WorldWideScience

Sample records for gel permeation chromatography

  1. Extraction of cocoa proanthocyanidins and their fractionation by sequential centrifugal partition chromatography and gel permeation chromatography.

    Science.gov (United States)

    Pedan, Vasilisa; Fischer, Norbert; Rohn, Sascha

    2016-08-01

    Cocoa beans contain secondary metabolites ranging from simple alkaloids to complex polyphenols with most of them believed to possess significant health benefits. The increasing interest in these health effects has prompted the need to develop techniques for their extraction, fractionation, separation, and analysis. This work provides an update on analytical procedures with a focus on establishing a gentle extraction technique. Cocoa beans were finely ground to an average particle size of centrifugal partition chromatography (SCPC) and gel permeation column chromatography using Sephadex LH-20. For SCPC, a two-phase solvent system consisting of ethyl acetate/n-butanol/water (4:1:5, v/v/v) was successfully applied for the separation of theobromine, caffeine, and representatives of the two main phenolic compound classes flavan-3-ols and flavonols. Gel permeation chromatography on Sephadex LH-20 using a stepwise elution sequence with aqueous acetone has been shown for effectively separating individual flavan-3-ols. Separation was obtained for (-)-epicatechin, proanthocyanidin dimer B2, trimer C1, and tetramer cinnamtannin A2. The purity of alkaloids and phenolic compounds was determined by HPLC analysis and their chemical identity was confirmed by mass spectrometry.

  2. Characterization of poly(D,L-lactic acid) by gel permeation chromatography

    NARCIS (Netherlands)

    Dijk, van J.A.P.P.; Smit, J.A.M.; Kohn, F.E.; Feijen, J.

    1983-01-01

    A number of samples of poly(D,L-lactic acid) (PLA) with weight-average molecular weights Ṁw in the range 15,000-350,000 were prepared by a ring-opening polymerization. The molecular weight distributions (MWDs) of these samples were determined by gel permeation chromatography (GPC). The method involv

  3. Analysis of lipoprotein profiles of healthy cats by gel-permeation high-performance liquid chromatography.

    Science.gov (United States)

    Mizutani, Hisashi; Sako, Toshinori; Okuda, Hiroko; Arai, Nobuaki; Kuriyama, Koji; Mori, Akihiro; Yoshimura, Itaru; Koyama, Hidekazu

    2016-09-01

    Density gradient ultracentrifugation (DGUC) and gel electrophoresis are conventionally used to obtain lipoprotein profiles of animals. We recently applied high-performance liquid chromatography with a gel permeation column (GP-HPLC) and an on-line dual enzymatic system to dogs for lipoprotein profile analysis. We compared the GP-HPLC with DGUC as a method to obtain a feline lipoprotein profile. The lipoprotein profiles showed large and small peaks, which corresponded to high-density lipoprotein (HDL) and low-density lipoprotein (LDL), respectively, whereas very low-density lipoprotein (VLDL) and chylomicron (CM) were only marginally detected. This profile was very similar to that of dogs reported previously. Healthy cats also had a small amount of cholesterol-rich particles distinct from the normal LDL or HDL profile. There was no difference in lipoprotein profiles between the sexes, but males had a significantly larger LDL particle size (P=0.015). This study shows the feasibility of GP-HPLC for obtaining accurate lipoprotein profiles with small sample volumes and provides valuable reference data for healthy cats that should facilitate diagnoses.

  4. AN ALTERNATIVE ROUTE TO PRODUCE STANDARDS FOR GEL PERMEATION CHROMATOGRAPHY USING NITROXIDE MEDIATED POLYMERIZATION

    Directory of Open Access Journals (Sweden)

    C. P. R. Malere

    Full Text Available Abstract All over the world standards for Gel Permeation Chromatography (GPC are produced using ionic polymerization. Standards are commercialized in a broad range of molecular weight and their dispersity (Ð must be lower than 1.1. This work proposes the synthesis of polystyrene standards using Nitroxide Mediated Polymerization (NMP, an alternative technique to produce controlled polymers that is much more robust when compared to ionic polymerization. Standards with different ranges of molecular weights were obtained, all of them with very narrow molecular weight distribution (MWD and dispersity (Ð lower than 1.10. In order to do that, several combinations of different initiators were tested. Advanced GPC Triple Detector was used to obtain important properties, such as absolute number and weight average molecular weights, dispersity and intrinsic viscosity. The analytical method used in the characterization of the samples was in-house validated in terms of linearity, accuracy, precision, repeatability and robustness. The validation study demonstrated the quality of the measurements and ensured that the information obtained for a given analyte by the GPC technique is reliable.

  5. Molecular weight distributions of industrially-produced poly-(epsilon-caprolactams) by gel permeation chromatography.

    Science.gov (United States)

    Mateos, Elena; Cebolla, Vicente L; Membrado, Luis; Piera, Elena; Caballero, Miguel A

    2007-09-01

    Gel permeation chromatography with differential refractometry is used to obtain molecular weight distributions (MWD) of poly-(epsilon-caprolactams). Elution is carried out using an m-cresolchlorobenzene mixture (50:50, v/v) at 50 degrees C. MW values are obtained by a Hamielec-based calibration method, using broad-MWD poly-(epsilon-caprolactam) standards with the same chemical nature and similar MWD to the samples. Relative errors for the number-average MW (Mn) using this calibration method range from 0.4% (in the low polyamide MW range) to 20% (in the high polyamide MW range). These values are much lower than those obtained from narrow-MWD polystyrene calibration, which range from 39% to 78%. Similar values have been obtained for the other usual average MW parameters. The ability to obtain repeatability parameters for a given confidence interval and the utilization of statistical criteria for chromatogram rejection allow this method to be used in quality control for MWD of poly-(epsilon-caprolactams). Thus, production variables are related to polyamide-6 behavior in its ulterior treatment. Typical relative standard deviation percentages (for n=6) of a polyamide sample range from 1.9% (for Mn) to 3.3% (for M(z+1)).

  6. Simultaneous determination of seven anticoagulant rodenticides in agricultural products by gel permeation chromatography and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Saito-Shida, Shizuka; Nemoto, Satoru; Matsuda, Rieko; Akiyama, Hiroshi

    2016-11-01

    A sensitive and reliable method for the simultaneous determination of hydroxycoumarin-type (brodifacoum, bromadiolone, coumatetralyl, and warfarin) and indandione-type (chlorophacinone, diphacinone, and pindone) rodenticides in agricultural products by gel permeation chromatography (GPC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The procedure involved extraction of the rodenticides from samples with acetone, followed by liquid-liquid partitioning with hexane/ethyl acetate (1:1, v/v) and 10% sodium chloride aqueous solution, then cleanup using GPC, and finally, analysis using LC-MS/MS. High recoveries from the GPC column were obtained for all rodenticides tested using a mobile phase of acetone/cyclohexane/triethylamine (400:1600:1, v/v/v). An ODS column, which contains low levels of metal impurities, gave satisfactory peak shapes for both hydroxycoumarin- and indandione-type rodenticides in the LC-MS/MS separation. The average recoveries of rodenticides from eight agricultural foods (apple, eggplant, cabbage, orange, potato, tomato, brown rice, and soybean) fortified at 0.0005-0.001 mg/kg ranged from 76 to 116%, except for bromadiolone in orange (53%) and diphacinone in soybean (54%), and the relative standard deviations ranged from 1 to 16%. The proposed method effectively removed interfering components, such as pigments and lipids, and showed high selectivity. In addition, the matrix effects were negligible for most of the rodenticide/food combinations. The results suggest that the proposed method is reliable and suitable for determining hydroxycoumarin- and indandione-type rodenticides in agricultural products.

  7. Analysis of polycyclic aromatic hydrocarbons in vegetable oils combining gel permeation chromatography with solid-phase extraction clean-up

    DEFF Research Database (Denmark)

    Fromberg, Arvid; Højgård, A.; Duedahl-Olesen, Lene

    2007-01-01

    of benzo[a]pyrene levels in foods laid down by the Commission of the European Communities. A survey of 69 vegetable oils sampled from the Danish market included olive oil as well as other vegetable oils such as rapeseed oil, sunflower oil, grape seed oil and sesame oil. Levels of benzo[a]pyrene in all......A semi-automatic method for the determination of polycyclic aromatic hydrocarbons (PAHs) in edible oils using a combined gel permeation chromatography/solid-phase extraction (GPC/SPE) clean-up is presented. The method takes advantage of automatic injections using a Gilson ASPEC XL sample handling...... system equipped with a GPC column (S-X3) and pre-packed silica SPE columns for the subsequent clean-up and finally gas chromatography-mass spectrometry (GC-MS) determination. The method was validated for the determination of PAHs in vegetable oils and it can meet the criteria for the official control...

  8. Selective modification of polylactide by introducing acrylate groups: IR spectroscopy, gel permeation chromatography, and differential thermal analysis

    Science.gov (United States)

    Shashkova, V. T.; Matveeva, I. A.; Glagolev, N. N.; Zarkhina, T. S.; Timashev, P. S.; Bagratashvili, V. N.; Solov'eva, A. B.

    2016-10-01

    One-stage modification of polylactide has been performed to obtain the acrylate derivatives of the polymer capable of further polymerization and preparation of cross-linked polymer materials suitable for creating implants. The reaction mechanism was determined by IR spectroscopy, gel permeation chromatography, and differential thermal analysis. It was shown for the first time that the reaction path changes depending on the ratio of components so that the desired product polylactide acrylate forms with a ~90% yield only in the presence of large (approximately tenfold) excesses of the isocyanate and acrylate components; at the equimolar ratio of components generally used in urethane formation, a mixture of the desired product (~30%), oligourethane diacrylates, and unchanged polylactide forms.

  9. [Determination of phthalate plasticizers in foods by high performance liquid chromatography with gel permeation chromatographic clean-up].

    Science.gov (United States)

    Zhang, Chunyu; Wang, Hui; Zhang, Xiaohui; Ma, Zhongqiang; Deng, Wanmei; Hu, Ke; Ding, Mingyu

    2011-12-01

    A method of gel permeation chromatography-high performance liquid chromatography (GPC-HPLC) was established for the simultaneous determination of 5 main phthalate plasticizers in foods (edible oil, instant noodles, fried pastries, Saqima, etc.). The samples were extracted with petroleum ether in an ultrasonator, purified by a GPC column, and analyzed by HPLC. The chromatographic separation was achieved on a Labtech-C18 column (250 mm x 4.6 mm, 5 microm) using acetonitrile and water mixture as the mobile phases in a gradient elution mode. The developed method exhibited a linear correlation coefficient of more than 0.997 and the detection limits of 3.25 - 13.4 microg/L. The spike recoveries were between 70.4% and 113.6% with the relative standard deviations (RSDs, n = 3) of 0.3% - 5.8% at the spiked level of 50 mg/L. This method is simple, rapid and practical, and can be used for the simultaneous determination of PAEs in grease food samples.

  10. Simultaneous enantioselective determination of triadimefon and its metabolite triadimenol in edible vegetable oil by gel permeation chromatography and ultraperformance convergence chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Yao, Zhoulin; Li, Xiaoge; Miao, Yelong; Lin, Mei; Xu, Mingfei; Wang, Qiang; Zhang, Hu

    2015-11-01

    A novel, sensitive, and efficient enantioselective method for the determination of triadimefon and its metabolite triadimenol in edible vegetable oil, was developed by gel permeation chromatography and ultraperformance convergence chromatography/tandem triple quadrupole mass spectrometry. After the vegetable oil samples were prepared using gel permeation chromatography, the eluent was collected, evaporated, and dried with nitrogen gas. The residue was redissolved by adding methanol up to a final volume of 1 mL. The analytes of six enantiomers were analyzed on Chiralpak IA-3 column (150 × 4.6 mm) using compressed liquid CO2-mixed 14 % co-solvents, comprising methanol/acetonitrile/isopropanol = 20/20/60 (v/v/v) in the mobile phase at 30 °C, and the total separation time was less than 4 min at a flow rate of 2 mL/min. Quantification was achieved using matrix-matched standard calibration curves. The overall mean recoveries for six enantiomers from vegetable oil were 90.1-97.3 %, with relative standard deviations of 0.8-5.4 % intra-day and 2.3-5.0 % inter-day at 0.5, 5, and 50 μg/kg levels. The limits of quantification were 0.5 μg/kg for all enantiomers based on five replicate extractions at the lowest fortified level in vegetable oil. Moreover, the absolute configuration of six enantiomers had been determined based on comparisons of the vibrational circular dichroism experimental spectra with the theoretical curve obtained by density functional theory calculations. Application of the proposed method to the 40 authentic vegetable oil samples from local markets suggests its potential use in enantioselective determination of triadimefon and triadimenol enantiomers. Graphical Abstract Chemical structures and UPC(2)-MS/MS separation chromatograms of triadimefon and triadimenol.

  11. Characterization and quantitation of polyolefin microplastics in personal-care products using high-temperature gel-permeation chromatography.

    Science.gov (United States)

    Hintersteiner, Ingrid; Himmelsbach, Markus; Buchberger, Wolfgang W

    2015-02-01

    In recent years, the development of reliable methods for the quantitation of microplastics in different samples, including evaluating the particles' adverse effects in the marine environment, has become a great concern. Because polyolefins are the most prevalent type of polymer in personal-care products containing microplastics, this study presents a novel approach for their quantitation. The method is suitable for aqueous and hydrocarbon-based products, and includes a rapid sample clean-up involving twofold density separation and a subsequent quantitation with high-temperature gel-permeation chromatography. In contrast with previous procedures, both errors caused by weighing after insufficient separation of plastics and matrix and time-consuming visual sorting are avoided. In addition to reliable quantitative results, in this investigation a comprehensive characterization of the polymer particles isolated from the product matrix, covering size, shape, molecular weight distribution and stabilization, is provided. Results for seven different personal-care products are presented. Recoveries of this method were in the range of 92-96 %.

  12. [Rapid determination of pesticide multiresidues in porphyra by dispersive solid-phase extraction coupled with online gel permeation chromatography-gas chromatography-mass spectrometry].

    Science.gov (United States)

    Sun, Xiaojie; Guo, Mengmeng; Wang, Suyue; Tan, Zhijun; Li, Zhaoxin; Zhai, Yuxiu

    2014-10-01

    A rapid method for the simultaneous identification and quantification of pesticide multiresidues in porphyra was developed using gel permeation chromatography (GPC) coupled to gas chromatography-mass spectrometry (GPC-GC/MS). Nineteen pesticides (organochlorines, organophosphoruses, triazines and pyrethroids) were selected as the target analytes. The pretreatment method was applied consisting of organic solvent extraction followed by dispersive solid-phase extraction with graphitized carbon black (GCB) and primary secondary amine (PSA) adsorbents. GPC was also employed online to remove the large molecules such as pigments and lipids. The quantitative analysis was carried out by external standard method using gas chromatography coupled with mass spectrometry in selective ion monitoring (SIM) mode. Moreover, a large volume of sample was allowed to be injected using the program of GPC programmed-temperature vaporizer of gas chromatography to improve the sensitivity of measurements. The results showed that the calibration curves were linear (r > 0.995) in the range of 10-1,000 μg/L for all the pesticides. The limits of detection (LODs) for the pesticides in porphyra were from 0.005 to 0.03 mg/kg, and the average recoveries were between 70% and 120%. The advantages of the method are simple, sensitive and shorter operation time for analysis of pesticide residues in porphyra samples.

  13. Simultaneous Determination of Perfluorinated Compounds in Edible Oil by Gel-Permeation Chromatography Combined with Dispersive Solid-Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Yang, Lili; Jin, Fen; Zhang, Peng; Zhang, Yanxin; Wang, Jian; Shao, Hua; Jin, Maojun; Wang, Shanshan; Zheng, Lufei; Wang, Jing

    2015-09-30

    A simple analytical method was developed for the simultaneous analysis of 18 perfluorinated compounds (PFCs) in edible oil. The target compounds were extracted by acetonitrile, purified by gel permeation chromatography (GPC) and dispersive solid-phase extraction (DSPE) using graphitized carbon black (GCB) and octadecyl (C18), and analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ES-MS/MS) in negative ion mode. Recovery studies were performed at three fortification levels. The average recoveries of all target PFCs ranged from 60 to 129%, with an acceptable relative standard deviation (RSD) (1-20%, n = 3). The method detection limits (MDLs) ranged from 0.004 to 0.4 μg/kg, which was significantly improved compared with the existing liquid-liquid extraction and cleanup method. The method was successfully applied for the analysis of all target PFCs in edible oil samples collected from markets in Beijing, China, and the results revealed that C6-C10 perfluorocarboxylic acid (PFCAs) and C7 perfluorosulfonic acid PFSAs were the major PFCs detected in oil samples.

  14. [Determination of 28 organochlorine and pyrethroid pesticides in pine nuts using solid-phase extraction and on-line gel permeation chromatography-gas chromatography/mass spectrometry].

    Science.gov (United States)

    Kang, Qinghe; Wu, Yan; Gao, Kaiyang; Li, Zhibin

    2009-03-01

    An analytical method has been developed for the determination of 28 organochlorine pesticides and pyrethroid pesticides in pine nuts. The sample was extracted With acetonitrile-water (4:1, v/v) as the extraction solution by means of high-speed homogenization. The crude extract was purified by an Aluminium-N solid phase extraction column to remove most of the fat and sterols in the sample, then on-line gel permeation chromatography-gas chromatography/ mass spectrometry (GPC-GC/MS) analysis was performed. The recoveries for the most of pesticides in the sample spiked with the standards of 0.05 mg/kg were 70%-120%, and the relative standard deviations were less than 15%. The limits of detection of 28 organochlorine pesti- and pyrethroid pesticides were 0.002-0.05 mg/kg. The linear relationship and the recovery results were satisfactory. The method is rapid, accurate, highly senstive, and can be used for the simultaneous determination of pesticide residues in pine nuts.

  15. Simultaneous determination of zearalenone and its derivatives in edible vegetable oil by gel permeation chromatography and gas chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Qian, Mingrong; Zhang, Hu; Wu, Liqin; Jin, Nuo; Wang, Jianmei; Jiang, Kezhi

    2015-01-01

    A sensitive gas chromatographic-triple quadrupole mass spectrometric (GC-QqQ MS) analytical method, for the determination of zearalenone and its five derivatives in edible vegetable oil, was developed. After the vegetable oil samples were prepared using gel permeation chromatography, the eluent was collected, evaporated and dried with nitrogen gas. The residue was silylated with N,O-bis-trimethylsilyltrifluoroacetamide, containing 1% trimethylchlorosilane. GC-QqQ MS was performed in the reaction-monitoring mode to confirm and quantify mycotoxins in vegetable oil. The limits of quantitation were 0.03-0.2 μg kg(-1) for the six mycotoxins. The average recoveries, measured at 2, 20 and 200 μg kg(-1), were in the range 80.3-96.5%. Zearalenone was detected in the range 5.2-184.6 μg kg(-1) in nine maize oils and at 40.7 μg kg(-1) in a rapeseed oil from the local market.

  16. GEL PERMEATION CHROMATOGRAPHIC ANALYSIS OF LACQUER POLYSACCHARIDE

    Institute of Scientific and Technical Information of China (English)

    QIU Xingping; ZHANG Lina; DU Yumin; QIAN Baogong; LU Zaimin

    1992-01-01

    Ten fractionated samples of Chinese lacquer polysaccharide in aqueous 0.1M NaCl solution were studied by aqueous-phase gel permeation chromatography (GPC). The universal calibration, broad MWD calibration and corrected column dispersion were adopted to the analysis of GPC chromatograms of the polysaccharide. The molecular weights Mw, Mn and polydispersity index Mw/Mn obtained from GPC are in good agreement with the results of light scattering and membrane osmometry. It is verified that the universal calibration concept is applicable to the lacquer polysaccharide having a number of side chains.

  17. Analysis of PEG 400 and 4000 in urine for gut permeability assessment using solid phase extraction and gel permeation chromatography with refractometric detection.

    Science.gov (United States)

    Loret, S; Nollevaux, G; Remacle, R; Klimek, M; Barakat, I; Deloyer, P; Grandfils, C; Dandrifosse, G

    2004-06-15

    We developed a treatment of urine samples allowing the analysis of two intestinal permeability markers: polyethylene glycol (PEG) 400 (highly diffusible; basal permeability indicator) and PEG 4000 (poorly diffusible; indicator of an abnormal increase of permeability) by a unique gel permeation chromatography (GPC) with refractometric detection. Urinary PEG were extracted using a mixed-bed resin composed of C2 and C18 layers. Permeability mean values determined in 11 human healthy subjects were 24.20 +/- 9.30% and 0.12 +/- 0.08% for, respectively, PEG 400 and 4000. The percentage of the PEG 4000 permeability value to the one of PEG 400 corresponded to an intestinal permeability index (IPI) of 0.52 +/- 0.35 expressing a low diffusion of this poorly permeability marker.

  18. Comparison of solid phase extraction, saponification and gel permeation chromatography for the clean-up of microwave-assisted biological extracts in the analysis of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Navarro, P; Cortazar, E; Bartolomé, L; Deusto, M; Raposo, J C; Zuloaga, O; Arana, G; Etxebarria, N

    2006-09-22

    The feasibility of different clean-up procedures was studied for the determination of polycyclic aromatic hydrocarbons (PAHs) in biota samples such as oysters, mussels and fish liver. In this sense, once the samples were extracted--essentially with acetone and in a microwave system--and before they could be analysed by gas chromatography-mass spectrometry (GC-MS), three different approaches were studied for the clean-up step: solid phase extraction (SPE), microwave-assisted saponification (MAS) and gel permeation chromatography (GPC). The main aim of this work was to maximise the recoveries of PAHs and to minimise the presence of interfering compounds in the last extract. In the case of SPE, Florisil cartridges of 1, 2 and 5 g, and silica cartridges of 5 g were studied. In that case, and with oysters and mussels, microwave-assisted extraction and 5 g Florisil cartridges provided good results. In addition, the concentrations obtained for Standard Reference Material (SRM) NIST 2977 (mussel tissue) were in good agreement with the certified values. In the case of microwave-assisted saponification, the extracts were not as clean as those obtained with 5 g Florisil and this fact lead to overestimate the concentration of the heaviest PAHs. Finally, the cleanest extracts were obtained by GPC. The method was successfully applied to mussels, oysters and hake liver, and the results obtained for NIST 2977 (mussel tissue) were within the confidence interval of the certified reference material for most of the certified analytes.

  19. Measuring the molecular dimensions of wine tannins: comparison of small-angle X-ray scattering, gel-permeation chromatography and mean degree of polymerization.

    Science.gov (United States)

    McRae, Jacqui M; Kirby, Nigel; Mertens, Haydyn D T; Kassara, Stella; Smith, Paul A

    2014-07-23

    The molecular size of wine tannins can influence astringency, and yet it has been unclear as to whether the standard methods for determining average tannin molecular weight (MW), including gel-permeation chromatography (GPC) and depolymerization reactions, are actually related to the size of the tannin in wine-like conditions. Small-angle X-ray scattering (SAXS) was therefore used to determine the molecular sizes and corresponding MWs of wine tannin samples from 3 and 7 year old Cabernet Sauvignon wine in a variety of wine-like matrixes: 5-15% and 100% ethanol; 0-200 mM NaCl and pH 3.0-4.0, and compared to those measured using the standard methods. The SAXS results indicated that the tannin samples from the older wine were larger than those of the younger wine and that wine composition did not greatly impact on tannin molecular size. The average tannin MWs as determined by GPC correlated strongly with the SAXS results, suggesting that this method does give a good indication of tannin molecular size in wine-like conditions. The MW as determined from the depolymerization reactions did not correlate as strongly with the SAXS results. To our knowledge, SAXS measurements have not previously been attempted for wine tannins.

  20. Improved Quantitation of Gluten in Wheat Starch for Celiac Disease Patients by Gel-Permeation High-Performance Liquid Chromatography with Fluorescence Detection (GP-HPLC-FLD).

    Science.gov (United States)

    Scherf, Katharina Anne; Wieser, Herbert; Koehler, Peter

    2016-10-12

    Purified wheat starch (WSt) is commonly used in gluten-free products for celiac disease (CD) patients. It is mostly well-tolerated, but doubts about its safety for CD patients persist. One reason may be that most ELISA kits primarily recognize the alcohol-soluble gliadin fraction of gluten, but insufficiently target the alcohol-insoluble glutenin fraction. To address this problem, a new sensitive method based on the sequential extraction of gliadins, glutenins, and gluten from WSt followed by gel-permeation high-performance liquid chromatography with fluorescence detection (GP-HPLC-FLD) was developed. It revealed that considerable amounts of glutenins were present in most WSt. The gluten contents quantitated by GP-HPLC-FLD as sum of gliadins and glutenins were higher than those by R5 ELISA (gluten as gliadin content multiplied by a factor of 2) in 19 out of 26 WSt. Despite its limited selectivity, GP-HPLC-FLD may be applied as confirmatory method to ELISA to quantitate gluten in WSt.

  1. Monitoring biodegradation of poly(butylene sebacate) by Gel Permeation Chromatography, (1)H-NMR and (31)P-NMR techniques.

    Science.gov (United States)

    Siotto, Michela; Zoia, Luca; Tosin, Maurizio; Degli Innocenti, Francesco; Orlandi, Marco; Mezzanotte, Valeria

    2013-02-15

    The increasing use of new generation plastics has been accompanied by the development of standard methods for studying their biodegradability. Generally, test methods are based on the measurement of CO(2) production, i.e. the mineralization degree of the tested materials. However, in order to describe the biodegradation process, the determination of the residual amount of tested material which remains in the environment and its chemical characterization can be very important. In this study, the biodegradation in soil of a model polyester (poly(butylene sebacate)) was monitored. Gel Permeation Chromatography and Nuclear Magnetic Resonance ((31)P-NMR and (1)H-NMR) were used in order to obtain information about the polyester structure and the possible by-products that can be found in soil during and at the end of the incubation. The polyester mineralization (i.e. the CO(2) production) was tested according to ASTM 5988 standard method for 245 days. When the polyester mineralization was about 21% and 37% (after 78 and 140 days of incubation) and at the end of the process (63% of mineralization, 100% if compared to the cellulose used as reference material), the soil was extracted with chloroform (solvent of the tested substance) and the extracts were analyzed using GPC and NMR acquisitions. The analytical acquisitions showed high molecular weight polyester in soil during the incubation (78 and 140 days): the polyester concentration decreased but its structure remained almost the same with a slow decreasing in molecular weight. At the end of the test (245 days) no film of the polyester could be extracted from the soil: NMR acquisitions and GPC analyses of the extracts suggested a strong degraded structure of the residual polyester. Even if at the end of the process only 63% of carbon had been lost by mineralization, the whole of the added polyester seems to have disappeared after about eight months of incubation, suggesting substantial biomass formation. Copyright © 2012

  2. Relationship between Icodextrin use and decreased level of small low-density lipoprotein cholesterol fractioned by high-performance gel permeation chromatography.

    Science.gov (United States)

    Kanda, Eiichiro; Ai, Masumi; Iwamoto, Asami; Okazaki, Mitsuyo; Maeda, Yoshitaka; Sasaki, Sei; Yoshida, Masayuki

    2013-10-26

    Because of the absorption of glucose in peritoneal dialysis (PD) solution, PD patients show an atherogenic lipid profile, which is predictive of poor survival in PD patients. Lipoprotein subclasses consist of a continuous spectrum of particles of different sizes and densities (fraction). In this study, we investigated the lipoprotein fractions in PD patients with controlled serum low-density lipoprotein (LDL) cholesterol level, and evaluated the effects of icodextrin on lipid metabolism. Forty-nine PD patients were enrolled in this cross-sectional study in Japan. The proportions of cholesterol levels to total cholesterol level (cholesterol proportion) in 20 lipoprotein fractions were measured using an improved method of high-performance gel permeation chromatography (HPGPC). Twenty-six patients used icodextrin. Although no significant differences in cholesterol levels in LDL and high-density lipoprotein (HDL) were observed between the patients using icodextrin (icodextrin group) and control groups, HPGPC showed that the icodextrin group had significantly lower cholesterol proportions in the small LDL (t-test, p=0.053) and very small LDL (p=0.019), and significantly higher cholesterol proportions in the very large HDL and large HDL than the control group (p=0.037; p=0.066, respectively). Multivariate analysis adjusted for patient characteristics and statin use showed that icodextrin use was negatively associated with the cholesterol proportions in the small LDL (p=0.037) and very small LDL (p=0.026), and positively with those in the very large HDL (p=0.040), large HDL (p=0.047), and medium HDL (p=0.009). HPGPC showed the relationship between icodextrin use and the cholesterol proportions in lipoprotein fractions in PD patients. These results suggest that icodextrin may improve atherogenic lipid profiles in a manner different from statin.

  3. [Determination of 30 organochlorine pesticides in animal-originated food products using combined purification by gel permeation chromatography and solid-phase extraction coupled with gas chromatography-mass spectrometry].

    Science.gov (United States)

    Du, Juan; Lü, Bing; Zhu, Pan; Miao, Hong; Wu, Yongning

    2013-08-01

    A new analytical method was developed for the determination of 30 organochlorine pesticides (OCPs) in animal-originated food, including pork, chicken, fish and shrimp. The combined purification by gel permeation chromatography (GPC) and solid-phase extraction (SPE) were established by optimizing different fraction collection times. The detection conditions can be achieved by gas chromatography-mass spectrometry (GC-MS) using selective ion monitoring (SIM). Isotopic internal standards were used for the quantitative determination of the 30 OCPs. The sample pretreatment procedure was based on acetonitrile extraction and combined purification of GPC and Florisil SPE cartridge. The experimental results showed that the linear ranges for 30 OCPs were 5.0 - 500.0 microg/L, the correlation coefficients were better than 0.996, and the method detection limits (MDLs) of the 30 OCPs were 0.2 - 2.7 microg/kg. The spiked recoveries at three levels of 5.0, 10.0 and 20.0 microg/kg using pork, chicken, fish and shrimp samples as blank matrices were in the range of 55.0% - 119.1%, the relative standard deviations (RSDs) were in the range of 0.4% - 15.0%. The method has the advantages of wide linear range, high sensitivity and efficient clean-up procedure, and consistent with the demand of pesticide routine analysis.

  4. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of semivolatile organic compounds in bottom sediment by solvent extraction, gel permeation chromatographic fractionation, and capillary-column gas chromatography/mass spectrometry

    Science.gov (United States)

    Furlong, E.T.; Vaught, D.G.; Merten, L.M.; Foreman, W.T.; Gates, Paul M.

    1996-01-01

    A method for the determination of 79 semivolatile organic compounds (SOCs) and 4 surrogate compounds in soils and bottom sediment is described. The SOCs are extracted from bottom sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography (GPC). The SOCs then are qualitatively identified and quantitative concentrations determined by capillary-column gas chromatography/mass spectrometry (GC/MS). This method also is designed for an optional simultaneous isolation of polychlorinated biphenyls (PCBs) and organochlorine (OC) insecticides, including toxaphene. When OCs and PCBs are determined, an additional alumina- over-silica column chromatography step follows GPC cleanup, and quantitation is by dual capillary- column gas chromatography with electron-capture detection (GC/ECD). Bottom-sediment samples are centrifuged to remove excess water and extracted overnight with dichloromethane. The extract is concentrated, centrifuged, and then filtered through a 0.2-micrometer polytetrafluoro-ethylene syringe filter. Two aliquots of the sample extract then are quantitatively injected onto two polystyrene- divinylbenzene GPC columns connected in series. The SOCs are eluted with dichloromethane, a fraction containing the SOCs is collected, and some coextracted interferences, including elemental sulfur, are separated and discarded. The SOC-containing GPC fraction then is analyzed by GC/MS. When desired, a second aliquot from GPC is further processed for OCs and PCBs by combined alumina-over-silica column chromatography. The two fractions produced in this cleanup then are analyzed by GC/ECD. This report fully describes and is limited to the determination of SOCs by GC/MS.

  5. Treatment of olive mill waste-water by aerobic biodegradation: an analytical study using gel permeation chromatography, ultraviolet-visible and Fourier transform infrared spectroscopy.

    Science.gov (United States)

    El Hajjouji, H; Fakharedine, N; Ait Baddi, G; Winterton, P; Bailly, J R; Revel, J C; Hafidi, M

    2007-12-01

    Liquid waste from olive oil mills was digested following inoculation with soil microorganisms and fractionated through various grades of gel. The fractionation showed the range of sizes of the molecules in the waste. In addition, the disappearance of the low molecular weight fraction, which is retained by the gel, and the increase of the high molecular weight fraction, which is excluded by the gel, during the last stages of the microbial treatment, indicates polymerisation of the low-molecular-weight subunits. Characterization of the fractions by UV-visible and FTIR spectroscopy confirmed the increase in their degree of polymerisation during the treatment. This is paralleled by a reduction in the amount of aliphatic components and a concomitant increase in aromatic structures.

  6. Determination of 6 Pesticide Residues in Peanut Using Gel Permeation Chromatography and Gas Chromatography-Mass Spectrometry%凝胶渗透色谱-气相色谱质谱法测定花生中6种除草剂农药残留

    Institute of Scientific and Technical Information of China (English)

    马金凤; 刘雪; 赵志强; 吴成; 许志强; 王明林

    2012-01-01

    A method was developed for the determination of 6 pesticides (trifluralin, clomazone, alachlor, pendimethalin, oxyfluorfen, quizalofop) in peanuts by gel permeation chromatography and gas chromatography-mass spectrometry(GPC-GCMS), The herbicide pesticide residues were extracted by acetonitrile. The extract was cleaned up with NH2 solid-phase extractor and gel permeation chromatography(GPC), then analyzed by gas chromatography-mass spectrometry(GC / MS) under selected ion monitoring(SIM) mode. The pesticide residues were calculated by external standard method. Good linear relation was obtained in the range of 0.02 -LOO mg / L with the correlation coefficient of 0.994 9-0.999 8. The average recoveries of six pesticides were 77.8%-101.6% with RSD of 4.4%-11.4%(n=5), The detection limit was 0.1-1.3 μg/kg.%建立了凝胶渗透色谱-气相色谱质谱( GPC-GC-MS)法测定花生中6种除草剂(氟乐灵、异恶草酮、甲草胺、二甲戊乐灵、乙氧氟草醚、喹禾灵)农药残留的方法.样品经乙腈提取,氨基固相萃取柱和凝胶渗透色谱净化,在选择离子扫描(SIM)模式下进行气相色谱质谱法测定,外标法定量.6种除草剂浓度在0.02~1.00 mg/L范围内与色谱峰面积呈良好的线性,线性相关系数为0.9949~0.9998,添加回收率为77.8%~ 101.6%,测定结果的相对标准偏差为4.4%~11.4%(n=5),方法的检出限为0.1~1.3 μg/kg.

  7. Determination of Polycyclic Aromatic Hydrocarbons(PAHS)in Infant Cereal Samples by Gel Permeation Chromatography Purification-Gas Chromatography- Mass Spectrometry%凝胶净化-气质联用法测定婴幼儿米粉中的多环芳烃

    Institute of Scientific and Technical Information of China (English)

    张萌萌; 丁云; 应晓虹; 陈剑伟; 孙军; 王韩英

    2014-01-01

    A new analytical method was developed for the determination of polycyclic-aromatic- hydrocarbons (PAHs)in rice samples by gas chromatography-mass spectrometry(GC-MS)based on isotope internal standard method and gel permeation chromatography purification(GPC).The target analytes in samples were extracted with the solution of acetonitrile(ACN),purified using GPC to eliminate most of the coextracts,detected by GC-MS,and then quantified by internal standard method. The method recovery percentages and relative standard deviations(RSD)were 62.8%~93.7%and 8.2%~21.0%.The method detection limit(MDL)was 0.3μg/kg~2.4μg/kg.%采用同位素内标法并结合凝胶净化技术,建立了婴幼儿米粉中多环芳烃残留的气相色谱一质谱(GC-MS)检测方法。样品中的多环芳烃经乙腈提取,凝胶渗透色谱柱去除杂质后,进行GC-MS测定,内标法定量。方法的样品加标回收率和相对标准偏差分别为62.8%~93.7%、8.2%~21.0%。多环芳烃的方法检测限为0.3μg/kg~2.4μg/kg。

  8. Simultaneous Determination of 22 Phthalate Acid Esters in Edible Oils by Gas Chromatography/Mass Spectrometry Coupled with Gel Permeation Chromatography%凝胶渗透色谱-气相色谱/质谱法同时测定食用油中22种邻苯二甲酸酯

    Institute of Scientific and Technical Information of China (English)

    黄永辉

    2012-01-01

    建立了凝胶渗透色谱-气相色谱/质谱法同时测定食用油中22种邻苯二甲酸酯的方法.方法具有良好线性,相关系数R均大于0.999,检测限在0.09~11.83 mg/kg之间,平均回收率在81.45%~113.90%范围内,相对标准偏差为1.55%~9.41%.采用该方法对国内食用油中邻苯二甲酸酯增塑剂进行检测,实际样品中检出邻苯二甲酸二异丁酯、邻苯二甲酸二丁酯和邻苯二甲酸二(2-乙基)己酯,可满足目前食用油中邻苯二甲酸酯的检测要求.%A method for the simultaneous determination of 22 phthalate acid esters in edible oils by gas chromatography-mass spectrometry coupled with gel permeation chromatography was developed. The correlation coefficients(i?) of 22 phthalate acid esters were over 0. 999 with detection limits from 0. 09~ 11. 83 mg/kg. The average recoveries of 22 phthalate acid esters in edible oils were ranged from 81. 45% ~113. 90%. In addition,the relative standard deviations(RSDs) were in the range of 1. 55%6~9.41%. The level of phthalate acid esters plasticizers in edible oils was investigated by this method .and di-iso-butyl phthalate, dibutyl phthalate, bis (2-ethylhexy1) phthalate were found in some real samples. The simplicity,sensitivity and precision of the method made it be well suitable for the analysis of phthalate acid esters in edible oils.

  9. Effect of permeation enhancers on the release and permeation kinetics of Lincomycin hydrochloride gel formulations through mouse skin

    Directory of Open Access Journals (Sweden)

    Panigrahi L

    2006-01-01

    Full Text Available Lincomycin hydrochloride is a systemic antibiotic, which is active against most common gram positive bacteria. It has proved to be excellent for infectious diseases like acne, anthrax, pneumonia, and also for the treatment of furunculosis, carbuncles, impetigo, burns and wounds, carrying to gram positive bacteria. Gels were prepared using carbopol 940 as gelling agent, and isopropyl myristate and dimethyl sulfoxide as permeation enhancer. The formulations were evaluated for drug content, viscosity, pH, extrudability, homogeneity, skin irritation test, spreadability, and gel strength. A formulation containing 1.5% carbopol with 10% isopropyl myristate, showed better in vitro skin permeation through abdominal mouse skin, and was found to be the best.

  10. Effect of permeation enhancers on the penetration mechanism of transfersomal gel of ketoconazole

    Directory of Open Access Journals (Sweden)

    Reshmy Rajan

    2012-01-01

    Full Text Available The aim of the present research work was to investigate the potential of transfersome formulations for transdermal delivery of Ketoconazole (KTZ. KTZ is a broad-spectrum antifungal agent that is active against a wide variety of fungi and yeasts. It is readily but incompletely absorbed after oral dosing and is highly variable. The transfersomes were formulated by lipid film hydration technique using Rotary vacuum Evaporator. The prepared transfersomes were converted into suitable gel formulation and is evaluated for their gel characteristics like pH, viscosity, spreadability, extrudability, homogeneity, drug content, etc. Suitable essential oils acting as natural permeation enhancers were added to the transfersomal formulation of KTZ for their release studies. Studies proved that addition of suitable permeation enhancers to the transfersomal formulation improved the release and permeation of KTZ, which showed that the permeation enhancers modify the barrier to penetration present in skin without itself undergoing any change. From the various essential oils which are used as permeation enhancers, the formulation containing Eucalyptus oil showed better in vitro release and permeation as compared with other formulations containing different permeation enhancers.

  11. Determination of immunoglobulin G in mare colostrum by high-performance gel permeation chromatography%高效凝胶渗透色谱法检测马初乳中的免疫球蛋白G

    Institute of Scientific and Technical Information of China (English)

    吕岳文; 王红娟; 杨洁

    2011-01-01

    A direct high-performance gel permeation chromatographic (HPGPC) method for the determination of immunoglobulin G in mare colostrum was established. HPGPC separation was performed on a TOSOH TSK-G4000PWxL column ( 300 mm × 7.8 mm, 5 μm ) with 0.05 mol/L phosphate buffer solution ( pH 6.9) as the mobile phase at a flow rate of 0.8 mL/min,and the column temperature was maintained at 25 ℃. The injection volume was 20 μL. At the detection wavelength of 280 nm, the linear range was from 0.2 to 3.0 g/L ( r2 = 0.999 5 ) with a detection limit of 0.08 mg/L ( S/N = 10 ). The recovery was 97.47% with a relative standard deviation ( RSD ) of 1.22%. The RSDs of the peak area of stability, accuracy and reproducibility for the established method were 2.86%, 1.62% and 1.82%, respectively. Mare milk was collected from Zhaosu ( China), a complete collection was stored in an ice box, then sent to a laboratory and stored in a low temperature refrigerator. The whey milk was prepared by centrifugation two times at 12 000 r/min and 4 ℃ for 30 min. The whey protein was obtained from the middle layer. A 2 mL volume of the whey milk was mixed with 23 mL of mobile phase. The average contents of IgG were from 35.0 g/L to 50. 0 g/L at the first lactation ( 2 h), and the average contents of IgG were from 2.0 g/L to 4.0 g/L after 72 h. The relatively simple analytical method was proved to be accurate and precise in its application to mare colostrum.%建立了高效凝胶渗透色谱(HPGPC)测定马初乳中免疫球蛋白G(IgG)含量的方法.采用TOSOH TSKG4000PWXL色谱柱(300 mm x7.8 mm,5μm)分离,以0.05 mol/L磷酸盐缓冲液(pH 6.9)为流动相,流速0.8mL/min,检测波长280 nm,温度25℃.结果表明:免疫球蛋白G的线性范围为0.2~3.0 g/L(γ2=0.999 5),平均回收率为97.47%,相对标准偏差(RSD)为1.22%,检出限(信噪比为10)为0.08 mg/L,方法的稳定性、精密度和莺现性(以峰面积的RSD计)分别为2.86%、1.62%、1.82%.在优先满足

  12. Rapid determination of pesticide multiresidues in vegetables and fruits by accelerated solvent extraction coupled with online gel permeation chromatography-gas chromatography-mass spectrometry%加速溶剂萃取-在线凝胶渗透色谱-气相色谱-质谱联用法快速测定蔬菜和水果中多农药残留

    Institute of Scientific and Technical Information of China (English)

    欧阳运富; 唐宏兵; 吴英; 李贵英

    2012-01-01

    A novel method was developed for the rapid determination of 22 representative pesticide residues in vegetables and fruits based on accelerated solvent extraction (ASE) coupled with online gel permeation chromatography-gas chromatography-mass spectrometry ( GPC-GC-MS). The sample was extracted by accelerated solvent extraction with dichloromethane-ace-tone (1:1 , v/v) and purified with a carbon/NH;column, evaporated to dryness by nitrogen, then dissolved in cyclohexane-acetone (7:3, v/v), and finally identified and quantified by GPC-GC-MS system in selected ion monitoring (SIM) mode. The results showed that the linearities of the 22 pesticides were good in their linear ranges. The limits of detection (S/N = 3 ) were 0. 3 - 1. 8μg/kg. The limits of quantification (S/N =10) ranged from 1 -6 jig/kg. The recoveries for all at three spiked levels in Chinese cabbages and apples ranged from 70. 5% to 107. 5% with the relative standard deviations (RSDs) of 2.1% - 8.7%. The proposed method is accurate, sensitive and highly efficient in the extraction, and can be used for the quick determination of the pesticide multiresidues in vegetables and fruits.%建立了加速溶剂萃取-在线凝胶渗透色谱-气相色谱-质谱联用(GPC-GC-MS)快速测定蔬菜、水果中代表性农药残留的检测方法.样品经二氯甲烷-丙酮(1∶1,v/v)加速溶剂提取,活性炭柱-氨基柱串联净化,氮吹至干,残留物用环己烷-丙酮(7∶3,v/v)溶解后经GPC-GC-MS系统以选择离子监测(SIM)模式测定.结果表明,22种农药在各自的线性范围内线性关系良好(相关系数不低于0.998 1),检出限(以信噪比(S/N)为3计算)为0.3~1.8μg/kg,定量限(S/N=10)为1~6μg/kg.在2种基质(大白菜、苹果)中3个添加水平下的回收率为70.5% ~107.5%,相对标准偏差为2.1% ~8.7%.该方法提取效率高,定性定量准确、灵敏,可实现对蔬菜、水果中多农药残留的快速检测.

  13. Simultaneous Determination of 34 Pesticide Residues in Vegetable Oil by QuEChERS-on-line Gel Permeation Chromatography-Gas Chromatography-Mass Spectrometry%QuEChERS-在线凝胶色谱-气相色谱-质谱法测定植物油中34种农药残留

    Institute of Scientific and Technical Information of China (English)

    阮华; 荣维广; 宋宁慧; 吉文亮; 刘华良; 马永建

    2014-01-01

    A method for the simultaneous determination of 34 pesticides in sunflower oil, soybean oil and corn oil was developed. The samples were extracted and purified by a modified QuEChERS method, and then the supernatant was analyzed by on-line gel permeation chromatography-gas chromatography-mass spectrometry ( GPC-GC-MS ) . The linear range was from 0 . 01 to 0 . 2 mg/L with a good correlation coefficients ( r≥0. 9913). The average recoveries of 31 pesticides (except p,p′-DDE, p,p′-DDD, p,p′-DDT. For detail, please reference to section 3 . 6 ) ranged from 70 . 3% to 115 . 4%, 69 . 5% to 112 . 6% and 70 . 2% to 116 . 1%spiked at 0. 05 μg/g and 0. 1 μg/g with the relative standard deviations (RSDs, n=6) less than 13. 3%, 13. 5% and 12. 1% in sunflower oil, soybean oil and corn oil samples, respectively. The LODs of this method ranged from 0. 0692 to 2. 28, 0. 0559 to 2. 01 and 0. 0584 to 2. 14μg/kg (S/N=3) in sunflower oil, soybean oil and corn oil samples respectively. The convenient operation and versatility of this method are suitable for the fast screening and detection of 34 pesticide residues in sunflower oil, soybean oil and corn oil.%建立了葵花油、大豆油和玉米油中34种中高毒农药的快速筛查方法。样品采用改进的QuEChERS方法进行提取净化,提取液采用在线GPC-GC-MS检测。结果表明,34种农药在0.01~0.2 mg/L范围内具有良好的线性关系,相关系数为0.9913~0.9997。除p,p′-DDE, p,p′-DDD, p,p′-DDT外的31种农药在葵花油、大豆油和玉米油中的检出限分别为0.0692~2.28μg/kg,0.0559~2.01μg/kg,0.0584~2.14μg/kg;在0.05和0.1μg/g添加水平的平均回收率分别为70.3%~115.4%,69.5%~112.6%,70.2%~116.1%;相对标准偏差(RSD, n=6)分别为2.9%~13.3%,3.9%~13.5%,4.2%~12.1%。本方法具有操作便捷、快速等特点,适用于葵花油、大豆油和玉米油中34种农药残留的快速筛查与检测。

  14. Effect of phonophoresis on skin permeation of commercial anti-inflammatory gels: sodium diclofenac and ketoprofen.

    Science.gov (United States)

    Souza, Jaqueline; Meira, Alianise; Volpato, Nadia Maria; Mayorga, Paulo; Gottfried, Carmem

    2013-09-01

    This study evaluated the use of ultrasound in combination with the commercial anti-inflammatory drugs ketoprofen and sodium diclofenac, according to the parameters used in physiotherapy. Ketoprofen and sodium diclofenac were used in the Franz diffusion cell model adapted to an ultrasound transducer in three conditions: no ultrasound, one application of ultrasound and two applications of ultrasound. High-performance liquid chromatography was used to quantify the total amount of drug permeating skin per unit area, as well as flux and latency. The results showed that for ketoprofen, the amount of drug permeating skin and flux increased with two ultrasound applications. Permeation of sodium diclofenac decreased in the presence of ultrasound. Ultrasound parameters and drug properties must be considered in the use of phonophoresis.

  15. Maximized mucoadhesion and skin permeation of anti-AIDS-loaded niosomal gels.

    Science.gov (United States)

    Zidan, Ahmed S; Habib, Muhammad J

    2014-03-01

    The low permeability of the anti-AIDS, tenofovir, limits its antiretroviral clinical potency. The proposed study aimed at assessing the critical biological responses of tenofovir through the development and optimization of its surfactant-based niosomal gels intended for vaginal delivery. Fatty acid chain length of the amphiphile and cholesterol loading were optimized using a 3² full factorial design. Vesicular size, shape and surface charge, drug entrapment efficiency, in vitro release, and skin permeation were used to assess the gels. In addition, their biological performance on Lactobacillus crispatus viability and mucoadhesion to porcine vaginal tissue was also assessed. Within the design space, mucoadhesion percentage ranged from 6.2% to 28.6% and increased nonlinearly by decreasing niosomal vesicular size and linearly by increasing surface charge. Moreover, these gels were not cytotoxic to Lactobacillus crispatus for 48 h. For maximizing tenofovir entrapment, percutaneous permeation, and mucoadhesion while achieving sustained-release features, an optimum formulation was proposed with the shortest length of fatty chain and 0.48 mM cholesterol content. Overall, applying quality by design paradigm to the development of tenofovir niosomal gels not only offered a promising nanomedicine for the vaginal microbicide delivery but also unveiled the critical formulation interactions influencing its biological performance.

  16. Transbuccal permeation, anti-inflammatory activity and clinical efficacy of piroxicam formulated in different gels.

    Science.gov (United States)

    Attia, M A; El-Gibaly, I; Shaltout, S E; Fetih, G N

    2004-05-19

    In attempts to avoid the systemic side effects of piroxicam (PC) (e.g. gastrotoxicity), several buccal gel formulations containing PC were prepared and their effects on the characteristics of the drug permeation through rabbit buccal mucosa in-vitro were evaluated using a Franz-type diffusion cell. The general rank order of the total flux of 0.5% PC from gels was found to be: hydroxypropylmethylcellulose (HPMC, 2.5%) > hydroxypropylcellulose (HPC, 2.5%) >or= sodium alginate (Na alg., 7%) > methylcellulose (MC, 3%) > hydroxyethylcellulose (HEC, 1.5%) > carbopol 934 (Carb. 934, 1%) >or= sodium carboxymethylcellulose (NaCMC, 2%) > pluronic F-127 (PF-127, 20%) > polyvinyl alcohol (PVA, 10%). The effect of various penetration enhancers 1% sodium lauryl sulphate (NaLS), 3% sodium deoxycholate (NaDC), 3% sodium tauroglycocholate (NaTGC) on the rate of permeation across the excised buccal mucosa (of 0.5% PC in gels prepared using 3% MC, 2.5% HPMC or 7% Na alg. base) and histology of the buccal epithelium was also investigated. Pharmacodynamic evaluation of the anti-inflammatory activity of PC in these gel formulations (containing 3% NaDC as an enhancer) was carried out using the kaolin-induced rat paw oedema method. The results obtained indicated that PC administered in 7% Na alg. or 2.5% HPMC gel bases was significantly more effective than the 3% MC gel and oral drug solution in suppressing oedema formation in rats. Comparative clinical studies were conducted in patients with post-operative dental pain and oedema following maxillofacial operations. The results revealed that 7% Na alg. and 2.5% HPMC gel formulations applied to the buccal mucosa were slightly better than or equally effective to the orally administered commercial product (Feldene Flash) tablet) in reducing pain level, swelling and tenderness within a period of 4 days. These findings suggest that PC (0.5%) administered in the buccal gel may present a potential therapeutical use as a strong anti

  17. Determination of 18 Organic Phosphorus and Pyrthroid Pesticides in Dried Vegetables using Solid-phase Extraction and On-line Gel Permeation Chromatography-GC/MS%固相萃取-在线凝胶渗透色谱-气相色谱质谱联用测定蔬菜干制品中的18种有机磷和拟除虫菊酯残留

    Institute of Scientific and Technical Information of China (English)

    薛丽; 钟艳梅

    2012-01-01

    建立了蔬菜干制品中18种有机磷农药和拟除虫菊酯农药残留的在线凝胶渗透色谱-气相色谱/质谱(GPC-GC/MS)分析方法.样品以乙腈为提取剂超声波高速匀浆提取,提取液经ENVI-Carb固相萃取柱净化,除去样品中大部分的色素等干扰基质,再经在线GPC进一步净化除去大分子干扰物质,有效降低了样品基质带来的背景干扰.采用外标法定量,在质量浓度为0.02 mg/kg~0.5mg/kg有良好的线性关系,加标水平为0.4 mg/kg时,18种农药的回收率基本都在80%~130%,相对标准偏差小于10%,检出限为0.001mg/kg~0.026 mg/kg.经实验证明,该方法是一种快速,准确,灵敏度高的同时检测梅菜干中多种农药残留的检测方法.%An on-line gel permeation chromatography-GC/MS analytical method was developed for the determination of 18 organic phosphorus pesticide and pyrethroid pesticides in dried vegetables.The samples were extracted with acetonitrile by means of ultrasonic high-speed homogenization, cleaned up by an ENVI-Carb solid phase extraction column to remove pigment in the sample and analyzed by on-line gel permeation chromatography-GC/MS. All the compounds demonstrated good linear relationship in the range of 0.02-0.5 mg/kg. The recoveries for the most of pestive standards of 0.4 mg/kg were 80%-130% and the relative standard deviations were less than 10%. The limits of detection were from 0.001 mg/kg to 0.026 mg/kg. The method was rapid, accurate and highly sensitive, which can be used for the simultaneous determination of pesticide residues in dried vegetables.

