Ultra-fast Liquid Chromatography-tandem Mass Spectrometry Research Articles

Highly Sensitive and Ultrafast Liquid Chromatography-tandem Mass Spectrometry Internal Standard Method for Determination of Alpha-Tocopherol in Serum and Application of Validated Method on Patient Serum Samples in Pakistan.

To optimize and validate a specific, sensitive and fast liquid Chromatography coupled to triple quadrupole Mass Spectrometric (LC-MS / MS) technique for accurate detection of serum α-tocopherol (Vitamin E) levels. An experimental based study. The Clinical and Forensic Toxicology section of Chughtai Lab, Jail Road Lahore, from April to September 2022. Methanol was used to deproteinize serum samples. The chromatographic separation was achieved using an Agilent Infinity-Lab Poroshell 120EC-C18 column, Agilent 6470 LC-MS/MS (equipped with an Electron Spray Ionization source) in gradient elution mode using 0.1% LCMS grade formic acid in water and LCMS-grade methanol as mobile phases. Hexa-deuterated α-tocopherol was employed as internal standard to minimise matrix interferences. The retention time of α-tocopherol was 3.0 ± 0.1 minutes. The linear concentrations obtained were ranged from 0.05-2 mg/dL with ≥0.985% coefficient of linearity. Detection and lower quantification limits determined were 0.025mg/dL and 0.05mg/dL, respectively. Recovery ranged from 96.5 to 99.8% and ionization suppression was -15.2% and -15.9% at high and low concentrations of α-tocopherol in serum. Intra-day and inter-day coefficient variation values were 4.2-4.9% and 5.0-5.9%, respectively. An efficient and reliable tandem mass spectrometric technique for vitamin E analysis in serum was optimized, validated, and applied to 80 patient samples. This method has usefulness in clinical application for the accurate determination of vitamin E without potential matrix interferences. Vitamin E, LC-MS/MS, Tocopherol, Internal standard, Validation.

Multi-mycotoxin detection and human exposure risk assessment in medicinal foods

Mycotoxin contamination in medicinal foods has attracted increasing global attention. In this study, a simple and sensitive ultrasonication assisted one-step extraction based ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method was developed for simultaneous detection of multi-mycotoxins in five kinds of medicinal foods rich in starch. Under optimal conditions, the developed technique displayed excellent analytical performances. Limits of detection and quantitation for the six mycotoxins were 0.04–0.25 ng/mL and 0.10–0.67 ng/mL, respectively. Average recoveries at three fortified levels ranged from 75.33 % to 118.0 %. Real-world application in 103 batches of medicinal foods displayed that 58 samples were positive with one or more mycotoxins at an occurrence rate of 56.31 % (58/103). Coix seed gave the highest positive rate of 96.15 %, followed by Lily (90 %), Chinese yam (50 %), Lotus seed (34.04 %) and Malt (30 %). Zearalenone had the highest positive rate of 28.16 % with contents in 5 Coix seeds exceeding the maximum residue limit (MRL), followed by aflatoxin B1 of 27.18 % (28/103) with contents in 7 Coix seed and 10 Lotus seeds over its MRL, and ochratoxin A (OTA) of 11.65 % with contents in 1 Lotus seed and 5 Lily samples greater than its MRL. Exposure risk assessment indicated that Coix seed and Lotus seeds that were susceptible to aflatoxins posed great threats to human health. Long-term consumption of Lily that was easily contaminated with OTA were also harmful. This work provides a robust platform for multi-mycotoxin monitoring in medicinal foods to protect the consumers from potential health risks.

Effects of high-altitude environment on pharmacokinetic parameters of gliquidone in rats.

