Ultra-performance Liquid Chromatography-tandem Mass Spectrometry Research Articles

A rapid and sensitive UPLC-MS/MS method for the determination of zanubrutinib in beagle plasma and its application in pharmacokinetics.

A reliable and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination of zanubrutinib in the plasma of beagle dogs. The column used was an Acquity BEH C18 column (2.1 mm × 50 mm, 1.7μm), maintained at 40°C with an injection volume of 2μl. The gradient elution program was as follows: 0-1min, 10-10% A; 1-1.1min, 10-90% A; 1.1-2.1min, 90-90% A; 2.1-2.2min, 90-10% A; 2.2-3.0min, 10-10% A. Mobile phase A was 0.1% formic acid, B was acetonitrile, and the total analysis time was 3min. The mass spectrometry was performed in positive ion mode, and the scanning mode was multi-reaction monitoring mode with electrospray ionization as the ion source; m/z 472.2 → 455.01 for zanubrutinib and m/z 441.03 → 137.99 for ibrutinib (internal standard). The plasma samples were processed by protein precipitation. The standard curve showed good linearity (r2 = 0.999 8) in the range of 1.0-1,000 ng/ml (zanubrutinib) with a low limit of quantification of 1ng/ml. Also, the intra-day and inter-day precision (RSD) was <5.88% and the accuracy (RE) ranged from -1.56 to 1.08%; the recoveries of zanubrutinib in beagle plasma ranged from 90.12 to 93.53% (RSD 1.67-6.42%) and the ME values of zanubrutinib were 98.70-101.06% (RSD5.37-8.49%, n = 6). All values meet US Food and Drug Administration requirements. A rapid, highly selective and sensitive method for the determination of zanubrutinib concentration in plasma by UPLC-MS/MS was successfully developed. This method is suitable for pharmacokinetic studies in beagle dogs by following oral administration of zanubrutinib.

The Characteristics and Potential Risks of Neonicotinoid Residues in Soils of Different Types of Land Use in Hangzhou

Due to the wide existence of neonicotinoid insecticides (neonics) and their potential impact on ecosystems and human health, they have received special attention in recent years. Soil is not only a sink of neonics but also a source of neonics, so it plays a key role in the ubiquity of neonics in the environment. The purpose of this research was to compare neonics residues in soils of different types of land use and estimate their exposure to different populations via ingestion. A total of 130 soil samples from six different types were collected. The concentrations of seven neonics in soil were simultaneous determined using isotope-dilution ultra-performance liquid chromatography–tandem mass spectrometry. The results showed that at least one neonic was analyzed in all samples. The highest average concentration was 3.42 ng/g (clothianidin), followed by 3.39 ng/g (thiamethoxam), 3.06 ng/g (acetamiprid), 2.84 ng/g (imidacloprid), 2.66 ng/g (nitenpyram), 2.43 ng/g (thiacloprid), and 1.89 ng/g (dinotefuran). IMI and ACE were the most commonly found neonics in soil. The neonic levels in different soils varied significantly. The integrated neonic residue in cropland was much higher than that in other types of land. The risk assessment revealed that the average daily dose (ADD) through ingestion contact with soil was acceptable to children and adults. With the increasing evidence that neonics could cause a variety of toxic effects on mammals and humans, ingestion exposure caused by neonics in soil should also receive continuous attention in future studies.

Development and validation of a multi-residue method for determination of antimicrobial sulfonamides, macrolides and quinolones in Iranian feta cheese by SPE clean-up and LC-MS/MS

A selective and sensitive multi-residue/multi-class ultra-performance liquid chromatography–tandem mass spectrometry method has been validated for simultaneous analysis of 25 antibiotic residues belong to sulfonamides, macrolides, and quinolones groups, as well as griseofulvin and trimethoprim, in Iranian feta cheese samples. Two specific precursor – product ion transitions were acquired per target compound by a positive electrospray ionisation in multiple reaction monitoring mode. Results were obtained as follows: limit of detection (LOD) and limit of quantification (LOQ) were respectively 3.3 ng g−1 and 10 ng g−1 (except for josamycin, LOD: 8.33 and LOQ: 25 ng g−1). Average recovery ranged between 70% and 120% and relative standard deviation of repeatability was lower than 20%. Finally, the method was applied to determination of target analytes in feta cheese samples obtained from the local hypermarkets and traditional dairy product markets in Tehran, Iran.

