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991.
Biodistribution study of free and microencapsulated 6‐methylcoumarin in Wistar rats by HPLC 下载免费PDF全文
Aura Rocío Hernández Luis Fernando Ospina Diana Marcela Aragón 《Biomedical chromatography : BMC》2015,29(2):176-181
A sensitive, specific and reproducible HPLC method has been developed and validated for the quantitative determination of 6‐methylcoumarin (6MC) in plasma and other tissues in Wistar rats. A C18 column was used with UV detection at 321 nm and a gradient system consisting of methanol‐deionized water was used as mobile phase. The retention time for 6MC was 14.921 min and no interfering peaks were observed for any of the matrices. Linear relationships (r2 > 0.997) were obtained between the peak height ratios and the corresponding biological sample concentrations over the range 0.4–12.8 µg/mL. Precision and accuracy were evaluated; the coefficient of variation and the relative error for all of the organs were <2 and 7%, respectively. The limit of quantitation was 0.20 µg/mL for the heart and 0.30 µg/mL for the other tissues evaluated. This HPLC method was successfully used in the determination of 6MC in the biodistribution study after administration of 200 mg/kg of both 6MC‐free and 6MC‐loaded polymeric microparticles. In this study, extensive 6MC was found, in both free and microencapsulated forms, in all the organs tested. The 6MC‐free showed a range of between 1.7 and 11.5 µg/g, while the microencapsulated 6MC showed concentrations of between 6.35 and 17.7 µg/g, suggesting that 6MC improved absorption rate. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
992.
Eun Joung Choi Eunha Kim Youngjun Lee Ala Jo Seung Bum Park 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(5):1370-1374
Fluorescence imaging enables the uniquely sensitive observation of functional‐ and molecular‐recognition events in living cells. However, only a limited range of biological processes have been subjected to imaging because of the lack of a design strategy and difficulties in the synthesis of biosensors. Herein, we report a facile synthesis of emission‐tunable and predictable Seoul‐Fluors, 9‐aryl‐1,2‐dihydrolopyrrolo[3,4‐b]indolizin‐3‐ones, with various R1 and R2 substituents by coinage‐metal‐catalyzed intramolecular 1,3‐dipolar cycloaddition and subsequent palladium‐mediated C H activation. We also showed that the quantum yields of Seoul‐Fluors are controlled by the electronic nature of the substituents, which influences the extent of photoinduced electron transfer. On the basis of this understanding, we demonstrated our design strategy by the development of a Seoul‐Fluor‐based chemosensor 20 for reactive oxygen species that was not accessible by a previous synthetic route. 相似文献
993.
A three-phase liquid-phase microextraction (LPME) method using porous polypropylene hollow fibre membrane with a sealed end was developed for the extraction of mirtazapine (MRT) and its two major metabolites, 8-hydroxymirtazapine (8-OHM) and demethylmirtazapine (DMR), from human plasma. The analytes were extracted from 1.0 mL of plasma, previously diluted and alkalinized with 3.0 mL 0.5 mol L−1 pH 8 phosphate buffer solution and supplemented with 15% sodium chloride (NaCl), using n-hexyl ether as organic solvent and 0.01 moL L−1 acetic acid solution as the acceptor phase. Haloperidol was used as internal standard. The chromatographic analyses were carried out on a chiral column, using acetonitrile-methanol-ethanol (98:1:1, v/v/v) plus 0.2% diethylamine as mobile phase, at a flow rate of 1.0 mL min−1. Multi-reaction monitoring (MRM) detection was performed by mass spectrometry (MS-MS) using a triple-stage quadrupole and electrospray ionization interface operating in the positive ion mode. The mean recoveries were in 18.3-45.5% range with linear responses over the 1.25-125 ng mL−1 concentration range for all enantiomers evaluated. The quantification limit (LOQ) was 1.25 ng mL−1. Within-day and between-day assay precision and accuracy (2.5, 50 and 100 ng mL−1) showed relative standard deviation and the relative error lower than 11.9% for all enantiomers evaluated. Finally, the method was successfully used for the determination of mirtazapine and its metabolite enantiomers in plasma samples obtained after single drug administration of mirtazapine to a healthy volunteer. 相似文献
994.