To investigate the effect of high-altitude hypoxia on the pharmacokinetics parameters of gliquidone. Twelve healthy male Wistar rats were randomly divided into plain group and high-altitude group with 6 rats in each group. Blood samples were collected after intragastric administration of gliquidone (6.3 mg/kg). Ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) was used to determine the concentration of gliquidone in rat plasma samples. And the expression of CYP2C9 in rat liver tissues was determined by Western blotting. Compared with the plain group, the peak concentration of gliquidone in the high-altitude rats was significantly increased, the absorption rate constant was decreased, the elimination rate constant and the absorption half-life were increased, the elimination half-life was shortened, the mean residence time and apparent volume of distribution were decreased (all P<0.05). Western blotting showed that the expression of CYP2C9 was significantly up-regulated in the liver tissues of high altitude group rats, compared with the plain group (4.18 ±0.06 vs. 2.13±0.06, t=11.57, P<0.01). Under the high-altitude hypoxia environment, the absorption of gliquidone in rats was reduced and the metabolism was accelerated in rats, which may be related to the up-regulation of CYP2C9 expression in liver tissues.

Short-term administration of Polypodium leucotomos extract does not inhibit CYP3A4-mediated metabolism of midazolam in healthy subjects: an open-label, two-period, fixed-sequence study.

The extract of Polypodium leucotomos is used as a dietary supplement for its ultraviolet radiation-protective properties. Polypodium leucotomos extract reportedly inhibits CYP3A, which is important for drug metabolism in vitro in human microsomes and in vivo in rats. Inthis study, we explored the inhibitory effect of the P. leucotomos extract on CYP3A4-mediated midazolam metabolism in humans. This open-label, two-period, fixed-sequence study was performed on six healthy, Japanese, male volunteers. During period 1 (control), midazolam (1 mg) was orally administered. After a wash-out period of at least 5 days, period 2 was initiated. Subjects ingested P. leucotomos extract (240 mg) once in the morning and once at noon on the day before midazolam administration, and once the next morning (thrice overall). Midazolam was administered as in period 1. Blood samples were regularly collected for 8 hours after drug administration, and serum midazolam concentration was determined by ultra-fast liquid chromatography-tandem mass spectrometry. The pharmacokinetic parameters of midazolam were calculated and compared between the two periods. The area under the concentration-time curve was 19.18 ± 3.65 ng h/ml, maximum serum concentration was 7.81 ± 1.25 ng/ml, and half-life was 2.32 ± 0.35 hours during period 2. These parameters did not differ from those recorded in period 1 (area under the concentration-time curve: 18.74 ± 2.97 ng h/ml, maximum serum concentration: 8.78 ± 1.67 ng/ml, half-life: 2.52 ± 0.52 h). Therefore, short-term oral administration of P. leucotomos extract did not cause food-drug interactions mediated by CYP3A4 inhibition in humans.

Adulteration identification of wheat flour in chestnut flour based on differences in mycotoxin contamination by liquid chromatography-tandem mass spectrometry

建立了分散固相萃取-超快速液相色谱-串联质谱法同时测定板栗粉和小麦粉中43种真菌毒素的方法,对48份板栗粉和80份小麦粉样品的污染状况进行调查,筛选出5种专属于小麦粉的标志性真菌毒素。样品采用84%(v/v)乙腈水溶液提取,提取液采用C18结合增强型脂质去除净化剂(EMR-Lipid)净化,采用响应曲面-中心组合设计优化分散固相萃取净化方法。净化液在BEH C18色谱柱(100 mm×2.1 mm, 1.7 μm)上分别采用0.1%甲酸水溶液和含0.1%甲酸的甲醇-乙腈(1:1, v/v)(电喷雾正离子模式)、水和乙腈(电喷雾负离子模式)为流动相进行梯度洗脱,分别采用电喷雾电离(ESI)正负离子模式检测,基质匹配曲线外标法定量。板栗粉中真菌毒素的3水平加标回收率在72.4%~109.4%之间,相对标准偏差(RSD)<7.5%;小麦粉中真菌毒素的3水平加标回收率在70.7%~112.9%之间,RSD<9.3%;两种基质中43种真菌毒素的定量限均在0.1~20.0 μg/kg之间,方法线性相关系数均大于0.9991。利用所建立的方法监测了128份样品,结果表明,两种基质普遍受到真菌毒素污染,其中脱氧雪腐镰刀菌烯醇及其衍生物3-乙酰化-脱氧雪腐镰刀菌烯醇、15-乙酰化-脱氧雪腐镰刀菌烯醇、雪腐镰刀菌烯醇、去环氧-脱氧雪腐镰刀菌烯醇仅在小麦粉中检出。采用GB 5009.111-2016同位素稀释液相色谱-串联质谱法验证,检测结果与本方法一致。所建立的方法简便、快速、灵敏、准确,可有效满足板栗粉和小麦粉中真菌毒素残留的检测要求,脱氧雪腐镰刀菌烯醇及其4种衍生物可以作为两种食品的掺假标志物。

The Effect of Vitamin D3 and Silver Nanoparticles on HaCaT Cell Viability.

