation efficiency of 68.23 ± 0.640% for MTX and 75.71 ± 0.216% for CUR with controlled release pattern for both the drugs. The scanning electron microscopy revealed nanoparticles exhibited a spherical shape. DSC study confirmed the absence of incompatibility between the drugs and the excipients. Half-life and area under the curve were significantly higher for MTX in the nanoparticulate form in comparison to free MTX. Pharmacodynamic studies revealed that BSA-MTX-CUR-NPs possessed better disease-modifying effects in comparison to free MTX. CONCLUSION: Hence, it can be concluded that albumin nanoparticles constitute a viable method for delivering MTX and CUR to inflamed joints simultaneously, because of the strong affinity of albumin and enhanced permeability and retention effect at the inflamed joint. This combinational therapy of MTX & CUR in nanoparticulate form has the potential for the holistic management of rheumatoid arthritis.

Population Pharmacokinetic Model of Methotrexate in Brazilian Pediatric Patients with Acute Lymphoblastic Leukemia.

OBJECTIVES: Methotrexate (MTX) is subject to therapeutic drug monitoring because of its high pharmacokinetic variability and safety risk outside the therapeutic window. This study aimed to develop a population pharmacokinetic model (popPK) of MTX for Brazilian pediatric acute lymphoblastic leukemia (ALL) patients who attended the Hospital de Clínicas de Porto Alegre, Brazil. METHODS: The model was developed using NONMEM 7.4 (Icon®), ADVAN3 TRANS4, and FOCE-I. To explain inter-individual variability, we evaluated covariates from demographic, biochemical, and genetic data (single nucleotide polymorphisms [SNPs] related to the transport and metabolism of drugs). RESULTS: A two-compartment model was built using 483 data points from 45 patients (0.33-17.83 years of age) treated with MTX (0.25-5 g/m2) in different cycles. Serum creatinine (SCR), height (HT), blood urea nitrogen (BUN) and a low BMI stratification (according to the z-score defined by the World Health Organization [LowBMI]) were added as clearance covariates. The final model described MTX clearance as [Formula: see text]. In the two-compartment structural model, the central and peripheral compartment volumes were 26.8 L and 8.47 L, respectively, and the inter-compartmental clearance was 0.218 L/h. External validation of the model was performed through a visual predictive test and metrics using data from 15 other pediatric ALL patients. CONCLUSION: The first popPK model of MTX was developed for Brazilian pediatric ALL patients, which showed that inter-individual variability was explained by renal function and factors related to body size.

Population pharmacokinetics of methotrexate in paediatric patients with acute lymphoblastic leukaemia and malignant lymphoma.

This study aimed to identify physiological and pharmacogenomic covariates and develop a population pharmacokinetic model of high-dose methotrexate (HD-MTX) in Chinese paediatric patients with acute lymphoblastic leukaemia (ALL) and malignant lymphoma.A total of 731 MTX courses and 1658 MTX plasm concentrations from 205 paediatric patients with ALL and malignant lymphoma were analysing using a non-linear mixed-effects model technique. 47 SNPs in 16 MTX-related genes were genotyped and screened as covariates. A PPK model was established to determine the influence of covariates, such as body surface area (BSA), age, laboratory test value, and SNPs on the pharmacokinetic process of HD-MTX.Two-compartmental model with allometric scaling using BSA could nicely characterise the in vivo behaviour of HD-MTX. After accounting for body size, rs17004785 and rs4148416 were the covariates that influence MTX clearance (CL). The PPK model obtained was: CL = 9.33 * (BSA/1.73)0.75 * e0.13*rs17004785 * e0.39*rs4148416 * eηCL, Vc = 24.98 * (BSA/1.73) * eηvc, Q = 0.18 * (BSA/1.73)0.75 * eηQ and Vp = 4.70 * (BSA/1.73) * eηvp.The established model combined with the Bayesian approach could estimate individual pharmacokinetic parameters and optimise personalised HD-MTX therapy for paediatric patients with ALL and malignant lymphoma.

The Daily Expression of ABCC4 at the BCSFB Affects the Transport of Its Substrate Methotrexate.