Development of UPLC-MS/MS Method to Study the Pharmacokinetic Interaction between Sorafenib and Dapagliflozin in Rats.

Sorafenib (SOR), an inhibitor of multiple kinases, is a classic targeted drug for advanced hepatocellular carcinoma (HCC) which often coexists with type 2 diabetes mellitus (T2DM). Dapagliflozin (DAPA), a sodium–glucose cotransporter-2 inhibitor (SGLT2i), is widely used in patients with T2DM. Notably, co-administration of SOR with DAPA is common in clinical settings. Uridine diphosphate-glucuronosyltransferase family 1 member A9 (UGT1A9) is involved in the metabolism of SOR and dapagliflozin (DAPA), and SOR is the inhibitor of UGT1A1 and UGT1A9 (in vitro). Therefore, changes in UGT1A9 activity caused by SOR may lead to pharmacokinetic interactions between the two drugs. The objective of the current study was to develop an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous determination of SOR and DAPA in plasma and to evaluate the effect of the co-administration of SOR and DAPA on their individual pharmacokinetic properties and the mechanism involved. The rats were divided into four groups: SOR (100 mg/kg) alone and co-administered with DAPA (1 mg/kg) for seven days, and DAPA (1 mg/kg) alone and co-administered with SOR (100 mg/kg) for seven days. Liquid–liquid extraction (LLE) was performed for plasma sample preparation, and the chromatographic separation was conducted on Waters XSelect HSS T3 column with a gradient elution of 0.1% formic acid and 5 mM ammonium acetate (Phase A) and acetonitrile (Phase B). The levels of Ugt1a7 messenger RNA (mRNA) were determined in rat liver and intestine using quantitative real-time polymerase chain reaction (qRT-PCR). The method was successfully applied to the study of pharmacokinetic interactions. DAPA caused a significant decrease in the maximum plasma concentrations (Cmax) and the area under the plasma concentration–time curves (AUC0–t) of SOR by 41.6% and 50.5%, respectively, while the apparent volume of distribution (Vz/F) and apparent clearance (CLz/F) significantly increased 2.85- and 1.98-fold, respectively. When co-administering DAPA with SOR, the AUC0–t and the elimination half-life (t1/2Z) of DAPA significantly increased 1.66- and 1.80-fold, respectively, whereas the CLz/F significantly decreased by 40%. Results from qRT-PCR showed that, compared with control, seven days of SOR pretreatment decreased Ugt1a7 expression in both liver and intestine tissue. In contrast, seven days of DAPA pretreatment decreased Ugt1a7 expression only in liver tissue. Therefore, pharmacokinetic interactions exist between long-term use of SOR with DAPA, and UGT1A9 may be the targets mediating the interaction. Active surveillance for the treatment outcomes and adverse reactions are required.

Determination of six core components from Mahuang Xuanfei Zhike syrup in rat plasma and tissues by UPLC-MS/MS: Application to a pharmacokinetics and tissue distribution study.

Mahuang Xuanfei Zhike (MXZ) syrup, a Chinese patent medicine, has been widely used in the clinical treatment of cough. However, there is no reported method for the quantitative analysis of the effective components of MXZ syrup in biological samples. In this study, the effective components of MXZ syrup were screened by network pharmacology and molecular docking technology. A sensitive and rapid ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established to test the active components of MXZ syrup in rat plasma and tissue homogenates, including ephedrine, amygdalin, chlorogenic acid, harpagoside, forsythin and forsythoside A. Chromatographic separation was performed on a Waters Acquity UPLC HSS T3 column (2.1 × 50 mm, 1.8μm) and the mass analysis was conducted using a Waters Xevo TQ mass spectrometer using multiple reaction positive and negative ion simultaneous monitoring mode. The results showed that the linearity ranged from 0.3 to 409.4ng/ml. The extraction recoveries were all <8.33%, and the matrix effects were all <8.45, which met the requirements. The pharmacokinetic and tissue distribution results indicated that the main active components of MXZ syrup were absorbed quickly and eliminated slowly in vivo, and there may be a reabsorption process.