Vitamin D3, known to regulate bone homeostasis, has recently been shown to have many pleiotropic effects in different tissues and organs due to the presence of its receptor in a wide range of cells. Our previous study demonstrated that vitamin D3 was able to increase the wound healing respect to the control sample, 24 h after cutting, without however leading to a complete repair. The aim of the study was to combine vitamin D3 with silver nanoparticles to possibly enable a faster reparative effect. The results showed that this association was capable of inducing a complete wound healing only after 18 h. Moreover, a treatment of vitamin D3 + silver nanoparticles yielded a small percentage of keratinocytes vimentin-positive, suggesting the possibility that the treatment was responsible for epithelial to mesenchymal transition of the cells, facilitating wound healing repair. Since vitamin D3 acts via sphingolipid metabolism, we studied the expression of gene encoding for the metabolic enzymes and protein level. We found an increase in neutral sphingomyelinase without involvement of neutral ceramidase or sphingosine kinase2. In support, an increase in ceramide level was identified by Ultrafast Liquid Chromatography–Tandem Mass Spectrometry, suggesting a possible involvement of ceramides in wound healing process.

Contamination status and the health risk evaluation of dietary exposure of quinolone and tetracycline antibiotics in animal derived foods in Ningbo City from 2018 to 2020

To investigate the dietary exposure of Ningbo residents to quinolones and tetracyclines antibiotics in animal derived foods, so as to estimate the health risk caused by the exposure. Animal derived foods in Ningbo markets from 2018 to 2020 were collected and analyzed by ultra-fast liquid chromatography-tandem mass spectrometry. Based on the result of the measurements, median(M), P97.5, average and the maximum values of the data were obtained. Coupling the food intake data of residents in Zhejiang Province, an international point estimate model was applied to evaluate the health risk caused by the dietary exposure. Enrofloxacin, ciprofloxacin, ofloxacin, doxycycline, oxytetracycline were detected in freshwater fishes, cultured pseudosciaena crocea, freshwater shrimps, chicken, eggs and pork. The detection rates of enrofloxacin, ciprofloxacin, ofloxacin, doxycycline, oxytetracycline were 21.2%(77/363), 11.6%(42/363), 2.8%(10/363), 1.4%(5/363), 0.6%(2/363), respectively. The dietary exposure of adults and children from animal derived foods were in the range of 0.8-909.0 and 0.6-518.9 ng/(kg·d), respectively. The hazard quotient(HQ) values were in the range of 0.000030-0.17. Quinolone and tetracycline antibiotics such as enrofloxacin and oxytetracycline have no dietary health risk to the population.

Determination of trace low molecular mass aldehydes in air by ultra-fast liquid chromatography-tandem mass spectrometry

To establish a rapid and accurate method for the determination of trace acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde in the air by ultra-fast liquid chromatography-tandem mass spectrometry(UFLC-MS/MS). The air sample was concentrated and derivatived by 3-methyl-2(3 H)-benzothiazolonhydrazone(MBTH), and the effect of derivative conditions including the concentration of MBTH, the pH, the derivative time and temperature was investigated. The stability of derivatives, the cracking mechanism of mass spectrometry, the matrix effect of the method and air sampling efficiency were studied. The chromatographic separation was carried out on a Shim-pack XR-ODS II column(100 mm×2. 0 mm, 2. 2 μm) by using water/methanol solution as the mobile phase with the gradient elution. Detection was performed in positive multi-reaction monitoring(MRM) mode for quantification by using external standard method. The four analytes showed good linear relationship within the range of 1. 00-100 μg/L(calculated by aldehyde) with a correlation coefficient r≥0. 9990. The limits of quantitation(LOQs) of the method(concentrated with 10 L air) were 0. 5 μg/m~3 in air, for acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde. The recoveries of the method were 90. 6%-97. 8% at the three spiked levels, and the relative standard deviations(RSDs) were between 1. 9%-6. 4%(n=6), the average sampling efficiency was between 91. 0%-97. 1%. The developed method is simple, less interference and specificity, and is suitable for the simultaneous rapid determination of trace acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde in air of work place.

