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No início dos anos 2000, as Novas Substâncias Psicoativas (NPS) emergiram de forma sem precedentes causando uma drástica mudança no mercado de drogas sintéticas mundial. Estas substâncias são sintetizadas para fins ilícitos e mimetizam o efeito psicoativo das drogas tradicionais. Até o momento, mais de 1000 substâncias foram reportadas mundialmente, representando um grande problema de saúde pública principalmente associado ao desconhecimento das suas propriedades toxicológicas. Por este motivo, métodos analíticos para detectar e quantificar estas substâncias em materiais biológicos são importantes nos casos de toxicologia analítica e forense. Contudo, a tendência de reduzir o impacto ambiental destas metodologias tem ganhado popularidade com a Toxicologia Analítica Verde (GAT). Portanto, o objetivo do presente trabalho foi desenvolver novas técnicas analíticas para analisar as principais classes de NPS em amostras biológicas enquanto aplicando os princípios sustentáveis estabelecidos pela GAT. Os resultados obtidos no presente trabalho são apresentados como coletânea de artigos científicos publicados em revistas. Estes estão descritos nos capítulos 4 a 8. No capítulo 4, uma revisão sobre os desafios no desenvolvimento de técnicas de preparo de amostra para fins forenses é abordada com foco no uso das matrizes secas. No Capítulo 5, está descrito a aplicação da microextração líquido-líquido dispersiva para catinonas sintéticas em amostras de sangue total e urina. No capítulo 6, o artigo descreve o desenvolvimento da técnica microextração líquido-líquido homogênea com solventes de hidrofilicidade comutável para canabinoides sintéticos em amostras de plasma. No capítulo 7, a microextração em fase líquida em placas de 96 poços, cunhada extração paralela em membranas artificiais líquidas, foi desenvolvida para diferentes classes de drogas de abuso, incluindo NPS. O capítulo 8 mostra o desenvolvimento de uma extração por eletromembrana também no formato de placa de 96 poços para catinonas sintéticas em amostras de sangue total. Em todos os trabalhos, as técnicas de extração foram desenvolvidas, otimizadas e validadas. Os princípios da GAT foram aplicados de diferentes formas, como reduzindo o volume de amostra, simplificando os procedimentos, evitando o uso de solventes orgânicos, dentre outros. Assim, alternativas mais sustentáveis para a análise de drogas de abuso em amostras biológicas foram apresentadas e estas ajudam a consolidar e difundir o conceito do desenvolvimento de métodos analíticos com consciência ambiental além de fornecer ferramentas para auxiliar o controle das NPS no país
In the early 2000s, New Psychoactive Substances (NPS) emerged and unprecedentedly changed the illicit drug market. These substances are synthesized for illicit purposes and mimic the psychoactive effect of traditional drugs of abuse. To date, more than 1000 substances have been reported worldwide, representing a major public health problem mainly associated with their mostly unknown toxicological properties. In this context, analytical methods able to detect and quantitate these new drugs in biological specimens are important in cases of analytical and forensic toxicology. However, reducing the environmental impact of these methodologies has recently gained popularity with Green Analytical Toxicology (GAT). Therefore, the aim of this work was to develop new analytical techniques to analyze the main classes of NPS in biological samples while applying the environmentally friendly principles established by GAT. The results obtained throughout the development of the present work were split into four papers (chapters 4-8). In chapter 4, a review of common challenges faced during the development of new sample preparation techniques for forensic applications is described focusing on the use of dried matrices. In chapter 5, the application of dispersive liquid-liquid microextraction for synthetic cathinones in whole blood and urine samples is described. In chapter 6, the application of the somewhat recent switchable hydrophilicity solvent-based homogenous liquidliquid microextraction to synthetic cannabinoids in plasma samples is reported. In chapter 7, liquid-phase microextraction in the 96-well plate format, termed parallel artificial liquid membrane extraction, for different classes of drugs of abuse, including NPS, in plasma samples is presented. In chapter 8, an electromembrane extraction in the 96-well plate format for synthetic cathinones in whole blood samples was developed. In this work, sample preparation techniques were developed, optimized and validated. The principles of sustainable chemistry in method development were applied in different ways, such as reducing the sample volume, simplifying procedures, avoiding the use of organic solvents, among others. Thus, greener alternatives were presented for the analysis of drugs of abuse in biological samples and contribute to consolidate and spread this trend of environmental consciousness during method development. Additionally, valuable techniques that can be used in the combat against NPS were provided