Content Determination and Release Characteristics of Six Components in the Different Phases of "Glycyrrhizaglabra-Nux vomica" Decoction by UPLC-MS/MS.

The decoction turns into a complex multiphase system following exposure to high temperature and a complex chemical environment. However, the differences in the concentration of key active ingredients in different phase states and the release of drugs in sedimentary phase have yet to be elucidated. A simple ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the simultaneous quantitative determination of brucine, strychnine, liquiritin, isoliquiritin, isoliquiritigenin and glycyrrhizic acid concentrations and it was applied to compare the content of different phases and measure the release characteristics of the sedimentary phase in “Glycyrrhiza glabra-Nux vomica” decoction (NGD). The results show that the method’s selectivity, precision (intraday and interday ≤ 2%), matrix effect (101–108%), recovery and stability results were acceptable according to the guidelines. The method is sensitive and reliable. The content determination results show that the most toxic strychnine in the sedimentary phase accounted for 75.70% of the total components. The different components exhibited differential release in different media, and its components were released in the artificial intestinal fluid up to 81.02% in 12 h. Several components conformed to the primary kinetic model and the Ritger–Peppas model, and the most toxic compound exhibited slow release, thus conforming to the Ritger–Peppas model. This study provides a standard of reference for studies investigating reduction in toxicity of the combination of Glycyrrhiza glabra (Glycyrrhiza glabra L.) and Nux vomica (Strychnos nux-vomica L.).

Aspartic acid enantiomer quantification using ultraperformance liquid chromatography–tandem mass spectroscopy combined with deuterium‐chloride hydrolysis to improve age estimation in Antarctic minke whale Balaenoptera bonaerensis

AbstractAspartic acid racemization is a useful tool for estimating age in marine mammals; however, acid hydrolysis during sample preparation may increase the D‐ to L‐enantiomer ratio. To improve age estimation in Antarctic minke whale (Balaenoptera bonaerensis), we optimized the quantification of aspartic acid enantiomers in ocular lens by using ultraperformance liquid chromatography–tandem mass spectrometry combined with sample preparation by hydrolysis with deuterium chloride. Using this approach, we determined D/L in fetal and adult whale lens, examined the degree of racemization induced by acid hydrolysis, and constructed equations for age estimation. In the fetal lens, D/L obtained after hydrolysis with HCl or DCl were positively correlated with gestation age. Estimates of D/L at birth using a DCl‐hydrolysis model were much lower than those obtained using a HCl‐hydrolysis model, indicating that racemization during hydrolysis with HCl reduces the precision of subsequently derived age estimates. Furthermore, the D/L0 unaffected by Asp‐D generated during hydrolysis was estimated. The loge[(1 + D/L)/(1 − D/L)] value was exponentially increased with increasing earplug‐derived age, and the standard error of the age estimates after hydrolysis with DCl was lower than that after HCl. We conclude that our method can provide precise age estimates without methodological bias.

Serum pharmacochemistry and pharmacokinetics of major components after oral administration of Luhong recipe in rats using ultra-performance liquid chromatography-tandem mass spectrometry.

Luhong recipe (LHR) is has been used as an empirical prescription for treating chronic heart failure for long, with safety, reliability, and significant efficacy. However, its pharmacokinetics has not yet been studied. This study aims to establish aultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous analysis of epimedin A, epimedin B, epimedin C, icariin, psoralen, and isopsoralen in rat plasma and apply it to the pharmacokinetic study of LHR after oral administration. These six analytes were ionized using positive electrospray ionization (ESI+ ). The MS/MS transitions used for monitoring are successively converted to m/z 839.3 → 369.1, m/z 809.2 → 369.1, m/z 823.3 → 369.1, m/z 677.2 → 205.2, m/z 187.1 → 115.2, and m/z 230 → 120.9. Linearity, precision, accuracy, stability, matrix effect, and recovery of the established method were within the acceptable range. The method was suitable for the determination of six analytes after oral administration of LHR. The pharmacokinetic results showed that the time to reach the peak concentration (Tmax ) was from 0.17 to 13.5h, the peak concentration (Cmax ) was 109.23-980 ng/mL, the area under the concentration-time curve (AUC[0 - t] ) was 65.48-8846.08 ng·h/mL, and the apparent distribution volume (Vd) was 24,772-896,132 mL/kg. These results provided a meaningful basis for formulating the clinical dose regimen of LHR.