Research progress in the application of magnetic solid phase extraction based on carbon based magnetic materials in food analysis

食品中残留的痕量有毒物质严重威胁人体健康,对其进行分析十分必要。然而,食品中有毒物质种类多、量少、基质复杂,需选择适当的样品预处理技术进行提取和净化。磁固相萃取(MSPE)因具有操作简单、省时快速、无需离心过滤、环境友好等优点,被认为是一种高效的样品预处理技术并应用于食品分析中。MSPE中使用的磁性吸附剂的吸附容量和选择性是影响MSPE萃取效率和选择性高低的关键,对所建立分析方法的准确度起着关键作用。碳基磁性材料是具有价格低廉、来源丰富、比表面积大、化学稳定性好、吸附容量高、绿色环保等优点的一类新型功能性磁性材料,可以富集不同性质的有机、无机分析物,在环境分析、生物检测、污染治理等多个领域取得了较大进展。近年来,基于碳基磁性材料的MSPE技术在食品分析预处理领域逐渐得到应用,但尚处于起步阶段,存在巨大的应用潜力。该文以碳基类别(碳纳米管、石墨烯、金属有机骨架衍生碳、活性炭等)为主线,综述了采用MSPE技术,以碳基磁性材料为吸附剂,对食品样品中酯类、真菌毒素、多环芳烃、抗生素、生物碱、酚类、维生素、抗菌药等物质进行萃取,进而采用液相色谱法等进行分析的应用实例,同时阐述了该技术存在的问题,并对其发展方向做出了展望。该综述将为基于碳基磁性材料的MSPE技术在食品分析中的广泛应用提供理论依据和技术支撑。

Contamination status and the evaluation of dietary exposure of marine biotoxins in seafood in Ningbo City in 2017-2019

Ultra-fast liquid chromatography-tandem mass spectrometry method was developed for the analysis of contamination degree of biotoxins in seafood in Ningbo City from 2017 to 2019 and the assessment of dietary exposure was conducted. Samples were extracted and purified with optimized pretreatment process and then injected for analysis. According to the result of the measurements, an international point estimate model was used to evaluate the dietary exposure of the population. For tetrodotoxin and 16 shellfish toxins monitored routinely, gonyautoxin5(GTX5), tetrodotoxin and homo-yessotoxin(hYTX) had higher detection rate, other toxins including okadaic acid(OA), dinophysistoxin1(DTX1), decarbamoyl gonyautoxin2(dcGTX2) and decarbamoyl gonyautoxin3(dcGTX3) were detected sporadically. The detection rates of TTX、GTX and hYTX were 27%, 52% and 12%, respectively. The concentration ranges of TTX, GTX and hYTX in polluted samples were 0. 003-0. 535, 0. 008-0. 189 and 0. 032-0. 110 mg/kg. The exposure risk indices(ERI) of TTX, GTX5, hYTX, dcGTX2 and dcGTX3 were 2. 5, 0. 026, 0. 0080, 0. 79 and 0. 32, respectively. Marine biotoxins have a lower dietary health risk to the population. It is must be given great attention that in the season of toxic red tide, the detection rates of higher toxic toxins, dcGTX2 and dcGTX3 increased significantly with high risks to human. Moreover, the dietary health risk of tetrodotoxin in routine surveillance in 2019 was higher.

Determinants of gefitinib pharmacokinetics in healthy Chinese male subjects: A pharmacogenomic study of cytochrome p450 enzymes and transporters.