Subject(s)
Psychotropic Drugs/adverse effects , Illicit Drugs/adverse effects , Forensic Toxicology/methods , Liquid Chromatography-Mass Spectrometry/methods , Cannabinoids/pharmacology , Pharmaceutical Preparations/analysis , Synthetic Cathinone/pharmacologyABSTRACT
AIM: To establish a method for quantitation of cefepime and avibactam in M-H broth, and applicated in the in vitro dynamic PK/PD model. METHODS: The cefepime was also determined using the high-performance liquid chromatography method (HPLC), the avibactam was also determined using the liquid chromatography-mass spectrometry (LC-MS/MS), an in vitro dynamic PK/PD model was established to study the PK/PD relationship of cefepime/avibactam against carbapenem resistant Klebsiella pneumoniae (CRKP). RESULTS: The linear ranges of cefepime and avibactam were good at (0.5-20) and (0.1-25) μg/mL (r=0.999), and the lower limit concentrations were 0.5 and 0.1 μg/mL. The extraction recoveries of cefepime and avibactam in M-H broth were 88.0%-101.7% and 90.9%-95.2%, the relative standard deviation of intra-day precision and inter-day precision were less than 5.2%. The concentration-time curves were well simulated by the PK/PD model. All observed concentrations in each experiment were in the range of 20% of the targeted values. For the CRKP of MIC=8 μg/mL and MIC=16 μg/mL, the colony decreased to 2.783Log10 CFU/mL and 1.325Log10 CFU/mL at the cefepime/avibactam 2.5 g q8 h administration after 24 h. CONCLUSION: The determination method of cefepime and avibactam in broth established in this study has high sensitivity and good stability. For the CRKP with MIC≤8 μg/mL,cefepime/avibactam showed that good anti-CRKP activity under routine administration in vitro dynamic PK/PD model.
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OBJECTIVE To establish a liquid chromatography-tandem mass spectrometry （LC-MS/MS） method for the simultaneous determination of bepotastine and hydroxychloroquine concentrations in human breast milk and apply it in clinical practice. METHODS The milk samples （50 μL） were precipitated with 200 μL methanol containing the internal standard （100 ng/mL chloroquine）， and the supernatant was taken for analysis after vortexing and centrifugation. The separation was performed on a Waters ACQUITY UPLC HSS T3 column with mobile phase consisted of 0.1% formic acid-10 mmol/L ammonium acetate solution （phase A） and methanol （phase B） at gradient elution of 0.35 mL/min. The injection volume was 2 μL， and the analysis time was 4 min. The detection of the analytes was performed by electrospray ionization in positive mode by multiple reaction monitoring with the transition of m/z 388.9→201.9 （bepotastine）， m/z 336.3→247.1 （hydroxychloroquine）， and m/z 320.2→247.2 （chloroquine）. The established LC-MS/MS method was researched in methodology and used to determine the drug concentrations in the breast milk of 1 case of lactating patient. RESULTS The linear range of bepotastine was 2-200 ng/mL（ r＝0.999）， and hydroxychloroquine was 50-1 000 ng/mL （r＝0.998）. The intra-assay and inter-assay precisions were both ≤15%， and the accuracy， extraction recovery， matrix effect， and stability all met the acceptance criteria for bioanalytical method validation. The concentration result of bepotastine and hydroxychloroquine in the breast milk of the lactating patient showed， after 2 h and 14 h， the concentrations of bepotastine in the breast milk of the patient were 34.95 ng/mL and 5.72 ng/mL； those of hydroxychloroquine were 211.92 ng/mL and 104.18 ng/mL， respectively. The relative infant doses were 1.83% and 0.56%， respectively. CONCLUSIONS The established method is simple， rapid， and sensitive. It is suitable for simultaneous determination of bepotastine and hydroxychloroquine concentrations in human milk and can provide reference for safe drug use during lactation.
