Search results for "Liquid Chromatography"

showing 10 items of 942 documents

Desarrollo de nuevas estrategias para el diseño de técnicas de cromatografía líquida miniaturizada en línea: nanopartículas, contaminación secundaria

2019

In recent years one of the most important trends in Analytical Chemistry has been the development of new analytical methodologies based on the miniaturization, simplification and automatization of the analytical process, in order to reduce the environmental impact of the analysis without compromising the sensitivity and selectivity. In this respect miniaturized liquid chromatography (LC) systems, such as capillary liquid chromatography (CapLC) and nanoliquid chromatography (NanoLC) are important achievements. These techniques are environmental friendly because the amount of material involved is limited and organic solvents, electricity and the wastes generated are lower than in conventional…

:QUÍMICA::Química analítica::Análisis cromatográfico [UNESCO]nanoparticlesUNESCO::QUÍMICA::Química analítica::Análisis cromatográficonano-liquid chromatographypolar pesticidescapillary liquid chromatographyin-tube solid-phase microextraction (IT-SPME)
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Polyoxypregnanes as safe, potent, and specific ABCB1-inhibitory pro-drugs to overcome multidrug resistance in cancer chemotherapy in vitro and in vivo

2021

Multidrug resistance (MDR) mediated by ATP binding cassette subfamily B member 1 (ABCB1) is significantly hindering effective cancer chemotherapy. However, currently, no ABCB1-inhibitory drugs have been approved to treat MDR cancer clinically, mainly due to the inhibitor specificity, toxicity, and drug interactions. Here, we reported that three polyoxypregnanes (POPs) as the most abundant constituents of Marsdenia tenacissima (M. tenacissima) were novel ABCB1-modulatory pro-drugs, which underwent intestinal microbiota-mediated biotransformation in vivo to generate active metabolites. The metabolites at non-toxic concentrations restored chemosensitivity in ABCB1-overexpressing cancer cells v…

ABCC1 ATP binding cassette subfamily C member 1IC50 half maximal inhibitory concentrationMultidrug resistancePharmacologyNADPH reduced nicotinamide adenine dinucleotide phosphateF bioavailabilitychemistry.chemical_compoundPCR polymerase chain reaction0302 clinical medicineMDR multidrug resistanceECL electrochemiluminescencet1/2 elimination half-lifeLC–MS liquid chromatography coupled with mass spectrometryN.D. not detectedGeneral Pharmacology Toxicology and PharmaceuticsBBB blood–brain barriermedia_commonATF3 activating transcription factor 30303 health sciencesChemistryABC ATP-binding cassetteNMPA National Medical Products AdministrationPXR pregnane X receptorSDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresisHBSS Hankʹs balanced salt solutionABCB1Combination chemotherapyProdrugMarsdenia tenacissimaCmax peak concentrationPaclitaxelGAPDH glyceraldehyde-3-phosphate dehydrogenase030220 oncology & carcinogenesisBHI brain heart infusionOriginal ArticleAUC0–∞ area under plasma concentration vs. time curveMRT mean residence timeDrugmedia_common.quotation_subjectRM1-950Vd volume of distributionABCB1 ATP binding cassette subfamily B member 1UIC-2 mouse monoclonal ABCB1 antibodyABCG2 ATP binding cassette subfamily G member 2Combination chemotherapyCYP cytochrome P450 isozymePI propidium iodideTEER transepithelial electrical resistance03 medical and health sciencesPBS phosphate buffer salineFBS fetal bovine serumDox doxorubicinIn vivoPOP polyoxypregnanemedicine030304 developmental biologyEVOM epithelial tissue voltohmmeterTmax time for peak concentrationCancerLBE lowest binding energyPE phycoerythrinmedicine.diseaseMultiple drug resistancePolyoxypregnanePapp apparent permeabilityN.A. not applicableCancer cellH&E hematoxylin and eosinMDR1a multidrug resistance protein 1aTherapeutics. PharmacologyqPCR quantitative PCRM. tenacissima Marsdenia tenacissimaCL clearanceSD standard derivationActa Pharmaceutica Sinica B
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Metabolic signatures across the full spectrum of non-alcoholic fatty liver disease.

