Analysis of riociguat and desmethyl riociguat by UPLC-MS/MS and its interaction with quercetin.

Riociguat, an orally soluble guanylate cyclase (sGC)-promoting drug, is mainly used in the clinical treatment of pulmonary hypertension (PH). In this study, a novel ultra-performance liquid chromatography-tandem mass spectrometry method was developed to quantify the concentrations of riociguat and its metabolite (M1) in plasma. The precision, stability, accuracy, matrix effect, and recovery of the methodology were satisfactory. Quercetin, a well-recognized compound, functions as a novel anticancer agent with the potential to alleviate symptoms of PH. Therefore, the potential interaction between quercetin and riociguat was investigated in this study. The levels of riociguat and M1 in rat plasma were measured using the method developed in this study to evaluate the interactions between riociguat and quercetin in rats. The results revealed that quercetin significantly inhibited riociguat and M1 metabolism with increased systemic exposure.

The pharmacokinetics and tissue distribution of curcumin following inhalation administration in rats-A comparative analysis with oral and intravenous routes.

A sensitive and simple method using ultra-liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed and validated to determine the concentration of curcumin in rat plasma and tissue samples. Emodin was selected as the internal standard (IS), and biological samples were pretreated with simple one-step acetonitrile precipitation. The calibration curves exhibited linearity within the range of 1-1000 ng/ml for both rat plasma and tissue samples. The accuracy and precision of intra-day as well as inter-day determinations ranged from 99.3% to 117.3% and from 98.2% to 105.1%, respectively. This method demonstrated excellent recovery rates ranging from 76.4% to 96.4% along with minimal matrix effect ranging from 86.5% to 99.6%. The effectiveness of this method was successfully demonstrated through its application in an in vivo pharmacokinetic and tissue distribution study after single administration via inhalation (100 mg/kg), oral gavage (100 mg/kg) and intravenous injection (2.5 mg/kg) of curcumin in rats. The results revealed that inhalation significantly improved the bioavailability of curcumin, with most of the drug being deposited in the lung. These findings highlight inhalation as an effective route for targeted delivery of drugs directly into lung tissues, thus suggesting potential future applications for treating pulmonary diseases utilizing inhaled curcumin.

Characterization and comparison of metabolites in colostrum from yaks, buffaloes, and cows based on UPLC-QTRAP-MS metabolomics.

Colostrum from yaks and buffaloes possesses substantial nutritional value, yet the complete array of metabolites within remains insufficiently elucidated. This study scrutinizes the metabolite profiles of yak, buffalo, and cow colostrum utilizing targeted metabolomics paired with ultra-performance liquid chromatography-tandem triple quadrupole linear ion trap mass spectrometry (UPLC-QTRAP-MS). The analysis detected 362 metabolites across all samples. Furthermore, 63, 77, and 46 differential metabolites were selected between yak and buffalo colostrum, yak and cow colostrum, and buffalo and cow colostrum, respectively. Yak colostrum notably contained higher concentrations of inositol, glycine, and carnitine, whereas buffalo colostrum was distinguished by a substantial presence of primary bile acids, which facilitate fat digestion. These findings offer profound insights into yak and buffalo colostrum, providing critical data to propel advancements in the dairy industry.

Derivatization to reduce background interferences for simultaneous quantitation of trimethylamine (TMA) and trimethylamine-N-oxide (TMAO) using liquid chromatography with tandem mass spectrometry.