  18. 凝胶净化/超高效液相色谱电喷雾质谱法检测调味油中11种禁用偶氮染料及罗丹明B%Determination of 11 Azo-dyes and Rhodamine B in Seasoning Oil by Gel Permeation Chromatography/Ultra Performance Liquid Chromatography with Electrospray Ionization Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    赵珊; 张晶; 丁晓静; 郭巧珍; 邵兵

    2012-01-01

    An analytical method was developed for the simultaneous determination of 11 banned azo-dyes (Sudan red I , Sudan red II , Sudan red III, Sudan red IV, Sudan red 7B, Sudan red G, Sudan yellow, Sudan orange G, Sudan blue II, toluidine red, para red) and rhodamine B in seasoning oil based on gel permeation chromatography followed by ultra performance liquid chromatogra-phy - tandem mass spectrometry ( UPLC - MS/MS). The seasoning oil samples were extracted with cyclohexane - ethyl acetate (1 : 1) , and then purified by gel permeation chromatography to remove the high molecular weight of interferences (e. g. fat, oil and natural pigments). Twelve target compounds were separated on an ACQUITY UPLC(R) BEH C18 column with 0. 1% formic acid and acetoni-trile as mobile phase by gradient elution, and detected by MS/MS under positive mode with multiple reaction monitoring (MRM). Good linearities for 12 dyes were achieved over the range of 1 -50 μg/L. The quantitation limits of 12 dyes in seasoning oil samples were in the range of 0. 2 -2. 5 μg/kg. The mean recoveries at three spiked level(5, 20, 40 μg/L) ranged from 54% to 125% , with relative standard deviations ( RSDs) of 2. 5% - 17. 2% . The method was used to analyze 35 seasoning oil samples taken randomly from the local market, and rhodamine B was found in 2 of the samples. The established method could be applied in the simultaneous extraction and purification of 11 azo-dyes and rhodamine B in seasoning oil matrix, and is suitable for the routine detection of illegally additive dyes in seasoning oil due to its simplicity and high sensitivity.%建立了凝胶渗透色谱(GPC)净化/超高效液相色谱-电喷雾串联四极杆质谱(UPLC - MS/MS)同时检测调味油中11种脂溶性偶氮类工业染料(苏丹红Ⅰ、苏丹红Ⅱ、苏丹红Ⅲ、苏丹红Ⅳ、苏丹红7B、苏丹红G、苏丹黄、苏丹橙G、苏丹蓝Ⅱ、甲苯胺红、对位红)和罗丹明B的分析方法.样品经乙酸乙酯-环己烷(1

  19. Determination of Polybrominated Diphenyl Ethers and Derivatives, Tetrabromobisphenol A, Hexabromocyclododecane in Egg Samples by Gel Permeation Chromatography and Dispersive Solid Phase Extraction%凝胶渗透色谱-分散固相萃取法同时测定鸡蛋中多溴联苯醚及其衍生物、四溴双酚A和六溴环十二烷

    Institute of Scientific and Technical Information of China (English)

    李敏洁; 金芬; 杨莉莉; 乌日娜; 邵华; 金茂俊; 王静

    2014-01-01

    建立了一种同时检测鸡蛋中四溴双酚A( TBBP A)、六溴环十二烷( HBCD)和多溴联苯醚( PBDEs)及其衍生物羟基多溴联苯醚( OH-PBDEs)和甲氧基多溴联苯醚( MeO-PBDEs)的凝胶渗透色谱( GPC)-分散固相萃取(DSPE)-液相色谱-串联质谱(HPLC-MS/MS)和气相色谱-负化学源质谱(GC-NCI/MS)的检测方法。样品经正己烷、二氯甲烷(1∶1, V/V)加速溶剂萃取,凝胶渗透色谱净化后,经100 mg十八烷基键合硅胶( C18)分散固相萃取吸附剂去除杂质,液相色谱-串联质谱和气相色谱-负化学源质谱方法测定,外标法定量。在蛋白和蛋黄样品中添加1.0或5.0μg/kg的目标物,其回收率分别为64.5%~97.2%和65.6%~109.2%(除BDE-85为54.8%,OH-BDE-137为47.4%外),相对标准偏差小于20.2%,定量限为0.01~0.2μg/kg。%A stimulate method for determination of polybrominated diphenyl ethers ( PBDEs) and derivatives (OH-PBDEs and MeO-PBDEs), tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD) in egg samples was developed by gel permeation chromatography ( GPC) and dispersive solid phase extraction ( DSPE) combined with liquid chromatography tandem mass spectrometric ( HPLC-MS/MS) and gas chroma-tography-negative chemical ionization mass spectrometry ( GC-NCI/MS ) . The analytes were extracted with mixture of hexane and dichloromethane (1∶1, V/V) by accelerated solvent extraction (ASE), and purified by 100 mg C18 dispersive solid phase extraction ( SPE) sorbents followed with gel permeation chromatography (GPC) , and then analyzed by liquid chromatography tandem mass spectrometric (HPLC-MS/MS) and gas chromatography-negative chemical ionization mass spectrometry (GC-NCI/MS), respectively. The quantita-tion was carried out external standard method. The recoveries of objects were 64. 5%-97. 2% and 65. 6%-109 . 2% ( except BDE85 was 54 . 8%, OH-BDE-137 was 47 . 4%) spiked at 1 . 0 μg/kg or 5 . 0 μg/kg in egg white and egg yolk, respectively. The relative standard

  20. Skin permeation enhancement effects of the gel and whole-leaf materials of Aloe vera, Aloe marlothii and Aloe ferox.

    Science.gov (United States)

    Fox, Lizelle T; Gerber, Minja; du Preez, Jan L; du Plessis, Jeanetta; Hamman, Josias H

    2015-01-01

    The aim of this study was to investigate the in-vitro permeation enhancement effects of the gel and whole-leaf materials of Aloe vera, Aloe marlothii and Aloe ferox using ketoprofen as a marker compound. The permeation studies were conducted across excised female abdominal skin in Franz diffusion cells, and the delivery of ketoprofen into the stratum corneum-epidermis and epidermis-dermis layers of the skin was investigated using a tape-stripping technique. A. vera gel showed the highest permeation-enhancing effect on ketoprofen (enhancement ratio or ER = 2.551) when compared with the control group, followed by A. marlothii gel (ER = 1.590) and A. ferox whole-leaf material (ER = 1.520). Non-linear curve fitting calculations indicated that the drug permeation-enhancing effect of A. vera gel can be attributed to an increased partitioning of the drug into the skin, while A. ferox whole leaf modified the diffusion characteristics of the skin for ketoprofen. The tape stripping results indicated that A. marlothii whole leaf delivered the highest concentration of the ketoprofen into the different skin layers. Of the selected aloe species investigated, A. vera gel material showed the highest potential as transdermal drug penetration enhancer across human skin. © 2014 Royal Pharmaceutical Society.

  1. 凝胶渗透色谱-固相萃取联合净化气相色谱-质谱联用法测定动物性食品中30种有机氯农药的残留量%Determination of 30 organochlorine pesticides in animal-originated food products using combined purification by gel permeation chromatography and solid-phase extraction coupled with gas chromatography-mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    杜娟; 吕冰; 朱盼; 苗虹; 吴永宁

    2013-01-01

    建立了猪肉、鸡肉、鱼肉和虾肉等动物性食品中30种有机氯农药残留的气相色谱-质谱联用检测方法.样品匀浆后,采用乙腈提取,以凝胶渗透色谱和弗罗里硅土固相萃取柱联合进行净化,气相色谱-质谱检测,以同位素内标法定量.30种有机氯农药的响应在5.0 ~ 500.0 μg/L范围内呈良好的线性,相关系数在0.996以上,各有机氯农药的检出限在0.2~2.7 μg/kg之间.以猪肉、鸡肉、鱼肉和虾肉作为代表性基质,进行5.0、10.0、20.0 μg/kg3个水平的加标回收试验,回收率在55.0%~119.1%之间,相对标准偏差在0.4% ~ 15.0%之间.该方法准确可靠,灵敏度高,样品净化效果好,能够满足动物性食品中有机氯农药多残留痕量分析的要求.%A new analytical method was developed for the determination of 30 organochlorine pesticides (OCPs) in animal-originated food,including pork,chicken,fish and shrimp.The combined purification by gel permeation chromatography (GPC) and solid-phase extraction (SPE) were established by optimizing different fraction collection times.The detection conditions can be achieved by gas chromatography-mass spectrometry (GC-MS) using selective ion monitoring (SIM).Isotopic internal standards were used for the quantitative determination of the 30 OCPs.The sample pretreatment procedure was based on acetonitrile extraction and combined purification of GPC and Florisil SPE cartridge.The experimental results showed that the linear ranges for 30 OCPs were 5.0-500.0 μg/L,the correlation coefficients were better than 0.996,and the method detection limits (MDLs) of the 30 OCPs were 0.2-2.7 μg/kg.The spiked recoveries at three levels of 5.0,10.0 and 20.0 μg/kg using pork,chicken,fish and shrimp samples as blank matrices were in the range of 55.0%-119.1%,the relative standard deviations (RSDs) were in the range of 0.4%-15.0%.The method has the advantages of wide linear range,high sensitivity and

  2. Recent Advances in Analytical Methods on Lipoprotein Subclasses: Calculation of Particle Numbers from Lipid Levels by Gel Permeation HPLC Using "Spherical Particle Model".

    Science.gov (United States)

    Okazaki, Mitsuyo; Yamashita, Shizuya

    2016-01-01

    Recently, we developed an analytical method for determining the lipid levels and particle numbers in lipoprotein subclasses covering a wide size range from chylomicrons to small high density lipoproteins, by using gel permeation high-performance liquid chromatography (GP-HPLC). The challenges in analytical methods on lipoprotein subclasses have been addressed from 1980 by Hara and Okazaki using commercial TSK gel permeation columns. Later, the improvements in the hardware, separation and detection of lipoproteins, and the data processing software, using a Gaussian distribution approximation to calculate lipid levels of lipoprotein subclasses, have been extensively utilized in these analytical methods for over thirty years. In this review, we describe on the recent advances in analytical methods on lipoprotein subclasses based on various techniques, and the calculation of particle numbers from lipid levels by GPHPLC using the "spherical particle model". Free/ester ratio of cholesterol in particular lipoprotein subclass was accurately estimated from triglyceride, total cholesterol (free and esterified) and the size of the particle based on this model originally proposed by Shen and Kezdy.

  3. In vitro permeation through porcine buccal mucosa of caffeic acid phenetyl ester (CAPE) from a topical mucoadhesive gel containing propolis.

    Science.gov (United States)

    Ceschel, G C; Maffei, P; Sforzini, A; Lombardi Borgia, S; Yasin, A; Ronchi, C

    2002-11-01

    Recent studies have shown that propolis has on the oral cavity appreciable antibacterial, antifungal and antiviral actions, as well as anti-inflammatory, anaesthetic and cytostatic properties. In light of these studies, an assessment of the diffusion and permeation of caffeic acid phenetyl ester (CAPE) through porcine buccal mucosa was considered useful as a possible application in the stomatological field. To do so, a mucoadhesive topical gel was prepared to apply to the buccal mucosa. The gel was formulated in such a way as to improve the solubility of the propolis, conducting to an increase of the flux. The mucosal permeation of CAPE from the formulation was evaluated using Franz cells, with porcine buccal mucosa as septum between the formulation (donor compartment) and the receptor phase chamber. The diffusion through the membrane was determined by evaluating the amount of CAPE present in the receiving solution, the flux and the permeation coefficient (at the steady state) in the different formulations at set intervals. Qualitative and quantitative determinations were done by HPLC analysis. From the results, CAPE allowed a high permeability coefficient in comparison to the coefficient of other molecules, as expected from its physical-chemical structure. Moreover, the developed gel improved the CAPE flux approximately 35 times more with respect to an ethanol solution formulated at the same gel concentration. The developed gel was also tested in order to evaluate the mucoadhesive behaviour and comfort in vivo on 10 volunteers in a period of 8 h. The in vivo evaluation of mucoadhesive gel revealed adequate comfort and non-irritancy during the period of study and it was well accepted by the volunteers.

  4. In Vitro Skin Permeation of Osthol from Hydro-Alcohofic Gel Formulations

    Institute of Scientific and Technical Information of China (English)

    YUANZhen-ting; DINGPing-tian; LuBo; CHENDa-wei

    2004-01-01

    Aim To evaluate the in vitro percutaneous absorption behavior of osthol from a series of hydro-alcoholic gel formulations containing three penetration enhancers through excised human skin (stratum cormeum and epidermis,SCE). Methods Excised human skin was mounted in Franz-type diffusion cells. The samples withdrawn from the receptor cell were analyzed for osthol content by high-performance liquid chromatography (HPLC). Results The enhancers azone, menthol and chenopodium increased the osthol percutaneous steady-state fluxes 3.12, 2.00 and 1.25 times those of the enhancer-free formulations (controls), separately. Conclusions The main enhancement mechanism of the skin penetration enhancers azone, menthol and chenopodium is to destroy the barrier fimction of stratum corneum, reducing the resistance of drug transport through the skin and increasing the diffusion coefficients of osthol.

  5. Surfactant free fractions of metallic and semiconducting single-walled carbon nanotubes via optimised gel chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Lukaszczuk, Pawel, E-mail: plukaszczuk@zut.edu.pl [West Pomeranian University of Technology, Institute of Chemical and Environment Engineering, ul. Pulaskiego 10, 70-322 Szczecin (Poland); Ruemmeli, Mark H.; Knupfer, Martin [Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstr. 20, 01069 Dresden (Germany); Kalenczuk, Ryszard J.; Borowiak-Palen, Ewa [West Pomeranian University of Technology, Institute of Chemical and Environment Engineering, ul. Pulaskiego 10, 70-322 Szczecin (Poland)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer The application of gel permeation chromatography technique in a field of SWCNT separation. Black-Right-Pointing-Pointer Non-commercial agarose gel used as a column filling. Black-Right-Pointing-Pointer Purification route is presented, quality and quantity estimation is shown. Black-Right-Pointing-Pointer Process is ready for high-scale separation of SWCNTs. -- Abstract: We report the procedure of sorting/purification of carbon nanotubes by electronic type using chromatographic column with sodium dodecylsulfate (SDS) and sodium deoxycholate (DOC) solutions as the eluents. The non-commercial agarose gel in different concentrations has been tested in the process. It was found that in optimal gel concentration the fractionation resulted in {approx}96.2% yield of semiconducting species. Importantly, to get surfactant-free fractions the post-separation purification procedure has been carried out. The UV-vis-NIR and Raman spectroscopy have been utilised for the samples analysis. High resolution transmission microscopy and thermogravimetric analysis allowed to study the sample morphology and purity, respectively.

  6. Sol-gel multicapillary columns for gas-solid chromatography.

    Science.gov (United States)

    Sidelnikov, Vladimir N; Patrushev, Yuri V; Belov, Yuri P

    2006-01-06

    In this work, we report the method for the preparation of multicapillary columns (MCCs) for gas-solid chromatography. The porous layer adsorbent is formed on capillary walls by the hydrolysis of aluminum alkoxide in the presence of polypropylene glycol (PPG) and HCl. Porosity and selectivity of the adsorbent depend on reaction conditions and the concentration of PPG. Sol-gel MCCs are well suited for high-speed chromatographic analysis of light hydrocarbons by gas-solid chromatography. Nine-component mixtures of C1-C4 hydrocarbons are separated within 8-12 s. The efficiency of 25-30 cm long alumina sol-gel MCCs consisting of approximately 1400 capillaries of 40 microm diameter is up to 2500-3000 theoretical plates.

  7. Poloxamer 407-based intranasal thermoreversible gel of zolmitriptan-loaded nanoethosomes: formulation, optimization, evaluation and permeation studies.

    Science.gov (United States)

    Shelke, Santosh; Shahi, Sadhana; Jalalpure, Sunil; Dhamecha, Dinesh

    2016-12-01

    Zolmitriptan is the drug of choice for migraine, but low oral bioavailability (<50%) and recurrence of migraine lead to frequent dosing and increase in associated side effects. Increase in the residence time of drug at the site of drug absorption along with direct nose to brain targeting of zolmitriptan can be a solution to the existing problems. Hence, in the present investigation, thermoreversible intranasal gel of zolmitriptan-loaded nanoethosomes was formulated by using mucoadhesive polymers to increase the residence of the drug into the nasal cavity. The preparation of ethosomes was optimized by using 3(2) factorial design for percent drug entrapment efficiency, vesicle size, zeta potential, and polydispersity index. Optimized formulation E6 showed the vesicle size (171.67 nm) and entrapment efficiency (66%) when compared with the other formulations. Thermoreversible gels prepared by using poloxamer 407 showed the phase transition temperature at 32-33 °C which was in line with the nasal physiological temperature. The optimized ethosomes were loaded into the thermoreversible mucoadhesive gel optimized by varying concentrations of poloxamer 407, carbopol 934, HPMC K100, and evaluated for gel strength, gelation temperature, mucoadhesive strength, in vitro drug release, and ex vivo drug permeation, where G3 and G6 were found to be optimized formulations. In vitro drug release was studied by different kinetic models suggested that G3 (n = 0.582) and G6 (n = 0.648) showed Korsemeyer-Peppas (KKP) model indicating non-Fickian release profiles. A permeation coefficient of 5.92 and 5.9 µg/cm(2) for G3 and G6, respectively, revealed very little difference in release rate after 24 h between both the formulations. Non-toxic nature of the gels on columnar epithelial cells was confirmed by histopathological evaluation.

  8. Development, stability and in vitro permeation studies of gels containing mometasone furoate for the treatment of dermatitis of the scalp

    Directory of Open Access Journals (Sweden)

    Ana Cristina Gomes Barros Salgado

    2010-03-01

    Full Text Available Dermatological inflammatory diseases such as atopic dermatitis, psoriasis and seborrhoeic dermatitis often affect the scalp and the eyebrows. Although there are many dosage forms available, these are particularly critical anatomic regions for application of topical formulations because of the presence of hair. Lotions are therefore the recommended type of drug delivery system for these areas. The presence of hair may limit the application and thus the acceptability of the formulation and its compliance. Because of its low apparent viscosity, lotion application is unpleasant. Gels, given their consistency and adhesiveness, are a suitable alternative to lotions in this situation. The aim of this study was to formulate a stable gel containing mometasone furoate, which is an anti-inflammatory and anti-pruritic corticosteroid, in order to improve topical treatment of scalp dermatitis. In this study, pharmaceutical development, physical-chemical characterization, stability and in vitro permeation studies were performed. In terms of the pH, viscosity, assay and macroscopic and microbiological properties, the gel was stable over the period of study. The in vitro permeation studies allowed the characterization of the mometasone furoate permeation profile for the gel through different membranes. Mometasone furoate presented a slow permeation through the skin. This gel appears safe for topical application.Afecções dermatológicas do tipo inflamatório como a dermatite atópica, psoríase e dermatite seborreica, afetam freqüentemente o couro cabeludo e sobrancelhas. Apesar de existirem várias formas farmacêuticas para o seu tratamento, apenas as loções são indicadas para estas zonas, mas devido à baixa viscosidade, a aplicação de loções torna-se desagradável. Os geles, pela maior consistência e capacidade de adesão, apresentam-se como alternativa nesta situação. Neste trabalho procedeu-se ao desenvolvimento galênico de um gel com furoato

  9. DETERMINATION OF PERMEATION PROPERTIES OF GAS THROUGH POLYMER MEMBRANE BY GAS CHROMATOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    JIN Xigao; FU Xiucheng; ZHAN Yongjian; QIAN Renyuan

    1987-01-01

    An apparatus constructed for measuring permeation properties of polymer membranes using a mixture of gases is described. A gas chromatographic system was applied to determine the individual transport characteristics of component gases without a vacuum line. This paper also discusses some experimental factors effecting the precision of measurement. The results show that there is a linear relationship between the permeation time and the volume of the gas permeated through the membrane within certain permeation period, which depends on the permeation rate (from 10-4 to 10-7 cm3 (STP)/cm2.sec. cmHg) of the membrane. The reproducibility has been found to be good with a relative standard deviation of 3.5%. This method is more sensitive, considerably faster and more convenient for determining both the permeability coefficient and the separation factor of a polymer membrane from a chromat ogram using mixed penetrant gases.

  10. Effects of Carbopol® 934 proportion on nanoemulsion gel for topical and transdermal drug delivery: a skin permeation study

    Directory of Open Access Journals (Sweden)

    Zheng Y

    2016-11-01

    Full Text Available Yin Zheng,1 Wu-Qing Ouyang,1 Yun-Peng Wei,1 Shahid Faraz Syed,2,3 Chao-Shuang Hao,1 Bo-Zhen Wang,4 Yan-Hong Shang1,5 1Department of Basic Veterinary Sciences, College of Veterinary Medicine, 2Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi; 3Faculty of Veterinary and Animal Sciences, Lasbella University of Agriculture Water and Marine Sciences, Uthal Baluchistan, Pakistan; 4College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 5College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China Abstract: Nanoemulsions (NEs are used as transdermal drug delivery systems for systematic therapeutic purposes. We hypothesized that the skin permeation profile of an NE could be modulated by incorporating it into a hydrogel containing differing proportions of thickening agent. The objectives of this study were as follows: 1 to determine the stability and skin irritability of NE gels (NGs containing 1%, 2%, and 3% (w/w Carbopol® 934 (CP934 (termed NG1, NG2, and NG3, respectively; 2 to compare the skin permeation profiles and drug deposition patterns of the NGs; and 3 to visualize the drug delivery routes of the NGs. Terbinafine and citral were incorporated into the NGs as model drugs. Ex vivo skin permeation tests indicated that the percutaneous flux rates of terbinafine decreased in the order NE (215 µg/cm2 > NG1 (213 µg/cm2 > NG2 (123 µg/cm2 > NG3 (74.3 µg/cm2. The flux rates of citral decreased in the order NE (1,026 µg/cm2 > NG1 (1,021 µg/cm2 > NG2 (541 µg/cm2 > NG3 (353 µg/cm2. The NGs accumulated greater amounts of the drugs in the stratum corneum and less in the epidermis/dermis than did the NE (P<0.05 over a period of 12 h. Laser scanning confocal microscopy indicated that the NGs altered the main drug delivery routes from skin appendages to intercellular paths. Histological images suggested

  11. Thermo- and pH-sensitive gel membranes based on poly-(acryloyl-L-proline methyl ester)-graft-poly(acrylic acid) for selective permeation of metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Shin; Ohashi, Hitoshi; Maekawa, Yasunari; Katakai, Ryoichi; Yoshida, Masaru E-mail: katsu@taka.jaeri.go.jp

    2005-04-01

    Thermo- and pH-responsive gel membranes were synthesized by {gamma}-ray grafting of pH-responsive poly(acrylic acid) (AAc) onto thermo-responsive polymer gel of acryloyl-L-proline methyl ester (A-ProOMe). The gel membranes of poly(A-ProOMe) with 15 mol% graft chains of AAc exhibited both thermo- and pH-responses. Under the condition (pH 6.0, 30 deg. C) in which the thermo-sensitive unit shrinks and the pH-sensitive unit swells, the selective permeation of Li ion over Co and Ni ions can be achieved.

  12. Performance of a Gel Permeation Chromatograph and its Usefulness in Examining Mixtures of Organic Materials,

    Science.gov (United States)

    1979-01-01

    chromatography (GPC) which is a method for the separation, purification and analysis of high molecular weight substances. The separation is usually carried...manufacturer is ± 1 x 10-7 R.I. units. Differential refractometry , while satisfactory for monitoring the fractionation of a mixture of compounds, can be used...chromatogram (9w = 3.13 x 105, -n _ 1.01 x 105 and w/Fin - 3.09) E.A. chromatogram (liw - 2.91 x 105, Mn = 0.96 x 105 and Mw/Nn - 3.04) The method of

  13. Establishment and application of milk fingerprint by gel filtration chromatography.

    Science.gov (United States)

    Gao, P; Li, J; Li, Z; Hao, J; Zan, L

    2016-12-01

    Raw milk adulteration frequently occurs in undeveloped countries. It not only reduces the nutritional value of milk, but it is also harmful to consumers. In this paper, we focused on investigating an efficient method for the quality control of raw milk protein. A gel filtration chromatography (GFC) fingerprint method combined with chemometrics was developed for fingerprint analysis of raw milk. To optimize the GFC conditions, milk fat was removed by centrifugation, and GFC analysis was performed on a Superdex 75 10/300GL column (Just Scientific, Shanghai, China) with 0.2 M NaH2PO4-Na2HPO4 buffer (pH 7.0) as the mobile phase. The flow rate was 0.5mL/min, and the detection wavelength was set at 280 nm. Ten batches of 120 raw milk samples were analyzed to establish the GFC fingerprint under optimal conditions. Six major peaks common to the chromatogram of each raw milk sample were selected for fingerprint analysis, and the characteristic peaks were used to establish a standard chromatographic fingerprint. Principal component analysis was then applied to classify GFC information of adulterated milk and raw milk, allowing adulterated samples to be effectively screened out from the raw milk in principal component analysis scores plot. The fingerprint method demonstrates promising features in detecting milk protein adulteration.

  14. Rapid method for characterization of heavy petroleum fractions. [Gel permeation chromatography for molecular weight distribution

    Energy Technology Data Exchange (ETDEWEB)

    Hodgin, J. C.; Kaiser, M. A.; Lubkowitz, J. A.; Rogers, L. B.

    1977-03-01

    The use of LiChrospher and LiChrosorb to obtain profiles of molecular weight distributions is shown for some petroleum crudes, pitches, and asphaltenes. The elution time was less than thirty minutes, and data were obtained on less than 16 ..mu..g of sample.

  15. Acquisition of Preparative Gel Permeation Chromatography for Research and Education in Energy Conversion and Nanocomposites

    Science.gov (United States)

    2017-04-19

    materials for energy. The pGPC acquired from SHIMADZU SCIENTIFIC INSTRUMENTS is equipped with one LC-20AR HPLC Pump (MAX flow rate 20ml/min), one...SIL-20A Prominence HPLC Autosampler (high-speed accurate injection of samples), one CBM-20A HPLC System Controller, one CTO-20A Prominence HPLC ...Column Ovens (large capacity, temperature up to 85 o C), one RID-20A Refractive Index Detector, two Shodex HPLC Preparatory Scale Column (KF-2004), one

  16. Purification of Peptide Components including Melittin from Bee Venom using gel filtration chromatography and propionic acid/urea polyacrylamide gel electrophoresis

    Directory of Open Access Journals (Sweden)

    Young Chon Choi

    2006-06-01

    Full Text Available Objectives : This study was conducted to carry out Purification of Melittin and other peptide components from Bee Venom using gel filtration chromatography and propionic acid/urea polyacrylamide gel electrophoresis Methods : Melittin and other peptide components were separated from bee venom by using gel filtration chromatography on Sephadex G-50 column in 0.05M ammonium acetate buffer. Results : Melittin and other peptide components were separated from bee venom by using gel filtration chromatography on Sephadex G-50 column in 0.05M ammonium acetate buffer. The fractions obtained from gel filtration chromatography was analyzed by using SDS-PAGE and propionic acid/urea polyacrylamide gel electrophoresis. The melittin obtained from the gel filtration contained residual amount of phospholipase A2 and a protein with molecular weight of 6,000. The contaminating proteins were removed by the second gel filtration chromatography. Conclusion : Gel filtration chromatography and propionic acid/urea polyacrylamide gel electrophoresis are useful to separate peptide components including melittin from bee venom.

  17. Regenerated silica gel as stationary phase on vacuum column chromatography to purify temulawak’s extracts

    Energy Technology Data Exchange (ETDEWEB)

    Cahyono, Bambang; Maduwu, Ratna Dewi; Widayat,; Suzery, Meiny [Organic Chemistry Laboratory, Departement of Chemistry, Diponegoro University Jln Prof. Soedharto SH, Tembalang, Semarang 50275, Indonesia Tel / Fax: (024) 7460058 (Indonesia)

    2015-12-29

    Commercial silica gel only used once by many researchers and affected high cost for purification process, also less support the green chemistry program. This research focused in regeneration silica gel that used purification of temulawak’s extracts (Curcuma xanthorrhiza Roxb) by vacuum column chromatography. Sample extracts (contains 10.1195±0.5971% of curcuminoids) was purified by vacuum column chromatography (pressure: 45 kPa, column: 100mm on length and 16mm on diameter). Ethanol 96% and acetone were compared as eluent. The amount of solvent and yield of curcuminoids used as indicator purification. The silica gel was regenerated with heating in 600°C for 8 hours The silica gels were analyzed by IR spectroscopy and X-ray diffraction. Furthermore, regenerated silica gel was used as the stationary phase in vacuum column chromatography under the same conditions with the previous purification. All the purification experiments were performed in three repetitions. Based on regression equation, y=0.132x+0.0011 (r{sup 2}=0.9997) the yield of curcuminoids on purified products using ethanol as the eluent was improved 4.26% (to 14.3724±0.5749%) and by acetone was improved 3,03% (to 13.1450 ±0.6318%). The IR spectrum of both silica gel showed the same vibration profile and also there were three crystallinity peaks missing on its X-ray diffraction. Regenerated silica gel has the same performance with new silica gel in purification of temulawak’s extract: by ethanol has increased 4.08% (14.1947±0.7415%) and 2.93% (13.0447±0.4822) by acetone. In addition, all purification products showed similar TLC profiles. Purification using regenerated silica gel as the adsorbent on vacuum column chromatography has exactly same potential with the new silica gel.

  18. Regenerated silica gel as stationary phase on vacuum column chromatography to purify temulawak's extracts

    Science.gov (United States)

    Cahyono, Bambang; Maduwu, Ratna Dewi; Widayat, Suzery, Meiny

    2015-12-01

    Commercial silica gel only used once by many researchers and affected high cost for purification process, also less support the green chemistry program. This research focused in regeneration silica gel that used purification of temulawak's extracts (Curcuma xanthorrhiza Roxb) by vacuum column chromatography. Sample extracts (contains 10.1195±0.5971% of curcuminoids) was purified by vacuum column chromatography (pressure: 45 kPa, column: 100mm on length and 16mm on diameter). Ethanol 96% and acetone were compared as eluent. The amount of solvent and yield of curcuminoids used as indicator purification. The silica gel was regenerated with heating in 600°C for 8 hours The silica gels were analyzed by IR spectroscopy and X-ray diffraction. Furthermore, regenerated silica gel was used as the stationary phase in vacuum column chromatography under the same conditions with the previous purification. All the purification experiments were performed in three repetitions. Based on regression equation, y=0.132x+0.0011 (r2=0.9997) the yield of curcuminoids on purified products using ethanol as the eluent was improved 4.26% (to 14.3724±0.5749%) and by acetone was improved 3,03% (to 13.1450 ±0.6318%). The IR spectrum of both silica gel showed the same vibration profile and also there were three crystallinity peaks missing on its X-ray diffraction. Regenerated silica gel has the same performance with new silica gel in purification of temulawak's extract: by ethanol has increased 4.08% (14.1947±0.7415%) and 2.93% (13.0447±0.4822) by acetone. In addition, all purification products showed similar TLC profiles. Purification using regenerated silica gel as the adsorbent on vacuum column chromatography has exactly same potential with the new silica gel.

  19. The Role Seemingly of Amorphous Silica Gel Layers in Chiral Separations by Planar Chromatography

    Directory of Open Access Journals (Sweden)

    Teresa Kowalska

    2007-12-01

    Full Text Available In planar chromatography, silica gel appears as the most frequently used adsorbent. Its preference as planar chromatographic stationary phase is due to its high specific surface area (ca. 700 m2 g-1 and relatively simple active sites (silanol groups, Si-OH. The high specific surface area of silica gel and a high density of coverage of its surface with the silanol active sites contribute jointly to an excellent separation performance of this adsorbent. In our experiments on chiral separation of the enantiomer pairs by planar chromatography, contradictory behavior of the silica gel layers versus the chiral compounds was observed. The migration tracks of chiral compounds in the ascending planar chromatographic mode were not vertical but bent on either side being a function of analyte chirality. This deviation of the analyte’s migration track was noticed, when using the densitometric scanner to quantify the respective chromatograms. In order to confirm the hypothesis as to the microcrystalline nature of silica gel used in liquid chromatography, it was further investigated through circular dichroism (CD and the data thereof confirmed that the ‘chromatographic’ silica gels are not amorphous but microcrystalline, contributing to the (partial horizontal enantioseparation of the antimer pairs. This paper summarizes the results of our investigation on the microcrystalline nature of silica gels used in planar chromatography and their impact on enantioseparation of the selected pairs of antimers.

  20. Topical delivery of clobetasol propionate loaded microemulsion based gel for effective treatment of vitiligo: ex vivo permeation and skin irritation studies.

    Science.gov (United States)

    Patel, Hetal K; Barot, Bhavesh S; Parejiya, Punit B; Shelat, Pragna K; Shukla, Arunkumar

    2013-02-01

    The aim of the present investigation was to evaluate microemulsion as a vehicle for dermal drug delivery and to develop microemulsion based gel (MBC) of clobetasol propionate (CP) for the effective treatment of vitiligo. D-Optimal mixture experimental design was adopted to optimize the amount of oil (X(1)), S(mix) (mixture of surfactant and cosurfactant) (X(2)) and water (X(3)) in the microemulsion. The formulations were assessed for globule size (nm) (Y(1)) and solubility of CP in microemulsion (mg/ml) (Y(2)). The microemulsion containing 3% oil, 45% S(mix) and 50% water was selected as the optimized batch (ME). The globule size and solubility of CP in ME were 18.26 nm and 36.42 mg/ml respectively. Transmission electron microscopy showed that ME globules were spherical in shape. Carbopol 934P was used to convert microemulsion containing drug into gel form without affecting its structure. Ex-vivo permeation studies showed that cumulative amount of CP permeated (Q(n)) from ME, MBC and market formulation (MFCP) at 8h after application were 53.6±2.18, 28.43±0.67 and 37.73±0.77 μg cm(-2) respectively. MBC showed greater retention of CP in to skin layers than ME and MFCP. Skin irritation studies showed MBC to be significantly less irritating than MFCP. Photomicrographs and scanning electron micrographs of skin sections treated with MBC showed significant changes in the skin structure, which was attributed to the interaction of microemulsion components with skin resulting in permeation enhancement and retention of CP into skin layers. It was concluded that CP loaded gel could be a promising formulation for effective treatment of vitiligo.

  1. A Laboratory Exercise for Visible Gel Filtration Chromatography Using Fluorescent Proteins

    Science.gov (United States)

    Zhang, Wenqiang; Cao, Yibin; Xu, Lishan; Gong, Jufang; Sun, Meihao

    2015-01-01

    Gel filtration chromatography (GFC) separates molecules according to size and is one of the most widely used methods for protein purification. Here, red fluorescent protein (RFP), green fluorescent protein (GFP), yellow fluorescent protein (YFP), cyan fluorescent protein (CFP), and/or their fusion proteins were prokaryotically expressed, purified,…

  2. A Laboratory Exercise for Visible Gel Filtration Chromatography Using Fluorescent Proteins

    Science.gov (United States)

    Zhang, Wenqiang; Cao, Yibin; Xu, Lishan; Gong, Jufang; Sun, Meihao

    2015-01-01

    Gel filtration chromatography (GFC) separates molecules according to size and is one of the most widely used methods for protein purification. Here, red fluorescent protein (RFP), green fluorescent protein (GFP), yellow fluorescent protein (YFP), cyan fluorescent protein (CFP), and/or their fusion proteins were prokaryotically expressed, purified,…

  3. DEAE-Affi-Gel Blue chromatography of human serum: use for purification of native transferrin.

    Science.gov (United States)

    Werner, P A; Galbraith, R M; Arnaud, P

    1983-10-01

    Human serum was subjected to chromatography on DEAE-Affi-Gel Blue which combines ion-exchange and pseudo-ligand-affinity chromatography in a 0.02 M phosphate buffer, pH 7.0. All serum proteins were bound with the exception of transferrin, IgG (immunoglobulin G) and trace amounts of IgA. After a second step of Sephadex G-100 gel chromatography, or affinity chromatography against goat anti-human IgG F(ab')2 coupled to AH-Sepharose 4B, IgG and IgA were removed. The transferrin obtained was homogeneous and of high yield (greater than 80%), and was unaltered as judged by analyses of molecular weight, isoelectric point, iron-binding capacity, antigenicity, and ability to bind to high-affinity specific cellular receptors. Thus, DEAE-Affi-Gel Blue chromatography may be used as the basis for a simple, rapid, two-step method for the purification of large amounts of native transferrin from serum.

  4. Monosized macroporous resins with epoxy groups and their structure and gel chromatography properties

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The monosized macroporous-polymer beads based on cross-linked poly(glycidyl methacrylate) have been synthesized by a new improving method--combining dispersion polymerization with swelling polymerization and polymeric solution porogens. The structure and gel chromatographic properties of the resins have been studied. The resins as matrix materials of various types of high performance liquid chromatography (HPLC) packings possess excellent separation properties

  5. One-step purification of mouse monoclonal antibodies from ascitic fluid by DEAE Affi-Gel blue chromatography.

    Science.gov (United States)

    Bruck, C; Portetelle, D; Glineur, C; Bollen, A

    1982-09-30

    Monoclonal antibodies can be purified directly from ascitic fluids by chromatography on a DEAE Affi-gel blue column. Optimal conditions were determined for the recovery of immunoglobulins free of contaminating protease and nuclease activities.

  6. Development and validation of a simple and rapid liquid chromatography method for the determination of genistein in skin permeation studies.

    Science.gov (United States)

    Maione-Silva, Lorena; Rocha, Kamilla Amaral David; de Oliveira, Lidiane Correia; Taveira, Stephânia Fleury; Lima, Eliana Martins

    2012-01-01

    Genistein (GEN) has potential advantages for topical skin delivery, but no literature data are available for its quantitation in different skin layers, such as the stratum corneum (SC). Therefore, a simple, rapid, selective and sensitive bioanalytical method was developed and validated for GEN quantitation in porcine skin samples following in vitro permeation studies. GEN was assayed by HPLC with UV-Vis detection (270 nm) using 0.5% acetic acid in water-n-propanol-acetonitrile (50 : 2 : 48, v/v/v) as mobile phase (flow-rate of 1.0 mL/min). Specificity was demonstrated since endogenous skin components did not interfere with GEN peak. Standard analytical curve was linear over the concentration range (0.1-60 µg/mL) and the lower limit of quantitation was determined for different skin layers (100 ng/mL). GEN recovery from skin layers ranged from 95.57 to 97.57%. Permeation studies were carried out using an automated vertical diffusion cell apparatus. No fluctuation on the amount of GEN retained in the SC was observed over time, but increasing amounts of the drug were found in deeper layers of the skin. The method was reliable and reproducible for the quantitation GEN in skin samples enabling the determination of the cutaneous penetration profile of this drug in permeation experiments.

  7. A simple method for purification of rat alpha-fetoprotein by affi-gel blue chromatography and disc electrophoresis

    Directory of Open Access Journals (Sweden)

    Miyazaki,Masahiro

    1981-12-01

    Full Text Available Alpha-getoprotein (AFP was purified from fetal rat serum by a combined technique of affinity chromatography with Affi-Gel Blue and disc electrophoresis followed by extraction of AFP from the gel. The purified AFP was immunologically identical with the original AFP in fetal rat serum.

  8. A simple method for purification of rat alpha-fetoprotein by affi-gel blue chromatography and disc electrophoresis

    OpenAIRE

    Miyazaki, Masahiro; Matsuura,Kazuhiko; Wahid, Syarifuddin; Izumi, Masaki; Taketa, Kazuhisa; Sato,Jiro

    1981-01-01

    Alpha-getoprotein (AFP) was purified from fetal rat serum by a combined technique of affinity chromatography with Affi-Gel Blue and disc electrophoresis followed by extraction of AFP from the gel. The purified AFP was immunologically identical with the original AFP in fetal rat serum.

  9. Novel techniques for petroleum analysis. Vol. 2. Fundamenals of chromatography, instruments and application - an extension of the application according to environmental analysis and forensic analysis according to the hydrocarbons in petroleum. 2. new rev. and enl. ed.; Neue Mineraloelanalyse. Bd. 2. Chromatographie in Grundlagen, Geraeten und Anwendung - Anwendung erweitert um die Umwelt- und forensische Analyse bezueglich der Mineraloelkohlenwasserstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Kaegler, S.H.; Schindlbauer, H. (eds.)

    2007-07-01

    The authors of the book under consideration report on the state-of-the-art of the chromatographic analysis technique and its applications. In particular the chapter of pure petroleum analysis was extended by the environmental analysis and forensic analysis. Following the introduction to chromatography the authors report on columnchromatography under standard conditions, high-pressure liquid chromatography (HPLC), ion chromatography, gel permeation chromatography, thin-film chromatography, gas chromatography as well as the linkage of gas chromatography with mass spectrometry.

  10. Enhancement of skin permeation of ibuprofen from ointments and gels by sesame oil, sunflower oil and oleic acid

    Directory of Open Access Journals (Sweden)

    Dinda S

    2006-01-01

    Full Text Available Several batches of paraffin ointments were prepared and ibuprofen was incorporated into them. Sesame oil, sunflower oil, and oleic acid in different concentrations were incorporated into different batches. Commercial ibuprofen gel was obtained and divided into several batches and different concentrations of sesame oil, sunflower oil, and oleic acid were incorporated into them. The in vitro drug release characteristics through hairless (88 mm rat skin was carried out by using modified Insertion cell designed in our laboratory. The cell was placed into a borosil beaker containing 50 ml of pH 7.4 phosphate buffer as the diffusion fluid. The beaker was placed over the magnetic stirrer, which was maintained at 37±0.5° to maintain the temperature of diffusion fluid. The released drug content at predetermined time interval was measured using U-V-double beam spectrophotometer at 272 nm. The drug release was raised with increase in oil concentration.

  11. Serial displacement chromatofocusing and its applications in multidimensional chromatography and gel electrophoresis: II. Experimental results.

    Science.gov (United States)

    Shen, Hong; Li, Xiang; Bieberich, Charles; Frey, Douglas D

    2009-02-06

    Part I of this study investigated the theory and basic characteristics of "serial displacement chromatofocusing" (SDC). In Part II of this study, SDC is applied to two prototype applications which have potential uses in proteomics and related areas involving the analysis of complex analyte mixtures. In the first application, SDC was used as a prefractionation method prior to two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) to separate a human prostate cancer cell lysate. It was observed that the resolution achieved in narrow-pI-range 2D-PAGE was improved when using SDC prefractionation, so that SDC may be useful as a low-cost, high-speed, and highly scalable alternative to electrophoretic prefractionation methods for 2D-PAGE. The second application involves the use of SDC as the first dimension, and reversed-phase chromatography as the second dimension, to produce a novel, fully automated, two-dimensional high-performance liquid chromatography technique. The method was shown to have performance advantages over one-dimensional reversed-phase chromatography for peptide separations.

  12. Preparation of baicalin nasal gel and its permeation through nasal mucosa%黄芩苷鼻用凝胶的制备及其经鼻扩散研究

    Institute of Scientific and Technical Information of China (English)

    国大亮; 何新; 刘玉璇; 张艳军

    2013-01-01

    目的 制备黄芩苷鼻用凝胶剂,并对其进行体外扩散评价.方法 以卡波姆-936为凝胶基质,以丙三醇为助溶剂,用三乙醇胺调节pH值和黏度,采用正交设计对处方进行优化,并以离体猪鼻黏膜透皮扩散法测定黄芩苷在鼻用凝胶中的释放速率.结果 黄芩苷鼻用凝胶最佳处方为卡波姆-936用量0.5%,丙三醇用量30%,载药量2%; pH值为6.85~7.00,平均黏度1 850~2 350 Pa.s;黄芩苷经猪鼻黏膜扩散符合一级动力学过程,回归方程为Y=0.280 6X+0.564 3,r=0.997,扩散速率约为0.280 6 μg/(mm2.h).结论 黄芩苷鼻用凝胶制备工艺简便,黄芩苷主要以简单扩散方式透过鼻黏膜.%Objective To prepare the nasal gel of baicalin and to evaluate its permeation in vitro.Methods The orthogonal design was carried out using Cabopol-936 as gel matrix,glycerine as solubilizer,and triethanolamine as pH value and viscosity adjuster.The permeating rate of baicalin from nasal gel was determined through pig nasal mucosa in vitro by transdermal diffusion method.Results The optimum nasal gel was made by 0.5% Carbomer-936,30% glycerine,and 2% baicalin,with pH value 6.85-7.00,and the average viscosity was 1 850-2 350 Pa·s.The permeation of baicalin through nasal mucosa was fitted with first-order kinetics,the regression equation was Y=0.280 6 X+0.564 3,r=0.997,and the permeating rate was 0.280 6 μg/(mm2·h).Conclusion The preparation of baicalin nasal gel is simple.Baicalin is almost permeated through nasal mucosa by simple diffusion.

  13. Quantitative analysis of natural cyclodextrins by high-performance liquid chromatography with pulsed amperometric detection: application to cell permeation study.

    Science.gov (United States)

    Toropainen, Tarja; Jarho, Pekka; Lehtonen, Marko; Keski-Rahkonen, Pekka; Raatikainen, Heli; Järvinen, Tomi

    2008-05-01

    Simple HPLC-PAD methods were developed for quantitation of cyclodextrins (CDs) in aqueous matrices from in vitro cell permeation studies. C-18 solid-phase extraction was used for sample pretreatment. Samples were analysed using acetonitrile-water mobile phase with post-column alkalization by 0.5M NaOH. Zorbax SB-Aq (for alpha-CD) and Zorbax SB-Phenyl (for beta-CD and gamma-CD) columns gave excellent peak shape and sufficient resolution of CD to glucose (2.7-3.2). The methods showed good concentration-response relationship (r > or = 0.999), precision (RSD% 0.7-5.1), repeatability (RSD% 3.4-13.7) and accuracy (87-107%). The limits of quantitation were 0.78, 0.46 and 0.52 microg/ml for alpha-CD, beta-CD and gamma-CD (RSD% of 10.6, 8.1 and 16.3, respectively).

  14. Open-Source-Based 3D Printing of Thin Silica Gel Layers in Planar Chromatography.

    Science.gov (United States)

    Fichou, Dimitri; Morlock, Gertrud E

    2017-02-07

    On the basis of open-source packages, 3D printing of thin silica gel layers is demonstrated as proof-of-principle for use in planar chromatography. A slurry doser was designed to replace the plastic extruder of an open-source Prusa i3 printer. The optimal parameters for 3D printing of layers were studied, and the planar chromatographic separations on these printed layers were successfully demonstrated with a mixture of dyes. The layer printing process was fast. For printing a 0.2 mm layer on a 10 cm × 10 cm format, it took less than 5 min. It was affordable, i.e., the running costs for producing such a plate were less than 0.25 Euro and the investment costs for the modified hardware were 630 Euro. This approach demonstrated not only the potential of the 3D printing environment in planar chromatography but also opened new avenues and new perspectives for tailor-made plates, not only with regard to layer materials and their combinations (gradient plates) but also with regard to different layer shapes and patterns. As such an example, separations on a printed plane layer were compared with those obtained from a printed channeled layer. For the latter, 40 channels were printed in parallel on a 10 cm × 10 cm format for the separation of 40 samples. For producing such a channeled plate, the running costs were below 0.04 Euro and the printing process took only 2 min. All modifications of the device and software were released open-source to encourage reuse and improvements and to stimulate the users to contribute to this technology. By this proof-of-principle, another asset was demonstrated to be integrated into the Office Chromatography concept, in which all relevant steps for online miniaturized planar chromatography are performed by a single device.

  15. Characterization of immunogenic Clonorchis sinensis protein fractions by gel fitration chromatography

    Directory of Open Access Journals (Sweden)

    Duan Pham Ngoc

    2015-04-01

    Full Text Available Objective: To characterize immunogenic protein fraction of Clonorchis sinensis (C. sinensis by partial purification. Methods: A total of 30 hamsters were infected with 50 C. sinensis metacercariae, and then C. sinensis protein was purified by gel filtration chromatography. Indirect ELISA and immunoblot were used to detect the antibody in sera of hamsters infected with C. sinensis. Results: The gel filtration showed 2 peaks at high (fraction No. 10 to 14 and low (fraction No. 21 to 26 molecular weight proteins. Indirect ELISA showed that both antibodies of clonorchiasis and opisthorchiasis reacted strongly with early fractions (6 to 14 and the reaction was gradually reduced at middle and late fractions (15 to 50. Both antibodies showed different individual fraction of C. sinensis by immunoblot. It showed several protein bands that the 34 and 37 kDa were major proteins. The 53 kDa protein which was only found in the clonorchiasis reacted with fraction 20. Conclusions: The purified antigen of C. sinensis reacted similarly with both antibodies of clonorchiasis and opisthorchiasis where strong reaction was seen with early fractions. The C. sinensis protein fraction No. 20 may be useful for immunodiagnosis of clonorchiasis.

  16. Comparison of antimicrobial peptide purification via free-flow electrophoresis and gel filtration chromatography.

    Science.gov (United States)

    Xia, Zhi-Jun; Liu, Zhen; Kong, Fan-Zhi; Fan, Liu-Yin; Xiao, Hua; Cao, Cheng-Xi

    2017-08-12

    Antimicrobial peptides (AMPs) are usually small and cationic biomolecules with broad-spectrum antimicrobial activities against pathogens. Purifying them from complex samples is essential to study their physiochemical properties. In this work, free-flow zone electrophoresis (FFZE) was utilized to purify AMPs from yeast fermentation broth. Meanwhile, gel filtration chromatography (GFC) was conducted for comparison. The separation efficiency was evaluated by SDS-PAGE analysis of the fractions from both methods. Our results demonstrated as follows: (i) FFZE had more than 30-fold higher processing capacity as compared with GFC; (ii) FFZE could achieve 87% purity and 89% recovery rate while in GFC these parameters were about 93 and 82%, respectively; (iii) the former had ∼2-fold dilution but the latter had ∼13-fold dilution. Furthermore, Tricine-SDS-PAGE, Native-PAGE, and gel IEF were carried out to characterize the purified AMPs. We found that two peptides existed as a pair with the molecular mass of ∼5.5 and 7.0 kDa, while the same pI 7.8. These two peptides were proved to have the antimicrobial activity through the standardized agar diffusion method. Therefore, FFZE could be used to continuously purify AMPs with high bioactivity, which will lead to its wide application in the clinical and pharmaceutical fields. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Short communication: Quantification of carbohydrates in whey permeate products using high-performance anion-exchange chromatography with pulsed amperometric detection.

    Science.gov (United States)

    Lee, Hyeyoung; de MeloSilva, Vitor Luiz; Liu, Yan; Barile, Daniela

    2015-11-01

    A method was developed for the characterization and quantification of the disaccharide lactose and 3 major bovine milk oligosaccharides (BMO) in dairy streams. Based on high-performance anion-exchange chromatography-pulsed amperometric detection (HPAE-PAD), this method is advantageous because it requires minimal sample preparation and achieves good chromatographic separation of oligosaccharide isomers within 30min. The linear dynamic range and limit of detection were 0.1 to 10mg/L and 0.03 to 0.22mg/L, respectively. Mean recoveries of the BMO were excellent and ranged from 98.4 to 100.4%. Without complicated sample preparation procedures, this HPAE-PAD method measured BMO [3'-sialyllactose (3'SL), 6'-sialyllactose (6'SL), and 6'-sialyllactosamine (6'SLN)] and lactose using a single instrument, therefore increasing the accuracy of the measurement and applicability for the dairy industry. In colostrum whey permeate, 3'SL, 6'SL, and 6'SLN were 94, 29, and 46mg/L, respectively. This work is the first to demonstrate that some commercial products, currently marketed for supporting a healthy immune system, contain significant amounts of bioactive BMO and therefore, carry additional bioactivities.

  18. Indirect fluorometric detection techniques on thin layer chromatography and effect of ultrasound on gel electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Yinfa, Ma.

    1990-12-10

    Thin-layer chromatography (TLC) is a broadly applicable separation technique. It offers many advantages over high performance liquid chromatography (HPLC), such as easily adapted for two-dimensional separation, for whole-column'' detection and for handling multiple samples, etc. However, due to its draggy development of detection techniques comparing with HPLC, TLC has not received the attention it deserves. Therefore, exploring new detection techniques is very important to the development of TLC. It is the principal of this dissertation to present a new detection method for TLC -- indirect fluorometric detection method. This detection technique is universal sensitive, nondestructive, and simple. This will be described in detail from Sections 1 through Section 5. Section 1 and 3 describe the indirect fluorometric detection of anions and nonelectrolytes in TLC. In Section 2, a detection method for cations based on fluorescence quenching of ethidium bromide is presented. In Section 4, a simple and interesting TLC experiment is designed, three different fluorescence detection principles are used for the determination of caffeine, saccharin and sodium benzoate in beverages. A laser-based indirect fluorometric detection technique in TLC is developed in Section 5. Section 6 is totally different from Sections 1 through 5. An ultrasonic effect on the separation of DNA fragments in agarose gel electrophoresis is investigated. 262 refs.