2022

Funder: European Commission

ALTtype 2 diabetes mellitusROC receiving operator characteristicaspartate aminotransferaseHSDLDL low-density lipoproteinUHPLC ultrahigh-performance liquid chromatographyROCHCCNon-alcoholic steatohepatitisGCPCANASHGastroenterology2-HB 2-hydroxybutanoic acid; 3-HB 3-hydroxybutanoic acid; ALT alanine aminotransferase; AST aspartate aminotransferase; CE cholesterol ester; Cer ceramide; FFA free fatty acid; FLIP Fatty Liver Inhibition of Progression; Fibrosis; GC gas chromatography; HCC hepatocellular carcinoma; HSD honest significant difference; LC lipid cluster; LDL low-density lipoprotein; LM lipid and metabolite; LMC lipid metabolite and clinical variable; LPC lysophosphatidylcholine; Lipidomics; Mass spectrometry; Metabolomics; NAFL non-alcoholic fatty liver; NAFLD non-alcoholic fatty liver disease; NAS NASH activity score; NASH non-alcoholic steatohepatitis; NIDDK NASH-CRN National Institute of Digestive Diseases and Kidney NASH Clinical Research Network; NRR non-rejection rate; Non-alcoholic steatohepatitis; PC(O) ether PC; PC phosphatidylcholine; PCA principal component analysis; PE phosphatidylethanolamine; QTOFMS quadrupole-time-of-flight mass spectrometry; ROC receiving operator characteristic; SAF steatosis activity and fibrosis; SM sphingomyelin; T2DM type 2 diabetes mellitus; TG triacylglycerol; UHPLC ultrahigh-performance liquid chromatographySAFSAF steatosis activity and fibrosisLM lipid and metabolitehonest significant differenceHSD honest significant differenceTG triacylglycerolnon-rejection ratecholesterol esterPCPEGC gas chromatographyfree fatty acidFLIPNASH non-alcoholic steatohepatitisNIDDK NASH-CRN National Institute of Digestive Diseases and Kidney NASH Clinical Research NetworkBIOMARKERST2DMPE phosphatidylethanolamineLDLlipidNAFLDFFA free fatty acid2-HBMetabolomicsNAFL non-alcoholic fatty liverLMCphosphatidylcholineScience & TechnologySM sphingomyelinGastroenterology & HepatologyMass spectrometryactivitynutritional and metabolic diseasesT2DM type 2 diabetes mellitusACIDSreceiving operator characteristicdigestive system diseasesquadrupole-time-of-flight mass spectrometryLC lipid clusterlow-density lipoproteinNAS2-HB 2-hydroxybutanoic acidNAS NASH activity scoreQTOFMSether PCNRRSCORING SYSTEMprincipal component analysisgas chromatographyLC2-hydroxybutanoic acidPROGRESSIONAST aspartate aminotransferaseLMPC phosphatidylcholinePC(O)MARKERSUHPLCsteatosisTOOLImmunology and AllergyINSULIN-RESISTANCECerSMFatty Liver Inhibition of Progressionhepatocellular carcinoma2-HB 2-hydroxybutanoic acid NIDDK NASH-CRN National Institute of Digestive Diseases and Kidney NASH Clinical Research Network NRR non-rejection rate Non-alcoholic steatohepatitis PC(O) ether PC PC phosphatidylcholine PCA principal component analysis PE phosphatidylethanolamine QTOFMS quadrupole-time-of-flight mass spectrometry ROC receiving operator characteristic SAF steatosis activity and fibrosis SM T2DM type 2 diabetes mellitus TG triacylglycerol UHPLC ultrahigh-performance liquid chromatographyultrahigh-performance liquid chromatographyCELPC3-HBNAFLnon-alcoholic fatty liverTGtriacylglycerolNRR non-rejection rateLife Sciences & BiomedicineNAFLD non-alcoholic fatty liver diseaseFLIP Fatty Liver Inhibition of Progressionalanine aminotransferasemetaboliteCer ceramideCE cholesterol estersphingomyelinlysophosphatidylcholineand fibrosisALT alanine aminotransferaseInternal MedicineceramideNational Institute of Digestive Diseases and Kidney NASH Clinical Research NetworkAST3-HB 3-hydroxybutanoic acidQTOFMS quadrupole-time-of-flight mass spectrometryPCA principal component analysisLPC lysophosphatidylcholineHepatologynon-alcoholic fatty liver diseaseand clinical variablePC(O) ether PC3-hydroxybutanoic acidFibrosisNASH activity scoreNIDDK NASH-CRNlipid clusterlipid and metabolitephosphatidylethanolamineLipidomicsLMC lipid metabolite and clinical variableFFAHCC hepatocellular carcinomaJHEP reports : innovation in hepatology
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Analysis of emerging and related pollutants in aquatic biota