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OBJECTIVE To establish a liquid chromatography-tandem mass spectrometry （LC-MS/MS） method for the simultaneous determination of bepotastine and hydroxychloroquine concentrations in human breast milk and apply it in clinical practice. METHODS The milk samples （50 μL） were precipitated with 200 μL methanol containing the internal standard （100 ng/mL chloroquine）， and the supernatant was taken for analysis after vortexing and centrifugation. The separation was performed on a Waters ACQUITY UPLC HSS T3 column with mobile phase consisted of 0.1% formic acid-10 mmol/L ammonium acetate solution （phase A） and methanol （phase B） at gradient elution of 0.35 mL/min. The injection volume was 2 μL， and the analysis time was 4 min. The detection of the analytes was performed by electrospray ionization in positive mode by multiple reaction monitoring with the transition of m/z 388.9→201.9 （bepotastine）， m/z 336.3→247.1 （hydroxychloroquine）， and m/z 320.2→247.2 （chloroquine）. The established LC-MS/MS method was researched in methodology and used to determine the drug concentrations in the breast milk of 1 case of lactating patient. RESULTS The linear range of bepotastine was 2-200 ng/mL（ r＝0.999）， and hydroxychloroquine was 50-1 000 ng/mL （r＝0.998）. The intra-assay and inter-assay precisions were both ≤15%， and the accuracy， extraction recovery， matrix effect， and stability all met the acceptance criteria for bioanalytical method validation. The concentration result of bepotastine and hydroxychloroquine in the breast milk of the lactating patient showed， after 2 h and 14 h， the concentrations of bepotastine in the breast milk of the patient were 34.95 ng/mL and 5.72 ng/mL； those of hydroxychloroquine were 211.92 ng/mL and 104.18 ng/mL， respectively. The relative infant doses were 1.83% and 0.56%， respectively. CONCLUSIONS The established method is simple， rapid， and sensitive. It is suitable for simultaneous determination of bepotastine and hydroxychloroquine concentrations in human milk and can provide reference for safe drug use during lactation.
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Objective To establish a method for determining hydrogen sulfide(H2S)in blood and apply it to practical cases.Methods A delute solution was achieved by adding 0.8 mL saturated borax solution into 0.2 mL blood sample was diluted with.1 mL acetonitrile solution containing 0.1％formic acid was then taken in a test tube,followed by adding 0.1 mL dilute solution and 0.1 mL thiozine aqueous solution(1％).After thorough mixing,the mixture was left to stand for 30 minutes.Subsequently,the sample was subjected to liquid chromatography-tandem mass spectrometry(LC-MS/MS)analysis after centrifugation and membrane filtration.Results The results showed that H2S exhibited good linearity within the concentration range of 10～2 000 ng/mL,with the R2 value of 0.998 5.The detection limit was 5 ng/mL,and the quantification limit was 10 ng/mL.In three cases of H2S poisoning,sulfur ions were detected in the blood of the deceased individuals,with concentrations ranging from 0.17 to 0.56 μg/mL.Conclusion For the first time,this study established a LC-MS/MS method for determining H2S in blood,which can meet the detection needs of H2S poisoning cases.
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Objective To develop a method for the determination of ketamine analogues in hair samples by liquid chromatography quadrupole linear ion trap mass spectrometry(QTRAP LC-MS/MS).Methods 20 mg of washed and dried hair was added to 1 mL extracting solution and then prepared using an ultrasonic extraction with frozen pulverization method.After centrifugation and purification with membrane,the supernatant was separated in a ACQUITY UPLC? HSS T3 column with gradient elution,finally tested with multiple reaction monitoring for the detection of 10 ketamine analogues.The above method was applied for quantitative analysis of ethylfluamine,F-norketamine and tiletamine in 20 positive samples.Results When the concentration ranged from 0.01 to 2.00 ng/mg,there was good linearity for 10 ketamine analogues with the correlation coefficients over 0.99.The recoveries ranged from 89.1％to 106.1％,and the matrix effects were between 88.3％and 106.0％.Among the 20 positive samples,the contents of ethylfluamine,F-norketamine and tiletamine in hair ranged between 0.02～8.35 ng/mg,0.01～0.94 ng/mg and 0.02～10.93 ng/mg,respectively.Their mean values were 1.59 ng/mg,0.28 ng/mg and 2.69 ng/mg.Their medians were 0.40 ng/mg,0.19 ng/mg and 2.11 ng/mg.Conclusion The established method was simple,efficient,reliable and suitable for the determination of ketamine analogues in hair.The data provided reference for the drug control and forensic science practice.