Gefitinib, an inhibitor of the epidermal growth factor receptor tyrosine kinase, exhibited a wide interindividual variability in pharmacokinetics. In the present study, we aimed to evaluate the impact of single-nucleotide polymorphisms in the metabolizing enzymes and transporters on gefitinib disposition in healthy Chinese subjects. Fourteen single-nucleotide polymorphisms, including polymorphisms of ATP-binding cassette (ABC) transporters and cytochrome P450 enzymes, were genotyped by Sanger sequencing, and the concentration of gefitinib was measured by ultrafast liquid chromatography-tandem mass spectrometry. The association between the pharmacokinetic parameters (peak plasma concentration [Cmax ], time to reach Cmax , plasma half-life, area under the concentration-time curve from 0 to 168hours [AUC(0-168h) ], AUC(0-∞) and plasma clearance [CL/F]) and genotypes was evaluated using unpaired t test or Mann-Whitney U test. A stepwise multiple linear regression analysis was applied to assess the relationships between multiple factors and gefitinib pharmacokinetics. Thirty-nine healthy Chinese male subjects were enrolled in the pharmacokinetic study. Subjects carrying an ABCG2 A allele (c.421CA+c.421AA genotypes) exhibited 33 and 37% increases in the mean gefitinib AUC(0-168h) and AUC(0-∞) values (P<.05), respectively, compared to that of subjects carrying wild-type ABCG2 (c.421CC). Additionally, the mean CL/F of the c.421A allele carriers was 32% less than that of the c.421CC carriers (P<.05). No associations were found between polymorphisms in other metabolic enzymes or ABC transporters and gefitinib pharmacokinetics. Our results suggested that a single-nucleotide polymorphism in ABCG2 (c.421C>A) significantly affected the pharmacokinetics of gefitinib. Further studies are required to evaluate the effects of single-nucleotide polymorphism on the pharmacokinetics, pharmacodynamics and toxicity of gefitinib.

Quality evaluation of Lonicerae Japonicae Flos and Lonicerae Flos based on simultaneous determination of multiple bioactive constituents combined with multivariate statistical analysis.

IntroductionLonicerae Japonicae Flos (LJF) and Lonicerae Flos (LF) belong to different genera of Caprifoliaceae. They have been historically utilised as herbal medicine to treat various diseases. However, the comprehensive assessment of them still remains a challenge.ObjectiveTo develop a comprehensive method of ultra‐fast liquid chromatography‐tandem triple quadrupole mass spectrometry (UFLC‐QTRAP‐MS/MS) coupled with multivariate statistical analysis for the quality evaluation and reveal differential components of LJF and LF.MethodologyA validated UFLC‐QTRAP‐MS/MS method was established for simultaneous determination of 50 constituents, including 12 organic acids, 12 flavonoids, 6 iridoids, 3 saponins, 13 amino acids and 4 nucleosides. The obtained data were employed to multivariate statistical analysis. Principal component anlysis (PCA) and partial least squares determinant analysis (PLS‐DA) were performed to classify and reveal differential components of samples; grey relational analysis (GRA) was introduced to assess the samples according to the contents of 50 constituents by calculating the relative correlation degree of each sample.ResultsFifty constituents were simultaneously determined of LJF and LF. Based on obtained data, PCA and PLS‐DA were easy to distinguish samples and the classification of the samples was related to 11 chemical constituents. GRA implied the quality of LJF was better, and that the flower buds were superior to the flowers. Moreover, organic acids are the main components of samples.ConclusionThis study not only established a method of simultaneous determination of multiple bioactive constituents in LJF and LF, but provided comprehensive information on the quality control of them. The developed method is conducive to distinguish orthologues or paralogues of them, and supply the support for “heterologous effects”.

Evaluating the treatment effectiveness of copper-based algaecides on toxic algae Microcystis aeruginosa using single cell-inductively coupled plasma-mass spectrometry

