A validated UPLC-MS/MS method for quantification of pyrotinib and population pharmacokinetic study of pyrotinib in HER2-positive breast cancer patients.

Objective: Pyrotinb has been approved for the treatment of HER2-positive advanced or metastatic breast cancer in China. However, the plasma concentration of pyrotinb in different patients varies greatly, and in the course of treatment, if patients have intolerable adverse reactions, the drug dosage will be reduced or even stopped. This study set out to establish an ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the determination of pyrotinb in human plasma, analyze the population pharmacokinetics (PPK) of pyrotinib and assess the influence of patient variables on PK of pyrotinib in patients with HER2 positive breast cancer. Method: An UPLC-MS/MS method was developed to measure pyrotinib in human plasma. Utilizing a gradient elution procedure and a Kinetex C18 column (2.1 mm × 100 mm, 1.7 µm), sample separation was accomplished in 5.5 min. Pyrotinb extraction via protein precipitation was used as a sample pre-treatment technique. In total, 50 patients provided 158 plasma samples, which were identified and used in the PPK investigation. The non-linear mixed-effects modeling (NONMEM) approach was used to assess the plasma concentrations and covariates information. For the final PPK model evaluation, external evaluation, non-parametric bootstrap, visual predictive check (VPC), and goodness-of-fit (GOF) were used. Results: The UPLC-MS/MS method for determining plasma concentration of pyrotinib in patients had good selectivity and linearity in the range of 1-1,000 ng/mL. Pyrotinib concentration profile in HER2-positive breast cancer patients was well described by a single-compartment PPK model with first-order absorption and elimination. The formulas for the final estimated values of overall parameters of CL/F and Vd/F and Ka are respectively: C L / F L / h = 88.8 × e TP / 67.2 × 0.376 , V / F L = 3940 , K A h - 1 = 0.357 F I X E D . No dosage adjustment was advised, despite the possibility that the total protein levels could have a substantial impact on the apparent distribution volume of pyrotinib with limited magnitude. Conclusion: In this study, an UPLC-MS/MS method was established to determine the concentration of pyrotinib in human plasma. A population pharmacokinetic model of pyrotinib in HER2 positive breast cancer patients suggested that low serum total protein reduced the clearance rate of pyrotinib in patients. Clinical medical staff should pay attention to the liver function of patients with abnormal serum total protein and be alert to the occurrence of adverse drug reactions.

Simultaneous determination of icotinib, osimertinib, aumolertinib, and anlotinib in human plasma for therapeutic drug monitoring by UPLC-MS/MS.

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) such as icotinib, osimertinib, and aumolertinib have emerged as promising treatment options for EGFR mutated Non-small cell lung cancer (NSCLC) patients. Additionally, anlotinib, an anti-angiogenic agent targeting VEGFR, FGFR, and PDGFR, has been used in combination with EGFR-TKIs in NSCLC cases. A method utilizing ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed and validated for quantifying icotinib, osimertinib, aumolertinib and anlotinib simultaneously in clinical TDM. The chromatographic separation was performed using a Kinetex C18 column (100 mm × 2.1 mm) and an elution gradient of ammonium acetate in water acidified with 0.1 % formic acid and in acetonitrile. The assay was validated over a linear range of 4-2000 ng/mL for icotinib, 2-1000 ng/mL for osimertinib, 1-500 ng/mL for aumolertinib, and 0.8-400 ng/mL for anlotinib, following the guidelines on bioanalytical methods by FDA. The quantification method exhibited satisfactory performance in terms of selectivity, accuracy (from 91.3 % to 107 %), precision (intra- and inter-day coeffficients of variation ranged from 0.944 % to 7.48 %), linearity, recovery (from 86.0 % to 91.9 %), matrix effect (IS-normalized matrix factors were from 96.7 % to 102 %), and stability. Overall, the method proved to be sensitive, reliable, and straightforward, enabling successful simultaneous determination of blood concentrations of icotinib, osimertinib, aumolertinib, and anlotinib in patients. The validity of the method has been confirmed across various instruments.