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The neuroprotective effect of flower and fruit parts of Capparis ovata Desf. var. palaestina Zoh. plant was investigated in H2O2-induced cytotoxicity in SH-SY5Y cells. The cells were treated with H2O2 alone or pretreated with flower (COMFL) and fruit extract (COMFR) of C. ovatavar. palaestina. MTT, xCELLigence, and qualitative and quantitative determination of phytochemical constituents in the extracts by LC-MS/MS methods were employed. COMFL and COMFR had a neuroprotective effect and this effect was stronger when the presence of oxidative stress. The mass spectrums revealed the presence of flavonoids and phenolic acid derivatives in the extracts. According to quantitative analyses, the main compounds were myristoleic acid, apigenin, caffeic acid, caffeic acid-3-glucoside, and 5-cynapoil quinic acid in both COMFL and COMFR and rutin was found in COMFL. The extracts could inhibit H2O2induced neuronal cell death which might be beneficial for the pretreatment of oxidative stress in neurodegenerative diseases.
Se investigó el efecto neuroprotector de flores y frutos de Capparis ovata Desf. var. palaestina Zoh sobre la citotoxicidad inducida por H2O2en células SH-SY5Y. Las células se trataron con H2O2solo o se pretrataron con extracto de flores (COMFL) y frutos (COMFR) de C. ovatavar. palaestina. Se emplearon MTT, xCELLigence y determinación cualitativa y cuantitativa de constituyentes fitoquímicos en los extractos mediante LC-MS/MS. COMFL y COMFR que tuvieron un efecto neuroprotector y este efecto fue mayor cuando hubo estrés oxidativo. Los espectros de masas revelaron la presencia de flavonoides y derivados del ácido fenólico en los extractos. Según los análisis cuantitativos, los compuestos principales fueron ácido miristoleico, apigenina, ácido cafeico, ácido cafeico-3-glucósido y ácido quínico 5-cinapoil tanto en COMFL como en COMFR y se encontró rutina en COMFL. Los extractos podrían inhibir la muerte celular neuronal inducida por H2O2, lo que podría ser beneficioso para el pretratamiento del estrés oxidativo en enfermedades neurodegenerativas.
Subject(s)
Plant Extracts/pharmacology , Neuroprotective Agents/pharmacology , Capparis/chemistry , Plant Extracts/chemistry , Neurotoxicity SyndromesABSTRACT
Abstract Dasatinib, a potent oral multi-targeted kinase inhibitor against Src and Bcr-Abl, can decrease inflammatory response in sepsis. A simple and cost-effective method for determination of an effective dose dasatinib was established. This method was validated in human plasma, with the aim of reducing the number of animals used, thus, avoiding ethical problems. Dasatinib and internal standard lopinavir were extracted from 180 uL of plasma using liquid-liquid extraction with methyl tert-butil ether, followed by liquid chromatography coupled to triple quadrupole mass spectrometry in multiple reaction monitoring mode. For the pharmacokinetic study, 1 mg/kg of dasatinib was administered to mice with and without sepsis. The method was linear over the concentration range of 1-98 ng/mL for DAS in mice and human plasma, with r2>0.99 and presented intra- and interday precision within the range of 2.3 - 6.2 and 4.3 - 7.0%, respectively. Further intra- and interday accuracy was within the range of 88.2 - 105.8 and 90.6 - 101.7%, respectively. The mice with sepsis showed AUC0-t = 2076.06 h*ng/mL and Cmax =102.73 ng/mL and mice without sepsis presented AUC0-t = 2128.46 h*ng/mL. Cmax = 164.5 ng/mL. The described analytical method was successfully employed in pharmacokinetic study of DAS in mice.