Trimethylamine (TMA) and trimethylamine-N-oxide (TMAO) play a crucial role in many biochemical processes within diverse organisms including animals, plants, fungi and bacteria. Studies have linked these metabolites with cardiovascular and kidney diseases; however, emerging evidence demonstrates their protective properties. Owing to these controversies and co-existence of these metabolites in biological samples, it is crucial to accurately quantify these metabolites to associate their concentrations with various physiological and pathophysiological conditions to elucidate their potential roles. We reported interferences on TMA quantification without derivatizing the analyte. A combined sample preparation method, including sample derivatization with ethyl bromoacetate and use of ion pairing reagent (sodium heptanesulfonate), minimized these interferences and provided improved accuracy and precision for simultaneous quantification of TMA and TMAO. The linearity for TMAO ranged from 0.01 µM to 300 µM and 0.1 µM - 300 µM for TMA. With the application of this method, we reported that the circulating concentrations of TMA was 4 times higher in male mice (33.1 ± 5.9 µmol/L) compared to females (8.3 ± 1.39 µmol/L), whereas TMAO levels were 6 times lower in male (7.2 ± 0.4 µmol/L) than female mice (42.1 ± 4.5 µmol/L). In contrast, concentrations of TMA and TMAO in the colonic tissue did not differ significantly between males and females. The robust analytical method for simultaneously quantifying TMA and TMAO presents a significant value in facilitating investigations on TMA and TMAO biology.

Identification of amino acids metabolomic profiling in human plasma distinguishes lupus nephritis from systemic lupus erythematosus.

Lupus nephritis (LN) is an immunoinflammatory glomerulonephritis associated with renal involvement in systemic lupus erythematosus (SLE). Given the close relationship between plasma amino acids (AAs) and renal function, this study aimed to elucidate the plasma AA profiles in LN patients and identify key AAs and diagnostic patterns that distinguish LN patients from those with SLE and healthy controls. Participants were categorized into three groups: normal controls (NC), SLE, and LN. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was employed to quantify AA levels in human plasma. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were utilized to identify key AAs. The diagnostic capacity of the models was assessed using receiver operating characteristic (ROC) curve analysis and area under the ROC curve (AUC) values. Significant alterations in plasma AA profiles were observed in LN patients compared to the SLE and NC groups. The OPLS-DA model effectively separated LN patients from the SLE and NC groups. A joint model using histidine (His), lysine (Lys), and tryptophan (Trp) demonstrated exceptional diagnostic performance, achieving an AUC of 1.0 with 100% sensitivity, specificity, and accuracy in predicting LN. Another joint model comprising arginine (Arg), valine (Val), and Trp also exhibited robust predictive performance, with an AUC of 0.998, sensitivity of 93.80%, specificity of 100%, and accuracy of 95.78% in distinguishing between SLE and LN. The joint forecasting models showed excellent predictive capabilities in identifying LN and categorizing lupus disease status. This approach provides a novel perspective for the early identification, prevention, treatment, and management of LN based on variations in plasma AA levels.

Headspace aroma and secondary metabolites profiling in 3 Pelargonium taxa using a multiplex approach of SPME-GC/MS and high resolution-UPLC/MS/MS coupled to chemometrics.

BACKGROUND: The present study focuses on the aroma and secondary metabolites profiling of three Pelargonium graveolens cultivars, baladi (GRB), sondos (GRS) and shish (GRSH), grown in Egypt. Utilizing a multiplex approach combining high resolution-ultraperformance liquid chromatography (HR-UPLC)/tandem mass spectrometry (MS/MS) and gas chromatography (GC)-MS coupled with chemometrics, the study aims to identify and profile various secondary metabolites and aroma compounds in these cultivars. RESULTS: HR-UPLC/MS/MS analysis led to the annotation of 111 secondary metabolites, including phenolics, flavonoids, terpenes and fatty acids, with several compounds being reported for the first time in geranium. Multivariate data analysis identified vinylanisole, dimethoxy-flavonol, and eicosadienoic acid as discriminatory metabolites among the cultivars, particularly distinguishing the GRS cultivar in its phenolics profile. In total, 34 aroma compounds were detected using headspace solid-phase microextraction coupled with GC-MS, including alcohols, esters, ketones, ethers and monoterpene hydrocarbons. The major metabolites contributing to aroma discrimination among the cultivars were ß-citronellol in GRB, α-farnesene in GRS and isomenthone in GRSH. CONCLUSION: The study provides a comprehensive profiling of the secondary metabolites and aroma compounds in the three Pelargonium graveolens cultivars. The GRS cultivar was identified as particularly distinct in both its phenolics and aroma profiles, suggesting its potential as a premium variety for cultivation and use. Future studies should focus on isolating and investigating the newly detected metabolites and exploring the biological effects of these compounds in food applications and other uses. © 2024 Society of Chemical Industry.