The choroid plexuses (CPs), located in the brain ventricles, form an interface between the blood and the cerebrospinal fluid named the blood-cerebrospinal barrier, which, by the presence of tight junctions, detoxification enzymes, and membrane transporters, limits the traffic of molecules into the central nervous system. It has already been shown that sex hormones regulate several CP functions, including the oscillations of its clock genes. However, it is less explored how the circadian rhythm regulates CP functions. This study aimed to evaluate the impact of sex hormones and circadian rhythms on the function of CP membrane transporters. The 24 h transcription profiles of the membrane transporters rAbca1, rAbcb1, rAbcc1, rAbcc4, rAbcg2, rAbcg4, and rOat3 were characterized in the CPs of intact male, intact female, sham-operated female, and gonadectomized rats. We found that rAbcc1 is expressed in a circadian way in the CPs of intact male rats, rAbcg2 in the CPs of intact female rats, and both rAbcc4 and rOat3 mRNA levels were expressed in a circadian way in the CPs of intact male and female rats. Next, using an in vitro model of the human blood-cerebrospinal fluid barrier, we also found that methotrexate (MTX) is transported in a circadian way across this barrier. The circadian pattern of Abcc4 found in the human CP epithelial papilloma cells might be partially responsible for MTX circadian transport across the basal membrane of CP epithelial cells.

Factors influencing methotrexate and methotrexate polyglutamate in patients with rheumatoid arthritis: a systematic review of population pharmacokinetics.

Low dose methotrexate (MTX) is commonly used in the treatment of rheumatoid arthritis. The clinical effect is mediated by its metabolite, methotrexate polyglutamate (MTX-PGn). The drug exhibits high interindividual pharmacokinetic variability and the optimal MTX dose is different among individuals. Thus, several MTX population pharmacokinetic (PopPK) models were developed to characterize factors affecting MTX pharmacokinetic variability. This review summarizes significant predictors for MTX pharmacokinetics and identifies knowledge gaps to be further examined. A total of 359 articles were identified from a systematic search of four databases: PubMed, Science Direct, and CINAHL Complete. Of these eight studies were included. Most studies investigated influential factors on MTX pharmacokinetics, but information on MTX-PGn is limited, with only one study performing a parent-metabolite (MTX-PG3) model. MTX pharmacokinetics was described using a two-compartment model with first-order elimination in most studies, with the MTX clearance ranging from 6.94 to 12.39 L/h. Significant predictors influencing MTX clearance included weight, creatinine clearance, sex, OATP1B3 polymorphism, and MTX multiple dosing. While body mass index and red blood cell counts were significant predictors for MTX-PG3 clearance. Providing that MTX-PGn plays a crucial role in clinical effect, further studies should determine other factors affecting MTX-PGn as well as its relationship with clinical response.

Prospective evaluation of high-dose methotrexate pharmacokinetics in adult patients with lymphoma using novel determinants of kidney function.

High-dose methotrexate (HDMTX) pharmacokinetics (PKs), including the best estimated glomerular filtration rate (eGFR) equation that reflects methotrexate (MTX) clearance, requires investigation. This prospective, observational, single-center study evaluated adult patients with lymphoma treated with HDMTX. Samples were collected at predefined time points up to 96 h postinfusion. MTX and 7-hydroxy-MTX PKs were estimated by standard noncompartmental analysis. Linear regression determined which serum creatinine- or cystatin C-based eGFR equation best predicted MTX clearance. The 80 included patients had a median (interquartile range [IQR]) age of 68.6 years (IQR 59.2-75.6), 54 (67.5%) were men, and 74 (92.5%) were White. The median (IQR) dose of MTX was 7.6 (IQR 4.8-11.3) grams. Median clearance was similar across three dosing levels at 4.5-5.6 L/h and was consistent with linear PKs. Liver function, weight, age, sex, concomitant chemotherapy, and number of previous MTX doses did not impact clearance. MTX area under the curve (AUC) values varied over a fourfold range and appeared to increase in proportion to the dose. The eGFRcys (ml/min) equation most closely correlated with MTX clearance in both the entire cohort and after excluding outlier MTX clearance values (r = 0.31 and 0.51, respectively). HDMTX as a 4-h infusion displays high interpatient pharmacokinetic variability. Population PK modeling to optimize MTX AUC attainment requires further evaluation. The cystatin C-based eGFR equation most closely estimated MTX clearance and should be investigated for dosing and monitoring in adults requiring MTX as part of lymphoma management.