The air quality in the Aragón valley, in the central Pyrenees, has been assessed by evaluation of lichen biodiversity and
mapped by elaboration of the Index of Air Purity (IAP) based on observations of the presence and abundance of eight kinds
of lichen with different sensitivity to air pollution. The IAP values obtained have been compared with quantitative analytical
measures of 16 PAHs in the lichen Evernia prunastri, because this species was associated with a wide range of traffic exposure and levels of urbanization. Analyses of PAHs were
carried out by the DSASE method followed by an SPE clean-up step and GC–MS analysis. The concentration of total PAHs found
in lichen samples from the Aragón valley ranged from 692 to 6420 ng g−1 and the PAHs profile showed predominance of compounds with three aromatic rings. The influence of the road traffic in the
area has been shown because values over the median concentration of PAHs (>1092 ng g−1), percentage of combustion PAHs (>50%), and equivalent toxicity (>169) were found in lichens collected at places exposed
to the influence of traffic. The combination of both methods suggests IAP as a general method for evaluating the air pollution
referenced to PAHs because it can be correlated with the content of combustion PAHs and poor lichen biodiversity can be partly
explained by the air pollution caused by specific PAHs.
Figure Map of the air pollution level in the Aragón valley (Pyrenees) based on the Index of Air Purity (IAP) calculation (lichen
biodiversity) 相似文献
995.
Hak-Ju Lee Sin Young Park Oh-Kyu Lee Hyun-Jin Jo Ha-Young Kang Don-Ha Choi Ki-Hyon Paik M. Khan 《Chemistry of Natural Compounds》2008,44(4):435-439
Two benzofurans (1, 2) along with five known compounds (3.7) were isolated from the seeds of S. obassia. Their structures
were elucidated as methyl 3-[7-methoxy-2-(3′,4′-methylenedioxyphenyl)-5-benzofuranyl]-propionate (1), methyl 3-[2-(3′,4′-methylenedioxyphenyl)-5-benzofuranyl]-propionate
(2), egonol (3), egonolacetate (4), egonol-2-methylbutanoate (5), 7-demethoxyegonol-2-methylbutanoate (6), and stigmasterol
(7) on the basis of their comprehensive spectroscopic analysis including 2D NMR data. Compounds 1, 2 are obtained for the
first time from nature, while this is the first record of compound 7 from the Styrax species.
Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 350-353, July-August, 2008. Original article submitted May 4, 2007. 相似文献
996.
Pereira CF Pimentel MF Galvão RK Honorato FA Stragevitch L Martins MN 《Analytica chimica acta》2008,611(1):41-47
This work presents a comparative study of calibration transfer among three near infrared spectrometers for determination of naphthenes and RON (Research Octane Number) in gasoline. Seven transfer methods are compared: direct standardization (DS), piecewise direct standardization (PDS), orthogonal signal correction (OSC), reverse standardization (RS), piecewise reverse standardization (PRS), slope and bias correction (SBC) and model updating (MU). Two pre-treatment procedures, namely standard normal variate (SNV) and multiplicative scatter correction (MSC), are also investigated. The choice of an appropriate number of transfer samples for each technique, as well as the effect of window size in PDS/PRS and OSC components, are discussed. A broad set of gasoline samples representative of the Northeastern states of Brazil is employed in the investigation. The results show that the use of calibration transfer yields prediction errors comparable to those obtained with complete recalibration of the secondary instrument. Overall, the results point to RS as the best method for the analytical problem under consideration. When storage and/or physical transportation of transfer samples are impractical, MU is more appropriate. The comprehensive investigation carried out in the present work will be of value for practitioners involved in networks of fuel monitoring. 相似文献
997.
Sikorska E Gliszczyńska-Swigło A Insińska-Rak M Khmelinskii I De Keukeleire D Sikorski M 《Analytica chimica acta》2008,613(2):207-217
The study demonstrates an application of the front-face fluorescence spectroscopy combined with multivariate regression methods to the analysis of fluorescent beer components. Partial least-squares regressions (PLS1, PLS2, and N-way PLS) were utilized to develop calibration models between synchronous fluorescence spectra and excitation-emission matrices of beers, on one hand, and analytical concentrations of riboflavin and aromatic amino acids, on the other hand. The best results were obtained in the analysis of excitation-emission matrices using the N-way PLS2 method. The respective correlation coefficients, and the values of the root mean-square error of cross-validation (RMSECV), expressed as percentages of the respective mean analytic concentrations, were: 0.963 and 14% for riboflavin, 0.974 and 4% for tryptophan, 0.980 and 4% for tyrosine, and 0.982 and 19% for phenylalanine. 相似文献
998.