Monitoring of ketamine-based emerging contaminants in wastewater: a direct-injection method and fragmentation pathway study.

The ketamine (KET) and its analogs consumed by humans are becoming emerging contaminants (ECs), as they at present in surface waters after being carried through wastewater systems. Drugs in wastewater can be analyzed using the direct-injection method, a simple wastewater analysis (WWA) method that can provide objective, continuous and nearly to real-time findings. This article describes an ultra-high-pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous quantification and confirmation of seven KET-based ECs in wastewater by direct injection. After optimization of the UPLC-MS/MS and sample pretreatment conditions, the method was validated and applied to samples (n = 157) collected from several wastewater treatment plants (WWTPs) in southern China in which KET had the highest detection rate. The established direct-injection method was not only simple to perform but also had better sensitivity, shorter detection times, and analyzed more KET-based ECs than currently published methods, meeting the requirements for the monitoring and high-throughput analysis of common KET-based ECs. We also analyzed the fragmentation pathway of KET-based ECs to obtain product ion information on other unknown substances. Additional studies are needed to establish a comprehensive direct-injection screening method of ECs in wastewater on model-based assessment.

A step-by-step progressive strategy exploring whole metabolic profiles in vivo for Polygalae Radix with/without licorice.

INTRODUCTION: Polygalae Radix (PR) is known to relieve toxicity and increase efficiency in various diseases after processing. However, there were few studies for aromatic carboxylic acids (ACAs) due to the limited detection, especially for the metabolites within m/z 100-2000. OBJECTIVES: This study aims to elucidate the whole metabolism of PR with/without licorice (LP), focusing on metabolites within m/z 100-2000 and pharmacodynamics in vivo. MATERIAL AND METHODS: This study was established by the combination of multidimensional ultra-high performance liquid chromatography coupled with a mass spectrometer (UPLC-MS) technology with protein sedimentation method to analyze metabolites in plasma, brain, colon, and stomach contents. Quantitative monitoring ACAs was enhanced with our novel stable isotope derivatization (SILD) technique. And then the pharmacokinetics (PK) study of relatively large metabolites was carried out. A targeted network pharmacology approach was established to avoid false positive results, mapping interactions relevant to Alzheimer's disease (AD), and other conditions. RESULTS: The 85 polygala metabolites were qualitatively analyzed in plasma, brain, colon, and stomach contents. The 11 types of relatively large metabolites and 8 types of ACAs were quantitatively monitored. Among them, nine types of relatively large metabolites were assessed through PK studies. In targeted network pharmacology, it highlighted the significance of small molecular metabolites, including ACAs et al, which were frequently overlooked. LP may play a more key role mainly through neural active ligand-receptor interaction, AD, and pertussis pathways. These findings have outlined a step-by-step strategy for in-depth research in vivo, laying a foundation for further verification of biological function.

Metabolomic characterization of COVID-19 survivors in Jilin province.

BACKGROUND: The COVID-19 pandemic has escalated into a severe global public health crisis, with persistent sequelae observed in some patients post-discharge. However, metabolomic characterization of the reconvalescent remains unclear. METHODS: In this study, serum and urine samples from COVID-19 survivors (n = 16) and healthy subjects (n = 16) underwent testing via the non-targeted metabolomics approach using UPLC-MS/MS. Univariate and multivariate statistical analyses were conducted to delineate the separation between the two sample groups and identify differentially expressed metabolites. By integrating random forest and cluster analysis, potential biomarkers were screened, and the differential metabolites were subsequently subjected to KEGG pathway enrichment analysis. RESULTS: Significant differences were observed in the serum and urine metabolic profiles between the two groups. In serum samples, 1187 metabolites were detected, with 874 identified as significant (457 up-regulated, 417 down-regulated); in urine samples, 960 metabolites were detected, with 39 deemed significant (12 up-regulated, 27 down-regulated). Eight potential biomarkers were identified, with KEGG analysis revealing significant enrichment in several metabolic pathways, including arginine biosynthesis. CONCLUSIONS: This study offers an overview of the metabolic profiles in serum and urine of COVID-19 survivors, providing a reference for post-discharge monitoring and the prognosis of COVID-19 patients.