Subject(s)
Animals , Male , Mice , Plasma , Chromatography, Liquid/methods , Tandem Mass Spectrometry/methods , Dasatinib/analysis , PharmacokineticsABSTRACT
OBJECTIVE@#The compatibility of Eucommia ulmoides (Eu) and Psoralea corylifolia (Pc) on the pharmacokinetic (PK) properties in the rat was explored in this study.@*METHODS@#Eu extract, Pc extract and the combined extracts (crude drug ratio was 2:1) was administered by gavage, respectively. Two PK experiments were conducted. In first one, the blood samples were collected via the occuli chorioideae vein to get the PK properties of the components. In second one, the blood samples were simultaneously collected via the internal jugular vein or portal vein at different time points and the concentrations of target ingredients were detected by LC/MS/MS to clear the location where the interaction of Eu and Pc took place in vivo.@*RESULTS@#Eight of 11 ingredients in Eu and Pc extract were determined in rat plasma. The exposure levels of geniposidic acid (GPA), aucubin (AU), geniposide (GP), pinoresinol diglucoside (PDG), psoralen glycosides (PLG) and isopsoralen glycosides (IPLG) were decreased 1/5-2/3 after administration of combined extracts. Comparing to the combined administration, the exposure of GPA and AU in plasma of single Eu administration collected via the portal vein were decreased 1/3-2/3, and the values of AUC0-24h and AUC0-∞ of GP collected from the portal vein or internal jugular vein were double increased. The other components' parameters were not significantly changed.@*CONCLUSION@#In summary, the Pc and Eu combined administration could affect the exposure of the main components of Eu extract in rats due to the changed intestinal absorption. The research on the compatibility of Pc and Eu was helpful to guide the clinical administration of Eu and Pc simultaneously.
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Objective To study the pharmacokinetics of HMS-01 in mice and provide support for subsequent studies. Methods Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to establish a sensitive and specific method for the determination of the concentration of HMS-01 in plasma and other biological samples. The pharmacokinetics of HMS-01 in C57BL/6J mice were studied by the established method. To obtain the basic pharmacokinetic parameters, three doses of HMS-01 were given orally and one dose of HMS-01 was given intravenously. Results The pharmacokinetic results of mice showed that the intestinal absorption of HMS-01 was fast, the oral bioavailability of HMS-01 in mice was moderate (50% to 70%). The exposure levels (AUC and cmax) of HMS-01 in mice increased with the increase of dosage, while the AUC was linearly correlated with the increase of dosage. After intravenous administration of HMS-01, the half-life period in mice was about 1 h which was not long. The plasma clearance rate (CLtotal.p) was 2.8 L/h·kg, which was similar to the hepatic blood flow of mice. The apparent volume of distribution (VSS) was 5 L/kg, which was much larger than the total mouse fluid. There were significant differences in AUC and F (P<0.05), but no significant differences in parameters such as cmax,AUC0−∞,t1/2,CLtot,p,MRT,Vss in male and female mice which were given 30 and 60mg/kg HWS-01 orally. Conclusion The pharmacokinetic process of HMS-01 in mice showed gender differences, and the area under the curve of blood concentration time and bioavailability of female mice were higher than that of male mice. As oral bioavailability was reasonable, further in vivo studies on HMS-01 in mice with heart failure by oral administration could be considered to provide evidence.
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OBJECTIVES@#To study the changes of protein levels in peripheral blood after it dried.@*METHODS@#The proteins from whole blood and bloodstains were detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and normalized by the label-free quantification (LFQ) method. The differential proteins were analyzed by using R 4.2.1 software, limma and edgeR package. The analysis of biological function, signaling pathway and subcellular localization for the differential proteins was then performed.@*RESULTS@#A total of 623 and 596 proteins were detected in whole blood and bloodstains, respectively, of which 31 were statistically significant in the quantitative results, including 10 up-regulated and 21 down-regulated proteins in bloodstains.@*CONCLUSIONS@#The protein abundances in whole blood and bloodstains are highly correlated, and the variation of protein abundances may be related to the changes of endogenous and structural proteins in cells. The application of proteomics technology can assist the screening and identification of protein biomarkers, thereby introducing new biomarkers for forensic research.