  19. Combined computational-experimental approach to predict blood-brain barrier (BBB) permeation based on "green" salting-out thin layer chromatography supported by simple molecular descriptors.

    Science.gov (United States)

    Ciura, Krzesimir; Belka, Mariusz; Kawczak, Piotr; Bączek, Tomasz; Markuszewski, Michał J; Nowakowska, Joanna

    2017-09-05

    The objective of this paper is to build QSRR/QSAR model for predicting the blood-brain barrier (BBB) permeability. The obtained models are based on salting-out thin layer chromatography (SOTLC) constants and calculated molecular descriptors. Among chromatographic methods SOTLC was chosen, since the mobile phases are free of organic solvent. As consequences, there are less toxic, and have lower environmental impact compared to classical reserved phases liquid chromatography (RPLC). During the study three stationary phase silica gel, cellulose plates and neutral aluminum oxide were examined. The model set of solutes presents a wide range of log BB values, containing compounds which cross the BBB readily and molecules poorly distributed to the brain including drugs acting on the nervous system as well as peripheral acting drugs. Additionally, the comparison of three regression models: multiple linear regression (MLR), partial least-squares (PLS) and orthogonal partial least squares (OPLS) were performed. The designed QSRR/QSAR models could be useful to predict BBB of systematically synthesized newly compounds in the drug development pipeline and are attractive alternatives of time-consuming and demanding directed methods for log BB measurement. The study also shown that among several regression techniques, significant differences can be obtained in models performance, measured by R(2) and Q(2), hence it is strongly suggested to evaluate all available options as MLR, PLS and OPLS. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Determination of carbofuran residue in strawberry by GC/MS coupled with gel permeation chromatographic purification%凝胶渗透色谱净化气相色谱质谱联用法测定草莓中残留的克百威

    Institute of Scientific and Technical Information of China (English)

    王天; 杨鸿波; 聂积; 王艳娇; 谭红; 何锦林

    2011-01-01

    A method to determination of carbofuran residue in strawberry, samples were cleaned up by auto gel permeation chromatography, gas chromatography-mass spectrometry(GC/MS) for quantitative and qualitative analysis.The standard cure was linear in the investigated range of 0.01~5.0mg/L with correlation coefficient is 0.9997; the recoveries were 87.6%~92.4% with the relative standard deviations(RSD)of 3.4%~5.1%; the detection limit of carbofuran was 0.01mg/kg.%建立草莓中残留的克百威的分析方法,样品采用凝胶色谱(GPC)净化技术,气相色谱-质谱联用(GC/MS)法定性和定量.线性范围为0.01~5.0mg/L,相关系数为0.9997;加标回收率为87.6%~92.4%,相对标准偏差(RSD)为3.4%~5.1%;方法的检出限为0.01mg/kg.

  1. NADP-specific isocitrate dehydrogenase of Escherichia coli. IV. Purification by chromatography on Affi-Gel Blue.

    Science.gov (United States)

    Vasquez, B; Reeves, H C

    1979-05-23

    Affinity chromatography on Affi-Gel Blue has been used to purify the NADP-specific isocitrate dehydrogenase (EC 1.1.1.42) from Escherichia coli. The protocol permits rapid purification of the enzyme in milligram quantities with a yield of 50% and is carried out almost entirely at room temperature. The preparation was judged to be homogeneous by non-denaturing electrophoresis at pH 7.5 and denaturing electrophoresis in the presence of sodium dodecyl sulfate. The subunit molecular weight of 53 000, determined by sodium dodecyl sulfate gel electrophoresis, is in reasonable agreement with the value of 46 900 estimated from the amino acid composition data.

  2. Germania-based, sol-gel hybrid organic-inorganic coatings for capillary microextraction and gas chromatography.

    Science.gov (United States)

    Fang, Li; Kulkarni, Sameer; Alhooshani, Khalid; Malik, Abdul

    2007-12-15

    Germania-based, sol-gel hybrid organic-inorganic coatings were developed for capillary microextraction and gas chromatography (GC). Being an isostructural analogue of SiO2, GeO2 is compatible with the silica network. Because of this similarity, germania-based materials possess great potential for being used in the areas of chromatographic separation and sample preparation. These possibilities, however, remain practically unexplored. To our knowledge, this is the first instance that a germania-based hybrid sol-gel material is used as a sorbent in analytical sample preparation or chromatographic separation. Tetramethoxygermane was used as a precursor to create a sol-gel network via hydrolytic polycondensation reactions performed within a fused-silica capillary. The growing sol-gel germania network was simultaneously reacted with an organic ligand that contained sol-gel-active sites in its chemical structure. Three different sol-gel-active ligands were used: (a) hydroxy-terminated poly(dimethylsiloxane), (b) hydroxy-terminated poly(dimethyldiphenylsiloxane), and (c) 3-aminopropyltrimethoxysilane. Sol-gel germania-coated capillaries of desired polarity and extraction selectivity were prepared by using an appropriately selected sol-gel-active ligand in the sol solution. These capillaries were further used to extract trace concentrations of polycyclic aromatic hydrocarbons, aldehydes, ketones, alcohols, phenols, and free fatty acids from aqueous samples. The extracted solutes were further analyzed by GC-FID. The new germania-based coatings showed excellent stability under harsh operation conditions involving extreme pH values, high temperatures, and aggressive solvents. Our preliminary results also indicate that sol-gel hybrid germania coatings have the potential to offer great analytical performance as GC stationary phases.

  3. Gel Electrophoresis, Gel Chromatography and Sedimentation Analysis of Histones and Protamines in the Presence of Nonionic Surfactants

    OpenAIRE

    Hamana, Koei

    1982-01-01

    Histones and protamines behaved as a monomeric form in 0.9M acetic acid. When gel electrophoresis was carried out in 0.9M acetic acid, the mobilities of calf H2A, H2B, H3 and H4 histones were decreased proportionaly to the helix content of the histones but the mobilities of calf H1 histone and fish protamines were not decreased by the addition of 6mM nonionic surfactant into the gel. Degree of the decreasing on the mobilities of four histones was also proportional to the molecular weight of t...

  4. A Continuous Procedure Based on Column Chromatography to Purify Anthocyanins from Schisandra chinensis by a Macroporous Resin plus Gel Filtration Chromatography.

    Science.gov (United States)

    Yue, Daran; Yang, Lei; Liu, Shouxin; Li, Jian; Li, Wei; Ma, Chunhui

    2016-02-06

    In our previous study, as natural food colorants and antioxidants, the color and content stabilities of Schisandra chinensis (S. chinensis) anthocyanins were investigated. In this work, the purification process parameters of S. chinensis anthocyanins using a macroporous resin and gel filtration chromatography were evaluated. The optimized parameters of static adsorption and desorption were as follows. The selected resin is HPD-300 (nonpolar copolymer styrene type resin), and the anthocyanins adsorption saturation capacity of HPD-300 resin was 0.475 mg/g dry resin. Adsorption time was 4 h, and 0.517 mg/mL of S. chinensis anthocyanins was adsorbed on the resin column with a flow rate of 39 mL/h (3 BV/h). After adsorption, the anthocyanins were completely desorpted with 2.5 BV of 90% (v/v) ethanol solution, and the desorption flow rate was 13 mL/h (1 BV/h). After purification by dynamic adsorption and desorption, the anthocyanins content in the effluent increased from 47.6 mg/g to 128.4 mg/g, the purity of anthocyanins increased six-fold from 5.08% to 30.43%, and the anthocyanins recovery was 96.5%. The major constituent of S. chinensis anthocyanins was isolated with Bio-Gel P2 gel filtration chromatography, and it was detected by liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS) as cyanidin-3-O-xylosylrutinoside. Moreover, the antioxidant activities of S. chinensis anthocyanins were investigated. After purification using the HPD-300 resin, the antioxidant activities of anthocyanins were increased 1.2-fold (FRAP) and 1.7-fold (ABTS).

  5. A Continuous Procedure Based on Column Chromatography to Purify Anthocyanins from Schisandra chinensis by a Macroporous Resin plus Gel Filtration Chromatography

    Directory of Open Access Journals (Sweden)

    Daran Yue

    2016-02-01

    Full Text Available In our previous study, as natural food colorants and antioxidants, the color and content stabilities of Schisandra chinensis (S. chinensis anthocyanins were investigated. In this work, the purification process parameters of S. chinensis anthocyanins using a macroporous resin and gel filtration chromatography were evaluated. The optimized parameters of static adsorption and desorption were as follows. The selected resin is HPD-300 (nonpolar copolymer styrene type resin, and the anthocyanins adsorption saturation capacity of HPD-300 resin was 0.475 mg/g dry resin. Adsorption time was 4 h, and 0.517 mg/mL of S. chinensis anthocyanins was adsorbed on the resin column with a flow rate of 39 mL/h (3 BV/h. After adsorption, the anthocyanins were completely desorpted with 2.5 BV of 90% (v/v ethanol solution, and the desorption flow rate was 13 mL/h (1 BV/h. After purification by dynamic adsorption and desorption, the anthocyanins content in the effluent increased from 47.6 mg/g to 128.4 mg/g, the purity of anthocyanins increased six-fold from 5.08% to 30.43%, and the anthocyanins recovery was 96.5%. The major constituent of S. chinensis anthocyanins was isolated with Bio-Gel P2 gel filtration chromatography, and it was detected by liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS as cyanidin-3-O-xylosylrutinoside. Moreover, the antioxidant activities of S. chinensis anthocyanins were investigated. After purification using the HPD-300 resin, the antioxidant activities of anthocyanins were increased 1.2-fold (FRAP and 1.7-fold (ABTS.

  6. Chromatography.

    Science.gov (United States)

    Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

    This booklet presents some activities on chromatography. Directions for preparing leaf pigment extracts using alcohol are given, and paper chromatography and thin-layer chromatography are described as modifications of the basic principles of chromatography. (KHR)

  7. Chromatography.

    Science.gov (United States)

    Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

    This booklet presents some activities on chromatography. Directions for preparing leaf pigment extracts using alcohol are given, and paper chromatography and thin-layer chromatography are described as modifications of the basic principles of chromatography. (KHR)

  8. Estudo de liberação e permeação in vitro do diclofenaco de dietilamônio em microemulsão gel-like In vitro release and permeation of a diclofenac diethylamine from microemulsion gel-like

    Directory of Open Access Journals (Sweden)

    José Alexsandro da Silva

    2009-01-01

    Full Text Available The goal of this study was to produce and characterize a new microemulsion gel-like carrier system (MEG by using the pseudo-ternary phase-diagram concept. The diclofenac diethylamine (DDA was incorporated in the MEG and its in vitro release and permeation profiles were performed using Franz-type diffusion cells. The results revealed that the commercial DDA emulgel provided significantly higher Kp of DDA (2.2-fold as compared to the MEG. Similar data were obtained in the permeation studies in which DDA Kp 4.7-fold higher. Therefore, MEG presents higher potential as a topical delivery system for DDA when compared to the commercial DDA emulgel.

  9. 透皮促渗剂对醋酸地塞米松壳聚糖凝胶透皮特性的影响%Effects of Transdermal Penetration Enhancers on the Permeation Properties of Dexamethasone Acetate Chitosan Gel

    Institute of Scientific and Technical Information of China (English)

    西娜; 段同华; 西传坡; 俞发; 何彬

    2011-01-01

    目的 观察透皮促渗剂对醋酸地塞米松壳聚糖凝胶透皮特性的影响.方法 实验分为无促渗剂组和促渗剂组.无促渗剂组为0.75%药物5%壳聚糖凝胶剂;促渗剂组根据含促渗剂不同又分为月桂氮酮+丙二醇、月桂氮酮、丙二醇+二甲亚砜、二甲亚砜+月桂氮酮组.以无毛大鼠皮肤为渗透屏障,进行体外渗透实验,分析该凝胶稳态透皮速率(Js)和Js提高率.结果 无促渗剂组①Js为(3.75±0.56) μg·(cm2)-1·h-1.促渗剂组效果明显,其中二甲亚砜+月桂氮酮组②Js为(8.12±0.58) μg·(cm2)-1·h-1,月桂氮酮+丙二醇组③Js为(5.41±0.74) μg·(cm2)-1·h-1,丙二醇+二甲亚砜组④Js为(4.31±0.42) μg·(cm2)-1·h-1,月桂氮酮组⑤Js为(4.35±0.36) μg·(cm2)-1·h-1.与①比较,②的Js提高率为2.17%(P<0.01),与③④⑤比较,②的Js分别为1.51,1.89,1.87倍(P<0.05或P<0.01).结论 混合促渗剂具有比单一促渗剂更好的促渗效果.%Objective To study effects of penetration enhancers on the transdermal permeation of dexamethasone acetate chitosan gel.Methods The permeation enhancer-free group and enhancer added group were set up.There were 0.75% dexamethasone acetate and 5% chitosan gel in the permeation enhancer-free group.The permeation enhancer group was composed of 0.75% dexamethasone acetate and 5% chitosan gel, which subdivided into azone plus propylene glycol, azone,propylene glycol plus dimethyl sulfoxide, and dimethyl sulfoxide plus azone groups.Skin samples as permeability barriers were obtained from hairless rats for in vitro tests of the drug permeability.The permeation parameters, named as steady srate flux( Js ) and Js enhancement ratio were evaluated.Results Js in the permeation enhancer-free group ①was (3.75 ± 0.56 ) μg · (cm2 )-1 · h-1 ,and that in the permeation enhancer group were( 8.12±0.58 ) μg · (cm2 ) · h-1( dimethyl sulfoxide plus azone group②)(5.41±0.74) μg · (cm2 )-1 · h-1( Azone plus

  10. Glycidol-modified gels for molecular-sieve chromatography. Surface hydrophilization and pore size reduction.

    Science.gov (United States)

    Eriksson, K O

    1987-11-01

    Divinyl sulfone-crosslinked agarose gels were made hydrophilic by coupling glycidol to the agarose chains. The concentration of glycidol in the reaction mixture determines the pore size of the gels (the glycidol molecules probably form polymers, the degree of polymerization increasing with the glycidol concentration). Gels prepared with moderate glycidol concentrations are still porous enough to be used for separation of proteins and peptides. Gels with a high degree of glycidol polymerization are suited for desalting of low-molecular-weight compounds, for instance peptides.

  11. Isolation and purification of uremic middle molecules by multi-step liquid chromatography

    Institute of Scientific and Technical Information of China (English)

    储结根; 何炳林; 刘晓航; 袁直

    2002-01-01

    Isolation and comparison of uremic sera and urine and normal sera and urine were performed by gel permeation chromatography, anion exchange chromatography and re-versed-phase high performance liquid chromatography. Two uremic middle molecular fractions (A and B) were obtained from uremic sera and urine and normal urine by gel permeation chromatography, but not from normal sera. The anion exchange chromatographic results of fraction A from different origins demonstrate that subfraction A-3 could be excreted in urine by healthy subject, but accumulated in uremic serum for renal failure of patient with uremia. After desalinization subfraction A-3 was analyzed by MALDI-TOF-MS. The results show that subfraction A-3 consists of six compounds with molecular weight 839, 873, 1007.94, 1106, 1680 and 2015 respectively. Finally, by reversed-phase high performance liquid chromatography, subfraction A-3 was further resolved into six independent fractions. Thus, the isolation and purification of six middle molecular c

  12. Rapid purification of mitochondrial hexokinase from rat brain by a single affinity chromatography step on Affi-Gel blue.

    Science.gov (United States)

    Wilson, J E

    1989-01-01

    The mitochondrial hexokinase from rat brain, selectively released from mitochondria by the action of glucose 6-phosphate, can be purified to greater than 90% homogeneity by a single affinity chromatography step on Affi-Gel Blue; the Cibacron Blue F3GA ligand bound to this matrix serves as an analog of ATP, the normal substrate for the enzyme, and selective elution is accomplished using glucose 6-phosphate which is a competitive ligand vs. ATP. With this and other modifications to the previously described procedure highly purified enzyme is readily obtained in good yield and with retention of the ability to rebind to mitochondria.

  13. Differential effects of DEAE negative mode chromatography and gel-filtration chromatography on the charge status of Helicobacter pylori neutrophil-activating protein.

    Science.gov (United States)

    Hong, Zhi-Wei; Yang, Yu-Chi; Pan, Timothy; Tzeng, Huey-Fen; Fu, Hua-Wen

    2017-01-01

    Helicobacter pylori neutrophil-activating protein (HP-NAP) is involved in H. pylori-associated gastric inflammation. HP-NAP is also a vaccine candidate, a possible drug target, and a potential diagnostic marker for H. pylori-associated diseases. Previously, we purified recombinant HP-NAP by one-step diethylaminoethyl (DEAE) negative mode chromatography by collecting the unbound fraction at pH 8.0 at 4°C. It remains unclear why HP-NAP does not bind to DEAE resins at the pH above its isoelectric point during the purification. To investigate how pH affects the surface net charge of HP-NAP and its binding to DEAE resins during the purification, recombinant HP-NAP expressed in Escherichia coli was subjected to DEAE negative mode chromatography at pH ranging from 7.0 to 9.0 at 25°C and the surface charge of purified HP-NAP was determined by capillary electrophoresis. A minimal amount of HP-NAP was detected in the elution fraction of DEAE Sepharose resin at pH 8.5, whereas recombinant HP-NAP was detected in the elution fraction of DEAE Sephadex resin only at pH 7.0 and 8.0. The purified recombinant HP-NAP obtained from the unbound fractions was not able to bind to DEAE resins at pH 7.0 to 9.0. In addition, the surface charge of the purified HP-NAP was neutral at pH 7.0 to 8.0 and was either neutral or slightly negative at pH 8.5 and 9.0. However, recombinant HP-NAP purified from gel-filtration chromatography was able to bind to DEAE Sepharose resin at pH 7.0 to 9.0 and DEAE Sephadex resin at pH 7.0. At pH 8.5 and 9.0, only the negatively charged species of HP-NAP were found. Thus, recombinant HP-NAP with different charge status can be differentially purified by DEAE negative mode chromatography and gel-filtration chromatography. Furthermore, the charge distribution on the surface of HP-NAP, the presence of impure proteins, and the overall net charge of the resins all affect the binding of HP-NAP to DEAE resins during the negative purification.

  14. Evaluation of whey, milk, and delactosed permeates as salt substitutes.

    Science.gov (United States)

    Smith, S T; Metzger, L; Drake, M A

    2016-11-01

    Whey and milk permeates are by-products of high-protein dairy powder manufacture. Previous work has shown that these permeates contribute to salty taste without contributing significantly to sodium content. The objective of this study was to explore the sensory characteristics and compositional analysis of permeates from different milk and whey streams and a low-sodium product application made from them. Skim milk, Cheddar, cottage, and Mozzarella cheese whey permeates were manufactured in triplicate, and delactosed whey permeate was obtained in triplicate. Composition (protein, fat, solids, minerals) was conducted on permeates. Organic acid composition was determined using HPLC. Volatile compounds were extracted from permeates by solid phase microextraction with gas chromatography-mass spectrometry. A trained sensory panel documented sensory attributes of permeates and cream of broccoli soups with and without salt or permeates followed by consumer acceptance testing (n=105) on the soups. Cottage cheese whey permeate contained a higher lactic acid content than other permeates, which has been shown to contribute to a higher salty taste. Cottage cheese whey permeate also contained potato or brothy and caramel flavors and sour and salty tastes, whereas delactosed whey permeate had high intensities of cardboard and beefy or brothy flavors and salty taste. Milk, Cheddar, and Mozzarella cheese whey permeates were characterized by sweet taste and cooked milky flavor. Permeates with higher cardboard flavor had higher levels of aldehydes. All permeates contributed to salty taste and to salty taste perception in soups; although the control soup with added salt was perceived as saltier and was preferred by consumers over permeate soups. Soup with permeate from cottage cheese was the least liked of all soups, likely due to its sour taste. All other permeate soups scored at parity for liking. These results demonstrate the potential for milk, whey, and delactosed permeates from

  15. Characterzation and separation of Al13 species using gel-filtration chromatography

    Institute of Scientific and Technical Information of China (English)

    CHU; Yongbao; GAO; Baoyu; YUE; Qinyan; WANG; Yan

    2006-01-01

    A polyaluminum chloride (PAC) sample was prepared using a slow alkaline titration method. The Bio-Gel P-100 gel column chromatographic technique was used to separate and characterize the various forms of aluminum present in the prepared PAC solution. The effluents from a gel column were monitored using online chemical method: Al-Ferron timed complexation spectrophotometry and by 27Al nuclear magnetic resonance (NMR) spectroscopy. Effects of different experimental conditions such as eluent flow rate, ionic strength and pH on separation of Al13 were investigated. Experimental results indicated that molecule size exclusion was not the only parameter affecting the column chromatographic separation efficiency of Al13 but molecule charge as well. Reducing the eluent flow rate, increasing the ionic strength and suitable pH resulted in increase in the separation efficiency. Experimental results clearly indicated that by varying the experimental conditions, it is possible to produce pure Al13 species using a gel column chromatographic technique.

  16. Phenyl Functionalized Sol-gel Silica Sorbent for Capillary Microextraction and Chromia-Based Sol-gel Ucon Stationary Phase for Capillary Gas Chromatography

    Science.gov (United States)

    McLean, Michael M.

    The first chapter of this thesis presents an introduction to sol-gel methodology whose usefulness as a synthetic route will be demonstrated with two applications in chromatography. The first application involves the fabrication of a capillary micro-extraction (CME) device by coating a phenyl functionalized extracting phase on the inner surface of a fused silica capillary for analyte pre-concentration. The device was coupled on-line to a RP-HPLC system and practicality was demonstrated using allergens as target analytes. The allergens chosen as model analytes are typically found in fragrance products and food. Most of the 26 fragrance allergens that are monitored by various government authorities have a phenyl organic moiety (a strong chromophore), thus making them appropriate probes for exploring the extraction efficiency of the coating using a UV detector. The CME device showed ppt level limit of detection which makes it suitable for trace analyses of allergens and similar compounds in a variety of matrices. The second application explores the feasibility of using sol-gel derived chromia-based stationary phase in gas chromatographic columns. The organic moiety of the stationary phase was derived from Ucon 75-H-90,000 while the inorganic backbone was prepared using chromium(III) dichloride hydroxide - methacrylic acid - aqua complex, 40% in isopropanol/acetone . Usefulness of prepared chromia-based GC stationary phase was examined for petrochemical application. Promising results were obtained using aliphatic-aromatics, polyaromatic hydrocarbons, BTEX test mixture, cycloalkanes, branched alkanes and akylbenzenes. The column was able to perform without degradation despite being rinsed multiples times sequentially with the following solvents: dichloromethane, methanol, water and finally methanol again. Maximum theoretical plate number calculated is around 2,400 plates/m. The plate number clearly needs improvement but is a promising result for the newly explored

  17. Sol-gel immunoaffinity chromatography for the clean up of ochratoxin A contaminated grains.

    Science.gov (United States)

    Reiter, Elisabeth Viktoria; Cichna-Markl, Margit; Tansakul, Natthasit; Shim, Won-Bo; Chung, Duck-Hwa; Zentek, Jürgen; Razzazi-Fazeli, Ebrahim

    2011-10-21

    This paper describes the application of sol-gel immunoaffinity columns for clean up of ochratoxin A contaminated cereal crops. Monoclonal antibodies selective for OTA have been entrapped into the pores of a sol-gel matrix in order to prepare immunoaffinity columns. Different parameters such as amount of entrapped antibodies and loading conditions were optimized to obtain highest possible recoveries of OTA. The method has been found to be a suitable tool in sample preparation prior to HPLC-FLD determination and as selective as conventional commercially available immunoaffinity columns. In the clean up of different cereals mean recoveries of 82±5%, 90±6% and 91±3%, were obtained for wheat, barley and rye, respectively, with sol-gel columns containing 1mg of anti-OTA antibodies. The detection limit (signal-to-noise ratio, 3) was 0.5 μg/kg and the limit of quantification (signal-to-noise ratio, 10) determined to be 1 μg/kg. Sol-gel columns can be reused 7 times without significant loss of recovery. After 10 applications the recovery decreased to approx. 50%.

  18. The Development of Gel Media and Columns for Large-Scale Chromatography of Proteins,a Historical Review

    Institute of Scientific and Technical Information of China (English)

    Jan-Christer; Janson

    2002-01-01

    Thr first dedicated protein chromatography media were introduced during the 1950s and 1960s.There was an early awareness of the possibility of using these for production applications within the biopharmaceutical industry.However,the crucial limitation was the fact that those media that were most compatible with proteins lent themselves less favourably to scaling-up.The problems were primarily physical.Thus the fibrous cellulose media showed bed cracking tendencies and the bead shaped polyacrylamide.dextran,and agarose gel media,then available, were too soft to stand the hydrodynamic forces acting in large columns,leading to bed compaction and increased pressure drop.At the time,the best solution to the latter problem,after a number of intermediary solutions were tried,was the introductionof the stacked column concept in which several short column segments were connected by small bore tubing,thus reducing the force acting on the particles in each bed com partment,However,the ultimate remedy,the introduction of chromatographic matrices that combine the desired features of adequate rigidity,macroporosity,biocompatibility,chemical stability(for CIP and SIP0and derivatizability,did not occur until the middle of the 1980s when adequately cross-linked agarose gel media such as Sepharose Fast Flow were made available.The paper also recognizes the many attempts made during the past 50 years to develop continous chromatography columns.Most of the designs are based on an annular bed or on an array of annularly arranged parallel columns continuously fed with samples in a cyclic manner.The introduction of media and columns for expanded bed adsorption followed a demand for rewer pruification steps and shorter process times.In recent years,columns have been ntroduced that allow packing and repacking without needing to open the column.The review provides an historical account of the developments that have led to the present state-of-the-art both regarding large diameter columns

  19. Solvent-resistant sol-gel polydimethyldiphenylsiloxane coating for on-line hyphenation of capillary microextraction with high-performance liquid chromatography.

    Science.gov (United States)

    Segro, Scott S; Malik, Abdul

    2008-09-26

    A sol-gel polydimethyldiphenylsiloxane (PDMDPS) coating was developed for capillary microextraction on-line hyphenated with high-performance liquid chromatography (HPLC). This coating was created using methyltrimethoxysilane (MTMS) as the sol-gel precursor and di-hydroxy-terminated PDMDPS as the sol-gel active polymer. The methyl and phenyl groups on the sol-gel active polymer and the methyl groups on the sol-gel precursor ultimately turned into pendant groups providing the ability to extract non-polar analytes. A 40-cm segment of 0.25 mm I.D. fused silica capillary containing the sol-gel PDMDPS coating was installed as an external sampling loop in an HPLC injection port. Aqueous samples containing polycyclic aromatic hydrocarbons (PAHs), aromatic compounds, ketones, and aldehydes were passed through this capillary wherein the analytes were extracted by the sol-gel coating. The extracted analytes were then transferred to the HPLC column using isocratic or gradient elution with an acetonitrile/water mobile phase. This capillary demonstrated excellent extraction capability for non-polar (e.g., polycyclic aromatic hydrocarbons and aromatic compounds) as well as moderately polar compounds, such as aromatic amines, ketones, and aldehydes. The test results indicate that PDMDPS can be successfully immobilized into a sol-gel network and that the resulting solvent-resistant sol-gel organic-inorganic hybrid coating can be effectively used for on-line hyphenation of capillary microextraction with high-performance liquid chromatography. The test results also indicate that the sol-gel PDMDPS coated capillary is resistant to high-temperature solvents, making it suitable for applications in high-temperature HPLC. To the best of our knowledge, this is the first report on the creation of a silica-based sol-gel PDMDPS coating used in capillary microextraction on-line hyphenated to HPLC.

  20. Characterization of phosphoproteins from electrophoretic gels by nanoscale Fe(III) affinity chromatography with off-line mass spectrometry analysis

    DEFF Research Database (Denmark)

    Stensballe, A; Andersen, Søren; Jensen, Ole Nørregaard

    2001-01-01

    Detailed characterization of phosphoproteins as well as other post-translationally modified proteins is required to fully understand protein function and regulatory events in cells and organisms. Here we present a mass spectrometry (MS) based experimental strategy for the identification and mapping...... chromatography (Fe(III)-IMAC) columns were employed for enrichment of phosphorylated peptides from crude peptide mixtures prior to off-line analysis by matrix-assisted laser desorption/ionization (MALDI) MS or nanoelectrospray tandem mass spectrometry (MS/MS). An optimized and sensitive procedure for alkaline...... of phosphorylation sites. The advantages and limitations of the experimental strategy was demonstrated by enrichment, identification and sequencing of phosphopeptides from the model proteins ovalbumin and bovine beta-casein isolated by gel electrophoresis. Furthermore, an autophosphorylation site at Ser-3...

  1. Determination of Formaldehyde in Frozen Fish with Formaldehyde Dehydrogenase Using a Flow Injection System with an Incorporated Gel-filtration Chromatography Column

    DEFF Research Database (Denmark)

    Bechmann, Iben Ellegaard

    1996-01-01

    in a FIA system. The FIA system is furnished with a gel-filtration chromatography column for on-line removal of the proteins from the extract before the enzymatic analysis is performed. Compared with the standard methods for determination of formaldehyde in fish products the present method is much faster...

  2. Detection of human butyrylcholinesterase-nerve gas adducts by liquid chromatography-mass spectrometric analysis after in gel chymotryptic digestion.

    Science.gov (United States)

    Tsuge, Kouichiro; Seto, Yasuo

    2006-06-21

    To verify the exposure to nerve gas, a method for detecting human butyrylcholinesterase (BuChE)-nerve gas adduct was developed using LC-electrospray mass spectrometry (ESI-MS). Purified human serum BuChE was incubated with sarin, soman or VX, and the adduct was purified by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and digested in gel by treatment with chymotrypsin. The resulting peptide mixture was subjected to LC-ESI-MS. From the chymotryptic digest of untreated human BuChE, one peak corresponding to the peptide fragment containing the active center serine residue was detected on the extracted ion chromatogram at m/z 948.5, and the sequence was ascertained to be "GESAGAASVSL" by MS/MS analysis. From the chymotryptic digest of the human BuChE-sarin adduct, a singly charged peptide peak was detected on the extracted ion chromatogram at m/z 1,069.5, and the sequence was ascertained to be "GEXAGAASVSL" by MS/MS analysis (X denotes isopropylmethylphosphonylated serine). The difference in molecular weight (120.0 Da) between the active center peptide fragments corresponding to the untreated BuChE and BuChE-sarin adduct was assumed to be derived from the addition of an isopropyl methylphosphonyl moiety to the serine residue. The formation of human BuChE adducts with soman, VX and an aged soman adduct was confirmed by detecting the respective active center peptide fragments using LC-ESI-MS. To apply the established method to an actual biological sample, human serum was incubated with VX, and the adduct was purified by procainamide affinity chromatography followed by SDS-PAGE. After chymotryptic in gel digestion, the ethylphosphonylated active center peptide fragment could be detected, and the structure of the residue was ascertained by LC-ESI-MS analysis.

  3. Sol-gel methyl coating in capillary microextraction hyphenated on-line with high-performance liquid chromatography Counterintuitive extraction behavior for polar analytes.

    Science.gov (United States)

    Segro, Scott S; Malik, Abdul

    2008-07-18

    A sol-gel coating with anchored methyl groups was developed for capillary microextraction hyphenated on-line with high-performance liquid chromatography (HPLC). This was accomplished by using methyltrimethoxysilane as the sol-gel precursor. The methyl group on the sol-gel precursor ultimately turned into a pendant group on the created sol-gel coating and was primarily responsible for the extraction of nonpolar analytes. A 40-cm segment of 0.25mm I.D. fused silica capillary containing the sol-gel methyl coating on the inner surface was installed as a sampling loop in an HPLC injection port. The analytes were extracted by the coating when an aqueous sample containing the analytes was passed through this capillary. The extracted analytes were then transferred to the HPLC column using isocratic elution with an acetonitrile/water mobile phase. This capillary demonstrated excellent extraction capability for polycyclic aromatic hydrocarbons and ketones. Unexpectedly, this coating also provided good extraction for polar analytes, including aromatic phenols, alcohols, and amines. Considering the fact that the methyl group is nonpolar in nature, such an extraction behavior of sol-gel methyl coating toward polar analytes is counterintuitive. Thus, sol-gel sorbents with short alkyl side chains have the potential to offer a polymer-free alternative to traditional sol-gel capillary microextraction (CME) media commonly prepared with the use of polymers in the sol solution. Elimination of polymers from the sol-gel coating solution is conducive to improving thermal stability and solvent tolerance of the created sol-gel extracting phase. This also makes the preparation of sol-gel coatings facile and cost-effective. Possessing excellent solvent stability, such sol-gel coatings offer the opportunity for effective on-line hyphenation of capillary microextraction with HPLC and other liquid-phase separation techniques that employ organo-aqueous mobile phases.

  4. Applying Chromatography.

    Science.gov (United States)

    Klein, Jessie W.; Patev, Paul

    1998-01-01

    Presents three experiments to introduce students to different kinds of chromatography: (1) paper chromatography; (2) gel filtration chromatography; and (3) reverse-phase liquid chromatography. Written in the form of a laboratory manual, explanations of each of the techniques, materials needed, procedures, and a glossary are included. (PVD)

  5. Synthesis of sugar-based silica gels by copper-catalysed azide-alkyne cycloaddition via a single-step azido-activated silica intermediate and the use of the gels in hydrophilic interaction chromatography.

    Science.gov (United States)

    Moni, Lisa; Ciogli, Alessia; D'Acquarica, Ilaria; Dondoni, Alessandro; Gasparrini, Francesco; Marra, Alberto

    2010-05-17

    Novel sugar-based silica gels were prepared by exploiting the copper-catalysed azide-alkyne cycloaddition (CuAAC) of two different sugar alkynes, namely, ethynyl C-galactoside 1 and propargyl O-lactoside 2, with new single-step azido-activated silica gels. The fully characterised stationary phases were generally used for hydrophilic interaction chromatography (HILIC), with particular application in the stereoselective separation of monosaccharides. Dynamic HILIC (DHILIC) experiments were performed to evaluate the influence of mutarotation on the chromatographic peak shapes of two interconverting sugar anomers. The potential of such materials was shown in the separation of other highly polar compounds, including amino acids and flavonoids.

  6. Sol-gel germania triblock polymer coatings of exceptional pH stability in capillary microextraction online-coupled to high-performance liquid chromatography.

    Science.gov (United States)

    Segro, Scott S; Triplett, Judy; Malik, Abdul

    2010-05-15

    For the first time, a germania-based sol-gel coating was used in capillary microextraction (CME) in combination with high-performance liquid chromatography (HPLC). A hydroxy-terminated triblock copolymer, poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide), was covalently bonded into a sol-gel germania matrix in the course of its creation from an alkoxide precursor via hydrolytic polycondensation reactions. A thin layer of this in situ-created sol-gel hybrid material was covalently anchored to the inner walls of a 0.25 mm i.d. fused silica capillary to produce a sol-gel germania triblock polymeric sorbent in the form of a highly stable surface coating. Such a coating served as an effective extracting phase for the preconcentration of a wide range of polar and nonpolar analytes (e.g., alcohols, amines, ketones, phenols, and polycyclic aromatic hydrocarbons) with nanomolar and picomolar detection limits. Most significantly, the sol-gel germania triblock polymer coating demonstrated impressive resistance to extreme pH conditions, surviving 5 days of continuous exposure to 1.0 M HCl (pH approximately 0.0) or 1.0 M NaOH (pH approximately 14.0), practically without any changes in performance. This shows the suitability of sol-gel germania hybrid organic-inorganic hybrid materials for use as sorbents or stationary phases under extreme pH conditions, often needed in a variety of separation and sample preparation techniques and applications, including ion chromatography, hydrophobic interaction chromatography, proteomics, HPLC with electrochemical detection, isoelectric focusing, and extraction of acidic and basic analytes.

  7. Permeation and distribution of ferulic acid and its α-cyclodextrin complex from different formulations in hairless rat skin.

    Science.gov (United States)

    Monti, Daniela; Tampucci, Silvia; Chetoni, Patrizia; Burgalassi, Susi; Saino, Veronica; Centini, Marisanna; Staltari, Lucia; Anselmi, Cecilia

    2011-06-01

    Ferulic acid (FA) is a natural product that occurs in seeds of many plants where it is generally located in the bran. This compound is a multifunctional ingredient endowed with antioxidative, radical scavenging, sunscreening and antibacterial actions. The aim of this study was to analyse the ferulic acid cutaneous permeation and distribution, through and into the skin layers, from different cosmetic vehicles, an O/W emulsion (pH 6.0) and two gel-type formulations at different pH levels (6.0 and 7.4), containing FA alone or an inclusion complex with α-cyclodextrin (CD-FA). In vitro permeation studies were performed in vertical diffusion cells using hairless rat excised skin. At appropriate intervals of time, the amount of permeated sunscreen/radical scavenger was evaluated by high-performance liquid chromatography (HPLC). At the end of experiments, treated skin samples were sectioned with a cryomicrotome and the FA content of the individual slices was analysed by HPLC. FA-containing formulations, O/W emulsion, gels A and B, originated FA fluxes of 8.48 ± 2.31, 8.38 ± 0.89 and 5.72 ± 0.50 μg/cm(2) h, respectively, thus suggesting the pH influence on FA percutaneous permeation. The use of the inclusion complex, CD-FA, determined in all cases a decrease of FA transdermal permeation while no influence of pH was observed. Gel-type formulations containing FA ensured higher sunscreen storage in the superficial layers if compared with O/W emulsion. When FA was included in α-cyclodextrin, FA amount retained into skin layers decreased markedly.

  8. Silica gel microspheres decorated with covalent triazine-based frameworks as an improved stationary phase for high performance liquid chromatography.

    Science.gov (United States)

    Zhao, Wenjie; Hu, Kai; Hu, Chenchen; Wang, Xiaoyu; Yu, Ajuan; Zhang, Shusheng

    2017-03-03

    A new stationary phase for high performance liquid chromatography (HPLC) applications based on silica gel microspheres decorated with covalent triazine-based frameworks (CTF-SiO2) composite has been reported here. In this new hybrid material, sheet-like covalent triazine-based frameworks (CTF) were grown onto the supporting silica spheres, in order to achieve improved chromatographic separation and selectivity. The new material was characterized by infrared spectroscopy, elemental analysis and thermogravimetric analysis. The chromatographic performance and retention mechanism of the new stationary phase were investigated in reversed-phase mode and compared against standard C18 and cyano-modified silica (CN-SiO2) columns. A variety of different probe molecules were analyzed, including mono-substituted benzenes, polycyclic aromatic hydrocarbons, phenols, anilines and bases. The synergism of triazine and aromatic moieties provided several different retention mechanisms, thus improving the selectivity in the CTF-SiO2 composite. The good column packing properties of the uniform silica microspheres combined with the separation ability of the CTF frameworks make the new CTF-SiO2 material a potentially useful stationary phase for the analysis of complex samples.

  9. Comparison of sulfuric acid treatment and multi-layer silica gel column chromatography in cleanup methods for determination of PCDDs, PCDFs and dioxin-like PCBs in foods.

    Science.gov (United States)

    Amakura, Yoshiaki; Tsutsumi, Tomoaki; Sasaki, Kumiko; Toyoda, Masatake; Maitani, Tamio

    2002-10-01

    Two typical cleanup methods, sulfuric acid treatment and multi-layer silica gel column chromatography, for the determination of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) in seventeen food samples were examined and compared. Vegetables, fruits, cereals, fish, meat and dairy foods were extracted by conventional methods (shaking with acetone/n-hexane or with n-hexane after alkaline treatment). The extracts were cleaned up by sulfuric acid treatment or multi-layer silica gel column chromatography, followed by several column chromatographic steps. Of the samples treated, the vegetable, fruit and cereal samples could be directly applied to the multi-layer silica gel column after extraction. However, the samples containing fats and oils such as fish, meat and dairy foods needed to be treated several times with concentrated sulfuric acid before multi-layer column chromatography, because these samples plugged the column with oily residues. Both cleanup methods gave similar values of isomeric concentrations and showed similar efficiency of purification, and the recoveries ranged from 40 to 120%. These results are considered to provide useful data for the efficient analysis of dioxins in foods which have wide-ranging compositions.

  10. The role of sodium in the salty taste of permeate.

    Science.gov (United States)

    Frankowski, K M; Miracle, R E; Drake, M A

    2014-09-01

    Many food companies are trying to limit the amount of sodium in their products. Permeate, the liquid remaining after whey or milk is ultrafiltered, has been suggested as a salt substitute. The objective of this study was to determine the sensory and compositional properties of permeates and to determine if elements other than sodium contribute to the salty taste of permeate. Eighteen whey (n=14) and reduced-lactose (n=4) permeates were obtained in duplicate from commercial facilities. Proximate analyses, specific mineral content, and nonprotein nitrogen were determined. Organic acids and nucleotides were extracted followed by HPLC. Aromatic volatiles were evaluated by gas chromatography-mass spectrometry. Descriptive analysis of permeates and model solutions was conducted using a trained sensory panel. Whey permeates were characterized by cooked/milky and brothy flavors, sweet taste, and low salty taste. Permeates with lactose removed were distinctly salty. The organic acids with the highest concentration in permeates were lactic and citric acids. Volatiles included aldehydes, sulfur-containing compounds, and diacetyl. Sensory tests with sodium chloride solutions confirmed that the salty taste of reduced-lactose permeates was not solely due to the sodium present. Permeate models were created with NaCl, KCl, lactic acid, citric acid, hippuric acid, uric acid, orotic acid, and urea; in addition to NaCl, KCl, lactic acid, and orotic acid were contributors to the salty taste. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  11. Permeation through graphene ripples

    Science.gov (United States)

    Liang, Tao; He, Guangyu; Wu, Xu; Ren, Jindong; Guo, Hongxuan; Kong, Yuhan; Iwai, Hideo; Fujita, Daisuke; Gao, Hongjun; Guo, Haiming; Liu, Yingchun; Xu, Mingsheng

    2017-06-01

    Real graphene sheets show limited anti-permeation performance deviating from the ideally flat honeycomb carbon lattice that is impermeable to gases. Ripples in graphene are prevalent and they could significantly influence carrier transport. However, little attention has been paid to the role of ripples in the permeation properties of graphene. Here, we report that gases can permeate through graphene ripples at room temperature. The feasibility of gas permeation through graphene ripples is determined by detecting the initial oxidation sites of Cu surface covered with isolated graphene domain. Nudged elastic band (NEB) calculations demonstrate that the oxygen atom permeation occurs via the formation of C-O-C bond, in which process the energy barrier through the rippled graphene lattice is much smaller than that through a flat graphene lattice, rendering permeation through ripples more favorable. Combining with the recent advances in atoms intercalation between graphene and metal substrate for transfer-free and electrically insulated graphene, this discovery provides new perspectives regarding graphene’s limited anti-permeation performance and evokes for rational design of graphene-based encapsulation for barrier and selective gas separation applications through ripple engineering.

  12. In-gel microwave-assisted acid hydrolysis of proteins combined with liquid chromatography tandem mass spectrometry for mapping protein sequences.

    Science.gov (United States)

    Sun, Difei; Wang, Nan; Li, Liang

    2014-01-07

    We report an enabling method for mapping the protein sequence with high sequence coverage. This method combines the high separation power of gel electrophoresis for protein separation with the high sequence coverage capability of microwave-assisted acid hydrolysis (MAAH) mass spectrometry (MS). In-gel MAAH using 25% trifluoroacetic acid was developed and optimized for degrading the gel-separated protein into small peptides suitable for tandem MS sequencing. For bovine serum albumin (BSA) (∼67 kDa), with 4 μg of protein loading onto a gel for separation, followed by excising the protein gel band for in-gel MAAH and then injecting ∼2 μg of the resultant peptides into a liquid chromatography quadrupole time-of-flight mass spectrometer for analysis, 689 ± 54 (n = 3) unique peptides were identified with a protein sequence coverage of 99 ± 1%. Both the number of peptides detected and sequence coverage decreased as the sample amount decreased, mainly due to background interference: 316 ± 59 peptides and 94 ± 3% coverage for 2 μg loading, 136 ± 19 and 76 ± 5% for 1 μg loading, and 30 ± 2 and 32 ± 2% for 0.5 μg loading. To demonstrate the general applicability of the method, 10 gel bands from gel electrophoresis of an albumin-depleted human plasma sample were excised for in-gel MAAH LC-MS analysis. In total, 19 relatively high abundance proteins with molecular weights ranging from ∼8 to ∼160 kD could be mapped with coverage of 100% for six proteins (MW 8759 to 68 425 Da), 96-98% for five proteins (MW 11 458 to 36 431 Da), 92% for three proteins (MW 15 971 to 36 431 Da), 80-87% for four proteins (MW 42 287 to 162 134 Da), and 56% for one protein (MW 51 358 Da). Finally, to demonstrate the applicability of the method for more detailed analysis of complex protein mixtures, two-dimensional (2D) gel electrophoresis was combined with in-gel MAAH, affinity purification, and LC-MS/MS to characterize six bovine alpha-S1-casein phosphoprotein

  13. Permeation of captan through disposable nitrile glove.

    Science.gov (United States)

    Phalen, R N; Que Hee, Shane S

    2003-06-27

    The purpose of this study was to investigate the permeation of an aqueous emulsion of the pesticide, captan, as a wettable powder (48.9% captan) through a disposable nitrile glove material using an American Society for Testing and Materials (ASTM)-type I-PTC-600 permeation cell. The goal was to investigate the protective capability of the gloves against dermatitis. The analytical method was based on gas chromatography-mass spectrometry (GC-MS) and gas chromatography-electron capture detection (GC-ECD). The least quantifiable limit (LQL) was 6 ng for GC-ECD and 30 ng for GC-MS. Testing was conducted using the ASTM F739 closed-loop permeation method and a worst-case aqueous concentration 217 mg/ml of captan 50-WP. The average permeation rates were low, with 12+/-5 ng/(cm(2)min) after 2h, 50+/-25 ng/(cm(2)min) after 4h, and 77+/-58 ng/(cm(2)min) after 8h. The calculated diffusion coefficient was (1.28+/-0.10) x 10(-5)cm(2)/h. No significant swelling or shrinkage occurred at Pcaptan. Because the ASTM normalized breakthrough detection time of 250 ng/cm(2) was captan has been shown to persist on crops with a half-life greater than the current reentry intervals of 1-4 days.

  14. High-temperature solvent stability of sol-gel germania triblock polymer coatings in capillary microextraction on-line coupled to high-performance liquid chromatography.

    Science.gov (United States)

    Segro, Scott S; Malik, Abdul

    2010-09-10

    Germania-based sol-gel organic-inorganic hybrid coatings were prepared for on-line coupling of capillary microextraction with high-performance liquid chromatography. For this, a germania-based sol-gel precursor, tetra-n-butoxygermane and a hydroxy-terminated triblock copolymer, poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) were used. These sol-gel germania triblock polymer coatings were chemically anchored to the inner walls of a fused silica capillary (0.25 mm I.D.) in course of its evolution from the sol solution. Scanning electron microscopy images of the sol-gel germania triblock polymer coating were obtained to estimate the coating thickness. For the first time, the analyte distribution constants between a sol-gel germania organic-inorganic hybrid coating and the samples (K(cs)) were determined. For a variety of analytes from different chemical classes, including polycyclic aromatic hydrocarbons (PAHs), ketones, alcohols, phenols and amines, the K(cs) values ranged from 8.1 x 10(1) to 5.6 x 10(4). Also, for the first time, the stability of the sol-gel germania-based coating in high-temperature reversed-phase solvent environment was evaluated. The sol-gel germania triblock polymer coatings were capable of surviving exposure to high-temperature solvent conditions (200 degrees C) with little change in extraction capabilities. This demonstrates that sol-gel germania triblock polymer hybrid materials might be suitable for further applications in high-temperature HPLC. The reproducibility of the method for preparation of the sol-gel germania triblock polymer coatings was also evaluated, and the capillary-to-capillary RSD values ranged from 5.3 to 6.5%. The use of higher flow rates in extraction was found to significantly reduce the time required (from 30-40 to 10-15 min) to reach equilibrium between the sol-gel germania triblock polymer coating and the analytes in the sample solution.

  15. Gel Formation in Polymers Undergoing Radiation-Induced Crosslinking and Scission

    DEFF Research Database (Denmark)

    Handlos, V. N.; Singer, Klaus Albert Julius

    1976-01-01

    A study was made of the solubility of irradiated polyethylene. The experimental data were treated according to the Saito-Inokuti theory for gel formation in polymers exposed to ionizing radiation. Among other things, this theory is based upon the molecular weight distribution of the unirradiated...... polymer; in the present work, the actual distributions were determined by high-temperature gel permeation chromatography and corrected for long-chain branching. Under these circumstances, good agreement between theory and experimental data was obtained, which allowed the determination of the radiation...

  16. Radioimmunoassay of ricin A- and B-chains applied to samples of ricin A-chain prepared by chromatofocusing and by DEAE Bio-Gel A chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishnan, S.; Eagle, M.R.; Houston, L.L. (Kansas Univ., Lawrence (USA). Dept. of Biochemistry)

    1982-11-24

    A radioimmunoassay for ricin and ricin A- and B-chains was developed. Amounts as low as 100 pg of A-chain and 500 pg of B-chain could easily be quantitated. We showed, however, that the free chains were more reactive in the radioimmunoassay than the equivalent quantity of the individual chains when combined in intact ricin. The usefulness of the assay was demonstrated by determining the concentration of contaminating A- or B-chains in preparations of the separate polypeptides purified by DEAE Bio-Gel A chromatography and by chromatofocusing.

  17. PURIFICATION OF WATER SOLUBLE PROTEINS (2S ALBUMINS EXTRACTED FROM PEANUT DEFATTED FLOUR AND ISOLATION OF THEIR ISOFORMS BY GEL FILTRATION AND ANION EXCHANGE CHROMATOGRAPHY

    Directory of Open Access Journals (Sweden)

    IMÈNE BOUALEG

    2017-06-01

    Full Text Available 2S albumins are water-soluble seed storage proteins present in dicotyledonous plants, including legumes. In peanuts, 2S albumins have been identified as major allergens. In this work, we aimed to study these water soluble allergenic proteins. They were extracted in water from peanut defatted flour (oilcake. It was quantified by Bradford method. The total and insoluble proteins content was determined by Kjeldahl method (% P = N x 6.25. The crude 2S albumins were purified using gel-filtration chromatography. Anion exchange chromatography analysis was applied to isolate their isoforms. The recorded values for total and insoluble proteins are 45.49 % and 36.65 % consecutively. A value of 9.99 % was determined for water soluble proteins content which correspond to 20 % compared to the total proteins. Analysis by Sephadex G-75 chromatography of soluble extract gave two majors peaks in which, the Mr ~ 25 kDa peak was predicted to be pure 2S albumin fraction. Using DAEA-cellulose chromatography, two peaks were appeared from pure 2S albumins, it were predicted that 2S albumin isoforms theoretically represent the peanut major allergens Ara h2 and Ara h6. These approaches are the basis for further studies may involve immunological analysis to understand the impact of these biomolecules on peanut allergenicity.

  18. Chemical characterization of the gels produced by the diazotrophic bacteria Rhizobium tropici and Mesorhizobium sp; Caracterizacao quimica dos geis produzidos pelas bacterias diazotroficas Rhizobium tropici e Mesorhizobium sp.

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Nilson Kobori [Departamento de Engenharia e Tecnologia de Alimentos, Instituto de Biociencias, Letras e Ciencias Exatas, Universidade Estadual Paulista, Sao Jose do Rio Preto - SP (Brazil); Aranda-Selverio, Gabriel; Exposti, Diego Tadeu Degli; Silva, Maria de Lourdes Corradi da [Departamento de Fisica, Quimica e Biologia, Faculdade de Ciencias e Tecnologia, Universidade Estadual Paulista, Presidente Prudente - SP (Brazil); Lemos, Eliana Gertrudes Macedo; Campanharo, Joao Carlos [Departamento de Tecnologia, Faculdade de Ciencias Agrarias e Veterinaria, Universidade Estadual Paulista, Jaboticabal - SP (Brazil); Silveira, Joana Lea Meira [Departamento de Bioquimica e Biologia Molecular, Universidade Federal do Parana, Curitiba - PR (Brazil)

    2012-07-01

    The exopolysaccharides with characteristics of gel produced by Rhizobium tropici (EPSRT) and Mesorhizobium sp (EPSMR) are acidic heteropolysaccharide composed mainly of glucose and galactose in a molar ratio of 4:1 and 5:1 respectively, with traces of mannose ({approx} 1%). Chemical analysis showed the presence of uronic acid, pyruvate and acetyl-substituents in the structures of both polymers. Experiments of gel permeation chromatography and polyacrylamide gel electrophoresis showed that EPSRT and EPSMR are homogeneous molecules with low grade of polydispersity. The EPS were characterized using spectroscopic techniques of FT-IR, {sup 1}H and {sup 13}C-NMR. (author)

  19. On Diffusion and Permeation

    KAUST Repository

    Peppin, Stephen S. L.

    2009-01-01

    Diffusion and permeation are discussed within the context of irreversible thermodynamics. A new expression for the generalized Stokes-Einstein equation is obtained which links the permeability to the diffusivity of a two-component solution and contains the poroelastic Biot-Willis coefficient. The theory is illustrated by predicting the concentration and pressure profiles during the filtration of a protein solution. At low concentrations the proteins diffuse independently while at higher concentrations they form a nearly rigid porous glass through which the fluid permeates. The theoretically determined pressure drop is nonlinear in the diffusion regime and linear in the permeation regime, in quantitative agreement with experimental measurements. © 2009 Walter de Gruyter, Berlin, New York.