Precise prostate cancer diagnosis using fluorescent nanoprobes for detecting PSA and PSMA in serum.

Novel Au-Se bond-based nanoprobes were designed for concurrent detection of PSA and PSMA in serum samples, aiming to enhance the early diagnosis of prostate cancer. These probes demonstrate robust stability, specificity and accuracy, underscoring their potential as non-invasive tools for diagnosis.

Advancing Nonsmall Cell Lung Cancer Diagnosis Accuracy via Dual Detection Fluorescent Nanoprobes.

Among the primary threats to human health worldwide, nonsmall cell lung cancer (NSCLC) remains a significant factor and is a leading cause of cancer-related deaths. Due to subtle early symptoms, NSCLC patients are diagnosed at advanced stages, resulting in low survival rates. Herein, novel Au-Se bond nanoprobes (NPs) designed for the specific detection of Calpain-2 (CAPN2) and Human Neutrophil Elastase (HNE), pivotal biomarkers in NSCLC, were developed. The NPs demonstrated exceptional specificity and sensitivity toward CAPN2 and HNE, enabling dual-color fluorescence imaging to distinguish between NSCLC cells and normal lung cells effectively. The NPs' performance was consistent across a wide pH range (6.2 to 8.0), and it exhibited remarkable resistance to biological thiol interference, indicating its robustness in complex physiological environments. These findings suggest the nanoprobe is a promising tool for early NSCLC diagnosis, offering a novel approach for enhancing the accuracy of cancer detection.

Dual-targets fluorescent nanoprobe for precise subtyping of lung cancer.

A Au-Se bond-based nanoprobe using 3',3-diselenopropionic acid to simultaneously link response chains for Pro-GRP protein and Cyfra21-1 was developed. Early diagnosis and subtyping of lung cancer can be achieved based on the nanoprobes' differential response of the probes to the two targets in lung cancer patients' serum.

Development and Validation a UPLC-MS/MS Method for Quantification of Pentoxifylline in Beagle Plasma: Application for Pharmacokinetic Study of Food Effect.

Purpose: To develop an UPLC-MS/MS method for the quantitative analysis of pentoxifylline in beagle dog plasma and apply it to a pharmacokinetic study of food effect. Methods: Sample separation was achieved using a Kinetex Phenyl-Hexyl column (50 × 2.1 mm, 1.7 µm) with a gradient elution program in 5.5 min after a simple protein precipitation with methanol. Using the mobile phase that made up by 0.2% formic acid and 5mM ammonium formate water (A) and methanol (B). Quantitation was carried out using the positive ionization mode with multiple reaction monitoring (MRM). A randomized, single-dose, two-period crossover study was conducted in six fasted or fed beagles that received 400 mg pentoxifylline sustained-release tablets (Brand name: Shuanling™, CSPC Pharmaceutical Group). WinNonlin® software was used to calculate pharmacokinetic parameters. Results: The linear calibration range was 2-1000 ng/mL (r2> 0.99). Both intra- and inter-batch precision were less than 6.27%, and the accuracy ranged from 88.65% to 97.18%. Pentoxifylline was readily absorbed in fasted and fed dogs administered a dose of 400 mg (tmax:1.54h vs 1.83h). Compared to the fasted group, the AUC0→t and Cmax in the fed group increased by 1.71-fold and 1.30-fold, respectively. In the fasted group, the AUC0→t and Cmax values were 4684.08 h•ng/mL and 2402.33 ng/mL, respectively. In the fed group, these values were 8027.75 h•ng/mL and 3119.67 ng/mL. The difference in AUC0-t between the fed and fasted group was statistically significant. Conclusion: The novel optimized UPLC-MS/MS assay is an effective tool for the determination of pentoxifylline and has been successfully applied in pharmacokinetic studies of pentoxifylline in beagle dogs. The administration of pentoxifylline sustained-release tablets with food significantly increased the area under the time curve, and it is recommended that they should be administered during or shortly after feeding.