PFAS in serum of residents living in the neighborhood of a major PFAS manufacturer plant in Belgium

Background and aim: Per- and polyfluoroalkyl substances (PFAS) contamination levels in the environment around a 3M PFAS production plant triggered the concern for health among residents in the neighbourhood. Following this concern, a blood collection was organized to assess residents’ exposure levels. Methods: During the summer of 2021, 800 residents (+12 years old) living within 3 km of the 3M plant provided serum samples in which 13 PFAS compounds were measured, using ultra-performance liquid chromatography-tandem mass spectrometry. All participants completed a questionnaire. Results and conclusion: The presentation will report the PFAS fingerprints in serum, the variation in PFAS serum levels within the community, and the key exposure determinants assessed using information retrieved from the questionnaire. PFAS exposure was dominated by PFOS (perfluorooctanesulfonic acid), with an important contribution of branched compounds. Consumption of locally-produced chicken eggs was identified as an important determinant for higher serum levels of several PFAS. Other significant determinants included geographical position of the homes, time living in the area, use of groundwater, contact with chemicals and soil particles and use of consumer products. The study results supported earlier implemented no-regret precautionary measures. We will also address the policy implementation of this study and the communication of the results to the local community, including advices for exposure reduction. Keywords: PFAS, exposure assessment, determinants, policy

Determination of Tropifexor in Beagle Dog Plasma by UPLC-MS/MS and Its Application in Pharmacokinetics.

The primary objective of this study was to develop and validate an efficient and accurate ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) approach as a means to detect tropifexor plasma concentrations in beagle dogs and to study its pharmacokinetic profile in beagle dogs. The chromatographic separation of tropifexor and oprozomib (internal standard, ISTD) on the column, with the addition of acetonitrile for rapid precipitation and protein extraction, was achieved with 0.1% formic acid aqueous solution-acetonitrile for the mobile phase. A Xevo TQ-S triple quadrupole tandem mass spectrometer, under the selective reaction monitoring (SRM) mode, for the determination of the concentrations in the positive ion mode. The mass transfer pairs of tropifexor and oprozomib (ISTD) were m/z 604.08 ⟶ 228.03 and m/z 533.18 ⟶ 199.01, respectively. The profile displayed well linearity with calibration curves for tropifexor and oprozomib (ISTD) ranging from 1.0 to 200 ng/mL. In parallel, the lower limit of quantification (LLOQ) value for tropifexor could be measured with the aid of this novel technique at 1.0 ng/mL. In addition, the scope of intraday and interday for analyte accuracy was between −4.86% and 1.16%, with a precision of <7.31%. The recoveries of the analytes were >88.13% and were free of significant matrix effects. The stability met the requirements for the quantification of plasma samples under various conditions. Finally, the pharmacokinetic profile of tropifexor in beagle dog plasma following oral administration of 0.33 mg/kg tropifexor was determined by using the method facilitated in this work.

Perovskites in photoelectrocatalytic water treatment: Bismuth ferrite - graphite nanoparticles composite photoanode for the removal of ciprofloxacin in water

Towards the application of perovskite in photoelectrocatalytic oxidation of organic pollutants in water, bismuth ferrite (BiFeO3) was prepared by facile hydrothermal method and composited with graphite nanoparticles (GNPs) to form BiFeO3/GNPs composite. The photoanodes of BiFeO3, GNPs and BiFeO3/GNPs were fabricated on a fluorine doped tin oxide (FTO) glass substrate. The materials and photoanodes were characterised with X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and UV–vis diffuse reflectance spectroscopy (UV-DRS). Furthermore, the photoanodes were photoelectrochemically characterised by evaluating their photocurrent response and charge transfer resistance with impedance spectroscopy. Results confirmed that the visible light absorbance of BiFeO3 was enhanced by the addition of GNPs. The BiFeO3/GNPs showed marked enhancement in the photocurrent density and low charge transfer resistance over BiFeO3 owing to the excellent electrical conductivity of graphite nanoparticle. The photoelectrocatalytic performance of BiFeO3, GNPs and BiFeO3/GNPs photoanodes were studied through the degradation of ciprofloxacin in aqueous solution. Degradation percentages of 48 %, 50 % and 78 % were recorded for BiFeO3, GNPs and BiFeO3/GNPs after 4 h respectively. In addition, the total organic carbon (TOC) removal analysis showed 30 %, 38 % and 56 % for BiFeO3, GNPs and BiFeO3/GNPs respectively. The study showed the beneficial effect of doping BiFeO3 with graphite nanoparticles and also the synergy of electrochemical oxidation and photocatalysis in photoelectrocatalytic process performance. Degradation pattern and product studies, obtained from ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS) and scavenger studies data, showed that the degradation of ciprofloxacin was activated by the hydroxyl and hole radicals and it followed a direct oxidation of piperazine ring with other intermediate degradation products. The composite photoanode exhibited good stability and reusability.