Single cell-inductively coupled plasma-mass spectrometry (SC-ICP-MS) is an emerging technology. In this work, we have developed a novel SC-ICP-MS method to quantify metal ions in individual cells of a toxic cyanobacterial species, Microcystis aeruginosa (M. aeruginosa), without complicated post-dosing sample preparation, and applied this method to study the treatment effectiveness of copper-based algaecides (cupric sulfate and EarthTec®) on the toxic algae M. aeruginosa. The developed SC-ICP-MS method uses new intrinsic metal element magnesium to determine real transport efficiency and cell concentration. The cell viability and microcystin-LR release by algaecide treatment were studied by flow cytometry and ultra-fast liquid chromatography-tandem mass spectrometry, respectively. The results showed that this novel method was very rapid, highly sensitive (detection limits of intracellular copper and magnesium were 65 ag/cell and 98 ag/cell, respectively), and reproducible (relative standard deviation within 12%). The algaecide effectiveness study further demonstrated that copper in the forms of cupric sulfate and copper-based algaecide EarthTec® successfully diminished M. aeruginosa populations. The higher the copper concentration used to treat the cells, the faster the speeds of copper uptake and cell lysis in the copper concentrations ranged from 0 to 200 μg/L of copper-based algaecide. The cells exhibit obvious heterogeneity in copper uptake. The result suggests that M. aeruginosa cells uptake and cumulate copper followed by cellular lysis and microcystin-LR release. These novel results indicated that though the copper-based algaecides could control this type of harmful algal bloom, further treatment to remove the released algal toxin from the treated water would be needed.Graphical abstract

Distribution of perfluorinated alkyl substances in marine shellfish along the Chinese Bohai Sea coast

Perfluorinated alkyl substances (PFASs) are emerging persistent organic pollutants, which pose a threat to human health primarily by dietary exposure, especially through seafood. Bohai Sea (a semi-closed sea located north of China) is an important shellfish aquaculture area that is possibly highly-polluted with PFASs. In this study, we first evaluated contamination by PFASs in a total of 230 samples of marine shellfish from the Bohai Sea. Samples included five important shellfish species, collected from important aquaculture spots distributed around the Bohai Sea. Samples were analyzed by an ultra-fast liquid chromatography-tandem mass spectrometry method, which could simultaneously detect 23 PFASs in shellfish. Our research verified that PFASs have become a threat to the safety of shellfish products in this area. Furthermore, contamination by PFASs in shellfish changed depending on the components of PFASs, the species of shellfish, and the sampling sites. Many of the 23 target compounds contributed to the high detection ratio (>50%) as follows: perfluorooctanoic acid (PFOA) > perfluorononanoic acid > perfluorodecanesulfonic acid > perfluorooctanesulfonic acid (PFOS). Compared with other dominant components, PFOA not only had the highest detection percentage in shellfish samples (98.3%), but its detection level contributed to 87.2% of total PFASs concentrations, indicating that PFOA is the major threat to the safety of shellfish products. The highest level of PFAS was found in clams (62.5 ng g−1 wet weight of PFOA). The concentration of total PFAS in different shellfish species showed the following trend: clams > mussels > scallops > whelks > oysters. The maximum concentration of total PFAS or PFOA was found in Shouguang. The total concentration of PFOS and its precursor were highest in Cangzhou, possibly due to local industrial activities. The results presented in this paper provide new data on the contamination of marine shellfish along the Bohai Sea coasts in China, and constitute a reference for future monitoring of contamination by emerging contaminants in Bohai coast.

A simple sensitive UFLC-MS/MS method for the simultaneous quantification of artesunate, dihydroartemisinin and quercetin in rat plasma and its application to pharmacokinetic studies.

An ultrafast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method was developed for the simultaneous estimation of artesunate (ART), dihydroartemisinin (DHA, an active metabolite of ART) and quercetin (QRT) in rat plasma. The separation was achieved using a Zorbax C18 column (3 μm, 50 mm × 4.6 mm) as a stationary phase with a mobile phase of 0.1% formic acid (10% by volume) and methanol (90% by volume) at a flow rate of 0.4 mL min−1 and an injection volume of 10 μL. Artemisinin (ATM) was used as the internal standard (IS). Mass detection was performed by electrospray ionization (ESI)-tandem mass spectrometry via multiple reaction monitoring (MRM) in positive mode except for QRT, where negative ionization was used. The extraction recoveries of ART, DHA, and QRT from plasma were found to be 91.05–99.62%, 95.12–98.56% and 89.35–98.90%, respectively. The developed method was validated and successfully applied to the quantitative analysis of ART, DHA and QRT in plasma samples after the oral administration of ART and ART–QRT pure drugs to rats at the dose of 5 mg kg−1 each. The results reveal that the developed method can be further used for the quantification of the proposed combination drugs in nanoformulations.