Application of a Novel UPLC-MS/MS Method for Analysis of Rivaroxaban Concentrations in Dried Blood Spot and Plasma Samples Collected from Patients with Venous Thrombosis.

Despite a higher safety profile compared to vitamin K antagonists, rivaroxaban therapy is still connected with multiple adverse effects, such as a high risk of bleeding. Thus, therapeutic drug monitoring (TDM) of rivaroxaban concentrations is suggested. An alternative to plasma samples can be dried blood spots (DBS), which minimize the cost of sample storage and transport. In this study, we developed a UPLC-MS/MS method for the analysis of rivaroxaban in DBS and plasma samples. Chromatographic separation was achieved on a Zorbax Eclipse Plus C18 column (2.1 × 100 mm; 3.5 µm, Agilent Technologies Inc., Santa Clara, CA, USA) with a mobile phase consisting of water and acetonitrile, both containing 0.1% formic acid. The analytes were detected using a positive ionization mode by multiple reaction monitoring. We validated the method according to ICH guidelines. The precision and accuracy were satisfactory. Extraction recovery was approximately 57% and 66% for DBS and plasma samples, respectively. A high correlation between rivaroxaban concentrations in plasma and DBS samples collected from patients was confirmed with Deming regression. The suitability of both sampling techniques for the rivaroxaban TDM was also verified by Bland-Altman plots based on DBS-predicted and observed plasma concentrations. In addition, we found a significant relationship between rivaroxaban concentrations and coagulation parameters, including prothrombin time (PT) and international normalized ratio (INR).

Simultaneous determination of Obeticholic acid and its two major metabolites in human plasma after administration of Obeticholic acid tablets using ultra-high performance liquid chromatography tandem mass spectrometry.

Obeticholic acid (OCA), a semisynthetic bile acid derivative, was approved for its therapeutic use in primary biliary cirrhosis. OCA has a enterohepatic circulation and host-gut microbiota metabolic interaction, which produce various metabolites. Such metabolites, especially structural isomers of OCA, together with the need to achieve idea lower limit of quantitation (LLOQ) with minimum matrix interference, bring about significant difficulties to the bioanalysis of OCA. Herein, by applying a combination of solid-phase extraction (SPE) and ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), we introduced an approach for the bioanalysis of OCA along with its two major metabolites-glyco-OCA (GOA) and tauro-OCA (TOA) in human plasma, the full validation results of which showed excellent performance. The quantitative range is 0.2506 âˆ¼ 100.2 ng/mL for OCA, 0.2500 âˆ¼ 100.0 ng/mL for GOA, as well as 0.1250 âˆ¼ 50.00 ng/mL for TOA, respectively. This method was successfully applied to the pharmacokinetic studies in healthy subjects following administration of OCA tablets.

Development and validation of a highly sensitive UPLC-MS/MS method for the determination of Huperzine A in rat plasma.

Huperzine A is a reversible and selective cholinesterase inhibitor and has been approved for the treatment of Alzheimer's diseases. In this study, we developed a highly sensitive and specific ulta-high-performance liquid chromatography-tandem mass spectrometry method for the determination of Huperzine A in rat plasma. An aliquot of 50 µL of rat plasma sample was pretreated with 200 µL of acetonitrile-methanol (v/v; 1:1) containing 0.2% formic acid followed by solid phase extraction. The resulting sample was separated on a Waters ACQUITY BEH C18 column using acetonitrile and water containing 0.2% formic acid as mobile phase, at a flow rate of 0.3 mL/min. Multiple-reaction monitoring (MRM) mode was used for quantitative analysis of Huperzine A in positive electrospray ionization. In the concentration range of 0.01-10 ng/mL, Huperzine A showed excellent linearity with correlation coefficient > 0.998. The intra- and inter-day RSD% were less than 9.7%, while the RE% ranged from -6.7% to 10.0%. The mean recovery was >84.5%. The validated method was demonstrated to be selective, sensitive, and reliable, which has been successfully applied to pharmacokinetic study of Huperzine A in rat plasma. Huperzine A displayed a long half-life in rat plasma and high oral bioavailability.