Establishment and validation of a sensitive LC-MS/MS method for quantification of urinary estrogens in women with gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is not only a threat to the health of pregnant women, but also has profound effects on the health of offspring. Studies have shown that the imbalance of estrogen metabolism is associated with an increased risk of GDM. In this study, an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established and validated for simultaneous quantification of thirteen estrogens in the urine of GDM women, including estrone (E1), estradiol (E2), estriol (E3), and their hydroxylated and methylated metabolites. The method was achieved on a Waters CORTECS C18 column (2.1 mm × 150 mm, 1.6 µm) within 8.5 min. The linear range of thirteen estrogens in urine was 2–1000 pg·mL−1. Both intra- and inter-day precision for each analyte were less than 15%, with accuracies ranging from 8.3% to 7.3%. The extraction recoveries rate were between 86% and 111%, and stability verification results met the requirements for determination of biological samples. The results suggested that the concentrations of estrogens in all urine samples range from 0.08 to 134.06 (pg·mg−1 creatinine). The mean levels of E1, E2 and most estrogen metabolites in the urine of GDM women were higher than those in healthy pregnant women. Notably, the mean level of 2-hydroxyestrone (2-OHE1) in GDM women was 13.2-fold lower than that in healthy pregnant women. The types of estrogens with the highest mean levels in the urine of GDM and healthy pregnant women were obviously different, which are 2-methoxyestrone (2MeOE1) and E3, respectively. Our results demonstrated that this specific and sensitive method is suitable for quantifying estrogens in human urine and could provide support for further research on estrogen-related pathological mechanisms in GDM and other diseases.

Determination of Ethyl Glucuronide and Ethyl Sulfate in Dried Blood Spots by UHPLC-MS-MS: Method Validation and Assessment of Ethanol Exposure in Postmortem Samples from Road Traffic Victims.

The determination of ethyl glucuronide (EtG) and ethyl sulfate (EtS) in blood has been proposed in clinical and forensic applications to identify recent alcohol consumption. Also, there is a growing interest on the use of dried blood spots (DBS) in toxicological analysis, allowing increased stability of the analytes and simplifying sample transportation and storage. This study presents the development and validation of a method for quantifying EtG and EtS in DBS using ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS-MS). The DBS samples were extracted with a mixture of methanol and acetonitrile (80:20 v/v) and analyzed using UHPLC-MS-MS with electrospray source in negative mode, after separation with a fluoro-phenyl stationary phase. Validation was performed according to the Scientific Working Group for Forensic Toxicology (SWGTOX) guidelines, with calibrations ranging from 0.10 to 18 µg/mL for EtG and 0.02 to 6 µg/mL for EtS. The analytes were stable in DBS stored from -20 to 45°C for 21 days. The method was successfully applied to capillary and venous DBS samples from 20 volunteers after ethanol ingestion and to DBS samples from 99 fatal victims of road traffic injuries. Capillary DBS was comparable to venous DBS and fresh whole blood in Passing-Bablok and Bland-Altman analysis, with correlation coefficients >0.91 (P < 0.001) for all comparisons. In postmortem application, the DBS EtG and EtS analysis indicated positive exposure to ethanol in 72.7% of the cases (EtG: 0.10-24.0 µg/mL and EtS: 0.03-4.11 µg/mL). The identification of ethanol consumption from blood alcohol concentrations (BACs) and EtG/EtS in DBS was in agreement in 98.6% of positive and 96.3% of negative cases (kappa 0.877, P < 0.001), indicating a high level of concordance with BAC in assessing alcohol use in postmortem samples.