Pt-Se-Bonded Nanoprobe for High-Fidelity Detection of Non-small Cell Lung Cancer and Enhancement of NIR II Photothermal Therapy.

Non-small cell lung cancer (NSCLC) accounts for a high proportion of lung cancer cases globally, but early detection remains challenging, and insufficient oxygen supply at tumor sites leads to suboptimal treatment outcomes. Therefore, the development of core-shell Au@Pt-Se nanoprobes (Au@Pt-Se NPs) with peptide chains linked through Pt-Se bonds was designed and synthesized for NSCLC biomarker protein calcium-activated neutral protease 2 (CAPN2) and photothermal therapy (PTT) enhancement. The NP can be specifically cleaved by CAPN2, resulting in fluorescence recovery to realize the detection. The Pt-Se bonds exhibit excellent resistance to biologically abundant thiols such as glutathione, thus avoiding "false-positive" results and enabling precise detection of NSCLC. Additionally, the platinum (Pt) shell possesses catalase-like properties that catalyze the generation of oxygen from endogenous hydrogen peroxide within the tumor, thereby reducing hypoxia-inducible factor-1α (HIF-1α) levels and alleviating the hypoxic environment at the tumor site. The Au@Pt-Se NPs exhibit strong absorption bands, enabling the possibility of PTT in the near-infrared II region (NIR II). This study presents an effective approach for the early detection of NSCLC while also serving as an oxygen supplier to alleviate the hypoxic environment and enhance NIR II PTT.

A Drug-Drug Interaction Study to Evaluate the Impact of Simvastatin and Itraconazole on Erlotinib Pharmacokinetics in Rats by UPLC-MS/MS.

Aim: The goal of our study was to investigate the effects of single-dose simvastatin and itraconazole application on the pharmacokinetics of erlotinib in rats. Methods: Twenty-one male Sprague-Dawley rats were randomly divided into 3 groups, including erlotinib combined with simvastatin, erlotinib combined with itraconazole and erlotinib alone groups. The rats were given a single dose of 2 mg/kg simvastatin, 15 mg/kg itraconazole or 0.5% sodium carboxymethyl cellulose followed by 12 mg/kg erlotinib. The concentration of erlotinib in rat plasma was determined by UPLC-MS/MS. As internal standard, tinidazole was used for chromatographic analysis on the Kinetex C18 column (100×2.1 mm, 2.6 µm). Results: Erlotinib was validated in the calibration range of 5-1000 ng/mL. The lower limit of quantification (LLOQ) was 5 ng/mL. The inter- and intra-day precisions for erlotinib were less than 10.56%, and the accuracies were in the range of 98.61-104.99%. The validated UPLC-MS/MS method was successfully applied to this study. Compared with the erlotinib alone group, the values of AUC0-t, AUC0-∞, Cmax, Vz/F and t1/2 in the simvastatin group showed no statistical differences among pharmacokinetic parameters (P>0.05). However, the values of AUC0-t, AUC0-∞ and Cmax, in the itraconazole group were approximately 1.32-fold, 1.32-fold and 1.34-fold higher, and the CL/F was lower than those in the erlotinib alone group; the difference was statistically significant (P<0.05). Conclusion: Simvastatin had no significant effect on the pharmacokinetics of erlotinib, whereas co-administration of itraconazole considerably increased the exposure of erlotinib. Therefore, we should pay more attention to the potential drug-drug interaction to ensure safety in cancer patient treatment.

Population pharmacokinetics of nalbuphine in patients undergoing general anesthesia surgery.