  20. Synthesis and properties of a newly obtained sorbent based on silica gel coated with a polyaniline film as the stationary phase for non-suppressed ion chromatography.

    Science.gov (United States)

    Sowa, Ireneusz; Wójciak-Kosior, Magdalena; Drączkowski, Piotr; Strzemski, Maciej; Kocjan, Ryszard

    2013-07-17

    The new sorbent for non-suppressed ion chromatography based on silica gel coated with a film of polyaniline (PANI) was obtained in a process of in situ polymerization of aniline by oxidation with ammonium peroxydisulfate. Raman analyses performed using a Thermo Scientific DXR confocal Raman Microscope equipped with the Omnic 8 software from Thermo Fisher Scientific have proved a uniform distribution of PANI on the surface of chromatographic beads and in the pores of the particle. The obtained stationary phase was packed into a stainless steel HPLC column. The quality of the prepared column was verified on the basis of hydrodynamic parameters such as column efficiency index (Ip) and separation impedance (E). The potential application of silica gel modified with polyaniline for separation and determination of selected anions using non-suppressed ion chromatography was also investigated. Chromatographic analyses were performed using of the ion chromatograph Dionex DX-500. The best results were obtained for the mobile phase consisting of an aqueous or methanolic solution of hydrochloric acid. The tested column and optimized chromatographic system were successfully used for the analysis of nitrate, bromide and iodide in waters samples.

  1. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of chlorinated pesticides in aquatic tissue by capillary-column gas chromatography with electron-capture detection

    Science.gov (United States)

    Leiker, Thomas J.; Madsen, J.E.; Deacon, J.R.; Foreman, W.T.

    1995-01-01

    A method for the determination of chlorinated organic compounds in aquatic tissue by dual capillary-column gas chromatography with electron-capture detection is described. Whole-body-fish or corbicula tissue is homogenized, Soxhlet extracted, lipid removed by gel permeation chromatography, and fractionated using alumina/silica adsorption chromatography. The extracts are analyzed by dissimilar capillary-column gas chromatography with electron-capture detection. The method reporting limits are 5 micrograms per kilogram (μg/kg) for chlorinated compounds, 50 μg/kg for polychlorinated biphenyls, and 200 μg/kg for toxaphene.

  2. Separation and quantitation of hepatoma-associated gamma-glutamyltransferase by affinity chromatography with Affi-Gel blue and Con A-Sepharose.

    Science.gov (United States)

    Izumi, M; Taketa, K

    1983-01-01

    Isozymes of serum gamma-glutamyltransferase (GGT) in patients with hepatocellular carcinoma (HCC) and other liver diseases were separated into two groups by double-affinity column chromatography with Affi-Gel blue and Con A-Sepharose, one recovered in the unbound fraction and the other in the bound fraction. Upon electrophoresis with polyacrylamide gradient gel slabs, the unbound fraction gave a GGTI1 band and a faint II1 band and the bound fraction gave a GGT I band and faint bands of GGT I", II' and X, when the original serum contained hepatoma-associated GGT (I1, I" and II') and high-molecular-weight lipid-protein complex, GGT(X). GGT I was present in all cases as a common isozyme. Other lipoprotein-associated GGT isozymes, III-IX, were removed by passing through Affi-Gel blue. GGT activities of unbound fraction in patients with HCC were generally higher than those in patients with non-HCC liver diseases, although the difference was not significant. When the percent of GGT activity of unbound (unbound + bound) was taken, 54% of patients with HCC had a ratio greater than 22%, whereas none of the healthy subjects or patients with other liver diseases gave values greater than this. The present technique may prove to be a useful clinical test for the diagnosis of HCC.

  3. Comparison of in vivo and in vitro Permeation Behaviors of the Ethosome Gels of Testosterone and Its Es-ters%睾酮及其酯类醇质体凝胶剂的体内外渗透行为比较

    Institute of Scientific and Technical Information of China (English)

    孟舒; 李杨; 张翀; 曲静; 张巍; 金瑛; 郭晶; 李淼

    2015-01-01

    OBJECTIVE:To compare in vivo and in vitro permeation behaviors of the ethosome gels of testosterone,testoster-one propionate and testosterone undecanoate. METHODS:The ethosome gels of testosterone,testosterone propionate and testoster-one undecanoate were prepared. With cumulative permeating amount and permeation rate as the indexes,Franz diffusion cell and HPLC were employed to compare in vitro permeation behaviors of 3 kinds of ethosome gels in mouse skin. With testosterone patch as the positive control drug, electrochemistry method was adopted to detect the concentration of testosterone in plasma 0,3,6, 9,12,24,36 and 48 h after applying such 3 kinds of ethosome gels on the back of rats,and then pharmacokinetic parameters were calculated with DAS 2.0 software. RESULTS:24 h cumulative permeating amounts of the ethosome gels of testosterone,tes-tosterone propionate and testosterone undecanoate were(234.31±13.8),(175.63±41.1)and(72.60±15.3)μg/cm2,and the per-meation rates were(10.25±1.9),(7.64±1.4)and(2.96±0.8)μg/(cm2·h),respectively. The pharmacokinetic parameters of the above-mentioned three kinds of ethosome gels and the positive control drug were respectively as follows as cmax of(20.19±2.57), (17.50±2.91),(0.23±0.04),(14.97±2.12)ng/ml,t1/2Ka of(2.80±0.45),(3.36±0.59),(4.02±0.62),(4.20±0.71)h,AUC0-48 h of(13.85±1.96),(13.93±2.13),(0.35±0.07),(11.76±2.31)ng·h/ml. CONCLUSIONS:in vivo and in vitro permeation behav-iors of the ethosome gels of testosterone and testosterone propionate are fairly good.%目的:比较睾酮、丙酸睾酮、十一酸睾酮醇质体凝胶剂的体内外渗透行为。方法:制备睾酮、丙酸睾酮、十一酸睾酮醇质体凝胶剂,采用Franz扩散池和高效液相色谱法,以累积透过量和渗透速率为指标,比较3种醇质体凝胶剂经小鼠皮肤的体外渗透行为;以睾酮贴剂为阳性对照,采用电化学法检测3种醇质体凝胶剂涂铺于大鼠背部0、3、6、9、12

  4. Rheology of κ/ι-hybrid carrageenan from Mastocarpus stellatus: Critical parameters for the gel formation.

    Science.gov (United States)

    Torres, M D; Chenlo, F; Moreira, R

    2016-05-01

    The sol-gel diagrams of kappa/iota-hybrid carrageenan (KI) extracted from Mastocarpus stellatus powders with two different average particle sizes of the seaweed powders (117.0 μm and 77.5 μm) prior to the biopolymer extraction, are reported for the first time, together with rheological properties of obtained KI gels. Extraction yields for KI isolated from algae and average molecular weight of KI, determined by gel permeation chromatography, decreased with increasing the particle size of the powder. Rheological results indicated that tested samples exhibited stable and weak gel properties, except those prepared at 1.5% KI in 1.0 mol/L NaCl where stronger gels were found. Aqueous KI extracts with larger molecular weight led to stronger gels and also formed gels at lower biopolymer concentration in NaCl above 0.15 mol/L. All gels reached stability after 20 min of maturation. The data sets showed a strong temperature dependency. Gel setting temperatures significantly depended on the KI and NaCl content, whereas gel melting temperatures (68.0 ± 0.7 °C) were independent of both salt concentrations.

  5. Permeation of captan through disposable nitrile glove

    Energy Technology Data Exchange (ETDEWEB)

    Phalen, R.N.; Que Hee, Shane S

    2003-06-27

    The purpose of this study was to investigate the permeation of an aqueous emulsion of the pesticide, captan, as a wettable powder (48.9% captan) through a disposable nitrile glove material using an American Society for Testing and Materials (ASTM)-type I-PTC-600 permeation cell. The goal was to investigate the protective capability of the gloves against dermatitis. The analytical method was based on gas chromatography-mass spectrometry (GC-MS) and gas chromatography-electron capture detection (GC-ECD). The least quantifiable limit (LQL) was 6 ng for GC-ECD and 30 ng for GC-MS. Testing was conducted using the ASTM F739 closed-loop permeation method and a worst-case aqueous concentration 217 mg/ml of captan 50-WP. The average permeation rates were low, with 12{+-}5 ng/(cm{sup 2} min) after 2 h, 50{+-}25 ng/(cm{sup 2} min) after 4 h, and 77{+-}58 ng/(cm{sup 2} min) after 8 h. The calculated diffusion coefficient was (1.28{+-}0.10)x10{sup -5} cm{sup 2}/h. No significant swelling or shrinkage occurred at P{<=}0.05. Infrared (IR) reflectance analysis of pre- and post-exposure glove surfaces confirmed no outer or inner surface degradation. The disposable nitrile glove showed excellent resistance to a highly concentrated aqueous emulsion of captan. Because the ASTM normalized breakthrough detection time of 250 ng/cm{sup 2} was <2 h, these gloves should not be reused once worn, and decontamination is not advised. Protection is also advised for agricultural reentry field workers, because captan has been shown to persist on crops with a half-life greater than the current reentry intervals of 1-4 days.

  6. Development of Novel Formulations to Enhance in Vivo Transdermal Permeation of Tocopherol

    Directory of Open Access Journals (Sweden)

    Nada Aly H.

    2014-09-01

    Full Text Available Tocopherol represents a big challenge for transdermal permeation owing to its extreme hydrophobicity and large molecular mass. The aim of the present study was to develop alpha-tocopherol (T topical formulations and evaluate their ex vivo and in vivo permeation. Franz diffusion cells were used for ex vivo permeation, and neonatal rats were used for in vivo permeation. Seven gel formulations and 21 liquid formulations were investigated for physical stability, viscosity and permeation of T. Analysis of T was performed by a validated HPLC method using a UV detector. The ex vivo permeation from gel and emulsion formulations was very poor (0.001-0.015 %. Highest permeation was observed from monophasic liquid formulations containing dimethyl sulfoxide (DMSO, tocopheryl polyethylene glycols (TPGs, propylene glycol, ethanol and 9.5 % T. The in vivo results demonstrated higher retention in the epidermis compared to subcutaneous tissues, 1377 and 1.13 μg g-1, respectively. Increasing T concentration from 4.8 to 9.5 % did not increase the amount permeated or % of T retained. It was concluded that simple solutions of T in the presence of DMSO and TPGs were more promising systems for effective transdermal permeation compared to gel, emulsion or oleaginous systems.

  7. Determination of toxaphene residues in aquatic products by gel permeation chromatography and gas chromatography%凝胶渗透色谱净化-气相色谱法测定水产品中毒杀芬残留量

    Institute of Scientific and Technical Information of China (English)

    刘慧慧; 徐英江; 邓旭修; 张华威; 刘云; 宫向红

    2013-01-01

    建立了水产品中毒杀芬残留量的凝胶渗透色谱净化-气相色谱检测方法.水产样品经匀浆后,用丙酮提取,经正己烷液液萃取、凝胶渗透色谱和浓硫酸净化后,用HP-5ms毛细管柱分离,电子捕获检测器检测,外标法定量.结果表明,毒杀芬在20~ 500 μg/L浓度范围内线性良好,相关系数R≥0.998.方法检出限1.0μg/kg,在添加量2.0~20.0 μg/kg范围内,回收率在73.7% ~78.7%之间,相对标准偏差≤6.3%.该方法灵敏、准确,可以满足水产品中毒杀芬检测要求.

  8. Equilibrium Gel Filtration Chromatography for the Measurement of Protein-Ligand Binding in the Undergraduate Biochemistry Laboratory

    Science.gov (United States)

    Craig, Douglas B.

    2005-01-01

    A laboratory exercise used in the senior biochemistry course at the University of Winnipeg for three years is discussed. It combines liquid chromatography and absorbance spectroscopy and also allows the students to produce a quantitative result within a single three-hour period.

  9. Differential refractometric determination of binding of sodium dodecyl sulfate to protein using high-performance gel chromatography.

    Science.gov (United States)

    Rao, P F; Takagi, T

    1988-10-01

    When sodium dodecyl sulfate (SDS) is added to a high-performance gel chromatographic column equilibrated with a buffer solution containing SDS at a level above the critical micelle concentration, the surplus SDS migrates as micelles giving a sharp peak. The presence of an unfolded protein in the sample solution gives a polypeptide peak in advance of the SDS micelle peak. As the result of SDS binding to the polypeptide, the SDS micelle peak is attenuated in comparison to that in the absence of protein. Thus the amount of SDS bound to the polypeptide can be determined accurately and simply from the decrease in the area of the SDS micelle peak. This approach is particularly useful for precise determination of bound SDS, which is pertinent to understanding the state of the protein polypeptide-SDS complex under the conditions of SDS-polyacrylamide gel electrophoresis.

  10. Isolation and purification of uremic middle molecules by multi-step liquid chromatography

    Institute of Scientific and Technical Information of China (English)

    储结根; 刘晓航; 袁直; 何炳林

    2002-01-01

    Isolation and comparison of uremic sera and urine and normal sera and urine were performed by gel permeation chromatography, anion exchange chromatography and reversed-phase high performance liquid chromatography. Two uremic middle molecular fractions (A and B) were obtained from uremic sera and urine and normal urine by gel permeation chromatography, but not from normal sera. The anion exchange chromatographic results of fraction A from different origins demonstrate that subfraction A-3 could be excreted in urine by healthy subject, but accumulated in uremic serum for renal failure of patient with uremia. After desalinization subfraction A-3 was analyzed by MALDI-TOF-MS. The results show that subfraction A-3 consists of six compounds with molecular weight 839, 873, 1007.94, 1106, 1680 and 2015 respectively. Finally, by reversed-phase high performance liquid chromatography, subfraction A-3 was further resolved into six independent fractions. Thus, the isolation and purification of six middle molecular compounds in subfraction A-3 came true by our method.

  11. Molecularly imprinted polymer-sol-gel tablet toward micro-solid phase extraction: I. Determination of methadone in human plasma utilizing liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    El-Beqqali, Aziza; Abdel-Rehim, Mohamed

    2016-09-14

    In the present work molecularly imprinted sol-gel tablet (MIP-Tablet) was prepared. The MIP-sol-gel was prepared as a thin layer on polyethylene material in a tablet form. Methadone-d9 was selected as the template and 3-(propylmethacrylate)-trimethoxysilane was used as precursor. MIP-Tablet was applied for micro-solid phase extraction (μ-SPE). The MIP-Tablet was used for the determination of methadone in human plasma samples utilizing liquid chromatography-tandem mass spectrometry; and each tablet could be used twenty times. The extraction time was 10 min while desorption time was 6 min. Factors affecting the extraction efficiency such as desorption solvents, sample pH, salt addition, extraction time, desorption time and adsorption capacity were investigated. The calibration curves were obtained within the range of 5-5000 ng/mL using methadone in human plasma samples. The coefficients of determination (r(2)) values were ≥0.999 for all runs and the extraction recovery was >80%. The accuracy values for quality control samples varied from +3.6 to +9.7% and the inter-day precision (RSD %) values were ranged from 5.0 to 8.0%. The limit of detection was 1.0 ng/mL and the lower limit of quantification was 5 ng/mL utilizing methadone in human plasma samples.

  12. Rapid, simple and stability-indicating determination of polyhexamethylene biguanide in liquid and gel-like dosage forms by liquid chromatography with diode-array detection

    Institute of Scientific and Technical Information of China (English)

    Markus Küsters; Sören Beyer; Stephan Kutscher; Harald Schlesinger; Michael Gerhartz

    2013-01-01

    A rapid and simple method for the determination of polyhexamethylene biguanide (polyhexanide, PHMB) in liquid and gel-like pharmaceutical formulations by means of high performance liquid chromatography coupled to diode-array detection (HPLC-DAD) was developed. Best separation was achieved using a cyanopropyl bonded phase (Agilent Zorbax Eclipse XDB-CN column 4.6 mm75 mm with particle size of 3.5 mm) as well as gradient elution consisting of acetonitrile/deionized water at a flow rate of 1.0 mL/min. The optimized and applied chromatographic conditions permitted separation of polyhexanide from interacting matrix with subsequent detection at a wavelength of 235 nm with good sensitivity. The method validation was carried out with regard to the guidelines for analytical procedures demanded by the International Conference on Harmonisation (ICH). Mean recoveries of 102% and 101% for gel-like as well as liquid preparations were obtained. Suitable repeatability as well as intermediate precision could be achieved with limits of detection r0.004 mg/mL for both formulations, equivalent to r0.004% PHMB concerning sample preparation. Determination of PHMB was accomplished without tedious sample preparation. Interacting matrix could be eliminated by the chromatographic procedure with excellent performance of system suitability. All analytical requirements were fulfilled permitting a reliable and precise determination of PHMB in pharmaceuticals. Furthermore, the developed method was applied to stability testing of pharmaceutical preparations containing PHMB.

  13. Molecularly imprinted sol-gel nanofibers based solid phase microextraction coupled on-line with high performance liquid chromatography for selective determination of acesulfame.

    Science.gov (United States)

    Moein, Mohammad Mahdi; Javanbakht, Mehran; Karimi, Mohammad; Akbari-adergani, Behrouz

    2015-03-01

    Sol-gel based molecularly imprinted polymer (MIP) nanofiber was successfully fabricated by electrospinning technique on the surface of a stainless steel bar. The manufactured tool was applied for on-line selective solid phase microextraction (SPME) and determination of acesulfame (ACF) as an artificial sweetener with high performance liquid chromatography (HPLC). The selective ability of method for the extraction of ACF was investigated in the presence of some selected sweeteners such as saccharine (SCH), aspartame (ASP) and caffeine (CAF). Electrospinning of MIP sol-gel solution on the stainless steel bar provided an unbreakable sorbent with high thermal, mechanical, and chemical stability. Moreover, application of the MIP-SPME tool revealed a unique approach for the selective microextraction of the analyte in beverage samples. In this work, 3-(triethoxysilyl)-propylamine (TMSPA) was chosen as a precursor due to its ability to imprint the analyte by hydrogen bonding, Van der Walls, and dipole-dipole interactions. Nylon 6 was also added as a backbone and support for the precursor in which sol could greatly growth during the sol-gel process and makes the solution electrospinable. Various effective parameters in the extraction efficiency of the MIP-SPME tool such as loading time, flow rate, desorption time, selectivity, and the sample volume were evaluated. The linearity for the ACF in beverage sample was in the range of 0.78-100.5 ng mL(-1). Limit of detection (LOD) and quantification (LOQ) were 0.23 and 0.78 ng mL(-1) respectively. The RSD values (n=5) were all below 3.5%at the 20 ng mL(-1) level.

  14. Enzymatic hydrolysis of lactose of whey permeate

    Directory of Open Access Journals (Sweden)

    Karina Nascimento de Almeida

    2015-09-01

    Full Text Available The whey permeate is the residual of the concentration process of the whey proteins by ultrafiltration method. It contains important nutrients such as lactose, minerals and some proteins and lipids. It is without an ending industrial waste that causes serious damage to the environment. For its full use the lactose must be hydrolyzed to enable its consumption by intolerant people. The enzymatic hydrolysis by lactase (β-galactosidase of Kluyveromyces lactis yeast is a safe method that does not compromise the integrity of other nutrients, enabling further use of the permeate as a raw material. This study aimed to perform tests of enzymatic hydrolysis of lactose in whey permeate formulations in a concentration of 0.2%, 0.7% and 1% at 30, 60 and 90 minutes with pH 6.3 medium and 37 °C. The reactions were monitored by high performance liquid chromatography which showed that the enzyme concentration of 0.7% at time 30 minutes formulations became safe for consumption by lactose intolerant people, according to minimum levels established by law.

  15. [Simultaneous determination of adapalene, 2-phenoxyethanol and methyl-4-hydroxybenzoate in adapalene gels using high performance liquid chromatography].

    Science.gov (United States)

    Zhang, Chunhong; Zhao, Yingchun; Han, Chunhui; Guo, Xingjie

    2008-09-01

    A reversed-phase high performance liquid chromatographic (RP-HPLC) method was developed for the simultaneous determination of the contents of adapalene and the preservatives (2-phenoxyethanol and methyl-4-hydroxybenzoate) in adapalene gels. The chromatographic analysis was carried out on a Tigerkin C18 column (150 mm x 4.6 mm, 5 microm). The mobile phase was 0.02 mol/L ammonium acetate buffer (pH 3.0) and tetrahydrofuran-acetonitrile with gradient elution, and the detection wavelength was set at 270 nm. The calibration curves were linear over the ranges of 10-100 mg/L (r = 0.9999), 4-40 mg/L (r = 0.9999) and 4-40 mg/L (r = 0. 9999) for 2-phenoxyethanol, methyl-4-hydroxybenzoate and adapalene, respectively. The average recoveries of the three substances were within 98.0%-98.6%. The method is simple, reliable and suitable for the simultaneous determination of adapalene, 2-phenoxyethanol and methyl-4-hydroxybenzoate in adapalene gels.

  16. Determination of high and low molecular weight molecules of icodextrin in plasma and dialysate, using gel filtration chromatography, in peritoneal dialysis patients.

    Science.gov (United States)

    García-López, Elvia; Anderstam, Björn; Heimbürger, Olof; Amici, Gianpaolo; Werynski, Andrzej; Lindholm, Bengt

    2005-01-01

    The aim of this study was to apply high performance liquid chromatography (HPLC) with modern gel filtration media to determine high molecular weight (HMW) icodextrin fractions and low molecular weight (LMW) icodextrin metabolites in dialysate and plasma in peritoneal dialysis (PD) patients on treatment with icodextrin, and to explore the potential relationships between these compounds, alpha-amylase activity, and glomerular filtration rate. Retrospective study of dialysate and plasma samples from PD patients. Samples were collected at one PD center. Blood and dialysate samples were obtained from PD patients who were subdivided into three groups: patients using only glucose-based peritoneal dialysis fluid (GPDF; GLU group, n = 23), patients studied after the first long dwell with icodextrin-based peritoneal dialysis fluid (IPDF; 1st ICO group, n = 24), and patients who were regular users of IPDF for the long dwells (ICO group, n = 9). LMW icodextrin metabolites [i.e., maltose (G2), maltotriose (G3), maltotetraose (G4), maltopentaose (G5), maltohexaose (G6), and maltoheptaose (G7)] and HMW fractions were determined in plasma and dialysate using two different gel filtration HPLC methods. Enzymatic hydrolysis with amyloglucosidase to glucose yielded the total carbohydrate content and this was used to validate the HPLC results. alpha-Amylase activity was determined using a routine method. The results obtained by gel filtration HPLC yielded values of LMW metabolites and HMW fractions in plasma and dialysate in agreement with results obtained with enzymatic hydrolysis. HMW fractions were not detectable in plasma. Absorption of icodextrin from the peritoneal cavity during the long dwell (10 - 16 hours) was, on average, 39% of the amount instilled. During the long dwell, there was a relative decrease in the dialysate concentration of the largest HMW fractions (>21.4 kDa). Plasma concentration of the LMW icodextrin metabolites G2-G7 was highest in the ICO group (2

  17. Isolation and purification of lignans from Schisandra chinensis by combination of silica gel column and high-speed counter-current chromatography

    Directory of Open Access Journals (Sweden)

    Sun Yu

    2013-01-01

    Full Text Available Silica gel column combined with high-speed counter-current chromatography separation was successfully applied to the separation of schizandrin (I, angeloylgomisin H (II, gomisin A (III, schisantherin C (IV, deoxyschizandrin (V, γ-schisandrin (VI and schisandrin C (VII from the fruits of Schisandra chinensis (Turcz. Baillon. The petroleum ether extracts of the fruits of S. chinensis were pre-separated first on a silica gel column and divided into two fractions as sample 1 and sample 2. 260 mg of sample 1 was separated by HSCCC using petroleum ether-ethyl acetate-methanol-water (10:8:10:8, v/v as the two-phase solvent system and 18.2 mg of schizandrin, 15.7 mg of angeloylgomisin H, 16.5 mg of gomisin A and 16.7 mg of schisantherin C were obtained. 230 mg of sample 2 was separated using petroleum ether-ethyl acetate-methanol-water (10:0.5:10:1, v/v as the two-phase solvent system and 19.7 mg of deoxyschizandrin, 23.4 mg of γ-schisandrin and 18.2 mg of schisandrin C were obtained. The purities of the separated compounds were all over 94% as determined by HPLC. The chemical structures of these compounds were confirmed by ESI-MS and 1H NMR. [Acknowledgments. Natural Science Foundation of China (20872083, scientific and technological major special project (2010ZX09401-302-5-12 and the Key Science and Technology Program of Shandong Province (BS2009SW047

  18. Separation of single-walled carbon nanotubes by gel-based chromatography using surfactant step-gradient techniques and development of new instrumentation for studying SWCNT reaction processes

    Science.gov (United States)

    Breindel, Leonard M.

    Single-walled carbon nanotube (SWCNT) synthesis methods such as CoMoCATTM, HiPcoTM, pulsed laser vaporization (PLV), and catalytic chemical vapor deposition (CCVD) produce several different distributions of (n,m) SWCNT structures, where ( n,m) defines the nanotube diameter and chiral wrapping angle. Post-synthesis processing such as functionalization and/or separations must therefore be employed to yield high purity electronic or single (n,m) samples. Through the use of a surfactant gradient across a gel-based chromatographic column, separations of single (n,m) species can be achieved. Anionic surfactants such as SDS, SDBS, and AOT display different separation effectiveness for single (n,m) species. Results of near-infrared optical absorption for separated SWCNT surfactant suspensions will be discussed, leading to a broader understanding of the important factors necessary for the gel chromatography separation technique. In particular, the effects of SWCNT/surfactant micelle structure are found to be key to achieving fast, simple SWCNT electronic type separations. Additionally, development of new instrumentation for the near-infrared spectrofluorimetric analysis (NIR-SFA) of SWCNTs is useful to the advancement of fundamental SWCNT research and applications. NIR-SFA, for instance, allows for the (n,m) structures of a sample to be identified and monitored during the progress of a chemical reaction or separation experiment. Seeking to achieve the time resolutions necessary for such experiments, the design and optimizations of a system utilizing single-wavelength excitation by diode lasers coupled with a fast NIR detection system are presented.

  19. Micelles and gels of oxyethylene-oxybutylene diblock copolymers in aqueous solution: The effect of oxyethylene-block length

    DEFF Research Database (Denmark)

    Derici, L.; Ledger, S.; Mai, S.M.

    1999-01-01

    Block copolymer E(90)B(10) (E = oxyethylene, B = oxybutylene) was synthesised and characterised by gel permeation chromatography and (13)C NMR spectroscopy. Dynamic light scattering (DLS) and static light scattering (SLS) were used to characterise the micelles in solution (both in water and in aq......Block copolymer E(90)B(10) (E = oxyethylene, B = oxybutylene) was synthesised and characterised by gel permeation chromatography and (13)C NMR spectroscopy. Dynamic light scattering (DLS) and static light scattering (SLS) were used to characterise the micelles in solution (both in water.......e., the association number, the hard-sphere radius, the micelle volume fraction and the corresponding expansion factors. A comparison of the appropriate quantities showed good agreement between the two techniques. SANS gave additional information e.g., volume fraction profiles for the micelles and volume fraction...... of water in the micelle core. Moderately concentrated solutions of copolymer E(90)B(10) were studied in the gel state by small-angle X-ray scattering (SAXS) in tandem with rheology (oscillatory shear). Values for the dynamic elastic modulus (G') of the gels significantly exceeded 10(4) Pa across the range...

  20. [Determination of estrogen residues in drinking water by on-line solid phase extraction based on sol-gel technique coupled with high performance liquid chromatography].

    Science.gov (United States)

    Li, Longfei; Su, Min; Shi, Xiaolei; Wang, Yana; Wang, Minmin; He, Jinxing

    2014-02-01

    A method for the determination of diethylstilbestrol (DES), hexestrol (HEX) and dienestrol (DS) residues in drinking water was established by on-line solid phase extraction (SPE) coupled with high performance liquid chromatography (HPLC). The material synthesized on the base of sol-gel technology was employed as adsorbent. This material was prepared using 3-aminopropyltriethoxysilane (APTES) as the functional monomer, tetraethoxysilane (TEOS) as the crosslinking agent, and acetic acid as the initiator. The synthesized adsorbent showed outstanding property for the estrogen extraction. The estrogen can be caught effectively from water samples and the extraction can be achieved rapidly. Some important parameters, such as pH of sample solution, eluent solvents, loading flow rate, which might influence extraction efficiency, were optimized. The results indicated that the limit of detection (S/N = 3) of the developed method could reach 0.07-0.13 microg/L under the conditions of pH 7.0 of sample solution, methanol and 1% (v/v) acetic acid aqueous solution as the eluent solvent and the loading flow rate of 2 mL/min. The recoveries of the three estrogens from the water samples at three spiked levels ranged from 82.31% to 99.43% with RSD of 1.61%-7.15%. The method was simple, rapid, and suitable to detect the trace residues of estrogens in drinking water.

  1. Physicochemical properties of silica gel coated with a thin layer of polyaniline (PANI) and its application in non-suppressed ion chromatography.

    Science.gov (United States)

    Sowa, Ireneusz; Kocjan, Ryszard; Wójciak-Kosior, Magdalena; Swieboda, Ryszard; Zajdel, Dominika; Hajnos, Mieczysław

    2013-10-15

    Physicochemical properties of a new sorbent and its potential application in non-suppressed ion chromatography (IC) have been investigated. The sorbent was obtained in a process of covering silica gel particles with a film of polyaniline (PANI). The properties of silica modified with polyaniline such as particle size, porosity, average quantity of polyaniline covering carrier and density of sorbent were determined. In our study the following methods were used: microscopic analysis, laser diffraction technique, combustion analysis, mercury porosimetry and helium pycnometry. Column with the newly obtained packing was used for the separation of inorganic anions. Optimized chromatographic system was successfully employed for analysis of iodide and bromide in selected pharmaceutical products (Bochnia salt and Iwonicz salt) applied in chronic respiratory disease. Analysis was carried out using 0.1M solution of HCl in mixture of methanol/water (50:50v/v) as a mobile phase; the flow rate was 0.3 mL min(-1), temperature was 24°C and λ=210 nm. Validation parameters such as correlation coefficient, RSD values, recovery, detection and quantification limits were found to be satisfactory. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Purification of d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) by a temperature-modulated silica gel column chromatography: use of Taguchi method to optimize purification conditions.

    Science.gov (United States)

    Chang, Yinzi; Cao, Yucheng; Zhang, Jin; Wen, Yangyi; Ren, Qilong

    2011-12-05

    The demand for high purity d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) is increasing with the exploitation of TPGS-related products. Previously, we synthesized a TPGS mixture by esterifying vitamin E succinate with polyethyleneglycol 1000. In this study, a temperature-modulated silica gel chromatographic column was used to purify the synthesized TPGS. Taguchi method was used to optimize purification conditions associated with column temperature, loading amount, feedstock concentration and flow rate of mobile phases. Purification efficacy under the Taguchi optimized conditions was predicted theoretically and the predicted results were verified experimentally. High-performance liquid chromatography was used to quantify the unpurified and purified TPGS. The Taguchi-based analysis separately produced an optimum combination of purification conditions for TPGS purity and recovery. Under the optimized conditions, both the theoretical prediction and the confirmatory experiment yielded TPGS purity and recovery approximating to 98% each. Impressively, the study also found that column temperature had a considerable effect on purification efficacy, in particular on TPGS purity, although it was a less influential factor compared to loading amount and feedstock concentration.

  3. The study of the influence of temperature and initial glucose concentration on the fermentation process in the presence of Saccharomyces cerevisiae yeast strain immobilized on starch gels by reversed-flow gas chromatography.

    Science.gov (United States)

    Lainioti, G Ch; Kapolos, J; Koliadima, A; Karaiskakis, G

    2012-01-01

    The technique of reversed-flow gas chromatography (RFGC) was employed for the determination of the alcoholic fermentation phases and of kinetic parameters for free and immobilized cell systems, at different initial glucose concentrations and temperature values. In addition to this, due to its considerable advantages over other techniques, RFGC was used for the characterization of a new biocatalyst, yeast cells immobilized on starch gel, and especially wheat starch gel. Immobilization of wine yeast Saccharomyces cerevisiae AXAZ-1 was accomplished on wheat and corn starch gels in order to prepare new biocatalysts with great interest for the fermentation industry. The RFGC led with great accuracy, resulting from a literature review, to the determination of reaction rate constants and activation energies at each phase of the fermentation processes. A maximum value of rate constants was observed at initial glucose concentration of 205 g/L, where a higher number of yeast cells was observed. The increase of glucose concentrations had a negative influence on the growth of AXAZ-1 cells and rate constants were decreased. The decrease of fermentation temperature caused a substantial reduction in the viability of immobilized cells as well as in rate constant values. Activation energies of corn starch gel presented lower values than those of wheat starch gel. However, the two supports showed higher catalytic efficiency than free cell systems, proving that starch gels may act as a promoter of the catalytic activity of the yeast cells involved in the fermentation process.

  4. Permeation of limonene through disposable nitrile gloves using a dextrous robot hand.

    Science.gov (United States)

    Banaee, Sean; S Que Hee, Shane

    2017-03-28

    The purpose of this study was to investigate the permeation of the low-volatile solvent limonene through different disposable, unlined, unsupported, nitrile exam whole gloves (blue, purple, sterling, and lavender, from Kimberly-Clark). This study utilized a moving and static dextrous robot hand as part of a novel dynamic permeation system that allowed sampling at specific times. Quantitation of limonene in samples was based on capillary gas chromatography-mass spectrometry and the internal standard method (4-bromophenol). The average post-permeation thicknesses (before reconditioning) for all gloves for both the moving and static hand were more than 10% of the pre-permeation ones (P≤0.05), although this was not so on reconditioning. The standardized breakthrough times and steady-state permeation periods were similar for the blue, purple, and sterling gloves. Both methods had similar sensitivity. The lavender glove showed a higher permeation rate (0.490±0.031 μg/cm(2)/min) for the moving robotic hand compared to the non-moving hand (P≤0.05), this being ascribed to a thickness threshold. Permeation parameters for the static and dynamic robot hand models indicate that both methods have similar sensitivity in detecting the analyte during permeation and the blue, purple, and sterling gloves behave similarly during the permeation process whether moving or non-moving.

  5. Separating xanthohumol from Munulus lupulus using silica gel column layer chromatography%硅胶柱层析分离啤酒花中的黄腐酚

    Institute of Scientific and Technical Information of China (English)

    夏娜; 赵仲凯; 黄志江; 魏洁麟; 徐效圣; 贾佳佳; 冯作山

    2012-01-01

    利用硅胶柱层析法对啤酒花浸膏中的黄腐酚进行了分离,采取了2种洗脱方法。方法一是采用石油醚和乙酸乙酯固定比例(2:1)洗脱2次,第1次洗脱后合并含有黄腐酚的洗脱液,浓缩成浸膏,进行第2次洗脱;方法二是以石油醚和乙酸乙酯的混合溶剂梯度洗脱2次,第1次梯度洗脱后合并含有黄腐酚的洗脱液,浓缩成浸膏,进行第2次梯度洗脱。结果表明,方法一的分离效率高、速度快,黄腐酚得率较高(44.88%),但黄腐酚的纯度较低(57.78%);方法二的黄腐酚得率较低(43.16%),但纯度高(81.10%),部分馏分浓缩后有结晶析出,经HPLC检测为黄腐酚结晶单体,纯度达到98.1%,因此可以应用硅胶柱层析法高效分离和纯化啤酒花黄腐酚。%Research was conducted using chromatography methods of silica gel column to purify xanthohumol from Munulus lupulus.Compared with the yield and purity of xanthohumol,two elution methods could be adopted,one of which is taking the petroleum ether:ethyl acetate(2:1)as the elution solvent,then,condense the output and do the same elution process.The other way is taking the mixed petroleum ether and ethyl acetate with different proportion as the elution solvent to do gradient elution,after that,mix the output with the solvent,do the same gradient elution.The result shows that:the first method is of higher efficiency,speed,and yield(44.88%),but the purity of xanthohumol is lower(57.78 %).In the second method,the yield of xanthohumol is lower(43.16%),but the purity of xanthohumol is higher(81.10%).Some of the output educed xanthohumol crystallization.This study determined the xanthohumol crystallization with the HPLC,the purity reach up to 98.1%.Thus,chromatography method of silica gel column is adoptable to purify the xanthohumol from Munulus lupulus.

  6. Purification of capsicum red pigments by saponification and silica gel column chromatography%皂化-硅胶柱层析法纯化辣椒红色素

    Institute of Scientific and Technical Information of China (English)

    庞敏; 王洪新; 殷飞

    2013-01-01

    In order to purify the natural capsicum red pigments,alkaline ethanol saponification was taken to remove the fatty acid from the capsicum oleoresin and silica gel column chromatography was used to separate the capsaicin from capsicum red pigments. The results showed that the optimal saponification conditions were as follows;the concentration of NaOH solution was 0.8mol/L,solid-liquid ratio was 1:15(g/mL),ethanol concentration(V/V) was 70%,the holding temperature was 50℃ and the saponification time was 2h. The optimum separation was achieved with sample volume at 1:40,diameter-length ratio at 1:10 and eluant flow rate at 1BV/h. The color value of purified capsicum red pigments was 672.%探讨了辣椒红色素的纯化工艺,首先采用碱性乙醇皂化法去除辣椒油树脂中的脂肪酸,然后经过硅胶柱层析脱除辣椒红色素中的辣椒碱.实验结果表明,最佳的皂化条件为:NaOH溶液浓度0.8mol/L,固液比1∶15(g/mL),皂化温度50℃,皂化时间2h,乙醇浓度70%(V/V),最佳的硅胶柱层析条件为:上样量1∶40(m样品∶m硅胶),径高比1∶10,洗脱流速1BV/h,得到的辣椒红色素的色价为672.

  7. Separation performance of cucurbit[7]uril in ionic liquid-based sol-gel coating as stationary phase for capillary gas chromatography.

    Science.gov (United States)

    Wang, Xiaogang; Qi, Meiling; Fu, Ruonong

    2014-12-05

    Here we report the separation performance of a new stationary phase of cucurbit[7]uril (CB7) incorporated into an ionic liquid-based sol-gel coating (CB7-SG) for capillary gas chromatography (GC). The CB7-SG stationary phase showed an average polarity of 455, suggesting its polar nature. Abraham system constants revealed that its major interactions with analytes include H-bond basicity (a), dipole-dipole (s) and dispersive (l) interactions. The CB7-SG stationary phase achieved baseline separation for a wide range of analytes with symmetrical peak shapes and showed advantages over the conventional polar stationary phase that failed to resolve some critical analytes. Also, it exhibited different retention behaviors from the conventional stationary phase in terms of retention times and elution order. Most interestingly, in contrast to the conventional polar phase, the CB7-SG stationary phase exhibited longer retentions for analytes of lower polarity but relatively comparable retentions for polar analytes such as alcohols and phenols. The high resolving ability and unique retention behaviors of the CB7-SG stationary phase may stem from the comprehensive interactions of the aforementioned interactions and shape selectivity. Moreover, the CB7-SG column showed good peak shapes for analytes prone to peak tailing, good thermal stability up to 280°C and separation repeatability with RSD values in the range of 0.01-0.11% for intra-day, 0.04-0.41% for inter-day and 2.5-6.0% for column-to-column, respectively. As demonstrated, the proposed coating method can simultaneously address the solubility problem with CBs for the intended purpose and achieve outstanding GC separation performance.

  8. Analysis of recombinant Schistosoma mansoni antigen rSmp28 by on-line liquid chromatography-mass spectrometry combined with sodium dodecyl sulfate polyacrylamide gel electrophoresis

    NARCIS (Netherlands)

    Klarskov, K.; Roecklin, D.; Bouchon, B.; Sabatie, J.; Van Dorsselaer, A.; Bischoff, Rainer

    1994-01-01

    A recombinant Schistosoma mansoni antigen produced in Saccharomyces cerevisiae and purified by glutathione-Sepharose affinity chromatography was analyzed by tryptic peptide mapping using on-line reversed-phase high-performance liquid chromatography pneumatically assisted electrospray mass

  9. [GPC Fingerprint Chromatograms of Aloe vera Leaf Gel Polysaccharides].

    Science.gov (United States)

    Wang, Qiao-e; Xie, Dan; Qian, Jie; Dong, Yin-mao

    2015-10-01

    To establish the gel permeation chromatography (GPC) fingerprint chromatograms of polysaccharides in Aloe vera leaf gel from the same habitat (Beijing) and different habitats for evaluating the quality of Aloe vera leaf gel products commercially available and testing common adulterated substances. The samples were prepared by water-extraction and alcohol-precipitation method. GPC separation was performed on a Shodex SUGAR KS-805 (300 mm x 8.0 mm, 7 μm) column and a Shodex SUGAR KS-803 (300 mm x 8.0 mm, 6 μm) column at the temperature of 60 degrees C by eluting with 0.1 mol/L NaNO3 (containing 0.2 per thousand NaN) at a flow rate of 0.8 mL/min, the chromatographic effluent was detected by refractive index detector (RID) at the temperature of 50 degrees C. The common pattern of GPC fingerprint chromatograms was established and four common peaks were demarcated. The similarities of samples from the same habitat (Beijing) and different habitats were over 0.9. Taking the GPC fingerprint chromatograms for the qualified model, three commercially available aloe products were evaluated to be made of Aloe vera by the different manufacturing processes and four common adulterated substances of aloe polysaccharides were identified effectively. The method is simple and accurate with a good reproducibility, and it can be used for the identification and quality evaluation of Aloe vera leaf gel products.

  10. Dermal permeation of biocides and aromatic chemicals in three generic formulations of metalworking fluids.

    Science.gov (United States)

    Vijay, Vikrant; White, Eugene M; Kaminski, Michael D; Riviere, Jim E; Baynes, Ronald E

    2009-01-01

    Metalworking fluids (MWF) are complex mixtures consisting of a variety of components and additives. A lack of scientific data exists regarding the dermal permeation of its components, particularly biocides. The aim of this study was to evaluate the dermal permeation of biocides and other aromatic chemicals in water and in three generic soluble oil, semi-synthetic, and synthetic MWF types in order to evaluate any differences in their permeation profiles. An in vitro flow-through diffusion cell study was performed to determine dermal permeation. An infinite dose of different groups of chemicals (6 biocides and 29 aromatic chemicals) was applied to porcine skin, with perfusate samples being collected over an 8-h period. Perfusate samples were analyzed by gas chromatography/mass spectrometry (GC-MS) and ultra-performance liquid chromatography/mass spectroscopy (UPLC-MS), and permeability was calculated from the analysis of the permeated chemical concentration-time profile. In general, the permeation of chemicals was highest in aqueous solution, followed by synthetic, semi-synthetic, and soluble oil MWF. The absorption profiles of most of the chemicals including six biocides were statistically different among the synthetic and soluble oil MWF formulations, with reduced permeation occurring in oily formulations. Permeation of almost all chemicals was statistically different between aqueous and three MWF formulation types. Data from this study show that permeation of chemicals is higher in a generic synthetic MWF when compared to a soluble oil MWF. This indicates that a soluble oil MWF may be safer than a synthetic MWF in regard to dermal permeation of chemicals to allow for an increased potential of systemic toxicity. Therefore, one may conclude that a synthetic type of formulation has more potential to produce contact dermatitis and induce systemic toxicological effects. The dilution of these MWF formulations with water may increase dermal permeability of biocides

  11. Hydrogen permeation through tritium permeation barrier in Pb-17Li

    Energy Technology Data Exchange (ETDEWEB)

    Aiello, A. E-mail: aiello@brasimone.enea.ie; Benamati, G.; Chini, M.; Fazio, C.; Serra, E.; Yao, Z

    2001-11-01

    One of the main problems in the development of water cooled lithium lead (WCLL) DEMO fusion reactor is the reduction of the tritium permeation from the Pb-17Li, or the plasma, into the cooling water. The control of tritium losses is an important issue in fusion technology because of its safety and operational implications. This goal can be achieved using a tritium permeation barrier (TPB). The use of aluminium rich coatings, which forms Al{sub 2}O{sub 3} at their surface, has been selected as reference solution for WCLL blanket in order to produce reliable TPB. The hot dipping process is one of the two candidates for the production of coatings on large blanket segments. The effectiveness of hot dipped aluminium coating on MANET II steel has been verified in gas phase and in liquid Pb-17Li, using a test apparatus named Corelli II. The permeation rate measured in gas phase is one order of magnitude lower than the one in liquid metal phase. Performing SEM-EDS analysis on the specimen, it was observed that micro cracks on the coating surface were present. The permeation curves in gas and Pb-17Li are reported and discussed. The characteristics of the new experimental device Vivaldi will be briefly described.

  12. Ultra-high-stability, pH-resistant sol-gel titania poly(tetrahydrofuran) coating for capillary microextraction on-line coupled to high-performance liquid chromatography.

    Science.gov (United States)

    Segro, Scott S; Cabezas, Yaniel; Malik, Abdul

    2009-05-15

    A sol-gel titania poly(tetrahydrofuran) (poly-THF) coating was developed for capillary microextraction hyphenated on-line with high-performance liquid chromatography (HPLC). Poly-THF was covalently bonded to the sol-gel titania network which, in turn, became chemically anchored to the inner surface of a 0.25mm I.D. fused silica capillary. For sample preconcentration, a 38-cm segment of the sol-gel titania poly-THF coated capillary was installed on an HPLC injection port as a sampling loop. Aqueous samples containing a variety of analytes were passed through the capillary and, during this process, the analytes were extracted by the sol-gel titania poly-THF coating on the inner surface of the capillary. Using isocratic and gradient elution with acetonitrile/water mobile phases, the extracted analytes were desorbed into the on-line coupled HPLC column for separation and UV detection. The sol-gel titania poly-THF coating was especially efficient in extracting polar analytes, such as underivatized phenols, alcohols, amines, and aromatic carboxylic acids. In addition, this coating was capable of extracting moderately polar and nonpolar analytes, such as ketones and polycyclic aromatic hydrocarbons. The sol-gel titania poly-THF coated capillary was also able to extract polypeptides at pH values near their respective isoelectric points. Extraction of these compounds can be important for environmental and biomedical applications. The observed extraction behavior can be attributed to the polar and nonpolar moieties in the poly-THF structure. This coating was found to be stable under extremely low and high pH conditions-even after 18h of exposure to 1M HCl (pH approximately 0.0) and 1M NaOH (pH approximately 14.0).

  13. GPC-ELSD法评价脱墨生产过程胶黏物含量的变化%Investigate the Change of the Stickies Content during Deinking Process by Gel Permeation Chromatography-Evaporative Light Scattering Detector

    Institute of Scientific and Technical Information of China (English)

    付时雨; 曾细玲; 俞霁川; Donald Macneil; 詹怀宇

    2009-01-01

    本文介绍了一种新的胶黏物含量测定方法--凝胶渗透色谱-蒸发光散射检测器联用(GPC-ELSD),并采用该方法考察脱墨浆生产过程中主要工段的浆料、纤维组分和细小纤维组分中的胶黏物的含量变化,评价胶黏物的去除效果.结果表明:脱墨浆生产线中主要工段的浆料、纤维组分和细小纤维组分的THF抽出物组成中胶黏物相对含量最小,木材抽出物次之,其他未知组分相对含量最大;细小纤维组分比纤维组分上含有更多的胶黏物;浮选工序有利于去除细小纤维组分上的胶黏物,但是其他后续工段对细小纤维组分上的胶黏物的除去较难;微细胶黏物的去除、细小纤维组分上胶黏物的去除以及减少白水循环过程中胶黏物的积累可能是解决胶黏物障碍问题的关键.

  14. Preconcentration and Determination of Mefenamic Acid in Pharmaceutical and Biological Fluid Samples by Polymer-grafted Silica Gel Solid-phase Extraction Following High Performance Liquid Chromatography

    OpenAIRE

    Bagheri Sadeghi, Hayedeh; Panahi, Homayon Ahmad; Mahabadi, Mahsa; Moniri, Elham

    2015-01-01

    Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) that has analgesic, anti-infammatory and antipyretic actions. It is used to relieve mild to moderate pains. Solid-phase extraction of mefenamic acid by a polymer grafted to silica gel is reported. Poly allyl glycidyl ether/iminodiacetic acid-co-N, N-dimethylacrylamide was synthesized and grafted to silica gel and was used as an adsorbent for extraction of trace mefenamic acid in pharmaceutical and biological samples. Different fa...

  15. Preconcentration and Determination of Mefenamic Acid in Pharmaceutical and Biological Fluid Samples by Polymer-grafted Silica Gel Solid-phase Extraction Following High Performance Liquid Chromatography

    Science.gov (United States)

    Bagheri Sadeghi, Hayedeh; Panahi, Homayon Ahmad; Mahabadi, Mahsa; Moniri, Elham

    2015-01-01

    Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) that has analgesic, anti-infammatory and antipyretic actions. It is used to relieve mild to moderate pains. Solid-phase extraction of mefenamic acid by a polymer grafted to silica gel is reported. Poly allyl glycidyl ether/iminodiacetic acid-co-N, N-dimethylacrylamide was synthesized and grafted to silica gel and was used as an adsorbent for extraction of trace mefenamic acid in pharmaceutical and biological samples. Different factors affecting the extraction method were investigated and optimum conditions were obtained. The optimum pH value for sorption of mefenamic acid was 4.0. The sorption capacity of grafted adsorbent was 7.0 mg/g. The best eluent solvent was found to be trifluoroacetic acid-acetic acid in methanol with a recovery of 99.6%. The equilibrium adsorption data of mefenamic acid by grafted silica gel was analyzed by Langmuir model. The conformation of obtained data to Langmuir isotherm model reveals the homogeneous binding sites of grafted silica gel surface. Kinetic study of the mefenamic acid sorption by grafted silica gel indicates the good accessibility of the active sites in the grafted polymer. The sorption rate of the investigated mefenamic acid on the grafted silica gel was less than 5 min. This novel synthesized adsorbent can be successfully applied for the extraction of trace mefenamic acid in human plasma, urine and pharmaceutical samples. PMID:26330865

  16. Optimization of Separation and Purification of Lactic Acid Bacterial Protein with Gel-filtrationChromatography%凝胶层析分离纯化乳酸菌菌体蛋白条件的优化

    Institute of Scientific and Technical Information of China (English)

    赵春燕; 康素花; 荣向华; 张旋

    2016-01-01

    The lactic acid bacterial protein were separated and purified by gel-filtration chromatography. Se-lecting different gel-filtration chromatography media,column height,flow rate and sample weight to elute lactic acid bacterial protein of Sephadex G-25 desalting. The elution peak was observed. The result showed that all theabove four factors could affect the separation and purification performance of the lactic acid bacterial protein ingel-filtration chromatography by various degrees. In this test,the best separation and purification performancewas achieved using Sephadex G-75 with 45 cm column height,0.75 mL/min flow rate and 5%CV sample weight.%采用凝胶过滤层析分离纯化乳酸菌菌体蛋白,选择不同的凝胶过滤介质、过滤柱高度、洗脱流速、样品上样量对经过SephadexG-25脱盐处理的乳酸菌菌体蛋白进行洗脱,观察洗脱峰.结果表明,凝胶过滤介质、过滤柱过度、洗脱流速和样品上样量均不同程度的影响菌体蛋白的纯化效果.在本试验中,分离纯化乳酸菌菌体蛋白的凝胶过滤层析参数为:SephadexG-75的层析介质以45 cm的柱床高度,洗脱流速0.75 mL/min,样品上样量为5%CV时,对乳酸菌菌体蛋白可达到最佳的分离纯化效果.

  17. Gold nanoparticles grafted modified silica gel as a new stationary phase for separation and determination of steroid hormones by thin layer chromatography

    Directory of Open Access Journals (Sweden)

    Mitra Amoli-Diva

    2015-06-01

    Full Text Available A new thin layer chromatographic layer using gold nanoparticles grafted 3-triethoxysilyl propylamine modified silica gel (Au NPs-APTS modified silica gel was developed as a stationary phase for separation and determination of two steroid hormones, namely progesterone and testosterone. Acetone–n-hexane 25:75 (v/v was used as the mobile phase, and the results were compared with those obtained using plain (i.e., unmodified silica gel plates. Some chromatographic parameters used for separation of the two steroids on an Au NPs-APTS modified silica gel plate as well as on a plain silica gel plate, including ΔRF, separation factor (α, and resolution (RS, were evaluated and compared. The reproducibility of RF values was also determined by analysis of the two steroids in 7 consecutive days on both plates. Validity of the method was investigated, and a wide linear range of 1–200 ng per spot, and low detection limits of 0.16 ng and 0.13 ng per spot, low quantification limits of 0.51 ng and 0.40 ng per spot, and good precision (expressed as percent relative standard deviation lower than 3.1% and 2.7% were obtained for progesterone and testosterone, respectively. As the results revealed, the proposed method is rapid and sensitive, and it is applicable to separation and determination of progesterone and testosterone in biological matrices such as urine samples.