[Chemical profiling of Xiaochaihu Granules and characterization of absorbed components in rat plasma after oral administration].

The chemical components of Xiaochaihu Granules and absorbed components in rats after oral administration were identified by using ultra performance liquid chromatography-quadrupole orbitrap mass spectrometry(UPLC-Q-Exactive-Orbitrap-MS)and UPLC-triple quadrupole mass spectrometry(UPLC-MS/MS). Separation was performed on a CORTECS UPLC C~+_(18)(2.1 mm×100 mm, 1.6 µm)column with gradient elution using acetonitrile-0.1% formic acid aqueous solution as the mobile phase. Data on the chemical components were collected in positive and negative ion modes and identified based on the retention time, precise molecular weight, fragment ion information in comparison with the reference substance, and literature report. The rat fever model was established by subcutaneous injection of dry yeast. Subsequently, the normal and model rats received oral administration of Xiaochaihu Granules. Blood samples were taken from the orbital vein at different time points after administration, and the plasma was isolated for scanning and identification of absorbed components using the multi reaction monitoring mode(MRM).A total of 112 chemical components were identified in Xiaochaihu Granules, including 63 flavonoids, 31 saponins, 6 organic acids, 4 phenylpropanoids, 3 amino acids and 5 other compounds. Additionally, 18 prototypical components were identified in rat plasma. This study lays the foundation for further study of the therapeutic material and quality control of Xiaochaihu Granules.

[Comparison on tissue distribution of five components in Shuganning Injection and Scutellariae Radix extract by UPLC-MS/MS].

This study established an ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) method to determine the content of five index components in rat tissues and organs after administration of Shuganning Injection or Scutellariae Radix extract. The dynamic changes and differences of the distribution of the five index components over time between the two groups were studied, and the effects of Scutellariae Radix alone or in combination with other medicines on the tissue distribution of the five components were explored. After Shuganning Injection or Scutellariae Radix extract was injected into the tail vein of rats, the heart, liver, spleen, lung, kidney, stomach, intestine, and brain tissue samples were collected at four time points of 0.17, 0.5, 1, and 2 h, respectively. UPLC-MS/MS was employed to measure the concentrations of the five index components(baicalin, baicalein, oroxylin A, oroxylin A-7-O-ß-D-glucuronide, and scutellarin) in the samples of the two groups. The results showed that the established method was simple, fast, and exclusively stable. After the administration of Shuganning Injection and Scutellariae Radix extract, the five index components presented wide distribution and had differences in vivo. The two groups showcased abundant distribution of baicalin, baicalein, and oroxylin A in the kidney and liver, oroxylin A-7-O-ß-D-glucuronide in the kidney and brain, and scutellarin in the kidney and heart. The content of baicalin in the heart, liver, kidney, and intestine, baicalein in the liver and kidney, and oroxylin A in the lung after administration of Shuganning Injection(Scutellariae Radix in combination with other medicines) was significantly higher than that after administration of Scutellariae Radix extract. The results of this study suggested that the five components of Shuganning Injection and Scutellariae Radix extract demonstrated wide distribution without accumulation in rats. The combination of Scutellariae Radix with other medicines can increase the distribution of active components in rats, which provided a basis for explaining the rationality of the compatibility of Shuganning Injection from in vivo processes.

UPLC-MS/MS method for fluconazole determination in plasma and its application in Mexican patients with candidaemia.