Subject(s)
Chromatography, Liquid/methods , Tandem Mass Spectrometry/methods , Proteomics/methods , Blood Stains , BiomarkersABSTRACT
AIM: To evaluate the bioequivalence of cinacalcet hydrochloride tablets in healthy Chinese volunteers. METHODS: A randomized, open, double-period and crossover trial was conducted, 48 healthy volunteers were administered a single dose of cinacalcet test tablets or reference tablets orally under each fasting and fed condition. The concentration of cinacalcet was determined by validated LC-MS/MS method. Pharmacokinetic parameters were calculated by Phoenix WinNonlin 8.0 to study its bioequivalence. RESULTS: The main pharmacokinetic parameters of test tablets and reference tablets under fasting condition were as follows: C
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Sialylated N-glycan isomers with α2-3 or 42-6 linkage(s)have distinctive roles in glycoproteins,but are difficult to distinguish.Wild-type(WT)and glycoengineered(mutant)therapeutic glycoproteins,cyto-toxic T lymphocyte-associated antigen-4-immunoglobulin(CTLA4-Ig),were produced in Chinese ham-ster ovary cell lines:however,their linkage isomers have not been reported.In this study,N-glycans of CTLA4-Igs were released,labeled with procainamide,and analyzed by liquid chromatography-tandem mass spectrometry(MS/MS)to identify and quantify sialylated N-glycan linkage isomers.The linkage isomers were distinguished by comparison of 1)intensity of the N-acetylglucosamine ion to the sialic acid ion(Ln/Nn)using different fragmentation stability in MS/MS spectra and 2)retention time-shift for a selective m/z value in the extracted ion chromatogram.Each isomer was distinctively identified,and each quantity(＞0.1％)was obtained relative to the total N-glycans(100％)for all observed ionization states.Twenty sialylated N-glycan isomers with only α2-3 linkage(s)in WT were identified,and each isomer's sum of quantities was 50.4％.Furthermore,39 sialylated N-glycan isomers(58.8％)in mono-(3 N-glycans;0.9％),bi-(18;48.3％),tri-(14;8.9％),and tetra-(4;0.7％)antennary structures of mutant were obtained,which comprised mono-(15 N-glycans;25.4％),di-(15;28.4％),tri-(8;4.8％),and tetra-(1;0.2％)sialy-lation,respectively,with only α2-3(10 N-glycans;4.8％),both α2-3 and α2-6(14;18.4％),and only α2-6(15;35.6％)linkage(s).These results are consistent with those for α2-3 neuraminidase-treated N-glycans.This study generated a novel plot of Ln/Nn versus retention time to distinguish sialylated N-glycan linkage isomers in glycoprotein.
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Xiaoyao pills are a famous traditional Chinese medicine collected in Welfare Pharmacy, which is a classic prescription for treating liver depression and spleen deficiency. However, its composition is complex. In order to better control the quality of Xiaoyao pills, in this study, HPLC-ion-trap time-of-flight mass spectrometry (LC-IT-TOF/MS) was used to identify the main ingredients of Xiaoyao pills, paeoniflorin, albiflorin, glycyrrhizic acid, saikosaponin A and saikosaponin B2. Then a liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed for simultaneous determination and quantification of the main compounds. Fragmentation pathways of five active components were obtained. The method was validated. Five active ingredients in Xiaoyao pills had a good linear relationship, and the values of RSD (%) of repeatability were all less than 5%, the recovery ranges were between 90% and 115%, and the values of RSD (%) of each substance were less than 10% after the sample solution is placed for 24 hours. Three batches of Xiaoyao pills (concentrated pellets) and two batches of Xiaoyao pills (water pellets) were determined, the contents of paeoniflorin in concentrated pills were more than 4.0 mg·g-1, and those in water pills were more than 2.5 mg·g-1, which was accordance with Chinese Pharmacopoeia. However, other compounds behave differently. This method has high sensitivity and reliable measurement results, which provides basis for quality control of Xiaoyao pills and material basis for pharmacology research.