Purpose: The aim of this study was to build a population pharmacokinetics (PopPK) model of nalbuphine and to estimate the suitability of bodyweight or fixed dosage regimen. Method: Adult patients who were undergoing general anesthetic surgery using nalbuphine for induction of anesthesia were included. Plasma concentrations and covariates information were analyzed by non-linear mixed-effects modeling approach. Goodness-of-fit (GOF), non-parametric bootstrap, visual predictive check (VPC) and external evaluation were applied for the final PopPK model evaluation. Monte Carlo simulation was conducted to assess impact of covariates and dosage regimens on the plasma concentration to nalbuphine. Results: 47 patients aged 21-78 years with a body weight of 48-86 kg were included in the study. Among them, liver resection accounted for 14.8%, cholecystectomy for 12.8%, pancreatic resection for 36.2% and other surgeries for 36.2%. 353 samples from 27 patients were enrolled in model building group; 100 samples from 20 patients were enrolled in external validation group. The results of model evaluation showed that the pharmacokinetics of nalbuphine was adequately described by a two-compartment model. The hourly net fluid volume infused (HNF) was identified as a significant covariate about the intercompartmental clearance (Q) of nalbuphine with objective function value (OFV) decreasing by 9.643 (p < 0.005, df = 1). Simulation results demonstrated no need to adjust dosage based on HNF, and the biases of two dosage methods were less than 6%. The fixed dosage regimen had lower PK variability than the bodyweight regimen. Conclusion: A two-compartment PopPK model adequately described the concentration profile of nalbuphine intravenous injection for anesthesia induction. While HNF can affect the Q of nalbuphine, the magnitude of the effect was limited. Dosage adjustment based on HNF was not recommended. Furthermore, fixed dosage regimen might be better than body weight dosage regimen.

Self-Assembly-Based Nanoprobes for the Simultaneous Detection and Downregulation of HSP90α mRNA to Enhance Photothermal Therapy.

Although photothermal therapy (PTT) has been widely applied for tumor treatment, tumor cells thermotolerance still limits PTT efficiency. Since the overexpressed HSP90α in tumor cells further enhances thermotolerance and protects them from PTT damage, a new nanoprobe that can specifically detect and downregulate HSP90α mRNA was developed to enhance the PTT effect. Based on the HSP90α mRNA sequence, the nanoprobe Au-DNA1/DNA2 can specifically bind to HSP90α mRNA for recovering its fluorescence and further inhibit the synthesis of HSP90α to reduce tumor heat tolerance. Moreover, another nanoprobe, Au-DNA3, can self-assemble with the Au-DNA1 nanoprobe after the detection to form Au aggregations to enhance PTT afterward for better efficiency. Simultaneously, such a design improves tissue penetration and tumor retention, thereby reducing the damage to the surrounding normal tissues. Both in vitro and in vivo experiments showed that the nanoprobes have excellent tumor diagnosis and cancer treatment capabilities, which is of great significance for clinical translational applications.

Gold Nanoparticles Functionalized with Au-Se-Bonded Peptides Used as Gatekeepers for the Off-Target Release of Resveratrol in the Treatment of Triple-Negative Breast Cancer.

Resveratrol has been garnering considerable attention as a promising chemopreventive and chemotherapeutic drug against metastatic tumors such as triple-negative breast cancer (TNBC). However, the potential in vivo application of resveratrol has been highly limited due to its poor solubility, rapid conjugation, low bioavailability, and bioactivity. In this study, a silica mesoporous nanoparticle (MSN)-based drug delivery system (DDS), named Au-Se@MSN, is developed to deliver the loaded resveratrol, endowing it with properties of targeted delivery, excellent bioavailability, and antioxidation of resveratrol. In Au-Se@MSN(RES), gold nanoparticles functionalized with selenol-modified uPA-specific peptides act as gatekeepers to avoid the interference of glutathione in the bloodstream and realize negligible premature release of resveratrol during delivery. Au-Se@MSN(RES) shows prolonged resveratrol release at the tumor site and endows resveratrol with a remarkable in vitro therapeutic effect. The pharmacological dose of resveratrol treatment on MDA-MB-231 cells was found to result in the generation of a high level of NAD(P)H other than H2O2, indicating reductive stress instead of oxidative stress involved in the resveratrol therapeutic process. In vivo experiments showed that Au-Se@MSN greatly improves the chemotherapeutic effect of resveratrol on mice bearing TNBC tumors, and damage to normal tissues and cells is negligible. Overall, Au-Se@MSN is a potential tool for further studies on the anticancer mechanism and clinical applications of resveratrol.