Pollution Characteristics and Source Apportionment of Typical and Emerging Per- and Polyfluoroalkylated Substances in Tuojiang River Basin

Forty-eight surface water samples were analyzed using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) in order to study the pollution characteristics and source apportionment of per- and polyfluoroalkylated substances (PFASs) in the Tuojiang River. The results showed that ΣPFASs in the Tuojiang River ranged from 12.5-3789 ng·L-1, and perfluorooctanoic acid (PFOA) was the predominant PFAS, with a concentration of 9.97-3764 ng·L-1 (73.6%-99.8%), suggesting that legacy PFASs were still the dominant PFASs in the Tuojiang River. The most frequently detected emerging PFASs was 9-chlorohexadecafluoro-3-oxanonane-1-sulfonate (F-53B), with a detection frequency of 100%, suggesting the wide use of F-53B in the Tuojiang River. Sodium 1H, 1H, 2H, 2H-perfluorooctane sulfonate (6:2 FTS) displayed the highest concentration among all emerging PFASs[nd-27.3 ng·L-1, mean:(9.12±7.70) ng·L-1], and the concentrations were at the higher levels compared to those in other rivers around the world. In addition, ΣPFASs showed the highest concentrations of ΣPFASs at the fluorochemical manufacturing park (FMP), followed by those in the Luzhou section (in the lower reaches of the Tuojiang River), indicating that the emission of FMP and human daily production activities were the main influencing factors of PFASs pollution in the Tuojiang River. The estimated flux of PFASs from the Tuojiang River to the Yangtze River was 353 kg·a-1, and PFOA displayed the greatest mass loading (348 kg·a-1), which could provide the basic data for controlling PFASs in the Tuojiang River.

CYP2D6 gene polymorphism and apatinib affect the metabolic profile of fluvoxamine.

This study aimed 1) to investigate the influence of CYP2D6 variants on the catalyzing of fluvoxamine, and 2) to study the interaction between fluvoxamine and apatinib. An enzymatic reaction system was setup and the kinetic profile of CYP2D6 in metabolizing fluvoxamine was determined. In vivo, drug-drug interaction was investigated using Sprague–Dawley (SD) rats. Fluvoxamine was given gavage with or without apatinib. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to determine the concentrations of fluvoxamine and desmethyl-fluvoxamine. The results demonstrated that the relative clearance rates of CYP2D6.A5V, V104A, D337G, F164L, V342M, R440C and R497C increased significantly compared with CYP2D6.1, ranging from 153.626% ± 6.718% to 394.310% ± 33.268%. The activities of other variants reduced to different extent, or even lost function, but there was no statistical difference. The IC50 of apatinib against fluvoxamine disposition was determined, which is 0.190 μM in RLM and 6.419 μM in HLM, respectively. In vivo, apatinib can enhance the plasma exposure of fluvoxamine remarkably characterized by increased AUC, Tmax and Cmax. Meanwhile, the produce of desmethyl fluvoxamine was dramatically inhibited, both AUC and Cmax decreased significantly. Mechanistically, apatinib inhibit the generation of fluvoxamine metabolite with a mixed manner both in RLM and HLM. Furthermore, there were differences in the potency of apatinib in suppressing fluvoxamine metabolism among CYP2D6.1, 2 and 10. In conclusion, CYP2D6 gene polymorphisms and drug-drug interaction can remarkably affect the plasma exposure of fluvoxamine. The present study provides basis data for guiding individual application of fluvoxamine.

Population pharmacokinetics of unbound ceftriaxone in a critically ill population.