2020

Water bodies cover approximately 70 % of the earth s surface, making them ecosystems with a high environmental value and the habitat for numerous species of flora and fauna. Emerging pollutants (EPs) are ubiquitous anthropogenic compounds of environmental concern that can be found at different concentration levels in matrices such as sediment, water and aquatic biota. In addition, EPs can be bioaccumulated and biomagnified, inducing adverse effects on biota, and posing a risk to humans when contaminated biota is consumed. Unlike abiotic matrices, the occurrence of EPs in aquatic biota has not been widely studied. This is probably because their complexity, due to the presence of lipids, prot…

Abiotic componentPollutantAquatic biotaGas chromatographySpectrometryFauna010401 analytical chemistryLiquid chromatographyMethodologySedimentBiotaExtraction010501 environmental sciencesAquatic biota01 natural sciences0104 chemical sciencesAnalytical ChemistryLipids removalHabitatEnvironmental chemistryEnvironmental ChemistryEnvironmental scienceEcosystem0105 earth and related environmental sciences
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Isocratic and gradient elution in micellar liquid chromatography with Brij-35

2015

Polyoxyethylene(23)lauryl ether (known as Brij-35) is a nonionic surfactant, which has been considered as an alternative to the extensively used in micellar liquid chromatography anionic surfactant sodium lauryl (dodecyl) sulfate, for the analysis of drugs and other types of compounds. Brij-35 is the most suitable nonionic surfactant for micellar liquid chromatography, owing to its commercial availability, low cost, low toxicity, high cloud temperature, and low background absorbance. However, it has had minor use. In this work, we gather and discuss some results obtained in our laboratory with several β-blockers, sulfonamides, and flavonoids, concerning the use of Brij-35 as mobile phase mo…

Absorbancechemistry.chemical_compoundChromatographyAqueous solutionPulmonary surfactantchemistryMicellar liquid chromatographyPhase (matter)Filtration and SeparationEtherAcetonitrileMicellar electrokinetic chromatographyAnalytical ChemistryJournal of Separation Science
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Micellar liquid chromatography for prediction of drug transport.

2000

Abstract The vast majority of well absorbed drugs are transported passively across the cell membranes. Physicochemical descriptors of drug molecules that are believed to influence transcellular transport are routinely used to predict drug absorption by means of complex mathematical models. In this paper, a new in vitro method, based on the retention data in micellar liquid chromatography (MLC), is validated for the prediction of passive drug absorption. The retention of a heterogeneous drugs set in MLC using Brij 35 as surfactant in the mobile phase is compared with the retention data reported in literature obtained in red cell membrane lipid liposomes, human red cell membranes vesicles (ve…

Absorption (pharmacology)LiposomeChromatographyChemistryVesicleOrganic ChemistryCell MembraneAdministration OralGeneral MedicineBiochemistryHigh-performance liquid chromatographyAnalytical ChemistryMembranePulmonary surfactantMicellar liquid chromatographyParacellular transportHumansPharmacokineticsSpectrophotometry UltravioletMicellesChromatography LiquidJournal of chromatography. A
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Quantitative evaluation of the phenolic profile in fruits of six avocado (Persea americana) cultivars by ultra-high-performance liquid chromatography…

2016

The phenolic profiles of six varieties of avocado (Persea americana) grown in Sicily were investigated. The ultra-high-performance liquid chromatography-heated electrospray-mass spectrometry method was developed to determine qualitative and quantitative changes in fruits at two different ripening stage. Nineteen individual phenolic compounds were detected in avocado pulp extracts. Gallic acid, sinapinic acid, vanillin, p-coumaric acid, and gentisic acid were present only in ripe fruits. On the contrary, epicatechin decreased with fruit ripening, whereas protocatechuic acid, 4-hydroxybenzoic acid, chlorogenic acid, and benzoic acid were relatively stable or exhibited erratic changes with fru…