Javier A. Cabeza Ignacio del Río Enrique Pérez-Carreño 《Journal of organometallic chemistry》2008,693(1):97-102
The cluster [Ru3(μ3-κ2-HNNMe2)(μ-κ2-PhCHCPh)(μ-CO)2(CO)6], which has a face-capping 1,1-dimethylhydrazido and an edge-bridging 1,2-diphenylethenyl ligand, reacts with diphenylbutadiyne or 2,4-hexadiyne to give the isomeric triruthenium carbonyl cluster complexes [Ru3(μ3-κ2-HNNMe2)(μ-κ2-PhCHCPh){μ3-κ4-RCCCC(R)C(R)CCCR}(CO)6] (3a, R = Ph; 3b, R = Me) and [Ru3(μ3-κ2-HNNMe2)(μ-κ2-PhCHCPh){μ3-κ4-RCCCC(R)C(CCR)CR}(CO)6] (4a, R = Ph; 4b, R = Me). These compounds contain a large unsaturated hydrocarbyl ligand that arises from a metal-cluster-mediated head-to-head (3) or head-to-tail (4) coupling of two diyne molecules and maintain the original hydrazido and ethenyl ligands. Metal clusters that contain a face-capping diyne coordinated through only one alkyne fragment, such as [Ru3(μ3-κ2-HNNMe2)(μ-κ2-PhCHCPh)(μ3-κ2-RCCCCR)(CO)7], have also been isolated (2a, R = Ph; 2b, R = Me). They are the intermediates that incorporate a second diyne reagent to give 3 and 4. The structural parameters of intermediate 2b have been obtained from DFT calculations. 相似文献
999.
?eljko Petrovski Susana S. Braga Márcia L. Matos Martyn Pillinger Carlos C. Romão 《Journal of organometallic chemistry》2008,693(4):675-684
Seven different ferrocene derivatives have been tested in vitro against Ehrlich ascites tumor cells. Neither ferrocene nor the monosubstituted derivative N,N-dimethylaminomethylferrocene showed cytotoxic activity (IC50 > 1000 μM for 3 h treatments). Better results were obtained with 1,2-disubstituted derivatives. The IC50 values ranged from 376.6 μM for 1,2-diformylferrocene to 71.2 μM for racemic 2-(N,N-dimethylaminomethyl)ferrocenecarboxamide. The latter derivative was also encapsulated in native β-cyclodextrin (CD), heptakis-2,3,6-tri-O-methyl-β-CD (TRIMEB) and 2-hydroxypropyl-β-CD (HPβCD) to give 1:1 (host:guest) inclusion compounds. The existence of true inclusion complexes in the solid state was confirmed by a combination of powder X-ray diffraction, thermogravimetric analysis, FTIR and 13C CP MAS NMR spectroscopy. The IC50 value for the β-CD inclusion compound was identical to that obtained for the nonincluded ferrocene derivative. By contrast, the inclusion compounds comprising TRIMEB and HPβCD yielded IC50 values of 25.2 and 20.0 μM, respectively. No obvious relationship could be established between the redox behavior of the compounds determined by cyclic voltammetry and the biochemical data. 相似文献
1000.
Miraç Ocak Nurhan Gümrükçüoğlu Ümmühan Ocak Hans-Jurgen Buschmann Eckard Schollmeyer 《Journal of solution chemistry》2008,37(11):1489-1497
Six new triazole compounds were synthesized. These compounds containing the substituted benzylidenamino group were obtained
by reaction of 3-(pyridine-4-yl)-5-p-tolyl-4-amino-4H-l,2,4-triazole 1 with the corresponding aldehyde. The reduced forms were prepared with NaBH4 in methanol. The structures of the compounds were determined by IR, 1H NMR, and 13C NMR spectral data, and their interaction with cations such as Li+, Na+, K+, Rb+, Cs+, Ba2+, Sr2+, Ca2+, Cu2+, Cr3+, Co2+, Ni2+, Zn2+, Cd2+, Pb2+ and Ag+ were investigated by using UV-visible spectrophotometry. Of the tested metal cations, Cu2+, Cr3+, Co2+, Ni2+, Zn2+, Cd2+, Pb2+ and Ag+ complexed with the ligands. The complex stability constants (log 10
K) were measured in slightly acidic aqueous media at 25.0±0.1 °C. These stability constants were determined by measuring the
increase in solubility of the nearly insoluble ligand molecule due to complex formation with a soluble cation, and this method
is discussed. It was found that the position of chlorine atoms on the benzene ring strongly affects the complexation of Cu2+ ion with these ligands. 相似文献