A Validated UHPLC-MS/MS Method for Determination of Nalbuphine in Human Plasma and Application for Pharmacokinetic Study of Patients Undergoing General Anesthesia.

Nalbuphine was a semisynthetic opioid analgesic widely used in the treatment of both acute and chronic pain. We developed and validated a rapid, simple and sensitive method by ultra-performance liquid chromatography-tandem mass spectrometry (MS/MS) for the simultaneous quantitation of nalbuphine in human plasma, and we reported the pharmacokinetic features of patients during general anesthesia for abdominal surgery. Sample separation was achieved on a Kinetex Phenyl-Hexyl column (50 × 2.1 mm, 1.7 µm) after simple protein precipitation with acetonitrile. The mobile phase was composed of acetonitrile and 3 mM of ammonium acetate aqueous solution with 0.1% formic acid. Gradient elution was used in 4.5 min with a flow rate of 0.5 mL/min at 40°C. MS detection using AB Sciex QTRAP 5500 mass spectrometer was characterized by electrospray ionization for positive ions in multiple reaction monitoring mode. Quantitative ion pairs were m/z 358.4 â†’ 340.1 for nalbuphine and m/z 340.0 â†’ 268.3 for nalmefene, which were used as the internal standard (IS). The calibration curves showed good linearity (r2>0.99) over concentration range of 0.1-500 ng/mL. The intra-and inter-batch precisions were within 10.67%, and accuracy ranged from 94.07 to 105.34%. The IS-normalized matrix factors were 1.02-1.03 with RSD% (≤5.82%). The recoveries ranged from 101.09 to 106.30%. In conclusion, a rapid, simple, sensitive and economical analytical method was developed and validated to detect the concentration in plasma samples obtained from patients receiving nalbuphine intravenous injection and was successfully applicated to human pharmacokinetic studies of nalbuphine.

A pH-responsive cascade nanoplatform with circulating oxygen supply for collaborative breast cancer treatment.

A pH-responsive cascade nanoplatform based on ZIF-8 disintegrates in the weakly acidic tumor microenvironment to release MnO2, CaO2 and Ce6. The drugs can cyclically generate O2 for sonodynamic therapy, consume glutathione to tune the redox hemostasis, and produce cytotoxic ˙OH to kill tumor cells via chemical dynamics therapy.

Pharmacokinetic Study of Nalbuphine in Surgical Patients Undergoing General Anesthesia with Varying Degrees of Liver Dysfunction.

Purpose: This study aimed to characterize the pharmacokinetics of nalbuphine in patients undergoing general anesthesia with varying degrees of liver dysfunction. Patients and Methods: Twenty-four patients were enrolled and divided into three cohorts based on liver function: normal liver function (n = 13), mild liver dysfunction (n = 5), and moderate/severe liver dysfunction (n = 6). During the induction of anesthesia, they received 15 mg of nalbuphine intravenously. Venous blood samples were collected from each patient. The plasma concentration of nalbuphine was determined using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The pharmacokinetic parameters of nalbuphine were calculated by non-compartmental analysis (NCA) using Phoenix WinNonlin software. Results: Compared with the normal liver function group, the plasma elimination half-life (T1/2) of nalbuphine was increased by approximately 33% in the moderate/severe liver dysfunction group (2.66 h vs 3.54 h, P<0.05), and the volume of distribution (Vd) increased by approximately 85% (100.08 L vs 184.95 L, P<0.05). Multivariate analysis revealed that weight and platelet were associated with clearance (CL); total bilirubin as an independent factor was associated with T1/2, and weight associated with area under the curve (AUC(0→∞)) independently. Conclusion: The T1/2, mean residence time, and Vd of nalbuphine in patients with moderate/severe liver dysfunction were prolonged or increased significantly compared with those in the normal liver function group. These data suggest that it may need to be used with caution when nalbuphine is administered to patients with moderate or severe liver dysfunction.