  18. Microemulsion as a vehicle for transdermal permeation of nimesulide

    Directory of Open Access Journals (Sweden)

    Derle D

    2006-01-01

    Full Text Available Topical microemulsions of nimesulide, a poorly water-soluble nonsteroidal antiinflammatory drug, using olive oil as oil phase and Tween 80/iso-octanol as surfactant/co-surfactant were designed. Various concentrations of surfactant: co-surfactant (2:1, 3:1, 4:1 were used in constructing a pseudoternary phase diagram. Oil-in-water microemulsions with ratio 15/35/50 (o/w/s was chosen for the present study after evaluating various parameters like centrifugation, viscosity and stability. Using 4:1 ratio of surfactant : co-surfactant, a microemulsion-based gel of nimesulide was prepared with 1% Carbopol 934. In vitro permeation study of the gel was carried out through excised hairless rat skin and compared with a marketed preparation. The drug release after 24 h from the prepared microemulsion gel and marketed formulation was found to be 72% and 81% respectively. No significant difference was observed between the release rates of nimesulide from both formulations despite their differences in alcohol content. Microemulsion-based gel of poorly water-soluble nimesulide was successfully developed with in vitro release rates comparable to that of the marketed gel formulation.

  19. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of organochlorine pesticides and polychlorinated biphenyls in bottom sediment by dual capillary-column gas chromatography with electron-capture detection

    Science.gov (United States)

    Foreman, William T.; Connor, Brooke F.; Furlong, Edward T.; Vaught, Deborah G.; Merten, Leslie M.

    1995-01-01

    A method for the determination of 30 individual organochlorine pesticides, total toxaphene, and total polychlorinated biphenyls (PCBs) in bottom sediment is described. The method isolates the pesticides and PCBs by solvent extraction with dichlorobenzene, removes inorganic sulfur, large naturally occurring molecules, and other unwanted interferences by gel permeation chromatography, and further cleans up and class fractionates the extract using adsorption chromatography. The com- pounds then are instrumentally determined using dual capillary-column gas chromatography with electron-capture detection. Reporting limits range from 1 to 5 micrograms per kilogram for 30 individual pesticides, 50 micrograms per kilogram for total PCBs, and 200 micrograms per kilogram for total toxaphene. The method also is designed to allow the simultaneous isolation of 79 other semivolatile organic compounds from the sediment, which are separately quantified using gas chromatography with mass spectrometric detection. The method was developed in support of the U.S. Geological Survey's National Water-Quality Assessment program.

  20. Drug silica nanocomposite: preparation, characterization and skin permeation studies.

    Science.gov (United States)

    Pilloni, Martina; Ennas, Guido; Casu, Mariano; Fadda, Anna Maria; Frongia, Francesca; Marongiu, Francesca; Sanna, Roberta; Scano, Alessandra; Valenti, Donatella; Sinico, Chiara

    2013-01-01

    The aim of this work was to evaluate silica nanocomposites as topical drug delivery systems for the model drug, caffeine. Preparation, characterization, and skin permeation properties of caffeine-silica nanocomposites are described. Caffeine was loaded into the nanocomposites by grinding the drug with mesoporous silica in a ball mill up to 10 h and the efficiency of the process was studied by XRPD. Formulations were characterized by several methods that include FTIR, XRPD, SEM and TEM. The successful loading of caffeine was demonstrated by XRPD and FTIR. Morphology was studied by SEM that showed particle size reduction while TEM demonstrated formation of both core-shell and multilayered caffeine-silica structures. Solid-state NMR spectra excluded chemical interactions between caffeine and silica matrix, thus confirming that no solid state reactions occurred during the grinding process. Influence of drug inclusion in silica nanocomposite on the in vitro caffeine diffusion into and through the skin was investigated in comparison with a caffeine gel formulation (reference), using newborn pig skin and vertical Franz diffusion cells. Results from the in vitro skin permeation experiments showed that inclusion into the nanocomposite reduced and delayed caffeine permeation from the silica nanocomposite in comparison with the reference, independently from the amount of the tested formulation.

  1. 大型蛋白质色谱柱及凝胶介质的综述%The Development of Gel Media and Columns for Large-Scale Chromatography of Proteins, a Historical Review

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The first dedicated protein chromatography media were introduced during the 1950s and 1960s. There was an early awareness of the possibility of using these for production applications within the biopharmaceutical industry. However, the crucial limitation was the fact that those media that were most compatible with proteins lent themselves less favourably to scaling-up. The problems were primarily physical. Thus the fibrous cellulose media showed bed cracking tendencies and the bead shaped polyacrylamide, dextran, and agarose gel media, then available,were too soft to stand the hydrodynamic forces acting in large columns, leading to bed compaction and increased pressure drop. At the time, the best solution to the latter problem, after a number of intermediary solutions were tried, was the introduction of the stacked column concept in which several short column segments were connected by small bore tubing, thus reducing the force acting on the particles in each bed compartment. However, the ultimate remedy, the introduction of chromatographic matrices that combine the desired features of adequate rigidity,macroporosity, biocompatibility, chemical stability (for CIP and SIP) and derivatizability, did not occur until the middle of the 1980s when adequately cross-linked agarose gel media such as Sepharose(R) Fast Flow were made available. The paper also recognizes the many attempts made during the past 50 years to develop continous chromatography columns. Most of the designs are based on an annular bed or on an array of annularly arranged parallel columns continuously fed with samples in a cyclic manner. The introduction of media and columns for expanded bed adsorption followed a demand for fewer purification steps and shorter process times. In recent years, columns have been introduced that allow packing and repacking without needing to open the column. The review provides an historical account of the developments that have led to the present state-of-the-art both

  2. Stratum corneum lipids liposomes for the topical delivery of 5-aminolevulinic acid in photodynamic therapy of skin cancer: preparation and in vitro permeation study

    Directory of Open Access Journals (Sweden)

    Bentley M Vitória LB

    2001-08-01

    Full Text Available Abstract Background Photodynamic therapy (PDT using 5-aminolevulinic acid (5-ALA is a skin cancer therapy that still has limitations due to the low penetration of this drug into the skin. We have proposed in this work a delivery system for 5-ALA based on liposomes having lipid composition similar to the mammalian stratum corneum (SCLLs in order to optimize its skin delivery in Photodynamic Therapy (PDT of skin cancers. Methods SCLLs were obtained by reverse phase evaporation technique and size distribution of the vesicles was determinated by photon correlation spectroscopy. In vitro permeation profile was characterized using hairless mouse skin mounted in modified Franz diffusion cell. Results Size exclusion chromatography on gel filtration confirmed vesicle formation. SCLLs obtained by presented a degree of encapsulation of 5-ALA around 5.7%. A distribution of vesicle size centering at around 500 nm and 400 nm respectively for SCLLs and SCLLs containing 5-ALA was found. In vitro 5-ALA permeation study showed that SCLLs preparations presented higher skin retention significantly (p Conclusions The in vitro delivery performance provided by SCLLs lead to consider this systems adequate for the 5-ALA-PDT of skin cancer, since SCLLs have delivered 5-ALA to the target skin layers (viable epidermis + dermis to be treated by topical PDT of skin cancer.

  3. Apparatus and methods for detecting chemical permeation

    Science.gov (United States)

    Vo-Dinh, Tuan

    1994-01-01

    Apparatus and methods for detecting the permeation of hazardous or toxic chemicals through protective clothing are disclosed. The hazardous or toxic chemicals of interest do not possess the spectral characteristic of luminescence. The apparatus and methods utilize a spectrochemical modification technique to detect the luminescence quenching of an indicator compound which upon permeation of the chemical through the protective clothing, the indicator is exposed to the chemical, thus indicating chemical permeation.

  4. Transdermal Iontophoretic Delivery of Atenolol in Combination with Penetration Enhancers: Optimization and Evaluation on Solution and Gels

    Directory of Open Access Journals (Sweden)

    Nandy B. C.

    2009-07-01

    Full Text Available In the present investigation, we prepared Atenolol (1.5 % w/w solution and various polymer formulations by incorporating the tween-20 or L-menthol, as a penetration enhancers and its effect on permeation of the drug through the excised abdominal rat skin were used to examined by using the vertical Franz-type diffusion cell. The physicochemical interactions between Atenolol and various polymers were investigated by performing the assay, ultra violet absorption maxima, Fourier transform infrared spectroscopy and it was further confirmed by thin layer chromatography studies, from which drug did not show any evidence of interaction with the polymers. We found that, L-menthol was superior than tween-20 to iontophoresis [current density applied 0.5 mA/cm2 and 90:10 (on: off ratio], in enhancing the transdermal permeation of Atenolol; it enhanced the flux of Atenolol by more than 2-folds, comparison to the preparations without penetration enhancer via passive diffusion, and 3 folds increased using iontophoresis alone with a shorter lag time. Atenolol also showed good stability in gel formulations. The basic parameters like % loading dose released at the end of the study, permeation coefficient and steady state flux (Jss were calculated and showed statistically significant difference (p<0.05. The results indicated that suitable iontophoretic delivery with desired permeability could be appeared and the cumulative amount-time curves were suitable to fit by a zero order equations which indicated a steady state permeation rate or sustained effect could be achieved from hydrogel; when it is combined with penetration enhancer, L-menthol. The results demonstrate that the semisolid gel formulations are more applicable than solution as a transdermal iontophoretic delivery system to administer clinically. Electrically assisted transdermal delivery of Atenolol significantly increased transport compared to passive delivery. Also, rapid and modulated delivery was

  5. In vitro study on baicalin pH-triggered ophthalmic in situ gel system%pH敏感型黄岑苷眼用原位凝胶剂的体外研究

    Institute of Scientific and Technical Information of China (English)

    武昊昀; 刘志东; 李琳; 李楠; 郭倩; 潘卫三

    2011-01-01

    Objective: To prepare baicalin pH-triggered ophthalmic in situ gel. Methods: Release behavior of baicalin from pH-triggered in situ gel was explored in a dissolution apparatus with paddle method. The released amount of baicalin from pH-triggered gel was determined by UV; the cornea permeation of gel formulations was determined in rabbit corneas. The permeated amount of baicalin was determined by high performance liquid chromatography. Results: The viscosity of gel increased with increasing pH value. The inflexion of viscosity was from 5.8 to 6.0. The in vitro release behavior of the formulation followed Ritger-Peppas equation. The in vitro permeation behavior followed the zero-order kinetic equation. Conclusion: The release time of baicalin from pH-sensitive ophthalmic in situ gel is longer than eye-drops.%目的:研究pH敏感型黄岑苷眼用原位凝胶剂.方法:采用桨法进行处方的体外释药试验,建立UV法测定体外释药量;应用离体角膜进行体外渗透试验,建立HPLC法测定离体角膜渗透量.结果:凝胶基质黏度随pH值的增大而增大,其拐点在pH 5.8-6.0之间;在一定范围内,亲水凝胶材料用量越大,凝胶基质的缓释作用越好;凝胶体外释放符合Ritger-Peppas方程;离体角膜渗透行为符合零级释放规律.结论:pH敏感型黄岑苷眼用原位凝胶剂达到了缓释释放的目的.

  6. Development of a fiber coating based on molecular sol-gel imprinting technology for selective solid-phase micro extraction of caffeine from human serum and determination by gas chromatography/mass spectrometry.

    Science.gov (United States)

    Rajabi Khorrami, Afshin; Rashidpur, Amene

    2012-05-21

    In this work, a molecular sol-gel imprinting approach has been introduced to produce a fiber coating for selective direct immersion solid-phase microextraction (SPME) of caffeine. The polymerization mixture was composed of vinyl trimethoxysilane and methacrylic acid as vinyl sol-gel precursor and functional monomer, respectively. Caffeine was used as template molecule during polymerization process. The prepared fibers could be coupled directly to gas chromatography/mass spectrometry (GC/MS) and used for trace analysis of caffeine in a complex sample such as human serum. The parameters influencing SPME such as time, temperature and stirring speed were optimized. The prepared coating showed good selectivity towards caffeine in the presence of some structurally related compounds. Also, it offered high imprinting capability in comparison to bare fiber and non-imprinted coating. Linear range for caffeine detection was 1-80 μg mL(-1) and the limit of detection was 0.1 μg mL(-1). The intra-day and inter-day precisions of the peak areas for five replicates were 10 and 16%, respectively.

  7. Permeation of macromolecules into the renal glomerular basement membrane and capture by the tubules

    Science.gov (United States)

    Lawrence, Marlon G.; Altenburg, Michael K.; Sanford, Ryan; Willett, Julian D.; Bleasdale, Benjamin; Ballou, Byron; Wilder, Jennifer; Li, Feng; Miner, Jeffrey H.; Berg, Ulla B.; Smithies, Oliver

    2017-01-01

    How the kidney prevents urinary excretion of plasma proteins continues to be debated. Here, using unfixed whole-mount mouse kidneys, we show that fluorescent-tagged proteins and neutral dextrans permeate into the glomerular basement membrane (GBM), in general agreement with Ogston's 1958 equation describing how permeation into gels is related to molecular size. Electron-microscopic analyses of kidneys fixed seconds to hours after injecting gold-tagged albumin, negatively charged gold nanoparticles, and stable oligoclusters of gold nanoparticles show that permeation into the lamina densa of the GBM is size-sensitive. Nanoparticles comparable in size with IgG dimers do not permeate into it. IgG monomer-sized particles permeate to some extent. Albumin-sized particles permeate extensively into the lamina densa. Particles traversing the lamina densa tend to accumulate upstream of the podocyte glycocalyx that spans the slit, but none are observed upstream of the slit diaphragm. At low concentrations, ovalbumin-sized nanoparticles reach the primary filtrate, are captured by proximal tubule cells, and are endocytosed. At higher concentrations, tubular capture is saturated, and they reach the urine. In mouse models of Pierson’s or Alport’s proteinuric syndromes resulting from defects in GBM structural proteins (laminin β2 or collagen α3 IV), the GBM is irregularly swollen, the lamina densa is absent, and permeation is increased. Our observations indicate that size-dependent permeation into the lamina densa of the GBM and the podocyte glycocalyx, together with saturable tubular capture, determines which macromolecules reach the urine without the need to invoke direct size selection by the slit diaphragm. PMID:28246329

  8. A Comparison Between Denaturing Gradient Gel Electrophoresis and Denaturing High Performance Liquid Chromatography in Detecting Mutations in Genes Associated with Hereditary Non-Polyposis Colorectal Cancer (HNPCC and the Identification of 9 New Mutations Previously Unidentified by DGGE

    Directory of Open Access Journals (Sweden)

    Meldrum Cliff J

    2003-12-01

    Full Text Available Abstract Denaturing high performance liquid chromatography is a relatively new method by which heteroduplex structures formed during the PCR amplification of heterozygote samples can be rapidly identified. The use of this technology for mutation detection in hereditary non-polyposis colorectal cancer (HNPCC has the potential to appreciably shorten the time it takes to analyze genes associated with this disorder. Prior to acceptance of this method for screening genes associated with HNPCC, assessment of the reliability of this method should be performed. In this report we have compared mutation and polymorphism detection by denaturing gradient gel electrophoresis (DGGE with denaturing high performance liquid chromatography (DHPLC in a set of 130 families. All mutations/polymorphisms representing base substitutions, deletions, insertions and a 23 base pair inversion were detected by DHPLC whereas DGGE failed to identify four single base substitutions and a single base pair deletion. In addition, we show that DHPLC has been used for the identification of 5 different mutations in exon 7 of hMSH2 that could not be detected by DGGE. From this study we conclude that DHPLC is a more effective and rapid alternative to the detection of mutations in hMSH2 and hMLH1 with the same or better accuracy than DGGE. Furthermore, this technique offers opportunities for automation, which have not been realised for the majority of other methods of gene analysis.

  9. Active Gel Model of Amoeboid Cell Motility

    CERN Document Server

    Callan-Jones, A C

    2013-01-01

    We develop a model of amoeboid cell motility based on active gel theory. Modeling the motile apparatus of a eukaryotic cell as a confined layer of finite length of poroelastic active gel permeated by a solvent, we first show that, due to active stress and gel turnover, an initially static and homogeneous layer can undergo a contractile-type instability to a polarized moving state in which the rear is enriched in gel polymer. This agrees qualitatively with motile cells containing an actomyosin-rich uropod at their rear. We find that the gel layer settles into a steadily moving, inhomogeneous state at long times, sustained by a balance between contractility and filament turnover. In addition, our model predicts an optimal value of the gel-susbstrate adhesion leading to maximum layer speed, in agreement with cell motility assays. The model may be relevant to motility of cells translocating in complex, confining environments that can be mimicked experimentally by cell migration through microchannels.

  10. Gel and gel-free approaches for the quantitative characterisation of complex protein mixtures

    CSIR Research Space (South Africa)

    Buthelezi, S

    2012-10-01

    Full Text Available -dimensional gel electrophoresis (2DE gels), solution phase isoelectric focusing (IEF), offline strong cation exchange (SCX) chromatography and offline high pH reverse phase (RP) chromatography. All fractions collected from the solution-based methods were... which fractionation method between 2DE gels, solution phase IEF, SCX-RP and RP-RP results in the highest number of protein identities RESULTS When the number of protein identities in the different fractionation techniques was compared (Figure 2...

  11. CM Affi-Gel Blue chromatography of human urine: a simple one-step procedure for obtaining erythropoietin suitable for in vitro erythropoietic progenitor assays.

    Science.gov (United States)

    Krystal, G; Eaves, C J; Eaves, A C

    1984-11-01

    A method for both concentrating and purifying human urinary erythropoietin (Ep) using CM Affi-Gel Blue is described. We have found that up to 40 litres of urine can be processed on a 1 litre gel bed of this material. This gives a 25-50-fold purification of Ep with an apparent Ep recovery in excess of 100%. The high recovery of Ep is probably due, in part, to the removal of inhibitors present in the initial urine. By selecting urine that contains high levels of Ep (greater than 0.5 units/ml), it is possible with this method routinely to obtain preparations with specific activities of 100-300 units of Ep per mg protein. Such preparations are noninhibitory when assayed in either short-term suspension cultures or in longer-term methylcellulose cultures at concentrations up to 5-10 units/ml. Similar tests with these same bioassay systems have shown that other non-Ep stimulating factors (i.e. erythroblast enhancing factor (EEF), granulocyte/macrophage colony stimulating factor (GM-CSF) and burst promoting activity (BPA) ) are also not present at detectable levels. In this study we also show that the loss of biological activity which often occurs when partially purified Ep preparations are stored in solution is markedly reduced in the presence of either 1% bovine serum albumin or 0.1% sodium dodecyl sulphate.

  12. COVALENTLY BONDING CHIRAL POLYURETHANE ON AMINATED SILICA GEL: A NEW STRATEGY TO PREPARE CHIRAL STATIONARY PHASE FOR HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    Shao-hua Huang; Zheng-wu Bai; Chuan-qi Yin; Shi-rong Li

    2006-01-01

    Two polyurethanes of different molecular weights were prepared by the copolymerization of phenyl diisocyanate and diisopropyl tartrate. The polyurethanes having terminal isocyanate groups were reacted with 3-aminopropyl silica gel to afford two chiral stationary phases. The (M-)n of the two polyurethanes were 4057 g/mol and 6442 g/mol. The polyurethanes and the corresponding chiral stationary phases were characterized by FT-IR, 1H NMR and elemental analysis. The loading capacities of the polyurethanes on silica gel were 0.68 mmol units/g and 0.61 mmol units/g, respectively. The separation performance and the influence of additives, triethylamine and trichloroacetic acid, on the separation of chiral compounds were investigated by HPLC. The chiral stationary phase prepared from polyurethane with (M-)n of 4057 g/mol demonstrated better enantioseparation capability than that with (M-)n of 6442 g/mol. Additionally, it was found that the addition of triethylamine and trichloroacetic acid in the mobile phases significantly improved the enantioseparation for these two chiral stationary phases.

  13. High performance thin-layer chromatography-mass spectrometry of Japanese knotweed flavan-3-ols and proanthocyanidins on silica gel plates.

    Science.gov (United States)

    Glavnik, Vesna; Vovk, Irena; Albreht, Alen

    2017-01-27

    On-line elution based TLC-MS is now a well-established technique, but the quality of the data obtained can sometimes be hampered by a severe spectral background or by strong ion suppression, especially when silica gel plates are used in combination with an acidic modifier in the developing solvent. We solved this issue simply and efficiently using two pre-developments of the plates, firstly with methanol-formic acid (10:1, v/v) and secondly with acetonitrile-methanol (2:1, v/v). This solution resulted in significant improvement in the sensitivity of HPTLC-MS methods. The applicability of this approach was proven on analysis of flavan-3-ols and proanthocyanidins in crude extracts of Japanese knotweed (Fallopia japonica Houtt.) rhizomes. Separations on HPTLC silica gel and HPTLC silica gel MS grade plates using developing solvents toluene-acetone-formic acid (3:3:1, 6:6:1, 3:6:1, v/v) and dichloromethane-acetone-formic acid (1:1:0.1, v/v) were followed by post-chromatographic derivatization with 4-dimethylaminocinnamaldehyde (DMACA) detection reagent. Examination of the stability of the analytes on the start confirmed that the plates should be developed immediately after the application of standards and sample test solutions. In a five hours stability testing after development we discovered an unexpected phenomenon of enhanced absorption at 280nm. However, based on an experiment with post-chromatographic derivatization with DMACA detection reagent, the analytes were proven to be sufficiently stable in the time frame of an HPTLC-MS analysis. This was important for development of the first HPTLC-MS and HPTLC-MS(n) methods for identification of flavan-3-ols and B-type proanthocyanidins from monomers up to decamers. For the first time, based on this research methodology, trimers, trimer gallates, tetramer gallates, pentamers, pentamer gallates, hexamers, hexamer gallates, heptamers, octamers, nonamers and decamers were tentatively identified in Japanese knotweed rhizomes

  14. Simultaneous determinations of Cr(VI) and Cr(III) by ion-exclusion/cation-exchange chromatography with an unmodified silica-gel column.

    Science.gov (United States)

    Hirata, Shizuko; Kozaki, Daisuke; Sakanishi, Kinya; Nakagoshi, Nobukazu; Tanaka, Kazuhiko

    2010-01-01

    In order to characterize the ion-exclusion and cation-exchange properties of an unmodified silica-gel column, the retention behaviors of Cr(VI) and Cr(III) ions were investigated using a Develosil 30-5 (150 x 4.6 mm i.d.) in the acidic region. Cr(VI) was separated from other anions by an ion-exclusion and ion-adsorption mechanism, and Cr(III) was separated from other cations with a cation-exchange mechanism. When using 2.0 mM oxalic acid (pH 2.6) as an eluent, a good separation of Cr(VI) and Cr(III) was obtained using conductimetric detection in 12 min. The method was successfully applied to the simultaneous determinations of Cr(VI) and Cr(III) added into tap-water and river-water samples.

  15. Opto-acoustic cell permeation

    Energy Technology Data Exchange (ETDEWEB)

    Visuri, S R; Heredia, N

    2000-03-09

    Optically generated acoustic waves have been used to temporarily permeate biological cells. This technique may be useful for enhancing transfection of DNA into cells or enhancing the absorption of locally delivered drugs. A diode-pumped frequency-doubled Nd:YAG laser operating at kHz repetition rates was used to produce a series of acoustic pulses. An acoustic wave was formed via thermoelastic expansion by depositing laser radiation into an absorbing dye. Generated pressures were measured with a PVDF hydrophone. The acoustic waves were transmitted to cultured and plated cells. The cell media contained a selection of normally- impermeable fluorescent-labeled dextran dyes. Following treatment with the opto-acoustic technique, cellular incorporation of dyes, up to 40,000 Molecular Weight, was noted. Control cells that did not receive opto-acoustic treatment had unremarkable dye incorporation. Uptake of dye was quantified via fluorescent microscopic analysis. Trypan Blue membrane exclusion assays and fluorescent labeling assays confirmed the vitality of cells following treatment. This method of enhanced drug delivery has the potential to dramatically reduce required drug dosages and associated side effects and enable revolutionary therapies.

  16. One-step purification of epigallocatechin gallate from crude green tea extracts by isocratic hydrogen bond adsorption chromatography on beta-cyclodextrin substituted agarose gel media.

    Science.gov (United States)

    Xu, Jun; Zhang, Guifeng; Tan, Tianwei; Janson, Jan-Christer

    2005-09-25

    An oligomerized beta-cyclodextrin ligand coupled to brominated allyl-group substituted Sepharose HP has been used for the one-step purification of polyphenolic epigallocatechin gallate (EGCG), an important antioxidant, by isocratic hydrogen bond adsorption chromatography. With a sample load of 1.33 mg crude green tea polyphenolic extract per ml column packing and with water/ethanol/acetonitrile (57/30/13, v/v) as the optimum mobile phase, an EGCG purity of about 98% with a recovery of approximate 73% could be achieved by proper peak cutting. After about 10 sample applications, the column performance started to deteriorate but could be regenerated to its original function by cleaning with 0.35 M NaOH.

  17. Dissolution and permeation characteristics of artemether tablets ...

    African Journals Online (AJOL)

    and permeation characteristics of the formulations were studied using USP methods. Results: Tablets .... Table 2: Physical properties of the artemether tablets. Batch. Code. CS (kgf) ..... metformin using prosopis gum with antidiabetic potential.

  18. Serratiopeptidase Niosomal Gel with Potential in Topical Delivery

    Directory of Open Access Journals (Sweden)

    Ujwala A. Shinde

    2014-01-01

    Full Text Available The objective of present study was to develop nonionic surfactant vesicles of proteolytic enzyme serratiopeptidase (SRP by adapting reverse phase evaporation (REV technique and to evaluate the viability of SRP niosomal gel in treating the topical inflammation. The feasibility of SRP niosomes by REV method using Span 40 and cholesterol has been successfully demonstrated in this investigation. The entrapment efficiency was found to be influenced by the molar ratio of Span 40 : cholesterol and concentration of SRP in noisome. The developed niosomes were characterized for morphology, particle size, and in vitro release. Niosomal gel was prepared by dispersing xanthan gum into optimized batch of SRP niosomes. Ex vivo permeation and in vivo anti-inflammatory efficacy of gel formulation were evaluated topically. SRP niosomes obtained were round in nanosize range. At Span 40 : cholesterol molar ratio 1 : 1 entrapment efficiency was maximum, that is, 54.82% ± 2.08, and showed consistent release pattern. Furthermore ex vivo skin permeation revealed that there was fourfold increase in a steady state flux when SRP was formulated in niosomes and a significant increase in the permeation of SRP, from SRP niosomal gel containing permeation enhancer. In vivo efficacy studies indicated that SRP niosomal gel had a comparable topical anti-inflammatory activity to that of dicolfenac gel.

  19. Ultrasound in Biomedical Engineering: Ultrasound Microbubble Contrast Agents Promote Transdermal Permeation of Drugs

    Directory of Open Access Journals (Sweden)

    Ai-Ho Liao

    2016-09-01

    Full Text Available This report discusses a new development in the use of ultrasound microbubble contrast agents on transdermal drug delivery. The medium surrounding the microbubbles at the optimum concentration from liquid to gel can be modified and it can still achieve the same enhancement for transdermal drug permeation as liquid medium. It was also found that under the same ultrasound power density, microbubbles of larger particle sizes can extend the penetration depths of dye at the phantom surface.

  20. Oxygen permeation through perovskitic membranes: The influence of steam in the sweep on the permeation performance

    Directory of Open Access Journals (Sweden)

    Michael Müller

    2016-08-01

    Full Text Available Experimental approaches are employed for the understanding of oxygen permeation through membranes. For the experiments, different oxygen partial pressures are applied to both sides of a BSCF5582 membrane, using synthetic air as feed and vacuum or steam/argon as sweep gas. Beside the partial pressure gradient, the permeation rate depends on the temperature and the membrane thickness. Sufficient permeation rates can be achieved by sweeping the membrane with water vapor (steam instead of a noble gas, which is optimized by ascending water content in the sweep gas. The influence of the steam content on the permeation performance as well as microstructural changes are demonstrated.

  1. Molecular dynamics computer simulation of permeation in solids

    Energy Technology Data Exchange (ETDEWEB)

    Pohl, P.I.; Heffelfinger, G.S.; Fisler, D.K.; Ford, D.M. [Sandia National Labs., Albuquerque, NM (United States)

    1997-12-31

    In this work the authors simulate permeation of gases and cations in solid models using molecular mechanics and a dual control volume grand canonical molecular dynamics technique. The molecular sieving nature of microporous zeolites are discussed and compared with that for amorphous silica made by sol-gel methods. One mesoporous and one microporous membrane model are tested with Lennard-Jones gases corresponding to He, H{sub 2}, Ar and CH{sub 4}. The mesoporous membrane model clearly follows a Knudsen diffusion mechanism, while the microporous model having a hard-sphere cutoff pore diameter of {approximately}3.4 {angstrom} demonstrates molecular sieving of the methane ({sigma} = 3.8 {angstrom}) but anomalous behavior for Ar ({sigma} = 3.4 {angstrom}). Preliminary results of Ca{sup +} diffusion in calcite and He/H{sub 2} diffusion in polyisobutylene are also presented.

  2. Combining blue native polyacrylamide gel electrophoresis with liquid chromatography tandem mass spectrometry as an effective strategy for analyzing potential membrane protein complexes of Mycobacterium bovis bacillus Calmette-Guérin

    Directory of Open Access Journals (Sweden)

    Li Weijun

    2011-01-01

    Full Text Available Abstract Background Tuberculosis is an infectious bacterial disease in humans caused primarily by Mycobacterium tuberculosis, and infects one-third of the world's total population. Mycobacterium bovis bacillus Calmette-Guérin (BCG vaccine has been widely used to prevent tuberculosis worldwide since 1921. Membrane proteins play important roles in various cellular processes, and the protein-protein interactions involved in these processes may provide further information about molecular organization and cellular pathways. However, membrane proteins are notoriously under-represented by traditional two-dimensional polyacrylamide gel electrophoresis (2-D PAGE and little is known about mycobacterial membrane and membrane-associated protein complexes. Here we investigated M. bovis BCG by an alternative proteomic strategy coupling blue native PAGE to liquid chromatography tandem mass spectrometry (LC-MS/MS to characterize potential protein-protein interactions in membrane fractions. Results Using this approach, we analyzed native molecular composition of protein complexes in BCG membrane fractions. As a result, 40 proteins (including 12 integral membrane proteins, which were organized in 9 different gel bands, were unambiguous identified. The proteins identified have been experimentally confirmed using 2-D SDS PAGE. We identified MmpL8 and four neighboring proteins that were involved in lipid transport complexes, and all subunits of ATP synthase complex in their monomeric states. Two phenolpthiocerol synthases and three arabinosyltransferases belonging to individual operons were obtained in different gel bands. Furthermore, two giant multifunctional enzymes, Pks7 and Pks8, and four mycobacterial Hsp family members were determined. Additionally, seven ribosomal proteins involved in polyribosome complex and two subunits of the succinate dehydrogenase complex were also found. Notablely, some proteins with high hydrophobicity or multiple transmembrane

  3. Polymer-functionalized single-walled carbon nanotubes as a novel sol-gel solid-phase micro-extraction coated fiber for determination of poly-brominated diphenyl ethers in water samples with gas chromatography-electron capture detection.

    Science.gov (United States)

    Zhang, Weiya; Sun, Yin; Wu, Caiying; Xing, Jun; Li, Jianying

    2009-04-15

    Single-walled carbon nanotubes (SWNTs) were functionalized with a hydroxyl-terminated silicone oil (TSO-OH). It is synthesized by the reactions of carbonyl chloride groups on the surface of SWNTs and hydroxyl groups of silicone oil (TSO-OH). The functionalized product SWNTs-TSO-OH was first used as precursor and selective stationary phase to prepare the sol-gel derived poly(SWNTs-TSO-OH) solid-phase microextraction (SPME) fiber for determination of polybrominated diphenyl ethers (PBDEs) in water samples. The possible major reaction of the sol-gel coating process was discussed and confirmed by IR spectra, Raman spectroscopy, and scanning electron microscopy. Some parameters of SPME fiber for the determination of PBDEs were investigated by headspace SPME/gas chromatography with electron-capture detection (HS-SPME/GC-ECD). Compared with the commercial SPME fiber, the new coated fiber showed higher extraction efficiency to PBDEs, better thermal stability (over 340 degrees C), and longer life span (over 200 times). All of these advantages are mainly due to the incorporation of SWNTs, which enhanced the pi-pi interaction with PBDEs and increased the surface area of extraction in contact with the sample. Moreover, the sol-gel coating technology additionally provided the porous structure of the 3-D silica network and the strong chemical binding provided which also will improve the extraction efficiency. Under optimized conditions, the method detection limits for seven PBDEs were 0.08-0.8 ng/L (S/N = 3) and the precision (RSD, n = 5) was 2.2-7.5% at the 50 ng/L level. The linearity of the developed method is in the range of 5-500 ng/L with coefficients of correlation greater than 0.995. The developed method was successfully applied for the analysis of trace PBDEs in reservoir water and wastewater samples. The recoveries obtained at spiking 50 ng/L were between 74% and 109% (n = 5) for PBDEs in water samples.

  4. Separating esterase targets of organophosphorus compounds in the brain by preparative chromatography.

    Science.gov (United States)

    Mangas, I; Vilanova, E; Benabent, M; Estévez, J

    2014-02-10

    Low level exposure to organophosphorus esters (OPs) may cause long-term neurological effects and affect specific cognition domains in experimental animals and humans. Action on known targets cannot explain most of these effects by. Soluble carboxylesterases (EC 3.1.1.1) of chicken brain have been kinetically discriminated using paraoxon, mipafox and phenylmethyl sulfonylfluoride as inhibitors and phenyl valerate as a substrate. Three different enzymatic components were discriminated and called Eα, Eβ and Eγ. In this work, a fractionation procedure with various steps was developed using protein native separation methods by preparative HPLC. Gel permeation chromatography followed by ion exchange chromatography allowed enriched fractions with different kinetic behaviors. The soluble chicken brain fraction was fractionated, while total esterase activity, proteins and enzymatic components Eα, Eβ and Eγ were monitored in each subfraction. After the analysis, 13 fractions were pooled and conserved. Preincubation of the soluble chicken brain fraction of with the organophosphorus mipafox gave rise to a major change in the ion exchange chromatography profile, but not in the molecular exchanged chromatography profile, which suggest that mipafox permanently modifies the ionic properties of numerous proteins. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  5. Synthesis and application of multi-walled carbon nanotubes-molecularly imprinted sol-gel composite material for on-line solid-phase extraction and high-performance liquid chromatography determination of trace Sudan IV

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zhaohui, E-mail: zhaohuizhang77@hotmail.com [College of Chemistry and Chemical Engineering, Jishou University, Jishou 416000 (China); State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Zhang Huabin; Hu Yufang [College of Chemistry and Chemical Engineering, Jishou University, Jishou 416000 (China); Yao Shouzhuo [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China)

    2010-02-28

    A novel composite material of multi-walled carbon nanotubes (MWNTs)-Sudan IV molecularly imprinted polymers (MIPs) was prepared by surface molecular imprinting technique in combination with sol-gel technology. The MWNTs-MIPs were evaluated by scanning electron micrograph (SEM), Fourier transform infrared spectroscopy (FT-IR), and adsorption experiments. The results showed that the MWNTs-MIPs exhibited good selective recognition to Sudan IV. The maximum saturated binding capacity (Q{sub max}) is 63.2 {mu}mol g{sup -1}. Applied as sorbent, the MWNTs-MIPs were used for the determination of trace Sudan IV in chilli powder by on-line solid-phase extraction-high-performance liquid chromatography (SPE-HPLC). The results showed that an enrichment factor of 741 was achieved with a loading flow rate of 1.0 mL min{sup -1} for sampling 50 mL. The MWNTs-MIPs provided a fast and convenience determination platform for Sudan IV in real samples.

  6. Ethosomes Loaded with Cryptotanshinone for Acne Treatment through Topical Gel Formulation

    OpenAIRE

    Zhenwei Yu; Hongyan Lv; Gang Han; Ke Ma

    2016-01-01

    The aim of this study was to develop ethosomes loaded with cryptotanshinone (CPT) and formulate them as a topical gel for the treatment of acne. Ethosomes were prepared and evaluated for vesicle size, CPT loading and encapsulation efficiency. Optimized ethosomes were formulated as Carbomer 974 gels and compared with conventional hydroethanolic gels for transdermal permeation and skin deposition in vitro. The anti-acne activity and skin irritation of the gel was investigated in rabbits. Optimi...

  7. Development of the ambroxol gels for enhanced transdermal delivery.

    Science.gov (United States)

    Cho, Cheong-Weon; Choi, Jun-Shik; Shin, Sang-Chul

    2008-03-01

    Ambroxol is an expectoration improver and mucolytic agent that has been used to treat acute and chronic disorders. However, ambroxol needs to be administered percutaneously in order to avoid systemic adverse effects, such as headache, drowsiness, dizziness, and insomnia, which can occur after oral administration. The aim of this study was to develop a gel preparation containing a permeation enhancer to enhance the delivery of ambroxol. The ambroxol gels were prepared using hydroxypropyl methylcellulose (HPMC) and poloxamer 407. The release characteristics of the drug from the gels were examined according to the receptor medium, drug concentration, and temperature. The rate of drug permeation into the skin was enhanced by incorporating various enhancers such as the ethylene glycols, the propylene glycols, the glycerides, the non-ionic surfactants, and the fatty acids into the gels. The permeation study through mouse skin was examined at 37 C. The rate of drug release increased with increasing drug concentration and temperature. Among the enhancers used, propylene glycol mono caprylate showed the best enhancing effects. The estimated activation energy of release (Ea), which was calculated from the slope of a log P versus 1000/T plot, was 14.80, 14.22, 13.91, and 12.46 kcal/mol for ambroxol loading doses of 2, 3, 4, and 5%, respectively. The results of this study show that the gel preparation of ambroxol containing a permeation enhancer could be developed for the enhanced transdermal delivery of ambroxol.

  8. Drug permeation through the three layers of the human nail plate.

    Science.gov (United States)

    Kobayashi, Y; Miyamoto, M; Sugibayashi, K; Morimoto, Y

    1999-03-01

    The in-vitro permeation characteristics of a water soluble model drug, 5-fluorouracil, and a poorly water soluble model drug, flurbiprofen, were investigated through three layers of the human nail plate (namely, the dorsal, intermediate and ventral nail plates), using a modified side-by-side diffusion cell. The dorsal-filed nail plate, the ventral-filed nail plate and the dorsal-and-ventral-filed nail plate were prepared to known thicknesses and then used with the full-thickness nail plate to investigate the permeation characteristics of each single layer. Most of the lipids in the human nail plate were found in the dorsal and ventral layers. The rank orders of the permeation fluxes for 5-fluorouracil and flurbiprofen were both: dorsal-and-ventral-filed nail plate > dorsal-filed nail plate > ventral-filed nail plate > full-thickness nail plate. With respect to 5-fluorouracil permeation through each single layer, the permeability coefficient of the intermediate layer was higher than those of other single layers. However in the case of flurbiprofen, the permeability coefficient of the ventral layer was higher than other single layers. The diffusion coefficients of 5-fluorouracil and flurbiprofen in the dorsal layer were the lowest of any single layer. The drug concentration in each layer was estimated using each respective permeation parameter. The drug concentration in the nail plate was observed to be dependent on the solubility and the flux of the drug. From these findings, we suggest that the human nail plate behaves like a hydrophilic gel membrane rather than a lipophilic partition membrane and that the upper layer functions as the main nail barrier to drug permeation through its low diffusivity against the drugs.

  9. SKIN PERMEATION ENHANCEMENT EFFECTS OF ASCORBIC ACID AND TRIETHYL CITRATE ON ROFECOXIB

    Directory of Open Access Journals (Sweden)

    MALAY K. DAS

    2008-01-01

    Full Text Available The enhancing effect of ascorbic acid and triethyl citrate (TEC on the in vitro skin permeation of rofecoxib across rat epidermis was investigated. Skin pre-treatment with ascorbic acid and TEC at different concentrations, followed by application of rofecoxib gel, showed higher permeation flux than the control condition. The mechanism underlying this permeation enhancement was probed with fourier transform infrared spectroscopy (FTIR. The FTIR spectra of rat epidermis treated with ascorbic acid revealed that ascorbic acid at low concentration appears to interact with dermal keratin, whereas at higher concentration it appears to interact with both dermal proteins and lipids. The FTIR spectra of rat epidermis treated with TEC showed a decrease in peak heights for both asymmetric and symmetric C-H stretching absorbance, indicating a change in the fluidity of alkyl chains in the intercellular lipids in the stratum corneum (SC. The protein disruption effect of TEC was probably due to the solvation of keratin by the formation of hydrogen bonds between TEC hydroxyl groups and keratin chain C=O groups. Skin pre-treatment with different concentrations of permeation enhancers did not show any significant change in lag time in comparison to control. The amount of rofecoxib retained in the skin after skin pre-treatment with enhancers was found to be higher than in the experiment without skin pre-treatment. Scanning electron microscopy (SEM confirmed the maintenance of skin integrity throughout the permeation experiment. The observed permeation enhancing effects of ascorbic acid and TEC in the present study indicate that a rapid percutaneous absorption of rofecoxib at effective therapeutic levels may facilitate faster anti-inflammatory activity.

  10. Mechanisms of gas permeation through polymer membranes

    Energy Technology Data Exchange (ETDEWEB)

    Stern, S.A.

    1991-01-01

    The objective of the present study is to investigate the mechanisms of gas transport in and through polymer membranes and the dependence of these mechanisms on pressure and temperature. This information is required for the development of new, energy-efficient membrane processes for the separation of industrial gas mixtures. Such processes are based on the selective permeation of the components of gas mixtures through nonporous polymer membranes. Recent work has been focused on the permeation of gases through membranes made from glassy polymers, i.e., at temperatures below the glass transition of the polymers (Tg). Glassy polymers are very useful membrane materials for gas separations because of their high selectivity toward different gases. Gases permeate through nonporous polymer membranes by a solution-diffusion'' process. Consequently, in order to understand the characteristics of this process it is necessary to investigate also the mechanisms of gas solution and diffusion in glassy polymers. 23 refs., 10 figs., 4 tabs.

  11. Development of Tritium Permeation Analysis Code (TPAC)

    Energy Technology Data Exchange (ETDEWEB)

    Eung S. Kim; Chang H. Oh; Mike Patterson

    2010-10-01

    Idaho National Laboratory developed the Tritium Permeation Analysis Code (TPAC) for tritium permeation in the Very High Temperature Gas Cooled Reactor (VHTR). All the component models in the VHTR were developed and were embedded into the MATHLAB SIMULINK package with a Graphic User Interface. The governing equations of the nuclear ternary reaction and thermal neutron capture reactions from impurities in helium and graphite core, reflector, and control rods were implemented. The TPAC code was verified using analytical solutions for the tritium birth rate from the ternary fission, the birth rate from 3He, and the birth rate from 10B. This paper also provides comparisons of the TPAC with the existing other codes. A VHTR reference design was selected for tritium permeation study from the reference design to the nuclear-assisted hydrogen production plant and some sensitivity study results are presented based on the HTGR outlet temperature of 750 degrees C.

  12. Permeation barrier for lightweight liquid hydrogen tanks

    Energy Technology Data Exchange (ETDEWEB)

    Schultheiss, D.

    2007-04-16

    For the future usage of hydrogen as an automotive fuel, its on-board storage is crucial. One approach is the storage of liquid hydrogen (LH2, 20 K) in double-walled, vacuum insulated tanks. The introduction of carbon fiber reinforced plastics (CFRP) as structural material enables a high potential of reducing the weight in comparison to the state-of-the-art stainless steel tanks. The generally high permeability of hydrogen through plastics, however, can lead to long-term degradation of the insulating vacuum. The derived objective of this dissertation was to find and apply an adequate permeation barrier (liner) on CFRP. The investigated liners were either foils adhered on CFRP specimens or coatings deposited on CFRP specimens. The coatings were produced by means of thermal spraying, metal plating or physical vapor deposition (PVD). The materials of the liners included Al, Au, Cu, Ni and Sn as well as stainless steel and diamond-like carbon. The produced liners were tested for their permeation behavior, thermal shock resistance and adherence to the CFRP substrate. Additionally, SEM micrographs were used to characterize and qualify the liners. The foils, although being a good permeation barrier, adhered weakly to the substrate. Furthermore, leak-free joining of foil segments is a challenge still to be solved. The metal plating liners exhibited the best properties. For instance, no permeation could be detected through a 50 {mu}m thick Cu coating within the accuracy of the measuring apparatus. This corresponds to a reduction of the permeation gas flow by more than factor 7400 compared to uncoated CFRP. In addition, the metal platings revealed a high adherence and thermal shock resistance. The coatings produced by means of thermal spraying and PVD did not show a sufficient permeation barrier effect. After having investigated the specimens, a 170 liter CFRP tank was fully coated with 50 {mu}m Cu by means of metal plating. (orig.)

  13. A solid phase microextraction coating based on ionic liquid sol-gel technique for determination of benzene, toluene, ethylbenzene and o-xylene in water samples using gas chromatography flame ionization detector.

    Science.gov (United States)

    Sarafraz-Yazdi, Ali; Vatani, Hossein

    2013-07-26

    Ionic liquid mediated sol-gel sorbents for head-space solid phase microextraction (HS-SPME) were developed for the extraction of benzene, toluene, ethylbenzene and o-xylene (BTEX) compounds from water samples in ultra-trace levels. The analytes were subsequently analyzed with gas chromatography coupled to flame ionization detector (GC-FID). Three different coating fibers were prepared including: poly(dimethylsiloxane) (PDMS), coating prepared from poly(dimethylsiloxane) in the presence of ionic liquid as co-solvent and conditioned at a higher temperature than decomposition temperature of ionic liquid (PDMS-IL-HT) and coating prepared from poly(dimethylsiloxane) in the presence of ionic liquid as co-solvent and conditioned at a lower temperature than decomposition temperature of ionic liquid (PDMS-IL-LT). Prepared fibers demonstrate many advantages such as high thermal and chemical stabilities due to the chemical bonding of the coatings with the silanol groups on the fused-silica surface fiber. These fibers have shown long life time up to 180 extractions. The scanning electron micrographs of the fibers surfaces revealed that addition of ionic liquid into the sol solution during the sol-gel process increases the fiber coating thickness, affects the form of fiber structure and also leaves high pores in the fiber surface that cause high surface area and therefore increases sample capacity of the fibers. The important parameters that affect the extraction efficiency are desorption temperature and time, sample volume, extraction temperature, extraction time, stirring speed and salt effect. Therefore these factors were investigated and optimized. Under optimal conditions, the dynamic linear range with PDMS-IL-HT, PDMS and PDMS-IL-LT fibers were 0.3-200,000; 50-200,000 and 170-150,000pgmL(-1) and the detection limits (S/N=3) were 0.1-2 and 15-200 and 50-500pgmL(-1), and limit of quantifications (S/N=10) were 0.3-8 and 50-700 and 170-1800, respectively. The relative

  14. Methods to simulate rubbing of topical formulation for in vitro skin permeation studies.

    Science.gov (United States)

    Nguyen, Hiep X; Puri, Ashana; Banga, Ajay K

    2017-03-15

    Rubbing a topical formulation on skin is generally assumed to enhance drug penetration. The aim of this study was to demonstrate different techniques such as using glass rod, rheometer, and gloved finger for rubbing a 2% salicylic acid gel on skin and investigate their effect on in vitro permeation of salicylic acid through dermatomed porcine ear skin. The studies included evaluation of the gel's rheological properties, gel distribution on skin surface, in vitro permeability, drug distribution in skin, skin extraction recovery, and mass balance. Rubbing with a gloved finger resulted in a uniform gel layer with a thickness of 49.61±15.33μm on the skin surface. No significant difference between the different test groups was observed in terms of the cumulative amount of drug that permeated in 24h (p>0.05). Drug levels in stratum corneum, epidermis, and dermis were also analyzed. Rubbing with gloved finger delivered significantly higher amount of drug into the skin layers as compared to other test groups (pskin was reliably correlated to the actual drug levels in skin (R(2)=0.99). Considering drug amounts in different compartments, mass balance ranged from 75.86±2.90% to 80.44±2.99%. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Enhanced local anesthetic action of mepivacaine from the bioadhesive gels.

    Science.gov (United States)

    Cho, Cheong-Weon; Choi, Jun-Shik; Shin, Sang-Chul

    2011-01-01

    Mepivacaine, an amide-type local anesthetic, has been used to relieve local pain. Among the many drug delivery systems, transdermal drug delivery has some advantages, as it provides controlled drug delivery for an extended period of time. To develop new gel formulations that have suitable bioadhesion, the bioadhesive force of hydroxypropyl methylcellulose (HPMC) was assessed using an auto-peeling tester. The effect of drug concentration on drug release from 2% HPMC gel was studied using synthetic cellulose membrane at 37±0.5°C. The drug concentrations tested were 0.5, 1, 1.5, 2, and 2.5%. The effect of temperature on drug release from the 2% drug gel was evaluated at 27, 32, 37 and 42°C. To increase the skin permeation of mepivacaine from HPMC gel, enhancers such as saturated and unsaturated fatty acids, pyrrolidones, propylene glycol derivatives, glycerides, and non-ionic surfactants were incorporated into the mepivacaine-HPMC gels. The enhancing effect of the enhancer on drug permeation was then examined in the modified Keshary-Chien cell. For the efficacy study, the anesthetic action of the formulated mepivacaine gel containing enhancer and vasoconstrictor was evaluated with the tail-flick analgesimeter. Among the various kinds of HPMC, HPMC-K100M gel showed the highest viscosity and bioadhesive force. As the viscosity of the HPMC gels increased, the bioadhesive forces increased. Increasing the drug concentration or temperature increased the drug release rate. Among the enhancers used, polyoxyethylene 2-oleyl ether showed the greatest enhancement of permeation. Based on the area under the efficacy curve of the rat tail flick test curve, mepivacaine gel containing polyoxyethylene 2-oleyl ether and tetrahydrozoline showed prolonged and increased local anesthetic action compared to the control. For bioadhesive mepivacaine gels with enhanced local anesthetic action, mepivacaine gels containing penetration enhancer and vasoconstrictor could be developed with the

  16. 16S-23S Internal Transcribed Spacer Region PCR and Sequencer-Based Capillary Gel Electrophoresis has Potential as an Alternative to High Performance Liquid Chromatography for Identification of Slowly Growing Nontuberculous Mycobacteria

    Science.gov (United States)

    Subedi, Shradha; Kong, Fanrong; Jelfs, Peter; Gray, Timothy J.; Xiao, Meng; Sintchenko, Vitali; Chen, Sharon C-A

    2016-01-01

    Accurate identification of slowly growing nontuberculous mycobacteria (SG-NTM) of clinical significance remains problematic. This study evaluated a novel method of SG-NTM identification by amplification of the mycobacterial 16S-23S rRNA internal transcribed spacer (ITS) region followed by resolution of amplified fragments by sequencer-based capillary gel electrophoresis (SCGE). Fourteen American Type Culture Collection (ATCC) strains and 103 clinical/environmental isolates (total n = 24 species) of SG-NTM were included. Identification was compared with that achieved by high performance liquid chromatography (HPLC), in-house PCR and 16S/ITS sequencing. Isolates of all species yielded a SCGE profile comprising a single fragment length (or peak) except for M. scrofulaceum (two peaks). SCGE peaks of ATCC strains were distinct except for peak overlap between Mycobacterium kansasii and M. marinum. Of clinical/environmental strains, unique peaks were seen for 7/17 (41%) species (M. haemophilum, M. kubicae, M. lentiflavum, M. terrae, M. kansasii, M. asiaticum and M. triplex); 3/17 (18%) species were identified by HPLC. There were five SCGE fragment length types (I–V) each of M. avium, M. intracellulare and M. gordonae. Overlap of fragment lengths was seen between M. marinum and M. ulcerans; for M. gordonae SCGE type III and M. paragordonae; M. avium SCGE types III and IV, and M. intracellulare SCGE type I; M. chimaera, M. parascrofulaceum and M. intracellulare SCGE types III and IV; M. branderi and M. avium type V; and M. vulneris and M. intracellulare type V. The ITS-SCGE method was able to provide the first line rapid and reproducible species identification/screening of SG-NTM and was more discriminatory than HPLC. PMID:27749897

  17. Gel chromatography coupled with post-column derivation to quickly identify orange juice adulteration%凝胶色谱分离-柱后染色法快速鉴别橙汁掺假

    Institute of Scientific and Technical Information of China (English)

    牛灿杰; 陈小珍; 张慧; 王展华; 马千里; 徐生坚

    2015-01-01

    Gel chromatography (GFC) coupled with post-column derivation was first used to detect the soluble protein in different regions of the orange juice.The protein fingerprint of orange juice has been established.Results showed that the fingerprint has four main characteristic peaks,the molecular weight was 7.5 × 104 Da and 0.5 × 104 Da-1.0 × 104Da.The protein fingerprint of other fruit juice and blending fruit are different from pure orange juice.The method has fewdisturbances and provides the references for orange juice adulteration identification and juice quality evaluation.%采用凝胶色谱(GFC)分离柱后复合考马斯亮蓝染色法,研究了不同地区橙汁中的可溶性蛋白质,建立了橙汁蛋白质按分子量分布的特征指纹图谱.结果表明:橙汁中可溶性蛋白质的凝胶过滤色谱指纹图谱具有4个主要特征峰,分子质量位于7.5×104Da及0.5×104~1.0×104Da.其他果汁及勾兑假果汁的蛋白质图谱不同于纯正橙汁的特征峰图谱,可用于橙汁掺假快速鉴别.该方法干扰少,检测快速,可用于浓缩还原橙汁掺假鉴别.

  18. 16S-23S Internal Transcribed Spacer Region PCR and Sequencer-Based Capillary Gel Electrophoresis has Potential as an Alternative to High Performance Liquid Chromatography for Identification of Slowly Growing Nontuberculous Mycobacteria.