Aim: An accurate and fast ultra-high performance liquid chromatography coupled with tandem mass spectrometry analytical method was developed and validated for quantifying fluconazole levels in human plasma according to the US FDA guidelines.Materials & methods: A simple protein precipitation by acetonitrile was employed for the sample preparation. The chromatographic separation was carried out using isocratic elution of water (0.1% formic acid) and acetonitrile on an Acquity ultra-high performance liquid chromatography HSS T3 column. Samples from ten adult patients diagnosed with candidemia who received fluconazole treatment were analyzed.Results & conclusion: The method demonstrated excellent linearity and stability within the 1-50 µg/ml range (r2 >0.999). The intraday and interday precision were determined with coefficient of variation values ranging from 1.4 to 4.38% and 2.8 to 6.6%, respectively. This rapid and selective method has successfully analyzed 27 plasma samples. The straightforward sample preparation in a single step and the reduced analysis time make this method suitable for adult patients with candidemia, leading to improved clinical outcomes.

[Box: see text].

Determination of azodicarbonamide in flour samples using high-performance liquid chromatography-tandem mass spectrometry with xanthydrol pre-column derivatisation.

Azodicarbonamide (ADA) is approved as a food additive in flour products due to its oxidising and bleaching properties. However, it is prohibited in Australia and Europe on account of its toxicity and the risk of causing asthma in humans. A method was developed to determine ADA in actual flour samples. This work presents an optimised methodology based on derivatisation and clean-up procedures followed by ultra-performance liquid chromatography coupled with electrospray ionisation tandem mass spectrometry (UPLC-ESI-MS/MS). The analytical method was successfully validated. An excellent result was obtained for the linearity of matrix-matched calibration curves (R2 > 0.99) in the concentration range of 0.10-80 mg/kg. The recovery rate varied from 81.7% to 102.3%. The relative standard deviations (RSDs) of repeatability (n = 6) were 1.3-4.1%, and inter-day RSDs (n = 6) were 2.2-4.8%. The limit of detection and the limit of quantification were 0.014 and 0.042 mg/kg, which were significantly lower than the requirement of 45 mg/kg stipulated in the Chinese National Food Safety Standard (GB 2760-2014). The detection rate of ADA in 26 flour samples was 23.1%, with the concentration ranging from 0.023 to 23.2 mg/kg.

Metabolites profiling of Sapota fruit pulp via a multiplex approach of gas and ultra performance liquid chromatography/mass spectroscopy in relation to its lipase inhibition effect.

Background: Sapota, Manilkara zapota L., are tasty, juicy, and nutrient-rich fruits, and likewise used for several medicinal uses. Methods: The current study represents an integrated metabolites profiling of sapota fruits pulp via GC/MS and UPLC/MS, alongside assessment of antioxidant capacity, pancreatic lipase (PL), and α-glucosidase enzymes inhibitory effects. Results: GC/MS analysis of silylated primary polar metabolites led to the identification of 68 compounds belonging to sugars (74%), sugar acids (18.27%), and sugar alcohols (7%) mediating the fruit sweetness. Headspace SPME-GC/MS analysis led to the detection of 17 volatile compounds belonging to nitrogenous compounds (72%), ethers (7.8%), terpenes (7.6%), and aldehydes (5.8%). Non-polar metabolites profiling by HR-UPLC/MS/MS-based Global Natural Products Social (GNPS) molecular networking led to the assignment of 31 peaks, with several novel sphingolipids and fatty acyl amides reported for the first time. Total phenolic content was estimated at 6.79 ± 0.12 mg gallic acid equivalent/gram extract (GAE/g extract), but no flavonoids were detected. The antioxidant capacities of fruit were at 1.62 ± 0.2, 1.49 ± 0.11, and 3.58 ± 0.14 mg Trolox equivalent/gram extract (TE/g extract) via DPPH, ABTS, and FRAP assays, respectively. In vitro enzyme inhibition assays revealed a considerable pancreatic lipase inhibition effect (IC50 = 2.2 ± 0.25 mg/mL), whereas no inhibitory effect towards α-glucosidase enzyme was detected. This study provides better insight into sapota fruit's flavor, nutritional, and secondary metabolites composition mediating for its sensory and health attributes.

Excretion characteristics of main compounds of Yigong San in urine, feces, and bile of rats.