Accurate mass; Fruit ripening; High-resolution mass spectrometry; LDA; Persea americana; Phenolic compounds; Ultra-high-performance liquid chromatography; Food SciencePerseaHigh-resolution mass spectrometrySettore CHIM/10 - Chimica Degli AlimentiLDAPhenolic compoundSinapinic acid01 natural sciencesProtocatechuic acidchemistry.chemical_compound0404 agricultural biotechnologyChlorogenic acidBotanySettore CHIM/01 - Chimica AnaliticaGallic acidFood scienceGentisic acidAccurate mabiologyVanillin010401 analytical chemistryfood and beveragesRipening04 agricultural and veterinary sciencesbiology.organism_classificationFruit ripening040401 food scienceSettore CHIM/08 - Chimica Farmaceutica0104 chemical sciencesSettore AGR/03 - Arboricoltura Generale E Coltivazioni ArboreechemistryPersea americanaUltra-high-performance liquid chromatographyPhenolic compounds; Persea americana; Accurate mass; Ultra-high-performance liquid chromatography; High-resolution mass spectrometry; LDA; Fruit ripeningFood Science
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Isocratic high-performance liquid chromatographic determination of tryptophan in infant formulas.

1996

The application to infant formulas of a method for tryptophan determination by isocratic HPLC with UV detection at 254 nm, after derivatization with phenyl isothiocyanate, was studied. Protein was hydrolysed by barium hydroxide at 120 degrees C for 8 h, followed by derivatization with phenyl isothiocyanate, HPLC and UV detection at 254 nm. The optimum chromatographic conditions (pH, ionic strength of elution solvent and eluent ratio) were established. The analytical parameters (linearity, precision, accuracy of derivatization and limits of detection and quantification) were determined. The values obtained demonstrated that the method is useful for determining the tryptophan content of infan…

AcetatesBiochemistryHigh-performance liquid chromatographySensitivity and SpecificityAnalytical ChemistryBarium hydroxidechemistry.chemical_compoundColumn chromatographyIsothiocyanatesHumansDerivatizationChromatography High Pressure LiquidAcetic AcidDetection limitChromatographyPhenyl isothiocyanateElutionOrganic ChemistryOsmolar ConcentrationTryptophanInfant NewbornTryptophanInfantGeneral MedicineHydrogen-Ion ConcentrationchemistrySolventsInfant FoodThiocyanatesJournal of chromatography. A
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Performance of different C18 columns in reversed-phase liquid chromatography with hydro-organic and micellar-organic mobile phases

2014

Column selection in reversed-phase liquid chromatography (RPLC) can become a challenge if the target compounds interact with the silica-based packing. One of such interactions is the attraction of cationic solutes to the free silanols in silica-based columns, which is a slow sorption-desorption interaction process that gives rise to tailed and broad peaks. The effect of silanols is minimised by the addition of a competing agent in the mobile phase, such as the anionic surfactant sodium dodecyl sulphate (SDS). In micellar-organic RPLC, the adsorption of an approximately fixed amount of SDS monomers gives rise to a stable modified stationary phase, with properties remarkably different from th…

AcetonitrilesAdrenergic beta-AntagonistsBiochemistryAnalytical ChemistrySurface-Active AgentsAdsorptionPulmonary surfactantPhenolsPhase (matter)Sodium dodecyl sulphateAcetonitrileMicellesChromatography Reverse-PhaseChromatographyElutionChemistryOrganic ChemistryCationic polymerizationC18 columnsSodium Dodecyl SulfateWaterGeneral MedicineReversed-phase chromatographySilanesMicellar liquid chromatographyβ-BlockersAdsorptionSelectivityMicellar liquid chromatography
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Comparative study of solvation parameter models accounting the effects of mobile phase composition in reversed-phase liquid chromatography

2007

Solvation parameter models relate linearly compound properties with five fundamental solute descriptors (excess molar refraction, dipolarity/polarizability, effective hydrogen-bond acidity and basicity, and McGowan volume). These models are widely used, due to the availability of protocols to obtain the descriptors, good performance, and general applicability. Several approaches to predict retention in reversed-phase liquid chromatography (RPLC) as a function of these descriptors and mobile phase composition are compared, assaying the performance with a set of 146 organic compounds of diverse nature, eluted with acetonitrile and methanol. The approaches are classified in two groups: those t…

AcetonitrilesChromatographyChemistryElutionMethanolOrganic ChemistryAnalytical chemistrySolvationGeneral MedicineReversed-phase chromatographyModels TheoreticalBiochemistryHigh-performance liquid chromatographyAnalytical ChemistrySolventchemistry.chemical_compoundPolarizabilityPhase (matter)SolventsAcetonitrileChromatography LiquidJournal of Chromatography A
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