To develop a reliable 2-compartment population pharmacokinetic (PK) model for unbound ceftriaxone in a critically ill population and determine an optimal dosing regimen. This was a prospective, single-center, observational study of critically ill patients treated with ceftriaxone. Unbound serum ceftriaxone concentrations were measured using validated ultrafiltration and ultra-performance liquid chromatography-tandem mass spectrometry. PK analysis and dosing simulations were performed using an iterative 2-stage Bayesian fitting procedure and Monte Carlo simulations. The PK/pharmacodynamics (PD) target was attained when unbound serum ceftriaxone concentrations exceeded 4 times the minimum inhibitory concentration (MIC) for ≥60% of the dosing interval (ƒT>4xMIC ≥ 60%). 91 patients were enrolled, and 173 unbound ceftriaxone concentrations were acquired. The population PK parameter estimates were hepatic clearance 5.2±0.9L/h/1.85m2, the unbound renal clearance of ceftriaxone divided by the creatinine clearance 0.61±0.24, lean body mass corrected volume of distribution of the central compartment 0.82±0.21L/kg, and intercompartmental distribution rate constant from central to peripheral compartment 0.18±0.08h-1. Dosing simulations predicted ƒT>4 mg/L of 88% (95% CI: 69-100%) for 2,000 mg ceftriaxone once daily and ƒT>4 mg/L of 100% (95% CI: 100-100%) both for 1,000 mg twice daily and continuous infusion of 2,000 mg daily. We developed a reliable population PK model for unbound ceftriaxone in a critically ill population. Dosing simulations revealed ƒT>4 mg/L ≥60% for 1,000mg twice daily and 2,000 mg once daily or by continuous infusion.

A Sensitive Liquid Chromatography-Mass Spectrometry Method for Determination of 14-Deoxy-12(R)-Sulfo Andrographolide Concentration in Rat Plasma and its Application to a Pharmacokinetic Study.

Andrographolide is a promising natural substance with numerous pharmacotherapy uses. 14-deoxy-12(R)-sulfo andrographolide (SAP) is the main metabolite of andrographolide in the intestine. To investigate the pharmacokinetic properties of SAP, a precise and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of SAP concentration in rat plasma was developed and validated in this study. Chromatographic separation was achieved on an Acpuity UPLC BEH C18 column with gradient elution that consisted of methanol and water at a flow rate of 0.3 mL/min. MS/MS detection was carried out by the multiple reaction monitoring (MRM) mode with negative electrospray ionization (ESI-) source, with the transitions of m/z 413.2→m/z 287.2 for SAP and m/z 269→m/z 133 for genistein [which was used as an internal standard (IS)]. The calibration curve of SAP was linear over the concentration range of 5-120 ng/mL. The selectivity, precision, accuracy, extraction recovery, matrix effect, and stability of the method were within acceptable ranges. This SAP quantification method was then successfully applied to a pharmacokinetic study of SAP. The area under the curve (AUC) of SAP in rats treated with SAP at 60 mg/kg by intravenous administration was 7498.53 ± 2405.02 mg/L·min. The AUC of SAP in rats treated with SAP at 60 mg/kg by oral administration was 97.74 ± 39.56 mg/L·min. Thus, the absolute oral bioavailability of SAP was determined to be 1.40%.

Clinical Usefulness of Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry Method for Low Serum Testosterone Measurement.

Mass spectrometry methods exhibit higher accuracy and lower variability than immunoassays at low testosterone concentrations. We developed and validated an ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) assay for quantifying serum total testosterone. We used an ExionLC UPLC (Sciex, Framingham, MA, USA) system and a Sciex Triple Quad 6500+ (Sciex) MS/MS system in electrospray ionization and positive ion modes with multiple reaction monitoring transitions to evaluate precision, accuracy, linearity, lower limit of quantitation (LLOQ), carryover, ion suppression, stability, and reference intervals. For method comparison, we measured serum testosterone concentrations using this method in 40 subjects whose testosterone concentrations ranged from 0.14 to 55.48 nmol/L as determined using the Architect i2000 immunoassay (Abbott Diagnostics, Abbott Park, IL, USA) and in an additional 160 sera with testosterone concentrations <1.67 nmol/L. The intra- and inter-run precision CVs were <2.81%, and the accuracy bias values were <3.85%, which were all acceptable. The verified linear interval was 0.03-180.84 nmol/L; the LLOQ was 0.03 nmol/L. No significant carryover and ion suppression were observed. The testosterone in serum was stable at 4°C, at -20°C, and after three freeze-thaw cycles. The reference intervals were successfully verified. The correlation was good at testosterone concentrations of 0.14-55.48 nmol/L; however, the Architect assay showed positive percent bias at concentrations <1.67 nmol/L. The UPLC-MS/MS assay shows acceptable performance, with a lower LLOQ than the immunoassay. This method will enable the quantitation of low testosterone concentrations.