Determination of the location of the needle entry point based on an improved pruning algorithm.

Since the emergence of new coronaviruses and their variant virus, a large number of medical resources around the world have been put into treatment. In this case, the purpose of this article is to develop a handback intravenous intelligence injection robot, which reduces the direct contact between medical staff and patients and reduces the risk of infection. The core technology of hand back intravenous intelligent robot is a handlet venous vessel detection and segmentation and the position of the needle point position decision. In this paper, an image processing algorithm based on U-Net improvement mechanism (AT-U-Net) is proposed for core technology. It is investigated using a self-built dorsal hand vein database and the results show that it performs well, with an F1-score of 93.91%. After the detection of a dorsal hand vein, this paper proposes a location decision method for the needle entry point based on an improved pruning algorithm (PT-Pruning). The extraction of the trunk line of the dorsal hand vein is realized through this algorithm. Considering the vascular cross-sectional area and bending of each vein injection point area, the optimal injection point of the dorsal hand vein is obtained via a comprehensive decision-making process. Using the self-built dorsal hand vein injection point database, the accuracy of the detection of the effective injection area reaches 96.73%. The accuracy for the detection of the injection area at the optimal needle entry point is 96.50%, which lays a foundation for subsequent mechanical automatic injection.

Au-Se bonded nanoprobe for prostate specific antigen detection in serum.

The detection of prostate specific antigen (PSA) in serum can realize early diagnosis of prostate cancer and prevent the occurrence of prostate tumors, as well as offering guidance during the therapy. Herein, a Au-Se bonded nanoprobes that can specifically detect PSA was designed and constructed. The peptide chains that can be specifically cleaved by PSA were firstly functionalized with fluorescent dye and selenol, and then bind to the Au nanoparticles to produce the probe. The dye's fluorescence was quenched due to the FRET effect, but recovered by PSA's cutting. The nanoprobe can detect PSA in serum with extraordinary anti-interference ability against other proteins (detection range 1-40 ng/mL). This work provides a new method for the detection of PSA in serum, and has potential guiding significance for clinical PSA detection.

A systematic review, meta-analysis and meta-regression of the global prevalence of Toxoplasma gondii infection in wild marine mammals and associations with epidemiological variables.

Toxoplasma gondii infection in wild marine mammals is a growing problem and is associated with adverse impacts on marine animal and public health. This systematic review, meta-analysis and meta-regression estimates the global prevalence of T. gondii infection in wild marine mammals and analyses the association between T. gondii infection and epidemiological variables. PubMed, Web of Science, Science Direct, China National Knowledge Infrastructure, and Wanfang Data databases were searched until 30 May 2021. Eighty-four studies (n = 14,931 wild marine mammals from 15 families) were identified from literature. The overall pooled prevalence of T. gondii infection was 22.44% [3848/14,931; 95% confidence interval (CI): 17.29-28.04]. The prevalence in adult animals 21.88% (798/3119; 95% CI: 13.40-31.59) was higher than in the younger age groups. North America had a higher prevalence 29.92% (2756/9243; 95% CI: 21.77-38.77) compared with other continents. At the country level, the highest prevalence was found in Spain 44.26% (19/88; 95%CI: 5.21-88.54). Regarding climatic variables, the highest prevalence was found in areas with a mean annual temperature >20°C 36.28% (171/562; 95% CI: 6.36-73.61) and areas with an annual precipitation > 800 mm 26.92% (1341/5042; 95% CI: 18.20-36.59). The subgroup and meta-regression analyses showed that study-level covariates, including age, country, continent, and mean temperature, partly explained the between-study heterogeneity. Further studies are needed to investigate the source of terrestrial to aquatic dissemination of T. gondii oocysts, the fate of this parasite in marine habitat and its effects on wild marine mammals.