    Science.gov (United States)

    Subedi, Shradha; Kong, Fanrong; Jelfs, Peter; Gray, Timothy J; Xiao, Meng; Sintchenko, Vitali; Chen, Sharon C-A

    2016-01-01

    Accurate identification of slowly growing nontuberculous mycobacteria (SG-NTM) of clinical significance remains problematic. This study evaluated a novel method of SG-NTM identification by amplification of the mycobacterial 16S-23S rRNA internal transcribed spacer (ITS) region followed by resolution of amplified fragments by sequencer-based capillary gel electrophoresis (SCGE). Fourteen American Type Culture Collection (ATCC) strains and 103 clinical/environmental isolates (total n = 24 species) of SG-NTM were included. Identification was compared with that achieved by high performance liquid chromatography (HPLC), in-house PCR and 16S/ITS sequencing. Isolates of all species yielded a SCGE profile comprising a single fragment length (or peak) except for M. scrofulaceum (two peaks). SCGE peaks of ATCC strains were distinct except for peak overlap between Mycobacterium kansasii and M. marinum. Of clinical/environmental strains, unique peaks were seen for 7/17 (41%) species (M. haemophilum, M. kubicae, M. lentiflavum, M. terrae, M. kansasii, M. asiaticum and M. triplex); 3/17 (18%) species were identified by HPLC. There were five SCGE fragment length types (I-V) each of M. avium, M. intracellulare and M. gordonae. Overlap of fragment lengths was seen between M. marinum and M. ulcerans; for M. gordonae SCGE type III and M. paragordonae; M. avium SCGE types III and IV, and M. intracellulare SCGE type I; M. chimaera, M. parascrofulaceum and M. intracellulare SCGE types III and IV; M. branderi and M. avium type V; and M. vulneris and M. intracellulare type V. The ITS-SCGE method was able to provide the first line rapid and reproducible species identification/screening of SG-NTM and was more discriminatory than HPLC.

  19. Permeation of volatile compounds through starch films

    NARCIS (Netherlands)

    Yilmaz, G.; Jongboom, R.O.J.; Feil, H.; Dijk, van C.; Hennink, W.E.

    2004-01-01

    The aim of this study was to gain insight into the factors that affect the permeation of volatiles through starch films. These films were obtained by casting gelatinized starch/water/glycerol mixtures. The films were dried and conditioned under different conditions (temperature and relative humidity

  20. Permeating the Culture of a State Association

    Science.gov (United States)

    Reeves, Pat

    2009-01-01

    In the four years since Courageous Journey was launched, the impact has permeated the Michigan Association of School Administrators (MASA). Already, 16 of 47 council and executive board members have joined a cohort. The Courageous Journey's Seven Points of Learning (or seven major superintendent responsibilities) help frame the organization's…

  1. Hydrogen Permeation Through Multilayer Metallic Membranes

    Science.gov (United States)

    Andrew, Philip L.

    Hydrogen transport across metal surfaces is pertinent not only to the fueling of a fusion reactor, but also to fusion related technologies such as tritium handling. The rates of these processes and that of hydrogen atoms permeating through the metal bulk were obtained by measuring the steady state permeation rate through polycrystalline metal membranes. The experimental investigation focussed on composite membranes made up of iron, palladium and copper layers. The measurements were made under ultrahigh vacuum conditions using either hydrogen molecules or neutral atoms as the incident species. The mathematical dependence of the steady state permeating flux on the incident flux was used to determine whether hydrogen transport at the vacuum/metal interfaces or within the metal bulk (diffusion) is rate-limiting. The chemical composition of the membrane surfaces, measured by Auger Electron Spectroscopy, was found to have a profound effect on surface-limited permeation. The removal of impurities on an iron surface by Ar ion sputtering was found to increase the magnitude and decrease the temperature dependence of the surface-limited permeation rate constant. Deposition of palladium or iron on sputter-cleaned iron surfaces resulted in a reduction of non-metal surface impurities and a further increase in the rate of surface processes. Application of copper on iron, however, had the opposite effect. This is thought to be due to the slow hydrogen adsorption rates peculiar to group IB metals. A thin copper layer on a palladium membrane had a similar effect: hydrogen transport across that surface was impeded. The results are discussed in terms of practical applications of membranes for pumping or detecting hydrogen. In these schemes it is desired that hydrogen, once dissolved in the metal, preferentially exit on the downstream surface.

  2. Permeation of bioactive constituents from Arnica montana preparations through human skin in-vitro.

    Science.gov (United States)

    Tekko, I A; Bonner, M C; Bowen, R D; Williams, A C

    2006-09-01

    This study investigated and characterised transdermal permeation of bioactive agents from a topically applied Arnica montana tincture. Permeation experiments conducted over 48 h used polydimethylsiloxane (silastic) and human epidermal membranes mounted in Franz-type diffusion cells with a methanol-water (50:50 v/v) receptor fluid. A commercially available tincture of A. montana L. derived from dried Spanish flower heads was a donor solution. Further donor solutions prepared from this stock tincture concentrated the tincture constituents 1, 2 and 10 fold and its sesquiterpene lactones 10 fold. Permeants were assayed using a high-performance liquid chromatography method. Five components permeated through silastic membranes providing peaks with relative retention factors to an internal standard (santonin) of 0.28, 1.18, 1.45, 1.98 and 2.76, respectively. No permeant was detected within 12 h of applying the Arnica tincture onto human epidermal membranes. However, after 12 h, the first two of these components were detected. These were shown by Zimmermann reagent reaction to be sesquiterpene lactones and liquid chromatography/diode array detection/mass spectrometry indicated that these two permeants were 11,13-dihydrohelenalin (DH) analogues (methacrylate and tiglate esters). The same two components were also detected within 3 h of topical application of the 10-fold concentrated tincture and the concentrated sesquiterpene lactone extract.

  3. Methods of analysis-Determination of pesticides in sediment using gas chromatography/mass spectrometry

    Science.gov (United States)

    Hladik, Michelle L.; McWayne, Megan M.

    2012-01-01

    A method for the determination of 119 pesticides in environmental sediment samples is described. The method was developed by the U.S. Geological Survey (USGS) in support of the National Water Quality Assessment (NAWQA) Program. The pesticides included in this method were chosen through prior prioritization. Herbicides, insecticides, and fungicides along with degradates are included in this method and span a variety of chemical classes including, but not limited to, chloroacetanilides, organochlorines, organophosphates, pyrethroids, triazines, and triazoles. Sediment samples are extracted by using an accelerated solvent extraction system (ASE®, and the compounds of interest are separated from co-extracted matrix interferences (including sulfur) by passing the extracts through high performance liquid chromatography (HPLC) with gel-permeation chromatography (GPC) along with the use of either stacked graphitized carbon and alumina solid-phase extraction (SPE) cartridges or packed Florisil®. Chromatographic separation, detection, and quantification of the pesticides from the sediment-sample extracts are done by using gas chromatography with mass spectrometry (GC/MS). Recoveries in test sediment samples fortified at 10 micrograms per kilogram (μg/kg) dry weight ranged from 75 to 102 percent; relative standard deviations ranged from 3 to 13 percent. Method detection limits (MDLs), calculated by using U.S. Environmental Protection Agency procedures (40 CFR 136, Appendix B), ranged from 0.6 to 3.4 μg/kg dry weight.

  4. Preparation and characterisation of mucoadhesive nasal gel of venlafaxine hydrochloride for treatment of anxiety disorders

    Directory of Open Access Journals (Sweden)

    Shyamoshree Basu

    2012-01-01

    Full Text Available The aim of the present study is to prepare and evaluate mucoadhesive nasal gels of venlafaxine hydrochloride. Mucoadhesive nasal gels were prepared using polymers like carbopol 934 and sodium alginate and characterized in terms of viscosity, texture profile analysis, ex vivo drug permeation profiles and histopathological studies. The results show that values of viscosity, hardness and adhesiveness increase while those of cohesiveness decrease with corresponding increase in concentration of the polymers. Ex vivo drug permeation profiles showed that formulation containing 5% sodium alginate provided a better controlled release of the drug than the other formulations over a period of 12 h. Histopathological studies assured that gels containing different polymers did not produce any significant change in the nasal mucosae of goat even after 12 h permeation study. Mucoadhesive nasal gel of venlafaxine hydrochloride is a novel dosage form which delivers the drug directly into systemic circulation and provides controlled release of the drug.

  5. Synergistic effect of iontophoresis and chemical enhancers on transdermal permeation of tolterodine tartrate for the treatment of overactive bladder

    Directory of Open Access Journals (Sweden)

    D. Prasanthi

    2013-01-01

    Full Text Available Purpose The objective of the study was to evaluate the synergistic transdermal permeation effect of chemical enhancers and iontophoresis technique on tolterodine tartrate (TT transdermal gel and to evaluate its pharmacokinetic properties. Materials and Methods Taguchi robust design was used for optimization of formulations. Skin permeation rates were evaluated using the Keshary-chein type diffusion cells in order to optimize the gel formulation. In-vivo studies of the optimized formulation were performed in a rabbit model and histopathology studies of optimized formulation were performed on rats. Results Transdermal gels were formulated successfully using Taguchi robust design method. The type of penetration enhancer, concentration of penetration enhancer, current density and pulse on/off ratio were chosen as independent variables. Type of penetration enhancer was found to be the significant factor for all the responses. Permeation parameters were evaluated when maximum cumulative amount permeated in 24 hours (Q24 was 145.71 ± 2.00µg/cm2 by CIT4 formulation over control (91.89 ± 2.30µg/cm2. Permeation was enhanced by 1.75 fold by CIT4 formulation. Formulation CIT4 containing nerolidol (5% and iontophoretic variables applied (0.5mA/cm2 and pulse on/off ratio 3:1 was optimized. In vivo studies with optimized formulation CIT4 showed increase in AUC and T1/2 when compared to oral suspension in rabbits. The histological studies showed changes in dermis indicating the effect of penetration enhancers and as iontophoresis was continued only for two cycles in periodic fashion so it did not cause any skin damage observed in the slides. Conclusion Results indicated that iontophoresis in combination with chemical enhancers is an effective method for transdermal administration of TT in the treatment of overactive bladder.

  6. Permeation properties of polymer/clay nanocomposites

    Science.gov (United States)

    Kalendova, A.; Merinska, D.; Gerard, J. F.

    2012-07-01

    The important characteristics of polymer/clay nanocomposites are stability, barrier properties and in the case of polyvinyl chloride also plasticizer migration into other materials. Therefore, the permeation properties of polymer/clay nanocomposites are discussed in this paper. The attention was focused to the polyethylene (PE) and polyvinyl chloride (PVC). Natural type of montmorillonite MMTNa+ and modified types of montmorillonite from Southern Clay Products were used as the inorganic phase. As the compounding machine, one screw Buss KO-kneader was employed. The principal aim is to fully exfoliate the clay into polymer matrix and enhanced the permeation properties. Prepared samples were tested for O2 and CO2 permeability. Polymer/clay nanocomposite structure was determined on the base of X-ray diffraction and electron microscopy (TEM).

  7. Evaluation of the suitability of chromatographic systems to predict human skin permeation of neutral compounds.

    Science.gov (United States)

    Hidalgo-Rodríguez, Marta; Soriano-Meseguer, Sara; Fuguet, Elisabet; Ràfols, Clara; Rosés, Martí

    2013-12-18

    Several chromatographic systems (three systems of high-performance liquid chromatography and two micellar electrokinetic chromatography systems) besides the reference octanol-water partition system are evaluated by a systematic procedure previously proposed in order to know their ability to model human skin permeation. The precision achieved when skin-water permeability coefficients are correlated against chromatographic retention factors is predicted within the framework of the solvation parameter model. It consists in estimating the contribution of error due to the biological and chromatographic data, as well as the error coming from the dissimilarity between the human skin permeation and the chromatographic systems. Both predictions and experimental tests show that all correlations are greatly affected by the considerable uncertainty of the skin permeability data and the error associated to the dissimilarity between the systems. Correlations with much better predictive abilities are achieved when the volume of the solute is used as additional variable, which illustrates the main roles of both lipophilicity and size of the solute to penetrate through the skin. In this way, the considered systems are able to give precise estimations of human skin permeability coefficients. In particular, the HPLC systems with common C18 columns provide the best performances in emulating the permeation of neutral compounds from aqueous solution through the human skin. As a result, a methodology based on easy, fast, and economical HPLC measurements in a common C18 column has been developed. After a validation based on training and test sets, the method has been applied with good results to the estimation of skin permeation of several hormones and pesticides. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Determination of the polymer in Cefmetazole Sodium for Injection by gel chromatography%凝胶色谱法测定注射用头孢美唑钠的聚合物

    Institute of Scientific and Technical Information of China (English)

    丁玉莲; 杜文革; 蔡蓉; 黄晓军

    2012-01-01

    目的 建立凝胶色谱法测定注射用头孢美唑钠中聚合物的方法.方法 采用分子排阻凝胶色谱进行测定,色谱柱为用葡聚糖凝胶G-10(40~120 μm)填充的玻璃柱;流动相A为pH7.0的0.02 mol/L磷酸盐缓冲液[0.02 mol/L Na2HPO4-0.02 mol/L NaH2PO4(体积比61∶39)],流动相B为纯化水;流速为1.5 mL/min;检测波长为254 nm.结果 采用本法对3批注射用头孢美唑钠中聚合物含量进行测定,结果均低于0.5%.结论 本方法简便、灵敏度高、重复性好,可用于注射用头孢美唑钠中聚合物的测定.%Objective To establish a method for the determination of the polymer in Cefmetazole Sodium for Injection. Methods Size exclusion gel chromatography was performed on the Sephadex G-10(40-120μm) column. The mobile phase was consisted of A: 0.02 mol/L phosphate buffer of pH 7.0 [0.02 mol/L dibasic sodium phosphate-0. 02 mol/L sodium dihydrogen phosphate (61:39) ] and B:water. The flow rate was 1.5 mL/min and the detection wavelength was 254 nm. Results The polymer in three batches of samples were all less than 0. 5% . Conclusion The method is simple,sensitive and reproducible. It can be used to determine the polymer in Cefmetazole Sodium for Injection.

  9. Release characteristics of dibucaine dispersed in konjac gels.

    Science.gov (United States)

    Nakano, M; Takikawa, K; Arita, T

    1979-09-01

    A possible use of konjac gel for sustained release of drugs was examined in a monolithic system containing dibucaine. Dibucaine was dispersed in the gel which was prepared by gelation of the konjac flour in a borax solution at 60 degrees. The cumulative amount of the drug released plotted against the square root of time was linear in the monolithic system. This relationship was in agreement with that expected from the theoretical equation for planar configuration. The mechanism of the release of the drug from the gel may be considered to be leaching of the drug by the permeating fluid. The release profile from dried konjac gel was similar to that from undried gel, but that from unwarmed gel showed a deviation from linearity although sustained release was similarly obtained.

  10. Development and in vitro evaluation of insulin-loaded buccal Pluronic F-127 gels.

    Science.gov (United States)

    Das, Nilanjana; Madan, Parshotam; Lin, Senshang

    2010-01-01

    Insulin-loaded buccal Pluronic F-127 (PF-127) gel formulations were fabricated to study the effect of PF-127 concentration, insulin concentration, presence of salt, addition of polymer, and permeation enhancer on their gelation time, mucoadhesion force, release and permeation characteristics of insulin from the gels. Thereafter, the principle of statistical optimization to prepare a gel formulation having the potential for buccal delivery of basal insulin in diabetic patients was employed. The gelation time decreased as the concentration of PF-127 increased. Presence of salts as well as addition of polymer, such as methyl cellulose (MC) and hydroxypropylmethyl cellulose (HPMC) decreased the gelation time. An increase in PF-127 concentration and addition of MC and HPMC increased the mucoadhesion force of the gel formulations. Release and permeation of insulin from the gel formulations decreased with increased concentration of PF-127, presence of salts, and addition of MC and HPMC. Permeation of insulin from the optimized gel formulation was 93.17 (+/- 0.058, n = 3) microg/cm(2) which was not only found in close agreement with predicted results from the model equations used for the formulation optimization but also considered comparable to clinical setting. Therefore, the development of optimized buccal insulin-loaded Pluronic F-127 gels using a statistical experimental design is feasible.

  11. Facile preparation of agarose-chitosan hybrid materials and nanocomposite ionogels using an ionic liquid via dissolution, regeneration and sol-gel transition

    CERN Document Server

    Trivedi, Tushar J; Kumar, Arvind

    2014-01-01

    We report simultaneous dissolution of agarose (AG) and chitosan (CH) in varying proportions in an ionic liquid (IL), 1-butyl-3-methylimidazolium chloride [C4mim][Cl]. Composite materials were constructed from AG-CH-IL solutions using the antisolvent methanol, and IL was recovered from the solutions. Composite materials could be uniformly decorated with silver oxide (Ag2O) nanoparticles (Ag NPs) to form nanocomposites in a single step by in situ synthesis of Ag NPs in AG-CH-IL sols, wherein the biopolymer moiety acted as both reducing and stabilizing agent. Cooling of Ag NPs-AG-CH-IL sols to room temperature resulted in high conductivity and high mechanical strength nanocomposite ionogels. The structure, stability and physiochemical properties of composite materials and nanocomposites were characterized by several analytical techniques, such as Fourier transform infrared (FTIR), CD spectroscopy, differential scanning colorimetric (DSC), thermogravimetric analysis (TGA), gel permeation chromatography (GPC), and...

  12. Fabrication, appraisal, and transdermal permeation of sildenafil citrate-loaded nanostructured lipid carriers versus solid lipid nanoparticles.

    Science.gov (United States)

    Elnaggar, Yosra S R; El-Massik, Magda A; Abdallah, Ossama Y

    2011-01-01

    Although sildenafil citrate (SC) is used extensively for erectile dysfunction, oral delivery of SC encounters many obstacles. Furthermore, the physicochemical characteristics of this amphoteric drug are challenging for delivery system formulation and transdermal permeation. This article concerns the assessment of the potential of nanomedicine for improving SC delivery and transdermal permeation. SC-loaded nanostructured lipid carriers (NLCs) and solid lipid nanoparticles (SLNs) were fabricated using a modified high-shear homogenization technique. Nanoparticle optimization steps included particle size analysis, entrapment efficiency (EE) determination, freeze-drying and reconstitution, differential scanning calorimetry, in vitro release, stability study and high-performance liquid chromatography analysis. Transdermal permeation of the nanocarriers compared with SC suspension across human skin was assessed using a modified Franz diffusion cell assembly. Results revealed that SLNs and NLCs could be optimized in the nanometric range (180 and 100 nm, respectively) with excellent EE (96.7% and 97.5%, respectively). Nanoparticles have significantly enhanced in vitro release and transdermal permeation of SC compared with its suspensions. Furthermore, transdermal permeation of SC exhibited higher initial release from both SLN and NLC formulations followed by controlled release, with promising implications for faster onset and longer drug duration. Nanomedicines prepared exhibited excellent physical stability for the study period. Solid nanoparticles optimized in this study successfully improved SC characteristics, paving the way for an efficient topical Viagra® product.

  13. Purification of Transglutaminase from High Salt Culture by Gel and Cation Exchange Chromatography%凝胶层析和离子交换层析结合法纯化高盐发酵液中谷氨酰胺转胺酶

    Institute of Scientific and Technical Information of China (English)

    张莉丽; 张兰威; 杜明; 韩雪; 易华西; 张英春; 张艳禾; 马微

    2012-01-01

    To purify the transglutaminase from high-salt medium, gel filtration combined with ion exchange chromatography method was employed. Two-step chromatographic conditions (flow rate and the sample volume) were optimized. The final sample volume and a flow rate for Gel chromatography were 6 mL and 0. 25 mL/min, respectively. Conditions for ion-exchange chromatography were a sample volume of 50 mL and flow rate of 3 mL/min. Enzyme was purified 4.22-fold, the specific activity and the recovery rate were 17. 33 U/mg protein and 77. 5%, respectrively. A comparison between liquid chromatography/tandem mass spectrometric identification and the protein database was carried out and the results showed that the purified enzyme had high homology with AAN01353.%采用凝胶层析和离子交换层析相结合的方法分离纯化高盐培养基中的谷氨酰胺转胺酶,优化的凝胶层析的条件,上样量6mL,流速为0.25 mL/min;离子交换层析的上样量50 mL,流速为3 mL/min.酶被纯化了4.22倍,比活力达17.33 U/mg蛋白,回收率为77.5%.液相色谱-串联质谱鉴定、蛋白质数据库比对结果表明,纯酶与AAN01353是同种蛋白质.

  14. Permeation of protective clothing materials by methylene chloride and perchloroethylene.

    Science.gov (United States)

    Vahdat, N

    1987-07-01

    The permeation of methylene chloride and perchloroethylene through seven protective clothing materials was studied to determine the permeation parameters, and to investigate the effect of solubility (polymer weight gain) and material thickness on the permeation parameters. The materials tested were two different nitrile rubbers, neoprene, Combination (a blend of natural rubber, neoprene and nitrile), two different polyvinyl chlorides, and polyvinyl alcohol. Methylene chloride permeated through all materials, except PVA, with breakthrough times in the range of 2 to 8 min, and permeation rates in the range of 1250-5800 micrograms/cm2 X min. PVA and unsupported nitrile offered good protection against perchloroethylene with breakthrough time occurring after 2 hr. Perchloroethylene permeated through the other materials with breakthrough times in the range of 8 to 36 min and permeation rates in the range of 200 to 1600 micrograms/cm2 X min. It was shown that for both chemicals, there is a correlation between the solubility (weight gain) and the ratio of permeation rate to breakthrough time (PR/BT). For all material/chemical pairs, an increase in solubility, increased (PR/BT). The change in material thickness had an effect on breakthrough time and permeation rate, but no effect on normalized breakthrough time. An increase in thickness reduced permeation rate and increased breakthrough time.

  15. PERMEATION OF POLYELECTROLYTES AND OTHER SOLUTES INTO THE PORE SPACES OF WATER-SWOLLEN CELLULOSE: A REVIEW

    OpenAIRE

    Ning Wu; Martin A. Hubbe; Rojas, Orlando J.; Sunkyu Park

    2009-01-01

    The rate and extent of transport of macromolecules and other solutes into cellulosic materials and fibers have important applications in such fields as papermaking, textiles, medicine, and chromatography. This review considers how diffusion and flow affect permeation into wood, paper, and other lignocellulosic materials. Because pore sizes within such materials can range from nanometers to millimeters, a broad perspective will be used, also considering some publications related to other por...

  16. The effect of nanoparticle permeation on the bulk rheological properties of mucus from the small intestine.

    Science.gov (United States)

    Wilcox, M D; Van Rooij, L K; Chater, P I; Pereira de Sousa, I; Pearson, J P

    2015-10-01

    The effectiveness of delivering oral therapeutic peptides, proteins and nucleotides is often hindered by the protective mucus barrier that covers mucosal surfaces of the gastrointestinal (GI) tract. Encapsulation of active pharmaceutical ingredients (API) in nanocarriers is a potential strategy to protect the cargo but they still have to pass the mucus barrier. Decorating nanoparticles with proteolytic enzymes has been shown to increase the permeation through mucus. Here we investigate the effect of poly(acrylic acid) (PAA) nanoparticles decorated with bromelain (BRO), a proteolytic enzyme from pineapple stem, on the bulk rheology of mucus as well as non-decorated poly(lactic-co-glycolic acid) (PLGA) nanoparticles. Porcine intestinal mucus from the small intestine was incubated for 30min in the presence of PLGA nanoparticles or polyacrylic nanoparticles decorated with bromelain (PAA-BRO). The effect of nanoparticles on the rheological properties, weight of gel, released glycoprotein content from mucus as well as the viscosity of liquid removed was assessed. Treatment with nanoparticles decreased mucus gel strength with PAA-BRO reducing it the most. PAA-BRO nanoparticles resulted in the release of increased glycoprotein from the gel network whereas mucus remained a gel and exhibited a similar breakdown stress to control mucus. Therefore it would be possible to use bromelain to increase the permeability of nanoparticles through mucus without destroying the gel and leaving the underlying mucosa unprotected.

  17. Etodolac Containing Topical Niosomal Gel: Formulation Development and Evaluation

    Directory of Open Access Journals (Sweden)

    Gyati Shilakari Asthana

    2016-01-01

    Full Text Available The present study aimed to investigate the delivery potential of Etodolac (ETD containing topical niosomal gel. Niosomal formulations were prepared by thin film hydration method at various ratios of cholesterol and Span 60 and were evaluated with respect to particle size, shape, entrapment efficiency, and in vitro characteristics. Dicetyl phosphate (DCP was also added in the niosomal formulation. Mean particle size of niosomal formulation was found to be in the range of 2 μm to 4 μm. Niosomal formulation N2 (1 : 1 ratio of cholesterol and surfactant displayed good entrapment efficiency (96.72%. TEM analyses showed that niosomal formulation was spherical in shape. Niosomal formulation (N2 displayed high percentage of drug release after 24 h (94.91 at (1 : 1 ratio of cholesterol : surfactant. Further selected niosomal formulation was used to formulate topical gel and was characterized with respect to its various parameters such as pH, viscosity, spreadability, ex vivo study, and in vivo potential permeation. Ex vivo study showed that niosomal gel possessed better skin permeation study than the plain topical gel. Further in vivo study revealed good inhibition of inflammation in case of topical niosomal gel than plain gel and niosomal formulation. The present study suggested that topical niosomal gel formulations provide sustained and prolonged delivery of drug.

  18. Etodolac Containing Topical Niosomal Gel: Formulation Development and Evaluation

    Science.gov (United States)

    Asthana, Abhay; Singh, Davinder; Sharma, Parveen Kumar

    2016-01-01

    The present study aimed to investigate the delivery potential of Etodolac (ETD) containing topical niosomal gel. Niosomal formulations were prepared by thin film hydration method at various ratios of cholesterol and Span 60 and were evaluated with respect to particle size, shape, entrapment efficiency, and in vitro characteristics. Dicetyl phosphate (DCP) was also added in the niosomal formulation. Mean particle size of niosomal formulation was found to be in the range of 2 μm to 4 μm. Niosomal formulation N2 (1 : 1) ratio of cholesterol and surfactant displayed good entrapment efficiency (96.72%). TEM analyses showed that niosomal formulation was spherical in shape. Niosomal formulation (N2) displayed high percentage of drug release after 24 h (94.91) at (1 : 1) ratio of cholesterol : surfactant. Further selected niosomal formulation was used to formulate topical gel and was characterized with respect to its various parameters such as pH, viscosity, spreadability, ex vivo study, and in vivo potential permeation. Ex vivo study showed that niosomal gel possessed better skin permeation study than the plain topical gel. Further in vivo study revealed good inhibition of inflammation in case of topical niosomal gel than plain gel and niosomal formulation. The present study suggested that topical niosomal gel formulations provide sustained and prolonged delivery of drug. PMID:27478643

  19. Gellan gum fluid gels for topical administration of diclofenac.

    Science.gov (United States)

    Mahdi, Mohammed H; Conway, Barbara R; Mills, Thomas; Smith, Alan M

    2016-12-30

    Diclofenac topical formulations are often preferred for drug administration to patients who experience serious GIT problems. Absorption of the drug through the skin, however, can be challenging due to the natural protective feature of the stratum corneum (SC). In this article, fluid gels prepared from gellan gum were explored as a topical drug delivery vehicle. Rheological analysis of the formulations showed that it was possible to produce a topical gel with a viscosity and the mechanical strength similar to that of the commercially available Voltaren(®) gel using 1% w/w of a 50:50 low acyl/high acyl (LA/HA) gellan blend. Soft-tribology was used to assess the lubrication properties of gellan fluid gels. The lubrication of the gellan gum fluid gel formulations at high rubbing speeds was similar to the lubrication of the Voltaren(®) gel. The use of gellan gum dramatically increased skin permeation of diclofenac when compared with the commercially available formulation and could be controlled by changing the gellan gum concentration and/or sodium ion concentration in the formulation. This study highlights the potential use of fluid gels that can be easily tuned to have physical properties suitable for topical formulations with the added advantage of increasing drug permeation.

  20. Effect of absorbents on permeation of norfloxacin.

    Science.gov (United States)

    Singh, G N; Gupta, R P

    1988-10-01

    Norfloxacin is a very potent drug. Adsorption of this drug may account for a significant fraction of total dose, hence the adsorption effect is of great significance. In the present investigation adsorption interaction study various adsorbents, was undertaken using, viz., activated charcoal, bentonite, kaolin, potato starch, talc and lactose by permeation technique. It was observed that forces through which the adsorption interaction is mediated are important to the effect obtained in vitro and that with further knowledge it may be possible to predict in vivo effect from the results of in vitro findings.

  1. Surface hardening of titanium alloys by oxygen-diffusion-permeation

    Institute of Scientific and Technical Information of China (English)

    马红岩; 王茂才; 张松; 辛公春; 魏政

    2003-01-01

    The surface oxygen-diffusion-permeation behaviors of Ti based alloys were investigated. MEF4A opticalmicroscopy and HMV-2000 micro-hardness tester were employed to characterize the microstructure and micro-hard-ness of the oxygen-permeated alloys. The results show that the micro-hardness of Ti based alloys are sharply en-hanced by the permeation of oxygen. The microstructure and micro-hardness of oxygen-permeated layer are stronglyrelated to the oxygen-diffusion-permeation techniques. The solid solution of oxygen in α phase can improve thetransformation temperature from α phase to β phase and enlarge the region of α phase so as to improve the micro-hardness of surface layer. Therefore, surface oxygen-diffusion-permeation would be a feasible method to reinforce Tibased alloys based on the solid solution of oxygen in α-Ti. At last, a diffusion-solution model was put forward.

  2. 凝胶过滤色谱和Bradford法测定发酵类抗生素中蛋白残留量%Gel Filtration Chromatography Combined with Bradford Method for Determination of Total Residual Protein in Ferment Antibiotics

    Institute of Scientific and Technical Information of China (English)

    许明哲; 马仕洪; 胡昌勤

    2004-01-01

    目的以发酵类抗生素盐酸林可霉素为例,建立一个快速、简单、灵敏度高的可用于发酵类抗生素中蛋白残留量控制的方法.方法利用凝胶过滤色谱(GFC)首先将蛋白质与抗生素分离,收集蛋白组分,再利用蛋白检测方法Bradford法(考马氏亮兰染色法)对残留的蛋白进行定量;色谱柱为SuperdexTM Peptide HR 10/30;检测波长为214 nm;流速为1 mL·min-1;流动相为0.01 mol·L-1磷酸盐缓冲液;进样量为500 μL.结果本方法蛋白(BSA)的平均回收率大于90%,蛋白浓度在0-12 μg·mL-1之间符合曲线方程y=-0.002 4x2 + 0.064 2x + 0.002 9,r2=0.999 9; 检测限为3 ng·mL-1(相当于盐酸林可霉素中蛋白的残留量为7×10-7).结论本方法简便,快速,灵敏,可以用于控制发酵类抗生素中蛋白的残留量.%Aim A novel method has been developed for evaluation of the levels of total residual protein in antibiotics produced by fermentation using gel filtration chromatography (GFC) combined with Bradford assay based on determination of residual protein in lincomycin hydrochloride. Methods The chromatographic conditions were SuperdexTM peptide column, 0.01 mol*L-1 phosphate buffer solution as mobile phase, and flow rate of 1 mL·min-1. Five hundred microliters of lincomycin hydrochloride solution (3 g of lincomycin hydrochloride dissolved in 10 mL of mobile phase) was injected into the chromatograph and the eluted solution was collected between 6 min and 14.5 min (protein eluted from column within this period), and the residual content of total protein in the eluted solution was assayed using Bradford assay method. Results The average recovery was more than 90% for bovine serum albumin, the calibration equation for the range of 0-12 μg·mL-1 of protein was y=-0.002 4x2+0.064 2x+0.002 9, r2=0.999 9, RSD=0.1%-0.9%, and the LOD and LOQ were 3 and 10 ng·mL-1 of protein, respectively. Conclusion The novel method for determining the residual protein in ferment antibio

  3. Assessment of Flavonoid Release with Different Permeation Enhancers

    OpenAIRE

    Vaisakh M N; Pandey A

    2012-01-01

    The aim of the study was to evaluate the effect of different permeation enhancers in the transdermal permeation of flavonoids. A weed plant named Chromolaena odorata have been employed as the flavonoid source. Six different cream formulations have been prepared with the Chromolaena extract using different permeation enhancers such as ethanol, dimethyl sulphoxide, surfactants and occlusive agents. The amount of flavonoids penetrated during a time period of four hours was noted. The highest amo...

  4. Optimization of silica gel column chromatography extraction process of oryzanol from rice bran oil soap stock by response surface methodology%响应面法优化柱层析工艺提取米糠油皂脚中的谷维素

    Institute of Scientific and Technical Information of China (English)

    沈鸿; 张培培; 庞敏; 姜绍通

    2016-01-01

    以米糠油加工所得的副产物皂脚为原料,用乙酸乙酯索氏抽提得到皂脚浸提物,采用硅胶柱层析的方法对皂脚浸提物分离纯化谷维素,采用单因素和响应面方法进行优化,确定浸提液的谷维素浓度为4.00%,上样量为8.70 g,硅胶用量为60.00 g。结果表明,此工艺得到的谷维素纯度88.5%,皂脚中谷维素的总提取率达到58.7%。%Soapstock,the byproduct of rice bran oil procossing,was used as raw material. Oryzanol was extracted with ethyl acetate from rice bran oil soap stock and purified by silica gel column chromatography methods. Based on single factor experiments and response surface methodology,the optimum conditions were as follows:oryzanol concentration of sample forsilica gelcolumn chromatography was 4.00%,the sample volume was 8.70 g,the amount of silica gel was 60 g. The results showed that the total extraction rate of oryzanol could reached 58.7% while oryzanol purity was 88.5%.

  5. Quantitative Analysis of Microbicide Concentrations in Fluids, Gels and Tissues Using Confocal Raman Spectroscopy

    Science.gov (United States)

    Chuchuen, Oranat; Henderson, Marcus H.; Sykes, Craig; Kim, Min Sung; Kashuba, Angela D. M.; Katz, David F.

    2013-01-01

    Topical vaginal anti-HIV microbicides are an important focus in female-based strategies to prevent the sexual transmission of HIV. Understanding microbicide pharmacokinetics is essential to development, characterization and implementation of efficacious microbicide drug delivery formulations. Current methods to measure drug concentrations in tissue (e.g., LC-MS/MS, liquid chromatography coupled with tandem mass spectrometry) are highly sensitive, but destructive and complex. This project explored the use of confocal Raman spectroscopy to detect microbicide drugs and to measure their local concentrations in fluids, drug delivery gels, and tissues. We evaluated three candidate microbicide drugs: tenofovir, Dapivirine and IQP-0528. Measurements were performed in freshly excised porcine buccal tissue specimens, gel vehicles and fluids using two Horiba Raman microscopes, one of which is confocal. Characteristic spectral peak calibrations for each drug were obtained using serial dilutions in the three matrices. These specific Raman bands demonstrated strong linear concentration dependences in the matrices and were characterized with respect to their unique vibrational signatures. At least one specific Raman feature was identified for each drug as a marker band for detection in tissue. Sensitivity of detection was evaluated in the three matrices. A specific peak was also identified for tenofovir diphosphate, the anti-HIV bioactive product of tenofovir after phosphorylation in host cells. Z-scans of drug concentrations vs. depth in excised tissue specimens, incubated under layers of tenofovir solution in a Transwell assay, showed decreasing concentration with depth from the surface into the tissue. Time-dependent concentration profiles were obtained from tissue samples incubated in the Transwell assay, for times ranging 30 minutes - 6 hours. Calibrations and measurements from tissue permeation studies for tenofovir showed good correlation with gold standard LC-MS/MS data

  6. Quantitative analysis of microbicide concentrations in fluids, gels and tissues using confocal Raman spectroscopy.

    Directory of Open Access Journals (Sweden)

    Oranat Chuchuen

    Full Text Available Topical vaginal anti-HIV microbicides are an important focus in female-based strategies to prevent the sexual transmission of HIV. Understanding microbicide pharmacokinetics is essential to development, characterization and implementation of efficacious microbicide drug delivery formulations. Current methods to measure drug concentrations in tissue (e.g., LC-MS/MS, liquid chromatography coupled with tandem mass spectrometry are highly sensitive, but destructive and complex. This project explored the use of confocal Raman spectroscopy to detect microbicide drugs and to measure their local concentrations in fluids, drug delivery gels, and tissues. We evaluated three candidate microbicide drugs: tenofovir, Dapivirine and IQP-0528. Measurements were performed in freshly excised porcine buccal tissue specimens, gel vehicles and fluids using two Horiba Raman microscopes, one of which is confocal. Characteristic spectral peak calibrations for each drug were obtained using serial dilutions in the three matrices. These specific Raman bands demonstrated strong linear concentration dependences in the matrices and were characterized with respect to their unique vibrational signatures. At least one specific Raman feature was identified for each drug as a marker band for detection in tissue. Sensitivity of detection was evaluated in the three matrices. A specific peak was also identified for tenofovir diphosphate, the anti-HIV bioactive product of tenofovir after phosphorylation in host cells. Z-scans of drug concentrations vs. depth in excised tissue specimens, incubated under layers of tenofovir solution in a Transwell assay, showed decreasing concentration with depth from the surface into the tissue. Time-dependent concentration profiles were obtained from tissue samples incubated in the Transwell assay, for times ranging 30 minutes - 6 hours. Calibrations and measurements from tissue permeation studies for tenofovir showed good correlation with gold

  7. Thermoresponsive Gels

    Directory of Open Access Journals (Sweden)

    M. Joan Taylor

    2017-01-01

    Full Text Available Thermoresponsive gelling materials constructed from natural and synthetic polymers can be used to provide triggered action and therefore customised products such as drug delivery and regenerative medicine types as well as for other industries. Some materials give Arrhenius-type viscosity changes based on coil to globule transitions. Others produce more counterintuitive responses to temperature change because of agglomeration induced by enthalpic or entropic drivers. Extensive covalent crosslinking superimposes complexity of response and the upper and lower critical solution temperatures can translate to critical volume temperatures for these swellable but insoluble gels. Their structure and volume response confer advantages for actuation though they lack robustness. Dynamic covalent bonding has created an intermediate category where shape moulding and self-healing variants are useful for several platforms. Developing synthesis methodology—for example, Reversible Addition Fragmentation chain Transfer (RAFT and Atomic Transfer Radical Polymerisation (ATRP—provides an almost infinite range of materials that can be used for many of these gelling systems. For those that self-assemble into micelle systems that can gel, the upper and lower critical solution temperatures (UCST and LCST are analogous to those for simpler dispersible polymers. However, the tuned hydrophobic-hydrophilic balance plus the introduction of additional pH-sensitivity and, for instance, thermochromic response, open the potential for coupled mechanisms to create complex drug targeting effects at the cellular level.

  8. Neuere Chromatographie

    Science.gov (United States)

    Hostettmann, K.

    1983-04-01

    Besides high-performance liquid chromatography (HPLC) which is now a well-established and currently used technique, several emerging methods for the isolation and separation of natural products are receiving considerable attention. Centrifugal thin-layer chromatography is a very rapid technique, but limited in resolution. Of special interest are the recently developed support-free liquid-liquid chromatography methods such as droplet counter-current chromatography (DCCC) and rotation locular counter-current chromatography (RLCC). This latter method was applied to the separation of the enantiomers of (±)-norephedrine.

  9. Synthesis of Novel Temperature- and pH-Sensitive ABA Triblock Copolymers P(DEAEMA-co-MEO2MA-co-OEGMA-b-PEG-b-P(DEAEMA-co-MEO2MA-co-OEGMA: Micellization, Sol–Gel Transitions, and Sustained BSA Release

    Directory of Open Access Journals (Sweden)

    Yanan Han

    2016-11-01

    Full Text Available Novel temperature- and pH-responsive ABA-type triblock copolymers, P(DEAEMA-co-MEO2MA-co-OEGMA-b-PEG-b-P(DEAEMA-co-MEO2MA-co-OEGMA, composed of a poly(ethylene glycol (PEG middle block and temperature- and pH-sensitive outer blocks, were synthesized by atom transfer radical polymerization (ATRP. The composition and structure of the copolymer were characterized by 1H NMR and gel permeation chromatography (GPC. The temperature- and pH-sensitivity, micellization, and the sol–gel transitions of the triblock copolymers in aqueous solutions were studied using transmittance measurements, surface tension, viscosity, fluorescence probe technique, dynamic light scattering (DLS, zeta-potential measurements, and transmission electron microscopy (TEM. The lower critical solution temperature (LCST of the triblock copolymer, which contains a small amount of a weak base group, (N,N-diethylamino ethyl methacrylate (DEAEMA, can be tuned precisely and reversibly by changing the solution pH. When the copolymer concentration was sufficiently high, increasing temperature resulted in the free-flowing solution transformation into a micellar gel. The sol-to-gel transition temperature (Tsol–gel in aqueous solution will continue to decrease as solution concentration increases.

  10. Mechanisms of gas permeation through polymer membranes

    Energy Technology Data Exchange (ETDEWEB)

    Stern, S.A.

    1990-01-01

    The objective of the present study is to investigate the mechanisms by which gases are transported in and through polymer membranes, and the dependence of these mechanisms on pressure and temperature. Recent work has been focused on the permeation of gases through membranes made from glassy polymers, i.e., at temperatures below the glass transition of the polymers (Tg). During the past report period, a new theoretical model of gas solubility in glassy polymers was developed and tested with experimental data from the literature. This model describes satisfactorily the shape of solubility isotherms over wide ranges of pressure and temperatures, and is particularly useful for penetrant gases which ranges of pressure and temperatures, and is particularly useful for penetrant gases which plasticize (swell) glassy polymers. Work also continued on the behavior of light gases in poly (alkyl methacrylates). 18 refs., 6 figs.

  11. A personal ammonia monitor utilizing permeation sampling

    Energy Technology Data Exchange (ETDEWEB)

    Benedict, A.F. (Occupational Safety and Health Administration, Baton Rouge, LA); Reiszner, K.D.; West, P.W.

    1983-01-01

    A method has been developed for the determination of the time-weighted-average personal exposure to ammonia. Sample collection was achieved by permeation through a silicone membrane into a boric acid solution. The trapped ammonia was then determined spectrophotometrically with Nessler's reagent or potentiometrically with an ion selective electrode. The device may be used for sampling periods as short as 5 minutes and was not affected by changes in the environmental parameters normally encountered at industrial locations. The detection limit is 0.4 ppm for an 8 hr sampling period and the monitor responds linearly to at least 150 ppm. The Nessler's method may be utilized in industrial environments containing monoethanol amine in conjunction with ammonia with no significant interference. Although some interference was observed from ethylenediamine with the Nessler's technique, little interference was found with the potentiometric determination.

  12. Permeation of Light Gases through Hexagonal Ice

    Directory of Open Access Journals (Sweden)

    Luis Gales

    2012-09-01

    Full Text Available Gas separation using porous solids have attracted great attention due to their energetic applications. There is an enormous economic and environmental interest in the development of improved technologies for relevant processes, such as H2 production, CO2 separation or O2 and N2 purification from air. New materials are needed for achieving major improvements. Crystalline materials, displaying unidirectional and single-sized pores, preferentially with low pore tortuosity and high pore density, are promising candidates for membrane synthesis. Herein, we study hexagonal ice crystals as an example of this class of materials. By slowly growing ice crystals inside capillary tubes we were able to measure the permeation of several gas species through ice crystals and investigate its relation with both the size of the guest molecules and temperature of the crystal.

  13. An unheated permeation device for calibrating atmospheric VOC measurements

    Directory of Open Access Journals (Sweden)

    J. Brito

    2011-05-01

    Full Text Available The development of an unpowered permeation device for continuous calibration of in-situ instruments measuring atmospheric volatile organic compounds (VOCs is described. Being lightweight and compact, and containing only negligible amounts of chemicals, the device is especially suited for field use such as onboard aircraft. Its speciality is to maintain the permeation process in thermal equilibrium, i.e. the instantaneous permeation rate can be ascribed via a simple temperature measurement. This equilibrium state is maintained by a combination of three features: (i a thin PTFE membrane as permeation medium which guarantees short stabilization times, (ii a water bath as heat buffer, and (iii a vacuum-panel based insulation, in which features (ii and (iii minimize temperature drifts. The uncertainty of the permeation rate due to thermal non-equilibrium is kept below 1 %. An extensive theory part details the major permeation processes of gases through porous polymers, being Fick's diffusion, Knudsen flow, and viscous flow. Both the measured stabilization time and the measured temperature dependence of the permeation rate independently indicate that the permeation can be described by a viscous flow model, where diffusion of the gas molecules in large pores (having a diameter of >0.05 μm dominates.

  14. An unheated permeation device for calibrating atmospheric VOC measurements

    Directory of Open Access Journals (Sweden)

    J. Brito

    2011-10-01

    Full Text Available The development of an unpowered permeation device for continuous calibration of in-situ instruments measuring atmospheric volatile organic compounds (VOCs is described. Being lightweight and compact, and containing only negligible amounts of chemicals, the device is especially suited for field use such as on board aircraft. Its speciality is to maintain the permeation process in thermal equilibrium, so that the instantaneous permeation rate can be ascribed to a simple temperature measurement. This equilibrium state is maintained by a combination of three features: (i a thin PTFE membrane as permeation medium which guarantees short stabilization times, (ii a water bath as heat buffer, and (iii a vacuum-panel based insulation, in which features (ii and (iii minimize temperature drifts to ~30 mK h−1 per Kelvin temperature difference to the environment. The respective uncertainty of the permeation rate due to thermal non-equilibrium is kept below 1%. An extensive theory part details the major permeation processes of gases through porous polymers, being Fick's diffusion, Knudsen flow, and viscous flow. Both the measured stabilization time and the measured temperature dependence of the permeation rate independently indicate that the permeation can be described by a viscous flow model, where diffusion of the gas molecules in large pores (having a diameter of >0.05 μm dominates.

  15. Polymethacrylate microparticles gel for topical drug delivery.

    Science.gov (United States)

    Labouta, Hagar Ibrahim; El-Khordagui, Labiba K

    2010-10-01

    Evaluating the potentials of particulate delivery systems in topical drug delivery. Polymethacrylate microparticles (MPs) incorporating verapamil hydrochloride (VRP) as a model hydrophilic drug with potential topical clinical uses, using Eudragit RS100 and Eudragit L100 were prepared for the formulation of a composite topical gel. The effect of initial drug loading, polymer composition, particularly the proportion of Eudragit L100 as an interacting polymer component and the HLB of the dispersing agent on MPs characteristics was investigated. A test MPs formulation was incorporated in gel and evaluated for drug release and human skin permeation. MPs showed high % incorporation efficiency and % yield. Composition of the hybrid polymer matrix was a main determinant of MPs characteristics, particularly drug release. Factors known to influence drug release such as MPs size and high drug solubility were outweighed by strong VRP-Eudragit L100 interaction. The developed MPs gel showed controlled VRP release and reduced skin retention compared to a free drug gel. Topical drug delivery and skin retention could be modulated using particulate delivery systems. From a practical standpoint, the VRP gel developed may offer advantage in a range of dermatological conditions, in response to the growing off-label topical use of VRP.

  16. [Non-target screening of organic pollutants in sediments and sludges using gas chromatography-mass spectrometry and automated mass spectral deconvolution].

    Science.gov (United States)

    Wang, Gang; Ma, Huilian; Wang, Longxing; Chen, Jiping; Hou, Xiaohong

    2015-12-01

    A screening method in the combination of ultrasonic extraction, gas chromatography-mass spectrometry detection and automated mass spectrometry deconvolution technique was developed for non-target screening of non-polar and weak polar pollutants in sediments and sludges. The samples were extracted by ultrasonication for 20 min using dichloromethane for three times. The extraction solutions were cleaned-up by gel permeation chromatography and a silica gel column, and then 3 g of copper powder was used to remove the sulfur by ultrasonication for 10 min. Parallel experiments were carried out for 5 times and the RSDs were ranged from 5.8% to 14.9%. Automated mass spectral deconvolution & identification system (AMDIS) would improve the resolution of overlapping peaks, and identify the pure mass spectrum of the analytes in the cases of stronger background interference and co-extracted substances covering. Standard spectrum databases, such as NISTDRUG, NISTEPA, NISTFDA, Mass Spectral Library, etc, would qualitatively identify the organic pollutants in the samples. As a result, a total of 290 organic pollutants were identified, of which 190 and 153 pollutants were found in sediments and sludges, respectively. The identified pollutants included the Environmental Protection Agency (EPA) priority pollutants, pharmaceuticals, herbicides, antioxidants, intermediates, organic solvents and chemical raw materials. The proposed method is proved to be a promising one for non-target screening of complex matrix samples with the advantages of higher sensitivity and better repeatability.

  17. Formulation of sage essential oil (Salvia officinalis, L.) monoterpenes into chitosan hydrogels and permeation study with GC-MS analysis.

    Science.gov (United States)

    Kodadová, Alexandra; Vitková, Zuzana; Herdová, Petra; Ťažký, Anton; Oremusová, Jarmila; Grančai, Daniel; Mikuš, Peter

    2015-01-01

    This study deals with the formulation of natural drugs into hydrogels. For the first time, compounds from the sage essential oil were formulated into chitosan hydrogels. A sample preparation procedure for hydrophobic volatile analytes present in a hydrophilic water matrix along with an analytical method based on the gas chromatography coupled with the mass spectrometry (GC-MS) was developed and applied for the evaluation of the identity and quantity of essential oil components in the hydrogels and saline samples. The experimental results revealed that the chitosan hydrogels are suitable for the formulation of sage essential oil. The monoterpene release can be effectively controlled by both chitosan and caffeine concentration in the hydrogels. Permeation experiment, based on a hydrogel with the optimized composition [3.5% (w/w) sage essential oil, 2.0% (w/w) caffeine, 2.5% (w/w) chitosan and 0.1% (w/w) Tween-80] in donor compartment, saline solution in acceptor compartment, and semi-permeable cellophane membrane, demonstrated the useful permeation selectivity. Here, (according to lipophilicity) an enhanced permeation of the bicyclic monoterpenes with antiflogistic and antiseptic properties (eucalyptol, camphor and borneol) and, at the same time, suppressed permeation of toxic thujone (not exceeding its permitted applicable concentration) was observed. These properties highlight the pharmaceutical importance of the developed chitosan hydrogel formulating sage essential oil in the dermal applications.

  18. Human skin permeation of emerging mycotoxins (beauvericin and enniatins).

    Science.gov (United States)

    Taevernier, Lien; Veryser, Lieselotte; Roche, Nathalie; Peremans, Kathelijne; Burvenich, Christian; Delesalle, Catherine; De Spiegeleer, Bart

    2016-01-01

    Currently, dermal exposure data of cyclic depsipeptide mycotoxins are completely absent. There is a lack of understanding about the local skin and systemic kinetics and effects, despite their widespread skin contact and intrinsic hazard. Therefore, we provide a quantitative characterisation of their dermal kinetics. The emerging mycotoxins enniatins (ENNs) and beauvericin (BEA) were used as model compounds and their transdermal kinetics were quantitatively evaluated, using intact and damaged human skin in an in vitro Franz diffusion cell set-up and ultra high-performance liquid chromatography (UHPLC)-MS analytics. We demonstrated that all investigated mycotoxins are able to penetrate through the skin. ENN B showed the highest permeation (kp,v=9.44 × 10(-6) cm/h), whereas BEA showed the lowest (kp,v=2.35 × 10(-6) cm/h) and the other ENNs ranging in between. Combining these values with experimentally determined solubility data, Jmax values ranging from 0.02 to 0.35 μg/(cm(2) h) for intact skin and from 0.07 to 1.11 μg/(cm(2) h) for damaged skin were obtained. These were used to determine the daily dermal exposure (DDE) in a worst-case scenario. On the other hand, DDE's for a typical occupational scenario were calculated based on real-life mycotoxin concentrations for the industrial exposure of food-related workers. In the latter case, for contact with intact human skin, DDE's up to 0.0870 ng/(kg BW × day) for ENN A were calculated, whereas for impaired skin barrier this can even rise up to 0.3209 ng/(kg BW × day) for ENN B1. This knowledge is needed for the risk assessment after skin exposure of contaminated food, feed, indoor surfaces and airborne particles with mycotoxins.

  19. Three-phase molecularly imprinted sol-gel based hollow fiber liquid-phase microextraction combined with liquid chromatography-tandem mass spectrometry for enrichment and selective determination of a tentative lung cancer biomarker.

    Science.gov (United States)

    Moein, Mohammad Mahdi; Javanbakht, Mehran; Karimi, Mohammad; Akbari-Adergani, Behrouz; Abdel-Rehim, Mohamed

    2015-07-15

    In the present study, the modification of a polysulfone hollow fiber membrane with in situ molecularly imprinted sol-gel process (as a novel and one-step method) was prepared and investigated. 3-(propylmethacrylate)trimethoxysilane (3PMTMOS) as an inorganic precursor was used for preparation of molecularly imprinted sol-gel. The modified molecularly imprinted sol-gel hollow fiber membrane (MSHM) was used for the liquid-phase microextraction (LPME) of hippuric acid (HA) in human plasma and urine samples. MSHM as a selective, robust, and durable tool was used for at least 50 extractions without significant decrease in the extraction efficiency. The non-molecularly imprinted sol-gel hollow fiber membrane (NSHM) as blank hollow fiber membrane was prepared by the same process, only without HA. To achieve the best condition, influential parameters on the extraction efficiency were thoroughly investigated. The capability of this robust, green, and simple method for extraction of HA was successfully accomplished with LC/MS/MS. The limits of detection (LOD) and quantification (LOQ) in human plasma and urine samples were 0.3 and 1.0nmolL(-1), respectively. The standard calibration curves were obtained within the concentration range 1-2000nmolL(-1) for HA in human plasma and urine. The coefficients of determination (r(2)) were ≥0.998. The obtained data exhibited recoveries were higher than 89% for the extraction of HA in human plasma and urine samples.