Effect of Rehmanniae Radix on depression-like behavior and hippocampal monoamine neurotransmitters of chronic unpredictable mild stress model rats

To investigate the effect of Rehmanniae Radix on depression-like behavior and monoamine neurotransmitters of chronic unpredictable mild stress(CUMS) model rats. CUMS combined with isolated feeding was used to induce the depression model of rats. The depression-like behavior of rats was evaluated by sucrose preference test, open field test, and forced swim test. Hematoxylin-Eosin(HE) staining was used to investigate the pathological changes of neurons in the CA1 and CA3 area of hippocampus. Ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS) was used to detect the contents of 5-hydroxytryptamine(5-HT), 5-hydroxyindoleacetic acid(5-HIAA), dopamine(DA), 3,4-dihydroxyphenylacetic acid(DOPAC), homovanillic acid(HVA), norepinephrine(NE), and 3-methoxy-4-hydroxyphenyl glycol(MHPG) in rats. Western blot was used to detect the protein expressions of tryptophan hydroxylase 2(TPH2), serotonin transporter(SERT), and monoamine oxidase A(MAO-A) in the hippocampus of rats. Compared with the normal group, depressive-like behavior of rats was obvious in the model group. The arrangements of neurons in the CA1 and CA3 area of hippocampus were loose and disorderly. The levels of 5-HT, 5-HIAA, and 5-HT/5-HIAA in the hippocampal area were decreased(P&lt;0.01). The protein expression of TPH2 was decreased(P&lt;0.01), but those of SERT and MAO-A were increased(P&lt;0.01). In the Rehmanniae Radix groups with 1.8 g·kg~(-1) and 7.2 g·kg~(-1), the depression-like behavior of CUMS rats and pathological changes of neurons in CA1, CA3 area of hippocampus were improved. The protein expression of TPH2(P&lt;0.05, P&lt;0.01) was increased, and those of SERT and MAO-A were down-regulated(P&lt;0.05, P&lt;0.01). The levels of 5-HT, 5-HIAA, and 5-HT/5-HIAA in hippocampus were increased(P&lt;0.05, P&lt;0.01). The changes in DA, DOPAC, HVA, DA/(DOPAC +HVA), NE, DHPG, and NE/DHPG were not statistically significant. The results suggested that Rehmanniae Radix improved depression-like behavior of CUMS rats, and the mechanism might be related to the regulation of synthesis, transportation, and metabolism of 5-HT neurotransmitter in the hippocampus.

Pharmacokinetic Interactions between Canagliflozin and Sorafenib or Lenvatinib in Rats.

Hepatocellular carcinoma (HCC) and type 2 diabetes mellitus (T2DM) are common clinical conditions, and T2DM is an independent risk factor for HCC. Sorafenib and lenvatinib, two multi-targeted tyrosine kinase inhibitors, are first-line therapies for advanced HCC, while canagliflozin, a sodium-glucose co-transporter 2 inhibitor, is widely used in the treatment of T2DM. Here, we developed an ultra-performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of canagliflozin, sorafenib, and lenvatinib, and investigated the pharmacokinetic drug interactions between canagliflozin and sorafenib or lenvatinib in rats. The animals were randomly divided into five groups. Groups I–III were gavage administrated with sorafenib, lenvatinib, and canagliflozin, respectively. Group IV received sorafenib and canagliflozin; while Group V received lenvatinib and canagliflozin. The area under the plasma concentration-time curves (AUC) and maximum plasma concentrations (Cmax) of canagliflozin increased by 37.6% and 32.8%, respectively, while the apparent volume of distribution (Vz/F) and apparent clearance (CLz/F) of canagliflozin significantly decreased (30.6% and 28.6%, respectively) in the presence of sorafenib. Canagliflozin caused a significant increase in AUC and Cmax of lenvatinib by 28.9% and 36.2%, respectively, and a significant decrease in Vz/F and CLz/F of lenvatinib by 52.9% and 22.7%, respectively. In conclusion, drug interactions exist between canagliflozin and sorafenib or lenvatinib, and these findings provide a reference for the use of these drugs in patients with HCC and T2DM.