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C17 is an orally available anti-tumor compound inhibiting cancer stem cell (CSC). In this study, a stable, sensitive and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established and validated, and was further applied to a pharmacokinetic study in nude mice receiving C17 by gavage. Using propranolol as the internal standard, the plasma samples were pre-treated by precipitation with methanol and analyzed on an Intersil C8-3 column (100 mm × 2.1 mm, 3 μm), and gradient elution was performed with a mobile phase consisting of 0.1% formic acid aqueous and solution mixed up by 90% isopropanol and 10% acetonitrile. The analyte was detected by a triple quadrupole tandem mass spectrometer, and multiple reaction monitoring was employed to select C17 at m/z 439.3/247.1 and propranolol at m/z 260.2/116.2 in the positive ion mode. The calibration curves were linear (r > 0.995) over the range of 5-800 ng·mL-1. The intra- and inter-day precisions and accuracies were 7.42%-13.22% and -8.99%-8.81% respectively. The method was successfully applied to a PK study in nude mice administered with a single oral dose of 50 mg·kg-1 C17, and the PK data were analyzed with non-linear mixed effect model (NONMEM). Two separated absorption peaks were found in the PK curve of C17, and a two-compartment model with two sequential first-order absorption rate was utilized to describe the PK properties of C17, and the model could provide insights into the physiological process and exposure of C17 in nude mice. All animal experiments were in strict accordance with the regulations of the Biomedical Ethics Committee of Peking University.
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OBJECTIVE To study the pharmacokinetics of paeoniflorin， hesperidin， naringenin， formononetin and enoxolone from Chitong xiaoyanling granules in rats. METHODS Six male SD rats fasted but not deprived of water for 12 h were given Chitong xiaoyanling granules （5.0 g/kg） intragastrically at one time. Blood was collected from inner canthus of rats at different time points after administration. Plasma samples were pretreated with acetonitrile precipitated protein （sulfamethoxazole as internal standard）， and the concentrations of 5 ingredients in plasma were determined by liquid chromatography-tandem mass spectrometry （LC-MS/MS）. The pharmacokinetic parameters of each ingredient were calculated using DAS 3.0 software. RESULTS After intragastric administration of Chitong xiaoyanling granules， tmax and t1/2 of formononetin were the shortest among 5 ingredients （0.25 h and 0.39 h， respectively）. For naringenin and enoxolone， the tmax was shorter， but t1/2 was longer， and there was an obvious double-peak phenomenon in the drug-time curve of naringenin. Compared with the other three components， cmax and AUC of paeoniflorin and hesperidin were not directly proportional to the content of in vitro components. CONCLUSIONS Formononetin， naringin and enoxolone in Chitong xiaoyanling granules were absorbed rapidly in rats， while paeoniflorin and hesperidin were absorbed slowly.
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Fatty acids(FAs),which were initially recognized as energy sources and essential building blocks of biomembranes,serve as the precursors of important signaling molecules.Tracing FA metabolism is essential to understanding the biochemical activity and role of FAs in physiological and pathological events.Inspired by the advances in click chemistry for protein enrichment,we herein established a click chemistry-based enrichment(CCBE)strategy for tracing the cellular metabolism of eicosapentaenoic acid(EPA,20:5 n-3)in neural cells.Terminal alkyne-labeled EPA(EPAA)used as a surrogate was incubated with N2a,mouse neuroblastoma cells,and alkyne-labeled metabolites(ALMs)were selectively captured by an azide-modified resin via a Cu(I)-catalyzed azide-alkyne cycloaddition reaction for enrichment.After removing unlabeled metabolites,ALMs containing a triazole moiety were cleaved from solid-phase resins and subjected to liquid chromatography mass spectrometry(LC-MS)analysis.The proposed CCBE strategy is highly selective for capturing and enriching alkyne-labeled metabolites from the complicated matrices.In addition,this method can overcome current detection limits by enhancing MS sensitivity of targets,improving the chromatographic separation of sn-position glycerophospholipid regioisomers,facilitating structural characterization of ALMs by a specific MS/MS fragmentation signature,and providing versatile fluorescence detection of ALMs for cellular distribution.This CCBE strategy might be expanded to trace the metabolism of other FAs,small molecules,or drugs.