  20. Formulation of niosomal gel for enhanced transdermal lopinavir delivery and its comparative evaluation with ethosomal gel.

    Science.gov (United States)

    Patel, Ketul K; Kumar, Praveen; Thakkar, Hetal P

    2012-12-01

    The aim was to develop niosomal gel as a transdermal nanocarrier for improved systemic availability of lopinavir. Niosomes were prepared using thin-film hydration method and optimized for molar quantities of Span 40 and cholesterol to impart desirable characteristics. Comparative evaluation with ethosomes was performed using ex vivo skin permeation, fluorescence microscopy, and histopathology studies. Clinical utility via transdermal route was acknowledged using in vivo bioavailability study in male Wistar rats. The niosomal formulation containing lopinavir, Span 40, and cholesterol in a molar ratio of 1:0.9:0.6 possessed optimally high percentage of drug entrapment with minimum mean vesicular diameter. Ex vivo skin permeation studies of lopinavir as well as fluorescent probe coumarin revealed a better deposition of ethosomal carriers but a better release with niosomal carriers. Histopathological studies indicated the better safety profile of niosomes over ethosomes. In vivo bioavailability study in male Wistar rats showed a significantly higher extent of absorption (AUC(0→∞), 72.87 h × μg/ml) of lopinavir via transdermally applied niosomal gel as compared with its oral suspension. Taken together, these findings suggested that niosomal gel holds a great potential of being utilized as novel, nanosized drug delivery vehicle for transdermal lopinavir delivery.

  1. Fouling of a microfiltration membrane by humic-like substances: a mathematical approach to modelling permeate flux and membrane retention.

    Science.gov (United States)

    Poorasgari, Eskandar; Farsi, Ali; Christensen, Morten Lykkegaard

    2016-01-01

    Membrane retention of the humic-like substances present in a soluble microbial products (SMP) suspension was studied by using a dead-end filtration system. The SMP suspension was extracted from the sludge of an enhanced biological phosphorus removal-membrane bioreactor. Our results showed that both adsorption and steric retention of the humic-like substances governed their transport through the membrane during the filtration. The adsorption, which followed pseudo-first order kinetics, did not cause substantial decline of permeate flux. The steric retention, on the other hand, formed a gel layer, which in turn led to a major decrease in the flux. The reduction of permeate flux was well predicted by cake filtration theory. Based on the adsorption and the steric retention, a new model was developed for predicting the overall membrane retention of the humic-like substances. The general trend of the modelled overall retention was in partial agreement with the experimental results.

  2. Influence of penetration enhancers and molecular weight in antifungals permeation through bovine hoof membranes and prediction of efficacy in human nails.

    Science.gov (United States)

    Miron, D; Cornelio, R; Troleis, J; Mariath, J; Zimmer, A R; Mayorga, P; Schapoval, E E S

    2014-01-23

    This work aimed to evaluate the effect of different substances on the permeation of geraniol through bovine hoof membranes. Different penetration enhancers were able to increase the permeability up to 25 times compared to control. It was demonstrated that acetilcysteine in association with ascorbic acid increased the permeation, even in acid formulations. In addition, some antifungal drugs were incorporated into a gel formulation of HPMC containing acetylcysteine 5% and ascorbic acid 0.2% and then the permeation coefficient through bovine hoof membranes was evaluated. The relationship between permeability and molecular weight was established for fluconazole, miconazole, terbinafine, butenafine, geraniol and nerol. Geraniol and nerol, the antifungals with lower molecular weight, had the better permeability results. Permeability coefficients for nail plates were estimated and geraniol demonstrated similar or even better efficacy index values against T. rubrum, T. menthagrophytes and M. canis compared with terbinafine and miconazole. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Biofilm increases permeate quality by organic carbon degradation in low pressure ultrafiltration.

    Science.gov (United States)

    Chomiak, A; Traber, J; Morgenroth, E; Derlon, N

    2015-11-15

    We investigated the influence of biofouling of ultrafiltration membranes on the removal of organic model foulants and ultimately on the quality of permeate. Gravity Driven Membrane ultrafiltration (GDM) membrane systems were operated with modified river water during five weeks without control of the biofilm formation. Three GDM systems were studied: two systems with biofilms exposed to (A) variable or (B) constant load of organic foulants, and (C) one system operated without biofilm and exposed to constant foulant loading. Biodegradable dextran or non-biodegradable polystyrene sulfonate model foulants were tested. Substrate biodegradability was confirmed by Size Exclusion Chromatography (SEC) and by degradation batch tests (D). The GDM systems (A) and (B) were fed with pre-filtered river water supplemented with dextran (Dex) of 1, 150 or 2000 kDa, or polystyrene sulfonate (PSS) of 1 or 80 kDa at concentrations of 2-3.5 mgC L(-1). In exp. (C) the feed water consisted of deionized water with 25 mgC L(-1) of either PSS 1, 80 kDa or Dex 2000 kDa. The biofilm formation on UF membrane surfaces controlled the foulant permeation and thus the permeate quality. Biofilms exposed to continuous foulant loading (exp. B) degraded low molecular weight (LMW) biodegradable foulants (1 kDa Dex), which improved the permeate quality. For high molecular weight (HMW) substrates (150, 2000 kDa Dex), the improvement of the permeate quality was observed after 7 days of biofilm formation, and resulted from the foulant hydrolysis followed by degradation. For non-biodegradable foulants, an improvement of 20% of the retention was observed for the polystyrene (1, 80 kDa PSS) due to the presence of biofilms on membrane surfaces. For variable foulant loading (exp. A) the biofilms hydrolysed the large biodegradable foulants but did not degraded them fully, which resulted a deterioration of the permeate quality (except for the LMW dextran (1 kDa) that was fully degraded). Overall, the "biofilm

  4. Gel formation driven by tunable hydrophobic domain: design of acrylamide macromonomer with oligo hydrophobic segment.

    Science.gov (United States)

    Nitta, Kyohei; Miyake, Junpei; Watanabe, Junji; Ikeda, Yoshiyuki

    2012-04-09

    Nowadays, biomaterials with amphiphilic properties are undergoing remarkable development. Here, we present one such development, in which we prepared amphiphilic graft copolymers, with a main chain composed of hydroxyethyl acrylamide (HEAA), to introduce hydrophilicity, and a side chain composed of poly(trimethylene carbonate) (PTMC) to introduce tunable hydrophobicity. These macromonomers were created with a novel molecular design, which introduced a ring-opening polymerization by the hydroxyl end group of HEAA in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene, and were analyzed by (1)H NMR and gel permeation chromatography. The amphiphilic graft copolymers were shown to form a hydrogel, the swelling ratio of which was greatly influenced by the number of trimethylene carbonate units. These copolymers also exhibited the Tyndall phenomenon in aqueous solution; they aggregated spontaneously due to hydrogen bonding and hydrophobic interactions, and a sodium 8-anilino-1-naphthalenesulfonate (ANS) fluorescence probe was introduced into the hydrophobic domain. The solution property of ANS in the polymer solution was analyzed by fluorescence measurement and (1)H NMR. The maximum fluorescence wavelength of ANS shifted to shorter wavelengths as the degree of polymerization of the hydrophobic PTMC, the composition of the macromonomer, and the concentration of the copolymer increased. The resulting copolymer formed a polymer micelle structure due to the tunable hydrophobic domain formation in selected solvents. Therefore, these amphiphilic graft copolymers containing a PTMC segment are excellent candidates for use as hydrophobic drug delivery carriers.

  5. Cavamax W7 composite psoralen ethosomal gel versus cavamax W7 psoralen solid complex gel for topical delivery: A comparative evaluation

    Science.gov (United States)

    Kumari, Smriti; Pathak, Kamla

    2013-01-01

    Aim: The present research work was aimed to formulate and characterize psoralen-encapsulated cavamax W7 composite ethosomal gel and compare its in vitro and ex vivo behavior against psoralen-cavamax W7-complex reference gel. Materials and Methods: A total of nine formulations of composite ethosomes were prepared by injection method using 32 factorial design and entrapment efficiency was designated as dependent variable. Concomitantly, psoralen was complexed with cavamax W7 (1:1 molar ratio) by kneading method and formation of complex was confirmed by Diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). Results: F9 with vesicle size of 183 ± 2.8 nm, and highest % entrapment efficiency of 98.12 ± 1.15 was selected as optimized formulation. Transmission electron microscopy (TEM) revealed uniform and spherical shaped vesicles. The optimized formulation F9 was formulated as carbapol gel and compared against ethosomal gel, psoralen gel, and psoralen cavamax W7 complex gel. The gels were evaluated for permeation characteristics and the rank order was composite ethosomal gel > ethosomal gel > psoralen-cavamax W7 complex gel > psoralen gel. The ethosomal gel (G5) with highest in vitro permeation of 82.48 ± 2.23% was subjected to in vivo Confocal laser scanning microscopy (CLSM) studies using rhodamine B as tracer. The penetration of rhodamine B was uniform, deeper, and two times faster into epidermis than control gel. Conclusion: Conclusively, cavamax W7 composite ethosomes present themselves as efficient carrier for superior topical delivery of psoralen and have potential for clinical applications in minimizing side effects associated with photosensitivity of psoralen. PMID:24350036

  6. Properties of nucleic acid staining dyes used in gel electrophoresis.

    Science.gov (United States)

    Haines, Alicia M; Tobe, Shanan S; Kobus, Hilton J; Linacre, Adrian

    2015-03-01

    Nucleic acid staining dyes are used for detecting nucleic acids in electrophoresis gels. Historically, the most common dye used for gel staining is ethidium bromide, however due to its toxicity and mutagenicity other dyes that are safer to the user and the environment are preferred. This Short Communication details the properties of dyes now available and their sensitivity for detection of DNA and their ability to permeate the cell membrane. It was found that GelRed™ was the most sensitive and safest dye to use with UV light excitation, and both GelGreen™ and Diamond™ Nucleic Acid Dye were sensitive and the safer dyes using blue light excitation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Lyophilized phytosomal nanocarriers as platforms for enhanced diosmin delivery: optimization and ex vivo permeation

    Directory of Open Access Journals (Sweden)

    Freag MS

    2013-07-01

    Full Text Available May S Freag, Yosra SR Elnaggar, Ossama Y AbdallahDepartment of Pharmaceutics, Faculty of Pharmacy, Alexandria University, Alexandria, EgyptAbstract: Diosmin (DSN is an outstanding phlebotonic flavonoid with a tolerable potential for the treatment of colon and hepatocellular carcinoma. Being highly insoluble, DSN bioavailability suffers from high inter-subject variation due to variable degrees of permeation. This work endeavored to develop novel DSN loaded phytosomes in order to improve drug dissolution and intestinal permeability. Three preparation methods (solvent evaporation, salting out, and lyophilization were compared. Nanocarrier optimization encompassed different soybean phospholipid (SPC types, different solvents, and different DSN:SPC molar ratios (1:1, 1:2, and 1:4. In vitro appraisal encompassed differential scanning calorimetry, infrared spectroscopy, particle size, zeta potential, polydispersity index, transmission electron microscopy, drug content, and in vitro stability. Comparative dissolution studies were performed under sink versus non-sink conditions. Ex vivo intestinal permeation studies were performed on rats utilizing noneverted sac technique and high-performance liquid chromatography analysis. The results revealed lyophilization as the optimum preparation technique using SPC and solvent mixture (Dimethyl sulphoxide:t-butylalchol in a 1:2 ratio. Complex formation was contended by differential scanning calorimetry and infrared data. Optimal lyophilized phytosomal nanocarriers (LPNs exhibited the lowest particle size (316 nm, adequate zeta-potential (−27 mV, and good in vitro stability. Well formed, discrete vesicles were revealed by transmission electron microscopy, drug content, and in vitro stability. Comparative dissolution studies were performed. LPNs demonstrated significant enhancement in DSN dissolution compared to crude drug, physical mixture, and generic and brand DSN products. Permeation studies revealed 80% DSN

  8. Purification of 1.9-nm-diameter semiconducting single-wall carbon nanotubes by temperature-controlled gel-column chromatography and its application to thin-film transistor devices

    Science.gov (United States)

    Thendie, Boanerges; Omachi, Haruka; Hirotani, Jun; Ohno, Yutaka; Miyata, Yasumitsu; Shinohara, Hisanori

    2017-06-01

    Large-diameter semiconductor single-wall carbon nanotubes (s-SWCNTs) have superior mobility and conductivity to small-diameter s-SWCNTs. However, the purification of s-SWCNTs with diameters larger than 1.6 nm by gel filtration has been difficult owing to the low selectivity of the conventional purification method in these large-diameter regions. We report a combination of temperature-controlled gel filtration and the gradient elution technique that we developed to enrich a high-purity s-SWCNT with a diameter as large as 1.9 nm. The thin-film transistor (TFT) device using the 1.9-nm-diameter SWCNT shows an average channel mobility of 23.7 cm2 V-1 s-1, which is much higher than those of conventional SWCNT-TFTs with smaller-diameters of 1.5 and 1.4 nm.

  9. 16S-23S Internal Transcribed Spacer Region PCR and Sequencer-Based Capillary Gel Electrophoresis has Potential as an Alternative to High Performance Liquid Chromatography for Identification of Slowly Growing Nontuberculous Mycobacteria

    OpenAIRE

    Subedi, Shradha; Kong, Fanrong; Jelfs, Peter; Gray, Timothy J; Xiao, Meng; Sintchenko, Vitali; Chen, Sharon C-A.

    2016-01-01

    Accurate identification of slowly growing nontuberculous mycobacteria (SG-NTM) of clinical significance remains problematic. This study evaluated a novel method of SG-NTM identification by amplification of the mycobacterial 16S-23S rRNA internal transcribed spacer (ITS) region followed by resolution of amplified fragments by sequencer-based capillary gel electrophoresis (SCGE). Fourteen American Type Culture Collection (ATCC) strains and 103 clinical/environmental isolates (total n = 24 speci...

  10. Cytoplasmic permeation pathway of neurotransmitter transporters.

    Science.gov (United States)

    Rudnick, Gary

    2011-09-06

    Ion-coupled solute transporters are responsible for transporting nutrients, ions, and signaling molecules across a variety of biological membranes. Recent high-resolution crystal structures of several transporters from protein families that were previously thought to be unrelated show common structural features indicating a large structural family representing transporters from all kingdoms of life. This review describes studies that led to an understanding of the conformational changes required for solute transport in this family. The first structure in this family showed the bacterial amino acid transporter LeuT, which is homologous to neurotransmitter transporters, in an extracellularly oriented conformation with a molecule of leucine occluded at the substrate site. Studies with the mammalian serotonin transporter identified positions, buried in the LeuT structure, that defined a potential pathway leading from the cytoplasm to the substrate binding site. Modeling studies utilized an inverted structural repeat within the LeuT crystal structure to predict the conformation of LeuT in which the cytoplasmic permeation pathway, consisting of positions identified in SERT, was open for diffusion of the substrate to the cytoplasm. From the difference between the model and the crystal structures, a simple "rocking bundle" mechanism was proposed, in which a four-helix bundle changed its orientation with respect to the rest of the protein to close the extracellular pathway and open the cytoplasmic one. Subsequent crystal structures from structurally related proteins provide evidence supporting this model for transport.

  11. Fabrication, appraisal, and transdermal permeation of sildenafil citrate-loaded nanostructured lipid carriers versus solid lipid nanoparticles

    Directory of Open Access Journals (Sweden)

    Elnaggar YS

    2011-12-01

    Full Text Available Yosra SR Elnaggar1, Magda A El-Massik2, Ossama Y Abdallah11Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, 2Department of Pharmaceutics, Faculty of Pharmacy and Drug Manufacturing, Pharos University, Alexandria, EgyptAbstract: Although sildenafil citrate (SC is used extensively for erectile dysfunction, oral delivery of SC encounters many obstacles. Furthermore, the physicochemical characteristics of this amphoteric drug are challenging for delivery system formulation and transdermal permeation. This article concerns the assessment of the potential of nanomedicine for improving SC delivery and transdermal permeation. SC-loaded nanostructured lipid carriers (NLCs and solid lipid nanoparticles (SLNs were fabricated using a modified high-shear homogenization technique. Nanoparticle optimization steps included particle size analysis, entrapment efficiency (EE determination, freeze-drying and reconstitution, differential scanning calorimetry, in vitro release, stability study and high-performance liquid chromatography analysis. Transdermal permeation of the nanocarriers compared with SC suspension across human skin was assessed using a modified Franz diffusion cell assembly. Results revealed that SLNs and NLCs could be optimized in the nanometric range (180 and 100 nm, respectively with excellent EE (96.7% and 97.5%, respectively. Nanoparticles have significantly enhanced in vitro release and transdermal permeation of SC compared with its suspensions. Furthermore, transdermal permeation of SC exhibited higher initial release from both SLN and NLC formulations followed by controlled release, with promising implications for faster onset and longer drug duration. Nanomedicines prepared exhibited excellent physical stability for the study period. Solid nanoparticles optimized in this study successfully improved SC characteristics, paving the way for an efficient topical Viagra® product.Keywords: nanomedicine, transdermal drug

  12. Relative Molecular Mass Distribution Measurement of Aliphatic Alcohol Ethoxylates by Gel Permeation Chromatography%凝胶渗透色谱法测脂肪醇聚氧乙烯醚产品的相对分子质量分布

    Institute of Scientific and Technical Information of China (English)

    庄美华; 郇宇

    2002-01-01

    应用高效液相色谱技术,采用凝胶色谱柱,用示差折光检测器,对AEO产品进行了分析,测出了产物的相对分子质量,并得到分布图,成功地实现了对产品的质量控制和中间控制.

  13. Rivalry and enmity are phenomena that seem to have permeated ...

    African Journals Online (AJOL)

    Tracie1

    permeated the Nigerian music industry, especially the hip hop genre. A strategy ... intended force of an utterance is suggested by the context ... Given this contextual background of events in the Nigerian hip hop .... The hearer has to depend.

  14. Determination of deltamethrin residues in plant materials by liquid chromatography/tandem mass spectrometry with electrospray ionization.

    Science.gov (United States)

    Zimmer, Dieter; Philipowski, Christiane; Posner, Birgit; Gnielka, Agnes; Dirr, Edgar; Dorff, Mario

    2006-01-01

    This paper describes a selective and sensitive method that uses liquid chromatography/tandem mass spectrometry with positive electrospray ionization (ESI+) for the determination of deltamethrin in a variety of crops. Samples were extracted by conventional high-speed blending. Some samples required no further cleanup; others were cleaned up by gel permeation chromatography, strong cation-exchange cartridges, or partitioning with n-hexane. In the determinative step, the buffered neutral mobile phase, consisting of 10 mM ammonium acetate (pH 6.8) and methanol, and ESI+ provided strong ammonium adduct formation to [M+NH4]+ at m/z 523, and the multiple-reaction monitoring (MRM) transition at m/z 523/281 was used for the quantitation of deltamethrin. A second MRM transition at m/z 525/283 was used for confirmation. The limit of quantitation (LOQ) values were 0.01 mg/kg for edible materials and 0.05 mg/kg for nonedible materials. Mean overall recoveries at the LOQ and the 10-fold LOQ ranged from 73 to 96%, and the relative standard deviations were <10% for all samples materials analyzed.

  15. Association of nicotinamide with parabens: effect on solubility, partition and transdermal permeation.

    Science.gov (United States)

    Nicoli, Sara; Zani, Franca; Bilzi, Stefania; Bettini, Ruggero; Santi, Patrizia

    2008-06-01

    Nicotinamide is a hydrophilic molecule, freely soluble in water, used as cosmetic active ingredient for its moisturizing and depigmenting properties. Moreover it has the ability to augment the solubility of poorly water-soluble molecules acting as a hydrotrope. The aim of this work was to study the effect of nicotinamide on the transdermal permeation of methyl, ethyl, propyl and butyl paraben. Parabens flux was measured in vitro in the presence and absence of different amounts of nicotinamide. From solubility studies it was found that nicotinamide forms one or more complexes with methyl, propyl and butyl paraben in water, even though with low stability constants. The interaction of ethyl paraben seems to be less easy to explain. The association of nicotinamide with parabens causes a significant reduction of the permeability coefficients of these preservatives through rabbit ear skin, caused by a reduction of the stratum corneum/vehicle partition coefficient. The effects of nicotinamide on parabens solubility, permeation and partitioning are potentially very interesting because nicotinamide can facilitate paraben dissolution in aqueous media (solutions, gels), reduce parabens partitioning in the oily phase thus guaranteeing an effective concentration in the water phase in emulsion and reduce transdermal penetration, thus reducing the toxicological risk.

  16. Permeation and Distribution of Ferulic Acid and Its α-Cyclodextrin Complex from Different Formulations in Hairless Rat Skin

    OpenAIRE

    Monti, Daniela; Tampucci, Silvia; Chetoni, Patrizia; Burgalassi, Susi; Saino, Veronica; Centini, Marisanna; Staltari, Lucia; Anselmi, Cecilia

    2011-01-01

    Ferulic acid (FA) is a natural product that occurs in seeds of many plants where it is generally located in the bran. This compound is a multifunctional ingredient endowed with antioxidative, radical scavenging, sunscreening and antibacterial actions. The aim of this study was to analyse the ferulic acid cutaneous permeation and distribution, through and into the skin layers, from different cosmetic vehicles, an O/W emulsion (pH 6.0) and two gel-type formulations at different pH levels (6.0 a...

  17. Effect of Sodium Alginate Concentration on Membrane Strength and Permeating Property of Poly-l-arginine Group Microcapsule

    Institute of Scientific and Technical Information of China (English)

    Shi Bin WANG; Yuan Gang LIU; Lian Jin WENG; Xiao Jun MA

    2004-01-01

    A novel poly-l-arginine microcapsule was prepared due to its nutritional function and pharmacological efficacy. A high-voltage electrostatic droplet generator was used to make uniform microcapsules. The results show that the membrane strength and permeating property are both remarkably affected with the changes of sodium alginate concentration. With the sodium alginate concentration increasing, gel beads sizes increase from 233μm to 350μm, release ratio is also higher at the same time, but the membrane strength decreases.

  18. Skin permeation of lidocaine from crystal suspended oily formulations.

    Science.gov (United States)

    Matsui, Rakan; Hasegawa, Masaaki; Ishida, Masami; Ebata, Toshiya; Namiki, Noriyuki; Sugibayashi, Kenji

    2005-09-01

    In vitro permeation of lidocaine (lidocaine base, LID) through excised rat skin was investigated using several LID-suspended oily formulations. The first skin permeation of LID from an LID-suspended oily solution such as liquid paraffin (LP), isopropyl myristate (IPM), polyoxyethylene (2) oleylether (BO-2), and diethyl sebacate (DES) was evaluated and compared with that from polyethylene glycol 400 (PEG400) solution, a hydrophilic base. The obtained permeation rate of LID, Japp, from PEG400, LP, IPM, BO-2, and DES was in the order of DES>BO-2=IPM>LP>PEG400, and increased with LID solubility in the oily solvents, although LID crystals were dispersed in all solvents. Subsequently, oily formulations that consisted of different ratios of the first oily solvent (IPM, BO-2, or DES) (each 0-20%), the second oily solvent (LP) and an oily mixture of microcrystalline wax/white petrolatum/paraffin (1/5/4) were evaluated. BO-2 groups at a concentration of 5% and 10% had the highest Japp among the oily formulations, although a higher BO-2 resulted in lower skin permeation. In addition, pretreatment with BO-2 increased the skin permeation of LID. These results suggest that the penetration enhancing effect by the system may be related to the skin penetration of BO-2 itself. Finally, mathematical analysis was done to evaluate the effect of BO-2, and it was shown that BO-2 improved the LID solubility in stratum corneum lipids to efficiently enhance the LID permeation through skin.

  19. Hydrogen permeation in iron and nickel alloys around room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, T., E-mail: t-otsuka@nucl.kyushu-u.ac.jp; Shinohara, M.; Horinouchi, H.; Tanabe, T.

    2013-11-15

    Hydrogen permeation and diffusion coefficients in alloys of iron (Fe) and nickel (Ni) with the Ni content of 5, 9, and 20 at.% and a crystal structure of α/α′ phase have been examined around room temperature (RT) using a tritium-tracer hydrogen-permeation experiment. Hydrogen permeation coefficients around RT agree well with values extrapolated from literature data obtained at higher temperatures for the respective alloys. On the other hand, apparent hydrogen diffusion coefficients determined using the time-lag method are several orders of magnitude smaller than extrapolated from the literature data. This could be caused by surface blocking and/or barrier effects due to surface oxide and/or other impurities. Initially, hydrogen permeation is suppressed by the existence of the surface oxide. It appears that hydrogen, mostly at the upstream side or even at the downstream side, can reduce and remove the surface oxides so that normal hydrogen steady-state permeation can occur without surface blocking or barrier effects. Thus, true hydrogen diffusion coefficients for respective Fe–Ni alloys during steady-state permeation must be much larger than those estimated from the time-lag method.

  20. Bacterial cellulose membranes as transdermal delivery systems for diclofenac: in vitro dissolution and permeation studies.

    Science.gov (United States)

    Silva, Nuno H C S; Rodrigues, Artur Filipe; Almeida, Isabel F; Costa, Paulo C; Rosado, Catarina; Neto, Carlos Pascoal; Silvestre, Armando J D; Freire, Carmen S R

    2014-06-15

    Bacterial cellulose (BC) membranes were explored as novel nanostructured transdermal delivery systems for diclofenac sodium salt (a typical non-steroidal anti-inflammatory drug). Diclofenac sodium salt loaded BC membranes were prepared through a simple methodology, using glycerol as plasticizer, and characterized in terms of structure, morphology and swelling behavior. The membranes were very homogeneous, quite flexible and presented a considerably higher swelling behavior when compared with pure BC. In vitro diffusion studies with Franz cells, were conducted using human epidermal membranes, and showed that the incorporation of diclofenac in BC membranes provided similar permeation rates to those obtained with commercial patches and substantially lower than those observed with a commercial gel. This release profile together with the ease of application and the simple preparation and assembly of the drug-loaded membranes clearly indicates the enormous potentialities of using BC membranes for transdermal administration of diclofenac. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. High-performance liquid chromatography of biopolymers

    Energy Technology Data Exchange (ETDEWEB)

    Regnier, F.E.

    1983-10-21

    The ability to separate biological macromolecules with good resolution on liquid chromatographic columns has depended on the development of suitable packing materials. In size exclusion chromatography, molecules are separated by size on the basis of differential permeation of the packing. Ion exchange, hydrophobic interaction (or reversed-phase), and affinity chromatography are all surface-mediated separation methods, although they depend on different retention mechanisms. High-performance liquid chromatographic columns designed for biopolymers offer major advantages over conventional columns in both speed and resolving power. The exponential growth of literature on the high-performance separation of peptides and proteins in particular indicates that the techniques will become the dominant form of column liquid chromatography. 92 refs., 4 figs.

  2. Determining the Encapsulation Efficiency of Dexamethasone-Loaded Nanoparticles Using Sephadex Gel Column Chromatography%葡聚糖凝胶色谱法用于纳米粒包封率的测定

    Institute of Scientific and Technical Information of China (English)

    赵锋; 栾瀚森; 罗华菲; 王浩

    2012-01-01

    OBJECTIVE To investigate the separating capacity of Sephadex gel for dexaraethasone-loaded nanoparticles. METHODS Single factor tests and central composite design-response surface methodology were employed for optimization of chromatograph-icparameters, and the established conditions were adopted to validate the encapsulation efficiency of dexamethasone-loaded nanoparticles. RESULTS The optimal eluting condition was as follows; the ratio of diameter to height was 0. 23, flowrate was 0. 52 mL· min-1 ,and the amount of loaded drug was 41 μg. These paration degree reached 79. 01%. CONCLUSION Sephadex gel can be u-tilized properly to separate free drug from dexamethasone-loaded nanoparticles.%目的 考察葡聚糖凝胶柱色谱法对分离地塞米松纳米粒的影响因素.方法 在单因素考察的基础上,星点设计效应面优化法优化色谱参数,并进行包封率的验证.结果 最优条件为径高比0.23,流速0.52 mL· min-1,载药量41μg,分离比可达79.01%.结论 葡聚糖凝胶色谱拄可用于纳米粒包封率的准确测定.

  3. Hydrogenation of chalcones using hydrogen permeating through a Pd and palladized Pd electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, M., E-mail: mcgutier@unse.edu.a [INQUINOA - CONICET, Instituto de Ciencias Quimicas, Facultad de Agronomia Agroindustrias, Universidad Nacional de Santiago del Estero, Avda, Belgrano (S) 1912, 4200, Santiago del Estero (Argentina); Nazareno, M.A. [INQUINOA - CONICET, Instituto de Ciencias Quimicas, Facultad de Agronomia Agroindustrias, Universidad Nacional de Santiago del Estero, Avda, Belgrano (S) 1912, 4200, Santiago del Estero (Argentina); Sosa, V. [Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Agencia postal 4, Casilla 61, 5000, Cordoba (Argentina); Lopez de Mishima, B.A., E-mail: bmishima@unse.edu.a [INQUINOA - CONICET, Instituto de Ciencias Quimicas, Facultad de Agronomia Agroindustrias, Universidad Nacional de Santiago del Estero, Avda, Belgrano (S) 1912, 4200, Santiago del Estero (Argentina); Mishima, H.T. [INQUINOA - CONICET, Instituto de Ciencias Quimicas, Facultad de Agronomia Agroindustrias, Universidad Nacional de Santiago del Estero, Avda, Belgrano (S) 1912, 4200, Santiago del Estero (Argentina)

    2010-08-01

    The hydrogenation of benzalacetone and benzalacetophenone was carried out using atomic hydrogen permeating through a palladium membrane. A two-compartment cell separated by a Pd sheet or a palladized Pd (Pd/Pd black) sheet electrode was employed. The reduction products were identified by (GC) gas chromatography, UV-vis absorption spectroscopy and NMR spectroscopy. The carbon-carbon double bond was hydrogenated and the benzylacetone and benzylacetophenone were obtained as products using palladium catalyst. The current efficiency for hydrogenation reaction increases when the current density for water electrolysis decreases and depends on the initial chalcone concentration. It is over 90% at the concentration of 10 mmol L{sup -1}. The hydrogen absorption and diffusion into and through a palladium membrane electrode has been studied by using an electrochemical impedance spectroscopy method. The impedance results would indicate that the hydrogen permeated through the membrane is consumed by the chalcone during the hydrogenation process keeping as the permeable boundary condition in the outer side of the Pd membrane the hydrogen activity almost zero. The hydrogen entering the metal through an adsorbed state and the rate of hydrogen absorption is diffusion-controlled.

  4. Determination of Encapsulation Efficiency of Curcumin Niosomes using Sephadex Gel Column Chromatography%葡聚糖凝胶柱色谱法测定姜黄素囊泡包封率

    Institute of Scientific and Technical Information of China (English)

    万胜利; 钟萌; 赵德璋; 王红; 张景勍

    2015-01-01

    目的::建立姜黄素囊泡包封率测定法。方法:以紫外分光光度法为分析手段,采用葡聚糖凝胶柱色谱法测定姜黄素囊泡包封率。结果:葡聚糖凝胶柱色谱法能有效地将姜黄素囊泡与游离药物分离,柱回收率测定结果为98.18%,3次包封率测定的平均值为85.28%,RSD 为0.99% 。结论:葡聚糖凝胶柱色谱法操作简单,结果重现性好,适用于姜黄素囊泡包封率的测定。%Objective: To establish the method for the determination of encapsulation efficiency of curcumin nio﹣somes. Methods: The curcumin niosomes and free drugs separated by sephadex column chromatography. Results:Sephadex column chromatography could effectively separate the curcumin niosomes from free drugs. The colum recovery was 98. 18% . The mean encapsulation efficiency of curcumin niosomes was 85. 28% ,with RSD was 0. 99% . Conclu﹣sion: The method was simple, accurate and rapid. It is suitable for the determination of encapsulation efficiency of curcumin niosomes.

  5. Tolterodine Tartrate Proniosomal Gel Transdermal Delivery for Overactive Bladder

    Directory of Open Access Journals (Sweden)

    Rajan Rajabalaya

    2016-08-01

    Full Text Available The goal of this study was to formulate and evaluate side effects of transdermal delivery of proniosomal gel compared to oral tolterodine tartrate (TT for the treatment of overactive bladder (OAB. Proniosomal gels are surfactants, lipids and soy lecithin, prepared by coacervation phase separation. Formulations were analyzed for drug entrapment efficiency (EE, vesicle size, surface morphology, attenuated total reflectance Fourier transform infrared (ATR-FTIR spectroscopy, in vitro skin permeation, and in vivo effects. The EE was 44.87%–91.68% and vesicle size was 253–845 nm for Span formulations and morphology showed a loose structure. The stability and skin irritancy test were also carried out for the optimized formulations. Span formulations with cholesterol-containing formulation S1 and glyceryl distearate as well as lecithin containing S3 formulation showed higher cumulative percent of permeation such as 42% and 35%, respectively. In the in vivo salivary secretion model, S1 proniosomal gel had faster recovery, less cholinergic side effect on the salivary gland compared with that of oral TT. Histologically, bladder of rats treated with the proniosomal gel formulation S1 showed morphological improvements greater than those treated with S3. This study demonstrates the potential of proniosomal vesicles for transdermal delivery of TT to treat OAB.

  6. Thermally reversible xyloglucan gels as vehicles for nasal drug delivery.

    Science.gov (United States)

    Mahajan, Hitendra S; Tyagi, Vinod; Lohiya, Gopal; Nerkar, Pankaj

    2012-01-01

    The aim of this study was to investigate the potential application of thermosensitive gels formed by a xyloglucan polysaccharide derived from tamarind seed for nasal drug delivery. Xyloglucan that had been partially degraded by β-galactosidase to eliminate 45% of galactose residues formed gels at concentrations of 2.5% w/w at gelation temperatures decreasing over the range 27-28°C. The in vitro release of ondansetron hydrochloride from the enzyme-degraded xyloglucan gels followed higuchi kinetics over a period of 5 h at 34°C by anomalous transport mechanism. The ex vivo permeation of ondansetron hydrochloride from the gels was sustained. Histological examination of nasal mucosa following a single administration of the gels showed no evidence of mucosal damage. Finally, the bioavailability study in rabbits revealed that the absolute bioavailability of ondansetron hydrochloride was significantly increased from 28.64% in the case of the oral drug solution to 52.79% in the case of the nasal in situ gel. The results of this study suggest the potential of the enzyme-degraded xyloglucan gels as vehicles for nasal delivery of drugs.

  7. Evaluation of protein stability and in vitro permeation of lyophilized polysaccharides-based microparticles for intranasal protein delivery.

    Science.gov (United States)

    Cho, Hyun-Jong; Balakrishnan, Prabagar; Chung, Suk-Jae; Shim, Chang-Koo; Kim, Dae-Duk

    2011-09-15

    Biocompatible microparticles prepared by lyophilization were developed for intranasal protein delivery. To test for the feasibility of this formulation, stability of the incorporated protein and enhancement of in vitro permeation across the nasal epithelium were evaluated. Lyophilization was processed with hydroxypropylmethylcellulose (HPMC) or water soluble chitosan (WCS) as biocompatible polymers, hydroxypropyl-β-cyclodextrin (HP-β-CD) and d-alpha-tocopheryl poly(ethylene glycol 1000) succinate (TPGS 1000) as permeation enhancers, sugars as cryoprotectants and lysozyme as the model protein. As a result, microparticles ranging from 6 to 12μm were developed where the maintenance of the protein conformation was verified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), circular dichroism and fluorescence intensity detection. Moreover, in vitro bioassay showed that the lysozyme activity was preserved during the preparation process while exhibiting less cytotoxicity in primary human nasal epithelial (HNE) cells. Results of the in vitro release study revealed slower release rate in these microparticles compared to that of the lysozyme itself. On the other hand, the in vitro permeation study exhibited a 9-fold increase in absorption of lysozyme when prepared in lyophilized microparticles with HPMC, HP-β-CD and TPGS 1000 (F4-2). These microparticles could serve as efficient intranasal delivery systems for therapeutic proteins. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. 应用中空纤维柱和凝胶色谱纯化鸡胚流感病毒%Application of hollow fiber filtration and gel chromatography in purification of chick embryo-derived influenza virus

    Institute of Scientific and Technical Information of China (English)

    杨欣; 刘杰; 刘瑛; 吴永林; 范凤鸣; 刘辉; 张鹏艳; 李玉华

    2012-01-01

    目的 研究鸡胚尿囊腔培养流感病毒的纯化方法.方法 采用中空纤维柱超滤、病毒裂解和两次Sepharose 4FF凝胶色谱纯化流感病毒.结果 通过中空纤维柱超滤可去除76.53%~93.66%卵清蛋白,再通过两次Sepharose 4FF凝胶色谱纯化,流感病毒样品总蛋白含量与血凝素含量比值小于4.5,卵清蛋白含量小于500 ng/mL,SDS-PAGE电泳和Western免疫印迹的电泳条带和血凝素特异性条带与英国国家生物制品检定所(NIBSC)的标准品一致.结论 该工艺纯化的流感病毒的纯度符合《中国药典》2010版的要求.%Purpose To study the purification methods of chick embryo-derived influenza virus. Methods Using hollow fiber filtration, split virus and sepharose 4FF chromatography to purify influenza virus. Results 76. 53%-93. 66% ovalburain was eliminated by hollow fiber filtration. Then, purified by twice sepharose 4FF chromatography, the total protein/hemagglutinin value was under 4. 5, ovalbumin content was less than 500 ng/mL,the electrophoretic bands of SDS-PAGE and the specific hemagglutinin reaction bands of Western blot were consistent with the influenza antigen of NIBSC. Conclusion The purity of the influenza virus purified by this process could meet the criteria of (Chinese Pharmacopoeia)2010 edition.

  9. Testosterone Nasal Gel

    Science.gov (United States)

    Testosterone nasal gel is used to treat symptoms of low testosterone in men who have hypogonadism (a condition in which the ... does not produce enough natural testosterone). Testosterone nasal gel is used only for men with low testosterone ...

  10. Radial Chromatography for the Separation of Nitroaniline Isomers

    Science.gov (United States)

    Miller, Robert B.; Case, William S.

    2011-01-01

    Separation techniques are usually presented in the undergraduate organic laboratory to teach students how to purify and isolate compounds. Often the concept of liquid chromatography is introduced by having students create "silica gel columns" to separate components of a reaction mixture. Although useful, column chromatography can be a laborious…

  11. Isolation of 6-gingerol, 8-gingerol and 6-shogaol from dry rhizome of Zingiber officinale Rosc.by silica gel column chromatography and high-speed counter-current chromatagraphy%高速逆流色谱结合硅胶柱色谱法分离制备干姜中的6-姜酚、8-姜酚、6-姜烯酚

    Institute of Scientific and Technical Information of China (English)

    徐美霞; 王晓; 刘建华; 耿岩玲; 王岱杰; 刘峰

    2013-01-01

    通过实验建立了高速逆流色谱(HSCCC)结合硅胶柱色谱法分离制备干姜中6-姜酚、8-姜酚和6-姜烯酚的方法.干姜样品采用乙酸乙酯超声提取,提取物经过硅胶柱色谱粗分,选取其中A3和A4两个馏分进行高速逆流色谱分离,所得单一成分采用高效液相色谱(HPLC)检测纯度,并采用电喷雾质谱(ESI-MS)、核磁共振氢谱(1H NMR)对所得化合物的结构进行鉴定.研究结果表明,该方法简便快捷,所得产物纯度高、制备量大、分离效率好.%We constructed the method of isolating 6-gingerol, 8-gingerol and 6-shogaol from dry rhizome of Zingiber officinale Rose, by silica gel column chromatography and high-speed counter-current chromatagraphy based on experiments. We extracted the samples of Zingiber officinale Rose, by ethyl acetate ultrasonic extraction and then coarsely treated them by silica gel column chromatography. We further selected fraction A3 and A4 to be separated by high-speed counter-current chromatography( HSCCC). The purity of the obtained single ingredient was detected by high-performance liquid chromatography(HPLC) and the structure of the obtained compound was identified by electrospray ionization(ESI-MS) and 1H-NMR. Results show that the method has such positives as simplicity, rapidity, high-purity products, large amount of preparation and high-efficiency separation.

  12. Evaluation of a dynamic dissolution/permeation model

    DEFF Research Database (Denmark)

    Sironi, Daniel; Christensen, Mette; Rosenberg, Jörg

    2017-01-01

    Combined dissolution/permeation testing is gaining increasing attention as an in vitro tool for predictive performance ranking of enabling oral formulations. The current aim was to study how in vitro drug permeation evolves under conditions, where the donor concentration is changing (non-steady s......Combined dissolution/permeation testing is gaining increasing attention as an in vitro tool for predictive performance ranking of enabling oral formulations. The current aim was to study how in vitro drug permeation evolves under conditions, where the donor concentration is changing (non......-steady state). To this end, a model case was construed: compacts of pure crystalline hydrocortisone methanolate (HC·MeOH) of slow release rates were prepared, and their dissolution and permeation determined simultaneously in a side-by-side setup, separated by a biomimetic barrier (Permeapad...... dissolution rate and flux influenced each other. Interestingly, for all the dynamic scenarios, the incremental flux values obtained correlated nicely with the corresponding actual donor concentrations. Furthermore, donor depletion was tested using a HC solution. The dynamic interplay between decrease in donor...

  13. Gas chromatography

    Science.gov (United States)

    Guiochon, Georges; Guillemin, Claude L.

    1990-11-01

    Gas chromatography is a powerful separation technique for gas and vapor mixtures. Combining separation and on-line detection permits accurate quantitative analysis of complex mixtures, including traces of compounds down to parts per trillions in some particular cases. The importance of gas chromatography in quality control and process control in the chemical and drug industry, in environmental pollution investigations and in clinical analysis is critical. The principles of the technique are discussed, the main components of a gas chromatograph are described and some idea of the importance of the applications is given.

  14. Formulation and in vitro evaluation of clotrimazole gel containing almond oil and tween 80 as penetration enhancer for topical application.

    Science.gov (United States)

    Nawaz, Asif; Jan, Syed Umer; Khan, Nauman Rahim; Hussain, Abid; Khan, Gul Majid

    2013-05-01

    Achieving a desirable percutaneous absorption of drug molecule is a major concern in formulating dermal and transdermal products. The use of penetration enhancers could provide a successful mean for this purpose. The aim of this study was to develop Clotrimazole gel and to evaluate the effect of almond oil and tween 80 (in different concentrations), on the permeation of drug through rabbit skin in vitro. In order to investigate the effect of penetration enhancers used in this study on the permeation of Clotrimazole through sections of excised rabbit skin, Franz diffusion cell was employed. Sample solution was withdrawn at specific time interval up to 24 h. Significant difference in permeation among the eight formulations was seen in the study. The permeation profile of various formulations also showed that the added enhancers in individual batches affected the permeation of the drug. Drug permeation increased with increased concentration of Tween 80 and decreased concentration of almond oil. Furthermore, almond oil combined with tween 80 showed synergistic effect. The clotrimazole gels were successfully formulated and could be beneficial for topical use.

  15. FORMULATION AND DEVELOPMENT OF LIPOSOMAL GEL FOR TOPICAL DRUG DELIVERY SYSTEM

    Directory of Open Access Journals (Sweden)

    Suraj R. Wasankar*, Syed M. Faizi and Abhisek D. Deshmuk

    2012-11-01

    Full Text Available Aim: The aims of this study were to develop liposome enriched Dexibuprofen liposomal hydrogels for topical delivery, perform in vitro release studies and in vivo permeation studies through mice/rat skin, and evaluate the efficacy of liposomal gels against inflammation induced rats. The purpose was to provide the delivery of the topical drug at a sustained rate across intact skin to improve bioavailability and inflammation control for longer period from liposomal gels.Method: Phosphatidylcholine, Cholesterol and Dexibuprofen were dissolved in chloroform/methanol (2:1, v/v mixture and subsequently transferred into a pear-shaped flask connected to a Rotavapor (Büchi- type. Rotary evaporation method was used for the formulation of liposomes.Result: liposome prepared was evaluated for particle size measurement, percent drug entrapment, diffusion study, skin permeation study and in vivo study. F-7 batch found to be optimized batch having particle size 5.40 µm, % drug entrapment 61.70, % CDR 75.35 %. Hence F-7 batch further evaluated for skin permeation study, skin deposition study, in vivo study and stability study.Conclusion: The present study has been a satisfactory attempt to formulate and evaluate liposome of Dexibuprofen and liposomal gel with a providing sustained delivery of drug. From skin permeation study and in vivo study it was concluded that the prepared liposome of Dexibuprofen may prove to be potential candidate for safe and effective sustained drug delivery over an extended period of time which can reduce dosing frequency.

  16. Thermoreversible nanoethosomal gel for the intranasal delivery of Eletriptan hydrobromide.

    Science.gov (United States)

    Shelke, Santosh; Shahi, Sadhana; Jadhav, Kiran; Dhamecha, Dinesh; Tiwari, Roshan; Patil, Hemlata

    2016-06-01

    The objective of the current study was to formulate and characterize thermoreversible gel of Eletriptan Hydrobromide for brain targeting via the intranasal route. Ethosomes were prepared by 3(2) factorial design with two independent variables (concentration of soya lecithin and ethanol) and two response variables [percent entrapment efficiency and vesicle size (nm)] using ethanol injection method. Formulated ethosomes were evaluated for preliminary microscopic examination followed by percent drug entrapment efficiency, vesicle size analysis, zeta potential, polydispersibility index and Transmission electron microscopy (TEM). TEM confirms spherical morphology of ethosomes, whereas Malvern zeta sizer confirms that the vesicle size was in the range of 191 ± 6.55-381.3 ± 61.0 nm. Ethosomes were incorporated in gel using poloxamer 407 and carbopol 934 as thermoreversible and mucoadhesive polymers, respectively. Ethosomal gels were evaluated for their pH, viscosity, mucoadhesive strength, in vitro drug release and ex vivo drug permeation through the sheep nasal mucosa. Mucoadhesive strength and pH was found to be 4400 ± 45 to 5500 ± 78.10 dynes/cm(2) and 6.0 ± 0.3 to 6.2 ± 0.1, respectively. In-vitro drug release from the optimized ethosomal gel formulation (G4) was found to be almost 100 % and ex vivo permeation of 4980 µg/ml with a permeability coefficient of 11.94 ± 0.04 × 10(-5) cm/s after 24 h. Histopathological study of the nasal mucosa confirmed non-toxic nature of ethosomal gels. Formulated EH loaded ethosomal thermoreversible gel could serve as the better alternative for the brain targeting via the intranasal route which in turn could subsequently improve its bioavailability.

  17. Electrostatic tuning of permeation and selectivity in aquaporin water channels

    DEFF Research Database (Denmark)

    Jensen, Mogens O Stibius; Tajkhorshid, E.; Schulten, K.

    2003-01-01

    -palmitoyloleylphosphatidylethanolamine membrane was used for the simulations. During the simulations, water molecules pass through the channel in single file. The movement of the single. le water molecules through the channel is concerted, and we show that it can be described by a continuous-time random-walk model. The integrity......Water permeation and electrostatic interactions between water and channel are investigated in the Escherichia coli glycerol uptake facilitator GlpF, a member of the aquaporin water channel family, by molecular dynamics simulations. A tetrameric model of the channel embedded in a 16:0/ 18:1c9...... of the single file remains intact during the permeation, indicating that a disrupted water chain is unlikely to be the mechanism of proton exclusion in aquaporins. Specific hydrogen bonds between permeating water and protein at the channel center (at two conserved Asp-Pro-Ala "NPA'' motifs), together...

  18. Permeation of "Hydromer" Film: An Elastomeric Hydrogen-Capturing Biopolymer.

    Energy Technology Data Exchange (ETDEWEB)

    Karnesky, Richard A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Friddle, Raymond William [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Whaley, Josh A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Smith, Geoffrey [New Mexico State Univ., Las Cruces, NM (United States)

    2015-12-01

    This report analyzes the permeation resistance of a novel and proprietary polymer coating for hydrogen isotope resistance that was developed by New Mexico State University. Thermal gravimetric analysis and thermal desoprtion spectroscopy show the polymer is stable thermally to approximately 250 deg C. Deuterium gas-driven permeation experiments were conducted at Sandia to explore early evidence (obtained using Brunauer - Emmett - Teller) of the polymer's strong resistance to hydrogen. With a relatively small amount of the polymer in solution (0.15%), a decrease in diffusion by a factor of 2 is observed at 100 and 150 deg C. While there was very little reduction in permeability, the preliminary findings reported here are meant to demonstrate the sensitivity of Sandia's permeation measurements and are intended to motivate the future exploration of thicker barriers with greater polymer coverage.

  19. Hydrogen permeation in stationary arc-melted nickel 200

    Science.gov (United States)

    Li, H.; North, T. H.; Sommerville, I. D.; McLean, A.

    1990-06-01

    A combination of hydrogen permeation experiments and computer simulation was used to evaluate the distributions of temperature and of the hydrogen transfer flux in a stationary arcmelted Nickel 200 disc over the entire hydrogen permeation zone. The results indicate that the markedly nonuniform temperature distribution in the hydrogen permeation zone involves widely varying hydrogen fluxes and even transfer of hydrogen in different directions. At steady state, the hydrogen distribution is determined by a thermally produced dynamic equilibrium. Hydrogen supersaturation occurs in solid nickel at the solid/liquid interface in the arc-melted pool. An increase in hydrogen partial pressure in the shielding gas increases the heat input to the melt and decreases the stability of the arc melting process.

  20. Double electrolyte sensor for monitoring hydrogen permeation rate in steels

    Energy Technology Data Exchange (ETDEWEB)

    Ouyang, Y.J. [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Department of Chemistry and Chemical Engineering, Huaihua College, Huaihua 418008 (China); Yu, G., E-mail: yuganghnu@163.co [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Ou, A.L.; Hu, L.; Xu, W.J. [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

    2011-06-15

    Highlights: {yields} Designed an amperometric hydrogen sensor with double electrolytes. {yields} Explained the principle of determining hydrogen permeation rate. {yields} Verified good stability, reproducibility and correctness of the developed sensor. {yields} Field on-line monitoring the susceptivity of hydrogen induced cracks. - Abstract: An amperometric hydrogen sensor with double electrolytes composed of a gelatiniform electrolyte and KOH solution has been developed to determine the permeation rate of hydrogen atoms in steel equipment owing to hydrogen corrosion. The gelatiniform electrolyte was made of sodium polyacrylate (PAAS), carboxyl methyl cellulose (CMC) and 0.2 mol dm{sup -3} KOH solution. The results show that the gelatiniform electrolyte containing 50 wt.% polymers has suitable viscosity and high electrical conductivity. The consistent permeation curves were detected by the sensor of the double electrolyte and single liquid KOH electrolyte, respectively. The developed sensor has good stability and reproducibility at room temperature.

  1. Sol-gel hybrid methyltrimethoxysilane-tetraethoxysilane as a new dispersive solid-phase extraction material for acrylamide determination in food with direct gas chromatography-mass spectrometry analysis.

    Science.gov (United States)

    Omar, Mei Musa Ali; Wan Ibrahim, Wan Aini; Elbashir, Abdalla Ahmed

    2014-09-01

    A sol-gel hybrid sorbent, methyltrimethoxysilane-tetraethoxysilane (MTMOS-TEOS) was successfully used as new dispersive solid phase extraction (dSPE) sorbent material in the determination of acrylamide in several Sudanese foods and analysis using GC-MS. Several important dSPE parameters were optimised. Under the optimised conditions, excellent linearity (r(2)>0.9998) was achieved using matrix matched standard calibration in the concentration range 50-1000 μg kg(-1). The limits of detection (LOD) and limit of quantification ranged from 9.1 to 12.8 μg/kg and 27.8-38.9 μg/kg, respectively. The precision (RSD%) of the method was ⩽6.6% and recoveries of acrylamide obtained were in the range of 88-103%, (n=3). The LOD obtained is comparable with the LODs of primary secondary amine dSPE. The proposed MTMOS-TEOS dSPE method is direct and safe for acrylamide analysis, showed reliable method validation performances and good cleanup effects. It was successfully applied to the analysis of acrylamide in real food samples.

  2. How membrane permeation is affected by donor delivery solvent.

    Science.gov (United States)

    Binks, Bernard P; Fletcher, Paul D I; Johnson, Andrew J; Elliott, Russell P

    2012-11-28

    We investigate theoretically and experimentally how the rate and extent of membrane permeation is affected by switching the donor delivery solvent from water to squalane for different permeants and membranes. In a model based on rate-limiting membrane diffusion, we derive explicit equations showing how the permeation extent and rate depend mainly on the membrane-donor and membrane-receiver partition coefficients of the permeant. Permeation results for systems containing all combinations of hydrophilic or hydrophobic donor solvents (aqueous solution or squalane), permeants (caffeine or testosterone) and polymer membranes (cellulose or polydimethylsiloxane) have been measured using a cell with stirred donor and re-circulating receiver compartments and continuous monitoring of the permeant concentration in the receiver phase. Relevant partition coefficients are also determined. Quantitative comparison of model and experimental results for the widely-differing permeation systems successfully enables the systematic elucidation of all possible donor solvent effects in membrane permeation. For the experimental conditions used here, most of the permeation systems are in agreement with the model, demonstrating that the model assumptions are valid. In these cases, the dominant donor solvent effects arise from changes in the relative affinities of the permeant for the donor and receiver solvents and the membrane and are quantitatively predicted using the separately measured partition coefficients. We also show how additional donor solvent effects can arise when switching the donor solvent causes one or more of the model assumptions to be invalid. These effects include a change in rate-limiting step, permeant solution non-ideality and others.