A simple, rapid and low-cost qPCR assay for evaluating the severity of exosomal PD-L1-mediated T cell exhaustion in blood samples.

A novel dual-aptamer activated proximity-induced qPCR assay was developed for the quantitative analysis of exosomal PD-L1 on T cell-exosome complexes in blood samples.

A Validated HPLC-MS/MS Method for Quantification of Methotrexate and Application for Therapeutic Drug Monitoring in Children and Adults with Non-Hodgkin Lymphoma.

PURPOSE: A simple, rapid and reliable method to quantify methotrexate (MTX) in human plasma by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established and validated in two laboratories. PATIENTS AND METHODS: Sample separation was achieved on a Synergi Hydro-RP column (50 mm×2.0 mm, 2.5 µm) with a gradient elution program in 3.5 min after a simple protein precipitation with methanol (MeOH) and acetonitrile (ACN) (1:1). About 5 mM ammonium formate aqueous solution with 0.2% formic acid and ACN were used as mobile phase with a flow rate of 0.5 mL/min at 40 °C. Mass spectrometry detection using AB Sciex Triple Quad 4500 mass spectrometer (4500 QQQ) and Qtrap 5500 mass spectrometer (5500 Q-trap) were both characterized by electrospray ionization (ESI) for positive ions in multiple reaction-monitoring (MRM) mode. Quantitative ion pairs were m/z 455.1→m/z 308.0 for MTX and m/z 248.1→m/z 121.0 for tinidazole (TNZ) used as internal standard (IS). RESULTS: Linear calibration curves were generated over the range of 5-1000 ng/mL (r2> 0.99) on both the 4500 QQQ and 5500 Q-trap, both of the intra- and inter-batch precision were less than 7.67% and accuracy ranged from 96.33% to 108.94%. The recovery and matrix effect were 82.20-93.98% and 102.69-105.28%, respectively. CONCLUSION: An analytical method transfer was achieved by re-verification in two laboratories to ensure stability and reproducibility and this method has been applied for therapeutic drug monitoring (TDM) successfully in children and adults with NHL, and during routine TDM, two delayed elimination of MTX cases were observed and analyzed.

Exploring the binding mechanism of positive allosteric modulators in human metabotropic glutamate receptor 2 using molecular dynamics simulations.

Positive allosteric modulators (PAMs) of human metabotropic glutamate receptor 2 (hmGlu2) are well-known in the treatment of psychiatric disorders for their higher selectivity and lower tolerance risk. A variety of PAMs have been reported over the last decade and two compounds were in Phase II clinical trials for schizophrenia and anxiety. These trials were discontinued on account of the unsatisfactory therapeutic efficacy, but PAMs were explored as novel treatments for addiction and epilepsy. Thus, it is still important to explore novel hmGlu2 PAMs in the near future. Nowadays, the challenges in optimizing drug potency and improving scaffold diversity for PAMs are the noncomprehensive character analyses of multiple scaffolds; the exploration of the binding modes of PAMs in the allosteric binding site have been proposed to reduce this difficulty. However, there has been no comprehensive research about the binding profiles of PAMs in the hmGlu2 receptor. To address this issue, this work explores the binding characters of eight PAMs representing five chemical series by multiple computational methods. As a result, the shared binding modes of the eight studied PAMs interacting with 15 residues in the allosteric binding site were defined. In addition, the reduced hydrophobicity with low electronegativity of R1, increased hydrophobicity with low negative electron density of R2 and the electronegativity of the linker were identified as indicators that regulate the affinity of PAMs. This finding agrees well with the physicochemical properties of reported multiple series PAMs. This comprehensive work sheds additional light on the binding mechanism and physicochemical regularity underlining PAMs affinity and could be further utilized as a structural and energetic blueprint for discovering and assessing novel PAMs for hmGlu2.