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Objective To develop a simple and sensitive LC-MS/MS method for the determination of polymyxin B in human serum.Methods Polymyxin E2 was used as an internal standard and acetonitrile(0.1%formic acid)was used for protein precipitation.Chromatographic separation was performed on a Hypersil GOLDTM C18 column.Mobile phase A was 0.1%formic acid in water,and mobile phase B was methanol.The flow rate was 0.4 mL·min-1,with gradient elution.The column temperature was 40℃.The injection volume was 2 μL and the analysis time was 3.3 min.Multiple reaction monitoring and electrospray ion source positive ion mode were applied for quantitative analysis.The quantitative analysis ion pairs were m/z 402.10>101.10(polymyxin B1),m/z 397.45>101.10(polymyxin B2),m/z 578.50>101.10(polymyxin E2).Results The linear relationship of polymyxin B1 was at 22-15 000 ng·mL-1 and B2 was at 5-1 700 ng·mL-1 in human serum,which achieved excellent linearity,and the correlation coefficient was higher than 0.999 0.The lower limit of quantification of polymyxin B1 and B2 were 22 ng·mL-1 and 5 ng·mL-1,respectively.The accuracies were 95.98%-104.60%for polymyxin B1,98.11%-105.59%for polymyxin B2,respectively.The RSDs of intra-and inter-day precision were less than 15%.The recoveries of polymyxin B1 and B2 were 97.26%-103.31%and 95.81%-101.22%,respectively,and the matrix effects were 96.52%-109.54%and 93.29%-109.95%,respectively.The RSDs of the samples were all less than 15%.The mean AUC0-24h was(72.85±17.87)mg·h·L-1 in six patients.Conclusion The established LC-MS/MS method for determining polymyxin B in human serum meets the requirements of biological sample analysis.It is suitable for determining polymyxin B in human serum.
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Objective To establish an animal model of postmortem redistribution of amantadine,and to study its postmortem redistribution in rats,so as to provide experimental evidence for forensic identification.Methods One hundred and twenty-six male SD rats were randomly divided into 3 groups and subjected to intragastric administration according to the maximum dose of treatment(L),LD50(M)and 2LD50(H).Those who did not die were killed according to the average time of death of LD50.Heart-blood,peripheral blood,heart,liver,spleen,lung,kidney,brain,muscle and testis were collected at 0 h,6 h,12 h,24 h,48 h,72 h and 96 h after death,and amantadine content was detected.Results For the rats in the L group,the concentration of amantadine decreased within 6 h after death and then increased in the heart-blood,heart and liver,unchanged within 48 h and reached the peak at 96 h in the spleen,kidney,brain,muscle and testis,while decreased in the lung.For the rats in the M group,the concentration of amantadine decreased within 24 h after death and then increased in all samples,and it reached the peak at 48 h after death in the peripheral blood,spleen,kidney and muscle tissues,at 72 h after death in the heart-blood and testis,and at 96 h after death in the liver,lung and brain tissues.For the rats in the H group,the concentration of amantadine showed a downward trend within 12 h after death in the heart and liver tissue,showed a downward trend within 48 h after death in the lung,brain and muscle tissue,and reached the peak at 96 h after death in the heart,liver,spleen,muscle and testicle tissues.Conclusion The postmortem redistribution was found in amantadine poisoning dead rats,which could provide experimental evidence for the forensic identification of death cases caused by amantadine poisoning.
ABSTRACT
OBJECTIVES@#To establish a method for the detection of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS).@*METHODS@#The blood samples were treated with 1-butyl-3-methylimidazolium hexafluorophosphate as an extraction solvent. The samples were extracted by ultrasound-assisted extraction and separated by ZORBAX Eclipse Plus C18, 95Å column. The mobile phase A aqueous solution containing 0.1% formic acid and 10 mmol/L ammonium acetate, and mobile phase B mixed organic solvent containing acetonitrile/methanol (Vacetonitrile∶Vmethanol=2∶3) were used for gradient elution at the flow rate of 1.00 mL/min. An electrospray ion source in positive mode was used for detection in the multiple reaction monitoring.@*RESULTS@#The linearities of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples were good within the corresponding range, with correlation coefficients (r) greater than 0.995 6. The limits of detection were 3.00, 0.40 and 1.30 ng/mL, respectively. The limit of quantitation were 8.00, 1.00 and 5.00 ng/mL, respectively. The extraction recoveries ranged from 76.00% to 106.44%. The relative standard deviations of the intra-day and inter-day precisions were less than 16%. Carbamazepine and its main metabolite 10,11-dihydro-10,11-epoxycarbamazepine were detected in blood samples of death cases with a mass concentration of 2.71 μg/mL and 252.14 ng/mL, respectively.@*CONCLUSIONS@#This method has high sensitivity and good selectivity, which is suitable for the detection of carbamazepine and its metabolites in blood samples, and can be used for carbamazepine-related forensic identifications.