Analysis of monofluoroacetic acid in human plasma by UFLC–MS/MS and its application in patients with sodium monofluoroacetate or monofluoroacetamide poisoning

Monofluoroacetic acid (FAcOH), was once widely used in baits as a rodenticide in agriculture. For intentional and unintentional misuses, the incidence of FAcOH poisoning has increased in recent years. Organic fluorine rodenticides such as sodium monofluoroacetate and monofluoroacetamide, the analogs of FAcOH, can easily be converted to FAcOH in vivo and cause injury. It is urgent to establish a simple and sensitive analytical method of FAcOH in human plasma and applied to clinical poison analysis. In this paper, an ultra-fast liquid chromatography-tandem mass spectrometry (UFLC–MS/MS) method was developed for determination of FAcOH in patient plasma. We used isotopic labelled FAcOH-13C2, D2 as the internal standard (IS). Plasma samples were simply precipitated with acetonitrile and the supernatant was injected directly for analysis. The chromatographic column was Phenomenex Luna® Silica column (100 × 2 mm, 3 μm), FAcOH was eluted by isocratic elution with a mobile phase of acetonitrile-water contains 5 mM ammonium formate with 0.2% formic acid. The retention time of FAcOH was 2.31 min A good linear response was from 0.25 to 200 μg/mL, with a correlation coefficient of r = 0.9980. The limit of detection was 0.05 μg/mL. The recoveries at three spiking levers were 89.51–93.03% with relative standard deviations ranged between 2.55–3.61%. This new method has been successfully applied to monitor 31 cases of patients suspected with sodium monofluoroacetate or monofluoroacetamide poisoning.

Measurement of pharmacokinetics and tissue distribution of three bioactive constituents from Zanthoxylum armatum DC in rat plasma and tissues through UFLC-MS/MS

The compounds of N-Methylanhydrotetrahydroberberrubine A, dictamnine and eudesmin were the primary bioactive components in the roots of Zanthoxylum armatum DC (Z. armatum). To clarify the pharmacokinetics and distribution of these three compounds, an ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) was employed to determine the contents of these three compounds in rat plasma and seven tissues. The separation was achieved on a Kinetex XB–C18 100A column (2.1 × 50 mm, 2.6 μm, Phenomenex). The optimized mobile phase system was set with 0.1‰ formic acid aqueous solution (A) and acetonitrile (containing 0.1‰ formic acid) (B) with a programmed elution of 0.00 to 0.50 min, 2% B; 0.51–4.00 min, 30%–60% B; and 4.01–5.00 min, 2% B. All analytes were measured with optimized multiple reaction monitoring (MRM) in the positive ion ESI mode. Berberine hydrochloride was selected as the internal standard (IS). The MS/MS transitions of N-Methylanhydrotetrahydroberberrubine A, dictamnine, eudesmin and IS were 339.9135.1, 200.1 → 129.1, 387.4 → 369.0 and 337.1 → 321.1, respectively. The lower limits quantification (LLOQ) of the three analytes was 0.5–20 ng/ml. The linear ranges were 0.5–400 ng/ml for N-Methylanhydrotetrahydroberberrubine A and dictamnine and 20–4000 ng/ml for eudesmin. The present analysis showed that the two alkaloids were quickly absorbed, with Tmax in 0.167–0.292 h, and eudesmin was absorbed in 2.5 h. Moreover, all compounds were found at high concentrations in the gastrointestinal track. These results are helpful for further investigation of the clinical application of Z. armatum.

Agarwood Essential Oil Displays Sedative-Hypnotic Effects through the GABAergic System.