Plasma Distribution of Methotrexate and Its Polyglutamates in Pediatric Acute Lymphoblastic Leukemia: Preliminary Insights.

BACKGROUND AND OBJECTIVE: High-dose methotrexate (HD-MTX) is the mainstream therapy of current acute lymphoblastic leukemia (ALL) regimens, but frequent intra- and interindividual differences in the clinical response to HD-MTX lead to chemotherapeutic interruption or discontinuation. The exact mechanism of transport across the cell membrane and the disposition of active methotrexate metabolites-methotrexate polyglutamates (MTXPGs)-are not well described in the literature. The aim of this study was to gain more insight into the plasma distribution of methotrexate and MTXPGs in pediatric patients with ALL and to clarify the obscure pathways of MTXPGs. METHODS: We prospectively measured the concentrations of MTXPG1-7 in plasma samples from three male pediatric patients treated with HD-MTX and leucovorin rescue according to the IC-BFM 2009 protocol using liquid chromatography-mass spectrometry (LC-MS). Blood samples were obtained at 24, 36, 42, and 48 h after the start of HD-MTX treatment. RESULTS: Noticeable plasma concentrations of MTXPGs with a 2.2-fold interpatient variability were detected. The highest interindividual variability in total plasma MTXPG concentration was observed at 36 h, and ranged from 13.78 to 30.82 µmol/L. Among all patients, the predominant polyglutamate types in relation to the total plasma MTXPG concentration at each time point were MTXPG3 (16.71-30.02%) and MTXPG5 (26.23-38.60%), while MTXPG7 was the least abundant MTXPG (3.22-5.02%). CONCLUSION: The presence of MTXPGs in plasma of patients with ALL could be related to the action of ABC efflux transporters on blood cells and hepatocytes resulting from the administration of high doses of methotrexate. This study may not draw definitive conclusions, but it does reduce uncertainty about the dynamics of methotrexate and its active metabolites, which may be of vital importance for achieving a clinical response.

Simultaneous measurement of upadacitinib and methotrexate by UPLC-MS/MS and its pharmacokinetic application in rats.

Upadacitinib, as a selective and reversible Janus kinase (JAK) inhibitor, has been widely used in the treatment of atopic dermatitis, ulcerative colitis and other inflammatory bowel diseases and other immune-mediated diseases. The combination of methotrexate and upadacitinib is a common clinical treatment strategy for rheumatoid arthritis (RA) in recent years. In this study, we established an ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) assay for quantitative measurement of upadacitinib and methotrexate, by which we successfully determined pharmacokinetic parameters of them in rat plasma. In order to pretreat the samples, we used acetonitrile as the precipitant, and for the internal standard (IS), we chose tofacitinib. The Acquity BEHC18 (2.1 mm × 50 mm, 1.7 µm) column, with acetonitrile and 0.1% formic acid aqueous solution composed mobile phases, was used to separate upadacitinib, methotrexate and tofacitinib. A Xevo TQ-S triple quadrupole tandem mass spectrometer was used as the detecting instrument in the positive ion mode. For upadacitinib, excellent linearity was shown of this assay in the calibration range with 0.1-200 ng/mL, and as for methotrexate, the range was 0.05-100 ng/mL. As the results indicated, the lower limit of quantification (LLOQ) was respectively 0.1 and 0.05 ng/mL for upadacitinib and methotrexate, the intra- and inter-day precision were ≤ 13.3%, and the accuracy of all the analytes ranged from -4.1% to 12.7%. The recovery of each analyte was > 80.2% in this experiment, and matrix effects we observed were unobvious. The establishment of this method and its successful application in rat plasma can provide a theoretical and technical support for the deeper study of pharmacodynamics and the clinical medication strategies.