Yigong San (YGS) is a traditional Chinese medicine formula used for pediatric anorexia, chronic atrophic gastritis, and irritable bowel syndrome. In this study, the excretion of eight main compounds, including liquiritin; isoliquiritin; hesperidin; ginsenosides Rb1, Re, and Rg1; and atractylenolides I and II, in rat urine, feces, and bile, was investigated by ultra-high performance liquid chromatography-tandem mass spectrometry. The results showed that the cumulative excretion rates of the compounds in rat urine, feces, and bile were 0.018-1.15%, 0.024-19.89%, and 0.0025-0.72%, respectively. Among the eight compounds detected, liquiritin was the richest in urine, and ginsenosides Re and Rg1 and atractylenolide I were mainly found in feces and bile. In summary, the main components of YGS are excreted via multiple approaches. Liquiritin is mainly through urine, whereas isoliquiritin; hesperidin; ginsenosides Rb1, Re, and Rg1; and atractylenolides I and II are mainly through feces. The excretion of these compounds in bile is usually positively correlated with that in feces. This study lays a foundation for further pharmacological research and application of YGS.

Squaraine-Linked Magnetic Covalent Organic Framework as a Solid-Phase Extraction Absorbent to Determine Trace Phenylpyrazoles.

Phenylpyrazoles are widely used pesticides in the food industry. It is highly desirable to develop efficient pre-treatment and analysis methods to extract and detect phenylpyrazoles in complex food matrices. Herein, the study reports novel squaraine-linked zwitterionic core-shell magnetic covalent organic frameworks (MCOFs),  which are found to be excellent pretreatment materials for the detection of trace phenylpyrazoles in samples. By coupling MCOFs to magnetic solid-phase extraction (MSPE) with Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS) analysis, the detection of phenylpyrazoles (fipronil, fipronil sulfone, fipronil sulfide, fipronil de-sulfoxide, fipronil desulfinyl, ethiprole, and flufiprole) is achieved and shows good linearity at concentrations of 1-800 µg L-1 (R2 ≥ 0.9930). The limit of detection (LOD), limit of quantification (LOQ), and recovery rates are 0.01-0.50 µg kg-1, 0.04-1.72 µg kg-1, and 70.96-115.32%, respectively. More importantly, this method is successfully applied to determine the phenylpyrazoles in commercial egg, poultry, milk, jujube, cabbage, tea, and rice with a detection rate of ≈0.04%. Therefore, the developed method may contribute to a new strategy for the purification and multi-target extraction of complex food matrices.

Application of newly developed and validated UPLC-MS/MS method for pharmacokinetic study of ROS1/NTRK inhibitor taletrectinib in beagle dog plasma.

Taletrectinib is a potent selective ROS and pan-NTRK tyrosine kinase inhibitor (TKI) and has been developed to treat non-small cell lung cancer (NSCLC). To facilitate pharmacokinetic and toxicokinetic studies of taletrectinib, we developed a procedure for ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) to detect the plasma level of taletrectinib in dogs. This assay procedure was validated in compliance with FDA guidance. The dog plasma samples were spiked with internal standard (IS), followed by protein precipitation, and analyzed using a Waters ACQUITY BEH C18 column coupled to a Thermo triple quadrupole mass spectrometer. Separation was executed using the acetonitrile-0.1 % formic acid solution with gradient elution, at a flow rate of 0.4 mL/min. Taletrectinib and IS were monitored by multiple reaction monitoring (MRM) with m/z 406.2 > 349.2 and m/z 441.2 > 138.1, respectively. The procedure demonstrated excellent linearity with a correlation coefficient greater than 0.999 within the concentration range of 0.2-200 ng/mL. The inter- and intra-day accuracy ranged from -5.25 % to 5.26 %, and the precision was below 6.39 %. Acetonitrile-mediated protein precipitation showed high extraction efficiency and a recovery above 85 %. The procedure was then applied to quantify taletrectinib in beagle dog plasma after oral and intravenous doses and achieved success. The obtained pharmacokinetic parameters indicated high bioavailability of taletrectinib (>85 %) and extensive tissue distribution (>40 L/kg).