Although agarwood has been used as a tranquilizer in Asian countries for hundreds of years, the underlying pharmacological basis is still unclear. This study investigated the sedative-hypnotic effect of agarwood essential oil (AEO) using locomotor activity and pentobarbital-induced sleeping assays in mice. Single (1-day) and multiple (7- and 14-days) administrations of 60 mg/kg AEO generated significant sedative effect on inhibiting locomotor activity and hypnotic effect on pentobarbital-induced sleeping in mice. Interestingly, prolonged AEO treatment did not result in obvious desensitization. Concoitant measurement of the levels of brain neurotransmitters using ultrafast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) indicated that AEO had no significant effect on the levels of glutamic acid (Glu) and γ-aminobutyric acid (GABA) in the brain. However, the sedative-hypnotic effects were blocked by the type A GABA (GABAA) receptor antagonists bicuculline and flumazenil. In addition, AEO significantly elevated the expression of GABAA receptor subunits and subtypes in the cerebral cortex. Furthermore, AEO increased chlorine ion (Cl−) influx through GABAA receptors in human neuroblastoma cells. These results together demonstrate that AEO exerts its sedative-hypnotic effects through regulating gene expression of GABAA receptors and potentiating GABAA receptor function.

Pharmacokinetics of the prototype and hydrolyzed carboxylic forms of ginkgolides A, B, and K administered as a ginkgo diterpene lactones meglumine injection in beagle dogs

AbstractGinkgo diterpene lactones meglumine injection (GDLI) is a commercially available product used for neuroprotection. However, the pharmacokinetic properties of the prototypes and hydrolyzed carboxylic forms of the primary components in GDLI, i.e., ginkgolide A (GA), ginkgolide B (GB), and ginkgolide K (GK), have never been fully evaluated in beagle dogs. In this work, a simple, sensitive, and reliable method based on ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) was developed, and the prototypes and total amounts of GA, GB, and GK were determined in beagle dog plasma. The plasma concentrations of the hydrolyzed carboxylic forms were calculated by subtracting the prototype concentrations from the total lactone concentrations. For the first time, the pharmacokinetics of GA, GB, and GK were fully assessed in three forms, i.e., the prototypes, the hydrolyzed carboxylic forms, and the total amounts, after intravenous administration of GDLI in beagle dogs. It was shown that ginkgolides primarily existed in the hydrolyzed form in plasma, and the ratio of hydrolysates to prototype forms of GA and GB decreased gradually to a homeostatic ratio. All of the three forms of the three ginkgolides showed linear exposure of AUC to the dosages. GA, GB, and GK showed a constant half-life approximately 2.7, 3.4, and 1.2 h, respectively, which were consistent for the forms at three dose levels (0.3, 1.0, and 3.0 mg·kg−1) and after a consecutive injection of GDLI for 7 days (1.0 mg·kg−1).

Development of an ultra-fast liquid chromatography-tandem mass spectrometry method for simultaneous determination of seven flavonoids in rat plasma: Application to a comparative pharmacokinetic investigation of Ginkgo biloba extract and single pure ginkgo flavonoids after oral administration.

For deeper pharmacokinetic investigation and further curative application of ginkgo flavonoids, a delicate, efficient and precise UFLC-MS/MS technique for synchronous quantitation of seven flavonoids, apigenin, luteolin, naringenin, quercetin, diosmetin, kaempferol and isorhamnetin in rat plasma has been established. After mixing with the internal standard (IS) linarin, bio-samples were pretreated via ethyl acetate for liquid-liquid extraction, then isolated at 0.2ml/min flow rate on a Venusil MP C18 chromatographic column (100mm×2.1mm, 3μm) by means of gradient elution. 0.1% formic acid-water and methanol system was used as the mobile phase. Mass spectrometric inspection was conducted on a 4000Q UFLC-MS/MS system with turbo ion spray source in patterns of negative ion and multiple reaction-monitoring (MRM). All calibration curves proved favorable linearity (R2≥0.9918) in linear ranges. Intra-day and inter-day precisions didn't exceed 14.0% for all the analytes, and the accuracy was within 6.9%. Extraction recoveries of analytes and IS were less than ±15.0% of nominal concentrations. This method has been under thorough and firm verification for a comparative pharmacokinetic research after gavage between Ginkgo biloba extract and single pure ginkgo flavonoids. The results demonstrated that there're evident pharmacokinetic discrepancies, and possible structural influences were innovatively proposed. Generally, substitution with 3-hydroxylation, a double bond in ring C, ring B methoxylation often confer longer onset period. The existence of ring B catechol group gives rise to faster clearance.