  3. Effect of alcohols and enhancers on permeation enhancement of ketorolac

    Directory of Open Access Journals (Sweden)

    Chandra Amrish

    2009-01-01

    Full Text Available A reservoir-type transdermal patch for the delivery of ketorolac was studied. The low permeability of the skin is the rate-limiting step for delivery of most of the drugs. Studies were carried out to investigate the effect of pH, alcohols, and chemical permeation enhancers on the in vitro permeation of ketorolac. The reservoir core of the transdermal patch was filled with the hydrogel of a nonionic polymer, methocel K 15 M (hydroxyl propyl methylcellulose, HPMC formulated at an optimized pH of 5.4. Enhanced in vitro permeation was achieved after the incorporation of the alcohols. Higher enhancement was produced by short-chain alcohols like ethanol and isopropyl alcohol (IPA. Propylene glycol (PG along with other alcohols, viz. n-propanol, n-butanol, and n-pentanol, lagged behind. An exponential rise in permeation was observed in flux with an increase in the concentration of IPA. At 25%w/w IPA concentration, the observed ketorolac flux was 18.04mg/cm 2 /h. Terpene containing eucalyptus oil was studied to determine its permeation enhancement capability. The increase in the concentration of eucalyptus oil enhanced the drug permeation and a maximum flux of 66.38 and 90.56mg/cm 2 /h was achieved at 10 and 15%w/w concentrations. The anti-inflammatory potential of the transdermal formulation was evaluated on a carrageenan-induced paw edema model, with 41.67% inhibition at 6 h. The skin irritation potential was evaluated by the Drazie test and the formulations prepared were found to be safe. The reservoir-type transdermal patch for the delivery of ketorolac appeared to be feasible for delivering ketorolac across the skin.

  4. Rapid quick, easy, cheap, effective, rugged, and safe extraction with novel phospholipid cleanup: A streamlined ultra high performance liquid chromatography with ultraviolet detection approach for screening polycyclic aromatic hydrocarbons in avian blood cells and plasma.

    Science.gov (United States)

    Provatas, Anthony A; Yevdokimov, Alexander V; King, Cory A; Gatley, Emma L; Stuart, James D; Evers, David C; Perkins, Christopher R

    2015-08-01

    A streamlined method has been developed for the isolation and analysis of polycyclic aromatic hydrocarbons in avian blood cells and plasma utilizing quick, easy, cheap, effective, rugged, and safe extraction in combination with novel phospholipid cleanup technology. A variety of traditional extraction and cleanup techniques have been employed in the preparation and analysis of polycyclic aromatic hydrocarbonsin a variety of matrices; liquid-liquid partitioning, solid-phase extractions, gel permeation chromatography, and column chromatography are all effective techniques, however they are laborious and time consuming processes that require large amounts of solvent. Using quick, easy, cheap, effective, rugged, and safe extraction coupled with phospholipid cleanup, samples can be quickly screened while maintaining high throughput and sensitivity. With a liquid chromatography approach, analysis times may be kept short at 16 min while maintaining high analyte recovery. Recoveries in quality control samples ranged from 70 to 109%, with average surrogate recoveries of 80.6 ± 1.10%. The result of using a quick, easy, cheap, effective, rugged, and safe extraction approach in conjunction with phospholipid cleanup is a methodology that significantly reduces sample preparation time and solvent use while maintaining high sensitivity and reproducibility.

  5. Green chromatography.

    Science.gov (United States)

    Płotka, Justyna; Tobiszewski, Marek; Sulej, Anna Maria; Kupska, Magdalena; Górecki, Tadeusz; Namieśnik, Jacek

    2013-09-13

    Analysis of organic compounds in samples characterized by different composition of the matrix is very important in many areas. A vast majority of organic compound determinations are performed using gas or liquid chromatographic methods. It is thus very important that these methods have negligible environmental impact. Chromatographic techniques have the potential to be greener at all steps of the analysis, from sample collection and preparation to separation and final determination. The paper summarizes the approaches used to accomplish the goals of green chromatography. While complete elimination of sample preparation would be an ideal approach, it is not always practical. Solventless extraction techniques offer a very good alternative. Where solvents must be used, the focus should be on the minimization of their consumption. The approaches used to make chromatographic separations greener differ depending on the type of chromatography. In gas chromatography it is advisable to move away from using helium as the carrier gas because it is a non-renewable resource. GC separations using low thermal mass technology can be greener because of energy savings offered by this technology. In liquid chromatography the focus should be on the reduction of solvent consumption and replacement of toxic and environmentally hazardous solvents with more benign alternatives. Multidimensional separation techniques have the potential to make the analysis greener in both GC and LC. The environmental impact of the method is often determined by the location of the instrument with respect to the sample collection point.

  6. Ion Chromatography.

    Science.gov (United States)

    Mulik, James D.; Sawicki, Eugene

    1979-01-01

    Accurate for the analysis of ions in solution, this form of analysis enables the analyst to directly assay many compounds that previously were difficult or impossible to analyze. The method is a combination of the methodologies of ion exchange, liquid chromatography, and conductimetric determination with eluant suppression. (Author/RE)

  7. In vitro evaluation of a hydroxypropyl cellulose gel system for transdermal delivery of timolol.

    Science.gov (United States)

    Stamatialis, D F; Rolevink, H H M; Gironès, M; Nymeijer, D C; Koops, G H

    2004-10-01

    In this work, the development of a gel reservoir for a timolol (TM) transdermal iontophoretic delivery system is investigated. TM gel is prepared using hydroxypropyl cellulose (HPC) and the permeability of TM from the gel through an artificial membrane (Polyflux) and pig stratum corneum (SC) is studied. For a constant TM donor concentration, the TM transport across the Polyflux membrane alone decreases when the concentration of the gel increases due to increase of the gel viscosity. For constant gel concentration, however, the TM permeation across the membrane increases when the TM donor concentration increases. In addition, no effect of the electrical current (iontophoresis, current density 0.5 mA cm-2) on the TM permeation is found. For the combination of the Polyflux membrane with pig SC, the TM transport is much lower than for the membrane alone and the SC fully controls the TM delivery. In this case, the application of electrical current enhances the TM delivery 13-15 times in comparison to passive (no current) transport. According to our estimation, the daily TM dose (10-60 mg) can be delivered by an iontophoretic patch with Polyflux membrane area of 6-36 cm2 containing 20% (w/w) HPC gel and 15 mg cm-3 of TM.

  8. Nanostructured lipid carriers (NLC) based topical gel of flurbiprofen: design, characterization and in vivo evaluation.

    Science.gov (United States)

    Han, Fei; Yin, Ran; Che, Xin; Yuan, Jing; Cui, Yanan; Yin, He; Li, Sanming

    2012-12-15

    Nanostructured lipid carriers (NLC)-based gel was developed as potential topical system for flurbiprofen (FP) topical delivery. The characterizations of the prepared semisolid formulation for topical application on skin were assessed by means of particle size distribution, zeta potential analysis, X-ray analysis, in vitro percutaneous penetration, rheological study, skin irritation test, in vivo pharmacodynamic evaluation and in vivo pharmacokinetic study. The NLC remained within the colloidal range and it was uniformly dispersed after suitably gelled by carbopol preparation. It was indicated in vitro permeation studies through rat skin that FP-NLC-gel had a more pronounced permeation profile compared with that of FP-loaded common gel. Pseudoplastic flows with thixotropy were obtained for all NLC-gels after storage at three different temperatures. No oedema and erythema were observed after administration of FP-NLC-gel on the rabbit skin, and the ovalbumin induced rat paw edema could be inhibited by the gel. The maximum concentration in plasma was 29.44 μg/ml and 2.49 μg/ml after oral and topical administration, respectively. While the amount of drug accumulated in skin after topical application was much higher than oral application. In conclusion, NLC-based gel could be a promising vehicle for topical delivery of FP. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Volatile Organic Compound (VOC Removal by Vapor Permeation at Low VOC Concentrations: Laboratory Scale Results and Modeling for Scale Up

    Directory of Open Access Journals (Sweden)

    Philippe Moulin

    2011-03-01

    Full Text Available Petroleum transformation industries have applied membrane processes for solvent and hydrocarbon recovery as an economic alternative to reduce their emissions and reuse evaporated components. Separation of the volatile organic compounds (VOCs (toluene-propylene-butadiene from air was performed using a poly dimethyl siloxane (PDMS/α-alumina membrane. The experimental set-up followed the constant pressure/variable flow set-up and was operated at ~21 °C. The membrane is held in a stainless steel module and has a separation area of 55 × 10−4 m². Feed stream was set to atmospheric pressure and permeate side to vacuum between 3 and 5 mbar. To determine the performance of the module, the removed fraction of VOC was analyzed by Gas Chromatography/Flame Ionization Detector (GC/FID. The separation of the binary, ternary and quaternary hydrocarbon mixtures from air was performed at different flow rates and more especially at low concentrations. The permeate flux, permeance, enrichment factor, separation efficiency and the recovery extent of the membrane were determined as a function of these operating conditions. The permeability coefficients and the permeate flux through the composite PDMS-alumina membrane follow the order given by the Hildebrand parameter: toluene > 1,3-butadiene > propylene. The simulated data for the binary VOC/air mixtures showed fairly good agreement with the experimental results in the case of 1,3-butadiene and propylene. The discrepancies observed for toluene permeation could be minimized by taking into account the effects of the porous support and an influence of the concentration polarization. Finally, the installation of a 0.02 m2 membrane module would reduce 95% of the VOC content introduced at real concentration conditions used in the oil industry.

  10. Volatile Organic Compound (VOC) Removal by Vapor Permeation at Low VOC Concentrations: Laboratory Scale Results and Modeling for Scale Up.

    Science.gov (United States)

    Rebollar-Perez, Georgette; Carretier, Emilie; Lesage, Nicolas; Moulin, Philippe

    2011-03-03

    Petroleum transformation industries have applied membrane processes for solvent and hydrocarbon recovery as an economic alternative to reduce their emissions and reuse evaporated components. Separation of the volatile organic compounds (VOCs) (toluene-propylene-butadiene) from air was performed using a poly dimethyl siloxane (PDMS)/α-alumina membrane. The experimental set-up followed the constant pressure/variable flow set-up and was operated at ~21 °C. The membrane is held in a stainless steel module and has a separation area of 55 × 10-4 m². Feed stream was set to atmospheric pressure and permeate side to vacuum between 3 and 5 mbar. To determine the performance of the module, the removed fraction of VOC was analyzed by Gas Chromatography/Flame Ionization Detector (GC/FID). The separation of the binary, ternary and quaternary hydrocarbon mixtures from air was performed at different flow rates and more especially at low concentrations. The permeate flux, permeance, enrichment factor, separation efficiency and the recovery extent of the membrane were determined as a function of these operating conditions. The permeability coefficients and the permeate flux through the composite PDMS-alumina membrane follow the order given by the Hildebrand parameter: toluene > 1,3-butadiene > propylene. The simulated data for the binary VOC/air mixtures showed fairly good agreement with the experimental results in the case of 1,3-butadiene and propylene. The discrepancies observed for toluene permeation could be minimized by taking into account the effects of the porous support and an influence of the concentration polarization. Finally, the installation of a 0.02 m2 membrane module would reduce 95% of the VOC content introduced at real concentration conditions used in the oil industry.

  11. Permeation Barrier Coatings for the Helical Heat Exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Korinko, P.S.

    1999-05-26

    A permeation barrier coating was specified for the Helical Heat Exchanger (HHE) to minimize contamination through emissions and/or permeation into the nitrogen system for ALARA reasons. Due to the geometry of the HHE, a special coating practice was needed since the conventional method of high temperature pack aluminization was intractable. A survey of many coating companies was undertaken; their coating capabilities and technologies were assessed and compared to WSRC needs. The processes and limitations to coating the HHE are described. Slurry coating appears to be the most technically sound approach for coating the HHE.

  12. Permeation of chromium salts through human skin in vitro

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Fullerton, A; Avnstorp, C

    1992-01-01

    Chromium permeation studies were performed on full thickness human skin in diffusion cells. All samples were analysed for the total chromium content by graphite furnace Zeeman-corrected atomic absorption spectrometry. Some samples were analysed by an ion chromatographic method permitting the simu......Chromium permeation studies were performed on full thickness human skin in diffusion cells. All samples were analysed for the total chromium content by graphite furnace Zeeman-corrected atomic absorption spectrometry. Some samples were analysed by an ion chromatographic method permitting...

  13. Lipophilicity and its relationship with passive drug permeation.

    Science.gov (United States)

    Liu, Xiangli; Testa, Bernard; Fahr, Alfred

    2011-05-01

    In this review, we first summarize the structure and properties of biological membranes and the routes of passive drug transfer through physiological barriers. Lipophilicity is then introduced in terms of the intermolecular interactions it encodes. Finally, lipophilicity indices from isotropic solvent systems and from anisotropic membrane-like systems are discussed for their capacity to predict passive drug permeation across biological membranes such as the intestinal epithelium, the blood-brain barrier (BBB) or the skin. The broad evidence presented here shows that beyond the predictive power of lipophilicity parameters, the various intermolecular forces they encode allow a mechanistic interpretation of passive drug permeation.

  14. Novel chemical permeation enhancers for transdermal drug delivery

    Directory of Open Access Journals (Sweden)

    Yang Chen

    2014-04-01

    Full Text Available Transdermal drug delivery has been accepted as a potential non-invasive route of drug administration, with advantages of prolonged therapeutic action, decreased side effect, easy use and better patient compliance. However, development of transdermal products is primarily hindered by the low permeability of the skin. To overcome this barrier effect, numerous new chemicals have been synthesized as potential permeation enhancers for transdermal drug delivery. In this review, we presented an overview of the investigations in this field, and further implications on selection or design of suitable permeation enhancers for transdermal drug delivery were also discussed.

  15. A novel solid-phase microextraction using coated fiber based sol-gel technique using poly(ethylene glycol) grafted multi-walled carbon nanotubes for determination of benzene, toluene, ethylbenzene and o-xylene in water samples with gas chromatography-flame ionization detector.

    Science.gov (United States)

    Sarafraz-Yazdi, Ali; Amiri, Amirhassan; Rounaghi, Gholamhossein; Hosseini, Hossein Eshtiagh

    2011-08-26

    In this study, poly(ethylene glycol) (PEG) grafted onto multi-walled carbon nanotubes (PEG-g-MWCNTs) were synthesized by the covalent functionalization of MWCNTs with hydroxyl-terminated PEG chains. For the first time, functionalized product of PEG-g-MWCNTs was used as selective stationary phase to prepare the sol-gel solid-phase microextraction (SPME) fiber in combination with gas chromatography-flame ionization detector (GC-FID) for the determination of ultra-trace levels of benzene, toluene, ethylbenzene and o-xylene (BTEX) in real water samples. The PEG-g-MWCNTs were characterized by Fourier transform infrared spectra and also thermo-gravimetric analysis, which verified that PEG chains were grafted onto the surface of the MWCNTs. The scanning electron micrographs of the fiber surface revealed a highly porous structure which greatly increases the surface area for PEG-g-MWCNTs sol-gel coating. This fiber demonstrated many inherent advantages, the main being the strong anchoring of the coating to the fused silica resulting from chemical bonding with the silanol groups on the fused-silica fiber surface. The new PEG-g-MWCNTs sol-gel fiber is simple to prepare, robust, with high thermal stability and long lifetime, up to 200 extractions. Important parameters influencing the extraction efficiency such as desorption temperature and time, extraction temperature, extraction time, stirring speed and salt effect were investigated and optimized. Under the optimal conditions, the method detection limits (S/N=3) were in the range of 0.6-3 pg mL(-1) and the limits of quantification (S/N=10) between 2 and 10 pg mL(-1). The relative standard deviations (RSDs) for one fiber (repeatability) (n=5) were obtained from 4.40 up to 5.75% and between fibers or batch to batch (n=3) (reproducibility) in the range of 4.31-6.55%. The developed method was successfully applied to real water samples while the relative recovery percentages obtained for the spiked water samples at 20 pg mL(-1

  16. Transport Phenomena in Gel

    Directory of Open Access Journals (Sweden)

    Masayuki Tokita

    2016-05-01

    Full Text Available Gel becomes an important class of soft materials since it can be seen in a wide variety of the chemical and the biological systems. The unique properties of gel arise from the structure, namely, the three-dimensional polymer network that is swollen by a huge amount of solvent. Despite the small volume fraction of the polymer network, which is usually only a few percent or less, gel shows the typical properties that belong to solids such as the elasticity. Gel is, therefore, regarded as a dilute solid because its elasticity is much smaller than that of typical solids. Because of the diluted structure, small molecules can pass along the open space of the polymer network. In addition to the viscous resistance of gel fluid, however, the substance experiences resistance due to the polymer network of gel during the transport process. It is, therefore, of importance to study the diffusion of the small molecules in gel as well as the flow of gel fluid itself through the polymer network of gel. It may be natural to assume that the effects of the resistance due to the polymer network of gel depends strongly on the network structure. Therefore, detailed study on the transport processes in and through gel may open a new insight into the relationship between the structure and the transport properties of gel. The two typical transport processes in and through gel, that is, the diffusion of small molecules due to the thermal fluctuations and the flow of gel fluid that is caused by the mechanical pressure gradient will be reviewed.

  17. Differentiation of black gel inks using optical and chemical techniques.

    Science.gov (United States)

    Wilson, Jeffrey D; LaPorte, Gerald M; Cantu, Antonio A

    2004-03-01

    Gel ink pens have become a common writing instrument in the United States. Questioned document examiners often attempt to optically differentiate gel inks from each other and from other non-ballpoint ink writings (e.g., those from roller-ball pens). Since early formulations were primarily pigment-based, they do not elute when analyzed by thin-layer chromatography. However, recent gel ink formulations (i.e., within the past five years) include dye-based inks that can be easily separated. This study differentiates black gel inks using optical and chemical techniques. The techniques include: microscopy, visible and near infrared reflectance, near infrared luminescence, thin-layer chromatography (TLC), spot tests, and gas chromatography/mass spectrometry (GC/MS). As a result of this study a flow chart has been developed allowing for a systematic determination of a questioned ink. In addition, an analysis of volatile compounds found in gel inks revealed that there are some unique ingredients that may be found in gel inks that are not typically found in other non-ballpoint inks.

  18. 玉米中三唑酮、三唑醇-a、三唑醇-b残留量的气相色谱-质谱检测%Analysis of Residual Triadimefon,Triadimenol-a,Triadimenol-b in Corn by Gas Chromatography-Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    张伟国; 陈姗姗; 高金山; 李重九

    2004-01-01

    A residue method is described for simultaneous analysis of triadimefon,triadimenol-a,triadimenol-b in corn. The pesticides were extracted using acetonitrile from sample. Most lipids in co-extractives were removed by liquid-liquid extraction and gel permeation chromatography (GPC). lutein was removed using solid-phase extraction (SPE) on a LC-ENVI-Carb column. The pesticides were finally determined by gas chromatographymass spectrometry in selective-ion mode (SIM) simultaneously. The average recoveries for most pesticides (spiked level 0.05, 0. 5 and 2μg/g) were in the range of 90%-110%.The coefficient of variation (CV) of the method was lower than 10% in every case..

  19. Characterization and purification of iodinated bovine thyrotropin by high performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Stanton, P.G.; Hearn, M.T.

    1986-08-01

    Reversed-phase (RP) HPLC, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and gel permeation chromatography have been used to study the incorporation of 125I into bovine (b) TSH by the lactoperoxidase-catalyzed radioiodination procedure. Two preparations of (/sup 125/I)bTSH were studied, being freshly iodinated bTSH and tracer purified from this preparation by the method of receptor adsorption. It is demonstrated with these methods that both the alpha- and beta-subunits of bTSH are labeled with 125I, and that the tracer purified by receptor adsorption retains this incorporation pattern. However, the implied theoretical specific activity of (at least) 2 I atoms per TSH molecule (or approximately 140 muCi/micrograms) suggested by this result was not achieved, with observed tracer specific activity being 30-60 muCi/micrograms, indicating that hormone molecules with varying extents of labeling must exist. Evidence to support this was provided by comparison of the MIT/DIT ratios for the 2 tracer preparations. Receptor adsorption decreased the MIT/DIT ratio from 75:25 in the freshly iodinated bTSH to 93:7, indicating the selection of particular iodinated species. Tryptic mapping by RP-HPLC was used to study both tracer preparations, and it is shown that at least 14 iodine-containing tryptic peptides may be resolved for each preparation, which is greater than the theoretical maximum of 13 peptides if every tyrosine was labeled and tryptic cleavage occurred at all possible lysine and arginine residues. Tracer heterogeneity was also studied by purification using RP-HPLC. Selection of peak fractions demonstrated that intact (/sup 125/I)bTSH may be recovered from RP-HPLC which in TSH radioreceptor assay exhibit increased assay sensitivity, increased saturable binding, and decreased nonsaturable binding.

  20. [Determination of 46 plasticizers in food contact polyvinyl chloride packaging materials and their migration into food simulants by gas chromatography-mass spectrometry].

    Science.gov (United States)

    Guo, Chunhai; Bo, Haibo; Duan, Wenzhong; Jia, Haitao; Chen, Ruichun; Ma, Yusong; Ai, Lianfeng

    2011-01-01

    A gas chromatography-mass spectrometry (GC-MS) method was developed for the determination of 46 plasticizers in food contact polyvinyl chloride (PVC) packaging materials and their migration into food simulants, i. e. water, 3% acetic acid, 10% ethanol and olive oil. Plasticizers in the PVC packaging materials, aqueous food simulants and olive oil food simulants were extracted by the dissolution-precipitation, liquid-liquid extraction and gel permeation chromatography (GPC) approaches, respectively. The extracts were analyzed by GC-MS in selective ion monitoring (SIM) mode and quantified using the external standard method. The cal-ibration curves were linear in the ranges of 0.1-2.0 mg/L with the correlation coefficients of 0.9910-0. 999 9. The limits of detection were from 0. 005 mg/kg to 0. 05 mg/kg ( S/N = 5 ). The recoveries at 3 spiked levels were 69.51%-107. 21% and the relative standard deviations (RSDs n = 6) ranged from 3.53% to 18.95%. These results show that this method is fast, sensitive and accurate for the qualitative and quantitative determination of plasticizers in food contact plastic products and 4 types of food simulants.

  1. [Screening method for 29 forbidden or limited synthetic pigments in cheese by liquid chromatography/quadrupole time-of-flight mass spectrometry].

    Science.gov (United States)

    Zhao, Yansheng; Yang, Minli; Zhang, Feng; Feng, Feng; Chu, Xiaogang; Dong, Ying

    2011-07-01

    A screening method for 29 forbidden or limited synthetic pigments in cheese samples was established by liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/Q-TOF MS). The pigments were extracted by n-hexane/water (3:1, v/v). After extraction, the n-hexane extract, water extract and residue, were obtained. The n-hexane extract was then cleaned-up by gel permeation chromatography (GPC). The water extract was extracted by acetonitrile, and the residue by ammonia water/methanol (1:99, v/v). The results showed that the 29 synthetic pigments with a wide range of polarities were extracted effectively with the recoveries between 70% and 95%, and matched well by Q-TOF MS precision mass searching to the mass spectral library with matching scores between 59. 66 and 99. 47. The quantitative analysis of the 29 pigments was carried out by Target MS/MS. The limits of detection (LODs) for 8 Sudan dyes were 0.4-2.5 micro/kg while for 21 water-soluble synthetic pigments were 20-80 microg/kg. The screening method is suitable for a wide range of synthetic pigments, and can be applied to food samples with proteins and fat in matrix.

  2. Sol-Gel Glasses

    Science.gov (United States)

    Mukherjee, S. P.

    1985-01-01

    Multicomponent homogeneous, ultrapure noncrystalline gels/gel derived glasses are promising batch materials for the containerless glass melting experiments in microgravity. Hence, ultrapure, homogeneous gel precursors could be used to: (1) investigate the effect of the container induced nucleation on the glass forming ability of marginally glass forming compositions; and (2) investigate the influence of gravity on the phase separation and coarsening behavior of gel derived glasses in the liquid-liquid immiscibility zone of the nonsilicate systems having a high density phase. The structure and crystallization behavior of gels in the SiO2-GeO2 as a function of gel chemistry and thermal treatment were investigated. As are the chemical principles involved in the distribution of a second network former in silica gel matrix being investigated. The procedures for synthesizing noncrystalline gels/gel-monoliths in the SiO2-GeO2, GeO2-PbO systems were developed. Preliminary investigations on the levitation and thermal treatment of germania silicate gel-monoliths in the Pressure Facility Acoustic Levitator were done.

  3. Optimization and formulation design of gels of Diclofenac and Curcumin for transdermal drug delivery by Box-Behnken statistical design.

    Science.gov (United States)

    Chaudhary, Hema; Kohli, Kanchan; Amin, Saima; Rathee, Permender; Kumar, Vikash

    2011-02-01

    The aim of this study was to develop and optimize a transdermal gel formulation for Diclofenac diethylamine (DDEA) and Curcumin (CRM). A 3-factor, 3-level Box-Behnken design was used to derive a second-order polynomial equation to construct contour plots for prediction of responses. Independent variables studied were the polymer concentration (X(1)), ethanol (X(2)) and propylene glycol (X(3)) and the levels of each factor were low, medium, and high. The dependent variables studied were the skin permeation rate of DDEA (Y(1)), skin permeation rate of CRM (Y(2)), and viscosity of the gels (Y(3)). Response surface plots were drawn, statistical validity of the polynomials was established to find the compositions of optimized formulation which was evaluated using the Franz-type diffusion cell. The permeation rate of DDEA increased proportionally with ethanol concentration but decreased with polymer concentration, whereas the permeation rate of CRM increased proportionally with polymer concentration. Gels showed a non-Fickian super case II (typical zero order) and non-Fickian diffusion release mechanism for DDEA and CRM, respectively. The design demonstrated the role of the derived polynomial equation and contour plots in predicting the values of dependent variables for the preparation and optimization of gel formulation for transdermal drug release. Copyright © 2010 Wiley-Liss, Inc.

  4. Comprehensive quantitative analysis of Chinese patent drug YinHuang drop pill by ultra high-performance liquid chromatography quadrupole time of flight mass spectrometry.

    Science.gov (United States)

    Wong, Tin-Long; An, Ya-Qi; Yan, Bing-Chao; Yue, Rui-Qi; Zhang, Tian-Bo; Ho, Hing-Man; Ren, Tian-Jing; Fung, Hau-Yee; Ma, Dik-Lung; Leung, Chung-Hang; Liu, Zhong-Liang; Pu, Jian-Xin; Han, Quan-Bin; Sun, Han-Dong

    2016-06-01

    YinHuang drop pill (YHDP) is a new preparation, derived from the traditional YinHuang (YH) decoction. Since drop pills are one of the newly developed forms of Chinese patent drugs, not much research has been done regarding the quality and efficacy. This study aims to establish a comprehensive quantitative analysis of the chemical profile of YHDP. ultra high-performance liquid chromatography quadrupole time of flight mass spectrometry (UHPLC-Q-TOF-MS/MS) was used to identify 34 non-sugar small molecules including 15 flavonoids, 9 phenolic acids, 5 saponins, 1 iridoid, and 4 iridoid glycosides in YHDP samples, and 26 of them were quantitatively determined. Sugar composition of YHDP in terms of fructose, glucose and sucrose was examined via a high performance liquid chromatography-evaporative light scattering detector on an amide column (HPLC-NH2P-ELSD). Macromolecules were examined by high performance gel permeation chromatography coupled with ELSD (HPGPC-ELSD). The content of the drop pill's skeleton component PEG-4000 was also quantified via ultra-high performance liquid chromatography coupled with charged aerosol detector (UHPLC-CAD). The results showed that up to 73% (w/w) of YHDP could be quantitatively determined. Small molecules accounted for approximately 5%, PEG-4000 represented 68%, while no sugars or macromolecules were found. Furthermore, YHDP showed no significant differences in terms of daily dosage, compared to YinHuang granules and YinHuang oral liquid; however, it has a higher small molecules content compared to YinHuang lozenge.

  5. Inertial Particle Migration in the Presence of a Permeate Flow

    Science.gov (United States)

    Garcia, Mike; Singelton, Amanda; Pennathur, Sumita

    2016-11-01

    Tangential Flow Filtration (TFF) is a rapid and efficient method for the filtration and separation of suspensions of particles such as viruses, bacteria or cellular material. Enhancing the efficacy of TFF not only requires a detailed understanding of particle transport mechanisms, but also the interactions between these mechanisms and a porous wall. In this work, we numerically and experimentally explore the mechanisms of inertial particle migration in the presence of a permeate flow through the porous walls of a microchannel. Numerically, we develop a force balance model to understand the competition between permeate and inertial forces and the resultant consequences on the particle equilibrium location. Experimentally, we fabricated MEMS TFF devices to study the migration of 5, 10 and 15 µm fluorescent polystyrene beads in straight channels with perpendicular permeate flow rates up to 90% of the inlet flow rate. We find that the permeate flow directly influences the inertial focusing position of the particles, both as a function of downstream channel position and ratio of inlet to outlet flow rate. Comparing experiments to our model, we can identify inertial, viscous and a co-dominant regimes.

  6. Glycerol inhibits water permeation through Plasmodium falciparum aquaglyceroporin.

    Science.gov (United States)

    Chen, Liao Y

    2013-01-01

    Plasmodium falciparum aquaglyceroporin (PfAQP) is a multifunctional membrane protein in the plasma membrane of P. falciparum, the parasite that causes the most severe form of malaria. The current literature has established the science of PfAQP's structure, functions, and hydrogen-bonding interactions but left unanswered the following fundamental question: does glycerol modulate water permeation through aquaglyceroporin that conducts both glycerol and water? This paper provides an affirmative answer to this question of essential importance to the protein's functions. On the basis of the chemical-potential profile of glycerol from the extracellular bulk region, throughout PfAQP's conducting channel, to the cytoplasmic bulk region, this study shows the existence of a bound state of glycerol inside aquaglyceroporin's permeation pore, from which the dissociation constant is approximately 14μM. A glycerol molecule occupying the bound state occludes the conducting pore through which permeating molecules line up in single file by hydrogen-bonding with one another and with the luminal residues of aquaglyceroporin. In this way, glycerol inhibits permeation of water and other permeants through aquaglyceroporin. The biological implications of this theory are discussed and shown to agree with the existent in vitro data. It turns out that the structure of aquaglyceroporin is perfect for the van der Waals interactions between the protein and glycerol to cause the existence of the bound state deep inside the conducting pore and, thus to play an unexpected but significant role in aquaglyceroporin's functions.

  7. Permeation of single gases in thin zeolite MFI membranes

    NARCIS (Netherlands)

    Burggraaf, A.J.; Vroon, Z.A.E.P.; Keizer, K.; Verweij, H.

    1998-01-01

    The permeation of a series of gases with widely different Lennard-Jones kinetic diameters and sorption properties is investigated as a function of feed pressure (up to 100 kPa) and temperature (298-473 K) with two different methods. The membrane system studied consists of an MFI (silicalite) top-lay

  8. Vacuum Permeator Analysis for Extraction of Tritium from DCLL Blankets

    Energy Technology Data Exchange (ETDEWEB)

    Humrickhouse, Paul Weston [Idaho National Laboratory; Merrill, Brad Johnson [Idaho National Laboratory

    2014-11-01

    It is envisioned that tritium will be extracted from DCLL blankets using a vacuum permeator. We derive here an analytical solution for the extraction efficiency of a permeator tube, which is a function of only two dimensionless numbers: one that indicates whether radial transport is limited in the PbLi or in the solid membrane, and another that is the ratio of axial and radial transport times in the PbLi. The permeator efficiency is maximized by decreasing the velocity and tube diameter, and increasing the tube length. This is true regardless of the mass transport correlation used; we review several here and find that they differ little, and the choice of correlation is not a source of significant uncertainty here. The PbLi solubility, on the other hand, is a large source of uncertainty, and we identify upper and lower bounds from the literature data. Under the most optimistic assumptions, we find that a ferritic steel permeator operating at 550 °C will need to be at least an order of magnitude larger in volume than previous conceptual designs using niobium and operating at higher temperatures.

  9. Hydrogen permeation behavior through F82H at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, S.; Katayama, K.; Shimozori, M.; Fukada, S. [Interdisciplinary Graduate School of Engineering Science, Kyushu University, Kyushu (Japan); Ushida, H. [Energy Science and Engineering, Faculty of Engineering, Kyushu University, Kyushu (Japan); Nishikawa, M. [Malaysia-Japan International Institute of Technology, UTM, Kuala Lumpur (Malaysia)

    2015-03-15

    F82H is a primary candidate of structural material and coolant pipe material in a blanket of a fusion reactor. Understanding tritium permeation behavior through F82H is important. In a normal operation of a fusion reactor, the temperature of F82H will be controlled below 550 C. degrees because it is considered that F82H can be used up to 30,000 hours at 550 C. degrees. However, it is necessary to assume the situation where F82H is heated over 550 C. degrees in a severe accident. In this study, hydrogen permeation behavior through F82H was investigated in the temperature range from 500 to 800 C. degrees. In some cases, water vapor was added in a sample gas to investigate an effect of water vapor on hydrogen permeation. The permeability of hydrogen in the temperature range from 500 to 700 C. degrees agreed well with the permeability reported by E. Serra et al. The degradation of the permeability by water vapor was not observed. After the hydrogen permeation reached in a steady state at 700 C. degrees, the F82H sample was heated to 800 C. degrees. The permeability of hydrogen through F82H sample which was once heated up to 800 C. degrees was lower than that of the original one. (authors)

  10. GAS PERMEATION PROPERTIES OF POLY(LACTIC ACID). (R826733)

    Science.gov (United States)

    AbstractThe need for the development of polymeric materials based on renewable resources has led to the development of poly(lactic acid) (PLA) which is being produced from a feedstock of corn rather than petroleum. The present study examines the permeation of nitrogen...

  11. Two component permeation through thin zeolite MFI membranes

    NARCIS (Netherlands)

    Keizer, K.; Burggraaf, A.J.; Vroon, Z.A.E.P.; Verweij, H.

    1998-01-01

    Two component permeation measurements have been performed by the Wicke-Kallenbach method on a thin (3 μm) zeolite MFI (Silicalite-1) membrane with molecules of different kinetic diameters, d(k). The membrane was supported by a flat porous α-Al2O3 substrate. The results obtained could be classified i

  12. two component permeation through thin zeolite MFI membranes

    NARCIS (Netherlands)

    Keizer, Klaas; Burggraaf, Anthonie; Burggraaf, A.J.; Vroon, Z.A.E.P.; Vroon, Z.A.E.P.; Verweij, H.

    1998-01-01

    Two component permeation measurements have been performed by the Wicke–Kallenbach method on a thin (3 μm) zeolite MFI (Silicalite-1) membrane with molecules of different kinetic diameters, dk. The membrane was supported by a flat porous -Al2O3 substrate. The results obtained could be classified in s

  13. Phase Change Permeation Technology For Environmental Control Life Support Systems

    Science.gov (United States)

    Wheeler, Raymond M.

    2014-01-01

    Use of a phase change permeation membrane (Dutyion [Trademark]) to passively and selectively mobilize water in microgravity to enable improved water recovery from urine/brine for Environment Control and Life Support Systems (ECLSS) and water delivery to plans for potential use in microgravity.

  14. Observations on the permeation performance of solvent resistant nanofiltration membranes

    NARCIS (Netherlands)

    Stamatialis, Dimitrios; Stafie, N.; Buadu, K.; Hempenius, Mark A.; Wessling, Matthias

    2006-01-01

    This work presents a systematic study of the influence of membrane–solvent–solute interactions on the permeation performance of solvent resistant nanofiltration (NF) membranes. Two different tailor-made composite membranes are prepared by dip coating of a polymer onto a polyacrylonitrile (PAN)

  15. In vitro-in vivo correlation in skin permeation.

    Science.gov (United States)

    Mohammed, D; Matts, P J; Hadgraft, J; Lane, M E

    2014-02-01

    In vitro skin permeation studies have been used extensively in the development and optimisation of delivery of actives in vivo. However, there are few reported correlations of such in vitro studies with in vivo data. The aim of this study was to investigate the skin permeation of a model active, niacinamide, both in vitro and in vivo. Conventional diffusion cell studies were conducted in human skin to determine niacinamide permeation from a range of vehicles which included dimethyl isosorbide (DMI), propylene glycol (PG), propylene glycol monolaurate (PGML), N-methyl 2-pyrrolidone (NMP), Miglyol 812N® (MG), and mineral oil (MO). Single, binary or ternary systems were examined. The same vehicles were subsequently examined to investigate niacinamide delivery in vivo. For this proof-of-concept study one donor was used for the in vitro studies and one volunteer for the in vivo investigations to minimise biovariability. Analysis of in vitro samples was conducted using HPLC and in vivo uptake of niacinamide was evaluated using Confocal Raman spectroscopy (CRS). The amount of niacinamide permeated through skin in vitro was linearly proportional to the intensity of the niacinamide signal determined in the stratum corneum in vivo. A good correlation was observed between the signal intensities of selected vehicles and niacinamide signal intensity. The findings provide further support for the use of CRS to monitor drug delivery into and across the skin. In addition, the results highlight the critical role of the vehicle and its disposition in skin for effective dermal delivery.

  16. GAS PERMEATION PROPERTIES OF POLY(LACTIC ACID). (R826733)

    Science.gov (United States)

    AbstractThe need for the development of polymeric materials based on renewable resources has led to the development of poly(lactic acid) (PLA) which is being produced from a feedstock of corn rather than petroleum. The present study examines the permeation of nitrogen...

  17. HOT DIPPING ALUMINIZED COATING AS HYDROGEN PERMEATION BARRIER

    Institute of Scientific and Technical Information of China (English)

    Z.Y. Yao; M. Chini; A. Aiello; Benamati

    2001-01-01

    The hydrogen permeation experiment of MANET II with hot dipping aluminized 1oat-ing was performed in temperature range of 573 to 623K, in gas phase and in liquiaPb-17Li phase. The hydrogen permeation reduction factor (PRF) evaluated in gasphase is 620 at 573K and 260 at 623K, and in liquid Pb-17Li phase is 24 45 at 573Kand 12-30 at 623K. The self-healing of coating is obvious and effective above 673K.The pressure dependence of permeation flux indicates strong surface contribution. Theway of filling hydrogen by continuous flow and/or bubble can increase permeation flux.The result of SEM-EDS shows that the microcrack is on the surface of the wetted part,but not on the not wetted part. The crack is superficial and affects only thin outsidelayer not penetrate aluminized layer. The surface elemental analysis shows that Al/Oatomic ratio changes from 2/3 of not wetted part to about 1 of wetted part. Thedamage of coating surface seems to be related to the interaction of outside layer withliquid Pb-17Li and thermal stress during heating sample.

  18. In vitro permeation of platinum and rhodium through Caucasian skin.

    Science.gov (United States)

    Franken, A; Eloff, F C; Du Plessis, J; Badenhorst, C J; Jordaan, A; Du Plessis, J L

    2014-12-01

    During platinum group metals (PGMs) refining the possibility exists for dermal exposure to PGM salts. The dermal route has been questioned as an alternative route of exposure that could contribute to employee sensitisation, even though literature has been focused on respiratory exposure. This study aimed to investigate the in vitro permeation of platinum and rhodium through intact Caucasian skin. A donor solution of 0.3mg/ml of metal, K2PtCl4 and RhCl3 respectively, was applied to the vertical Franz diffusion cells with full thickness abdominal skin. The receptor solution was removed at various intervals during the 24h experiment, and analysed with high resolution ICP-MS. Skin was digested and analysed by ICP-OES. Results indicated cumulative permeation with prolonged exposure, with a significantly higher mass of platinum permeating after 24h when compared to rhodium. The mass of platinum retained inside the skin and the flux of platinum across the skin was significantly higher than that of rhodium. Permeated and skin retained platinum and rhodium may therefore contribute to sensitisation and indicates a health risk associated with dermal exposure in the workplace.

  19. In vitro permeation of platinum through African and Caucasian skin.

    Science.gov (United States)

    Franken, A; Eloff, F C; du Plessis, J; Badenhorst, C J; Du Plessis, J L

    2015-02-03

    The majority of the South African workforce are Africans, therefore potential racial differences should be considered in risk and exposure assessments in the workplace. Literature suggests African skin to be a superior barrier against permeation and irritants. Previous in vitro studies on metals only included skin from Caucasian donors, whereas this study compared the permeation of platinum through African and Caucasian skin. A donor solution of 0.3 mg/ml of potassium tetrachloroplatinate (K₂PtCl₄) dissolved in synthetic sweat was applied to the vertical Franz diffusion cells with full thickness abdominal skin. Skin from three female African and three female Caucasian donors were included (n=21). The receptor solution was removed at various intervals during the 24 h experiment, and analysed with high resolution inductively coupled plasma-mass spectrometry (ICP-MS). Skin was digested and analysed by inductively coupled plasma-optical emission spectrometry (ICP-OES). Significantly higher permeation of platinum through intact African skin (p=0.044), as well as a significantly higher mass of platinum retention in African skin in comparison with Caucasian skin (p=0.002) occurred. Significant inter-donor variation was found in both racial groups (pplatinum salts. These results are contradictory to limited literature suggesting a superior barrier in African skin and further investigation is necessary to explain the higher permeation through African skin.

  20. 硅胶柱色谱结合高速逆流色谱法分离纯化丹参中丹参酮%Separation and purification of tanshinone from Salvia miltiorrhiza by combination of silica gel and high-speed counter-current chromatography

    Institute of Scientific and Technical Information of China (English)

    蓝天凤; 于宗渊; 王岱杰; 王晓; 管仁军

    2011-01-01

    Objective To develop a method for separation and purification of tanshinone from Salvia miltiorrhiza by combination of silica gel and high-speed counter-current chromatography (HSCCC). Methods The crude extract of S. miltiorrhiza was separated by silica gel chromatography and Fl and F2 were obtained. Then, Fl and F2 were separated by HSCCC with a two-phase solvent system composed of petroleum ether-methanol-water (4: 3: 4: 2 and 8: 5: 8: 3), respectively. The lower phase was used as the mobile phase with a flow rate of 2.0 mL/min, while the apparatus rotated at 850 r/min and the eluates were detected at 254 nm. The structures of the target compounds were identified by ESI-MS and NMR. Results From 80 mg of F1, three compounds with tanshinone Ⅰ (14 mg), dihydrotanshinone Ⅰ (22 mg), and tanshinone ⅡA (26 mg) were obtained. And from 80 mg of F2,dihydrotanshinone (11 mg), trijuganone B (15 mg), and cryptotanshinone (30 mg) were obtained. The purities of these six compounds determined by HPLC were all over 96%, respectively. Conclusion Combination of silica gel and HSCCC is an efficient method for separation of tanshinone from S. miltiorrhiza.%目的 建立硅胶柱色谱结合高速逆流色谱(HSCCC)法分离纯化丹参中丹参酮的方法.方法 丹参粗提物经硅胶柱色谱分离,得到组分F1、F2,分别采用石油醚-醋酸乙酯-甲醇-水(4:3:4:2)、(8:5:8:3)的溶剂系统进行HSCCC分离,下相为流动相,体积流量2.0 mL/min,转速850 r/min,检测波长254 nm,所得产物采用ESI-MS、NMR进行结构鉴定.结果 80 mg组分F1分离得到丹参酮I(14 mg)、二氢丹参酮I (22 mg)、丹参酮IIA (26 mg); 80 mg组分F2分离得到二氢丹参酮(11 mg)、三叶鼠尾酮B (15 mg)、隐丹参酮(30 mg); 6个化合物进行HPLC分析,质量分数均大于96%.结论 硅胶柱色谱结合HSCCC是一种有效的分离制备丹参酮的方法.

  1. Nanostructured lipid carrier based topical gel of Ganoderma Triterpenoids for frostbite treatment.

    Science.gov (United States)

    Shen, Cheng-Ying; Dai, Ling; Shen, Bao-De; Zhou, Xu; Bai, Jin-Xia; Xu, He; Lv, Qing-Yuan; Han, Jin; Yuan, Hai-Long

    2015-06-01

    The objective of this study was to prepare nanostructured lipid carrier (NLC)-based topical gel of Ganoderma Triterpenoids (GTs) and evaluate their effects on frostbite treatment. GT-NLCs was prepared by the high pressure homogenization method and then characterized by morphology and analyses of particle size, zeta potential, entrapment efficiency (EE), and drug loading (DL). The NLCs was suitably gelled for skin permeation studies in vitro and pharmacodynamic evaluation in vivo, compared with the GT emulgel. The GT-NLC remained within the colloidal range and was uniformly dispersed after suitably gelled by carbopol preparation. Transmission electron microscopy (TEM) study showed GT-NLCs was spherical in shape. The EE (%) and DL (%) could reach up to (81.84 ± 0.60)% and (2.13 ± 0.12)%, respectively. The result of X-ray diffractograms (XRD) showed that GTs were in an amorphous state in the NLC-gel. In vitro permeation studies through rat skin indicated that the amount of GTs permeated through skin of GT-NLCs after 24 h was higher than that of GT emulsion, and GT-NLCs increased the accumulative amounts of GTs in epidermis 7.76 times greater than GT emulsion. GT-NLC-gel was found to possess superior therapeutic effect for frostbite, compared with the GT emulgel. The NLC based topical gel of GTs could improve -their therapeutic effect for frostbite.

  2. Headspace Gas Chromatography Method for Studies of Reaction and Permeation of Volatile Agents with Solid Materials

    Science.gov (United States)

    2015-01-01

    oxidation using potassium iodide solution. 13.2.1. Repeated sampling of the same sample vial: Each vial was remeasured in this experiment. Results for...criteria. 9.1 Routine stability testing The QC sensitivity measurement can be done by preparing a vial with a standard quantity of a reagent... stability checks has been a problem for this method. The problem is illustrated in Figure 1. Volatile compounds like triethylphosphate or

  3. Determination of diniconazole in agricultural samples by sol-gel immunoaffinity extraction procedure coupled with HPLC and ELISA.

    Directory of Open Access Journals (Sweden)

    Zhenjiang Liu

    Full Text Available BACKGROUND: In the European Union (EU, the use of diniconazole-M is no longer authorized. However, residues of diniconazole-M occur in various plant commodities. METHODOLOGY/PRINCIPAL FINDINGS: A selective and simple analytical method for the trace level determination of diniconazole in soil, fruit, vegetables and water samples was developed based on immunoaffinity extraction followed by Enzyme-linked immunosorbent assay (ELISA and the high-performance liquid chromatography (HPLC analysis. The ELISA was based on monoclonal antibodies highly specific to diniconazole and was a fast, cost-effective, and selective screening method for the detection of diniconazole. The results of the ELISA correlated well with gas chromatography (GC results, with the correlation coefficient of 0.9879 (n = 19. A simple gel permeation chromato- graphy clean-up method was developed to purify extracts from matrices containing high amounts of fat and natural pigments, without the need for a large dilution of the sample. The immunoaffinity column (IAC capacity was 0.180 mg g(-1. The columns could be re-used approximately 20 times with no significant alteration in capacity. The recoveries from complex samples were in the range of 89.2% to 96.1% with a relative standard deviation (RSD of 0.770%-6.11% by ELISA. The results were in good agreement with those obtained by HPLC method. CONCLUSION/SIGNIFICANCE: The IAC extraction procedure coupled with HPLC and ELISA analysis could be also used as alternative effective analytical methods for the determination of diniconazole concentrations in complex samples.

  4. In Vitro Skin Permeation Enhancement of Sumatriptan by Microneedle Application.

    Science.gov (United States)

    Nalluri, Buchi N; Anusha, Sai Sri V; Bramhini, Sri R; Amulya, J; Sultana, Ashraf S K; Teja, Chandra U; Das, Diganta B

    2015-01-01

    Different dimensions of commercially available microneedle devices, namely, Admin- Patch(®) microneedle arrays (MN) (0.6, 0.9, 1.2 and 1.5 mm lengths) and Dermaroller(®) microneedle rollers (DR) (0.5 and 1mm lengths) were evaluated for their relative efficiency in enhancement of transdermal permeation of Sumatriptan (SMT). Solubility assessment of SMT was carried out using propylene glycol (PG), polyethylene glycol (PEG) in combination with saline (S) at different ratios and the order of solubility was found to be 70:30 > 80:20 > 90:10 %v/v in both PG:S and PEG:S. In vitro skin permeation studies were performed using PG:S (70:30 %v/v) as donor vehicle. A significant increase in cumulative amount of SMT permeated, steady state flux, permeability coefficient and diffusion coefficient values were observed after microneedle treatment, and the values were in the order of 1.5mm MN >1.2mm MN >0.9mm MN >1mm DR >0.6mm MN >0.5mm DR > passive permeation. Lag times were significantly shorter after longer microneedle application (0.24h for 1.5mm MN). Arrays were found to be superior to rollers with similar microneedle lengths in enhancing SMT permeation and may be attributed to higher density of microneedles and force of application onto skin. The in vitro flux values revealed that 2.5cm(2) area patch is sufficient for effective therapy after treatment of skin with 1.5mm MN. It may be inferred that microneedle application significantly enhances the transdermal penetration of SMT and that it may be feasible to deliver clinically relevant therapeutic levels of SMT using microneedle assisted transdermal delivery systems.

  5. Pulse Field Gel Electrophoresis.

    Science.gov (United States)

    Sharma-Kuinkel, Batu K; Rude, Thomas H; Fowler, Vance G

    2016-01-01

    Pulse Field Gel Electrophoresis (PFGE) is a powerful genotyping technique used for the separation of large DNA molecules (entire genomic DNA) after digesting it with unique restriction enzymes and applying to a gel matrix under the electric field that periodically changes direction. PFGE is a variation of agarose gel electrophoresis that permits analysis of bacterial DNA fragments over an order of magnitude larger than that with conventional restriction enzyme analysis. It provides a good representation of the entire bacterial chromosome in a single gel with a highly reproducible restriction profile, providing clearly distinct and well-resolved DNA fragments.

  6. CONFORMANCE IMPROVEMENT USING GELS

    Energy Technology Data Exchange (ETDEWEB)

    Randall S. Seright

    2003-09-01

    This report describes work performed during the second year of the project, ''Conformance Improvement Using Gels.'' The project has two objectives. The first objective is to identify gel compositions and conditions that substantially reduce flow through fractures that allow direct channeling between wells, while leaving secondary fractures open so that high fluid injection and production rates can be maintained. The second objective is to optimize treatments in fractured production wells, where the gel must reduce permeability to water much more than that to oil. Pore-level images from X-ray computed microtomography were re-examined for Berea sandstone and porous polyethylene. This analysis suggests that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than a gel-ripping mechanism. This finding helps to explain why aqueous gels can reduce permeability to water more than to oil. We analyzed a Cr(III)-acetate-HPAM gel treatment in a production well in the Arbuckle formation. The availability of accurate pressure data before, during, and after the treatment was critical for the analysis. After the gel treatment, water productivity was fairly constant at about 20% of the pre-treatment value. However, oil productivity was stimulated by a factor of 18 immediately after the treatment. During the six months after the treatment, oil productivity gradually decreased to approach the pre-treatment value. To explain this behavior, we proposed that the fracture area open to oil flow was increased substantially by the gel treatment, followed by a gradual closing of the fractures during subsequent production. For a conventional Cr(III)-acetate-HPAM gel, the delay between gelant preparation and injection into a fracture impacts the placement, leakoff, and permeability reduction behavior. Formulations placed as partially formed gels showed relatively low pressure gradients during placement, and yet substantially reduced the

  7. Preparation and characterization of carbosilane denddmer-bonded silica gel and its use in LC

    Institute of Scientific and Technical Information of China (English)

    Chen Guowen; Zhao Shigui; Feng Shengyu

    2006-01-01

    Divergently synthesized carbosilane dendrimers generations 1(G1) and 2 (G2) with allyl end groups were bonded onto silica gel.Reactions between the dendrimers and acid-processed silica gel took place,with toluene reflux and organic base as catalyst.Chemically bonded silica gel was characterized by transmission electron microscopy (TEM),infrared (IR),and other methods.The chemically modified silica gels were packed into high-pressure liquid chromatography (HPLC) column and their separation characters were evaluated.G2-bonded silica gel was effective in separating homologous compounds of alcohol, alkyl-substituted benzene,N-substituted benzene,metacrylic acid ester and phthalate.

  8. SYNTHESIS OF NaA ZEOLITE MEMBRANE FROM CLEAR SOLUTION AND ITS GAS PERMEATION PROPERTIES%澄清溶液中NaA型分子筛膜的合成及气体渗透性能

    Institute of Scientific and Technical Information of China (English)

    徐晓春; 刘杰; 朱兵; 房廉清; 杨维慎; 熊国兴; 林励吾

    1999-01-01

    @@ The use of zeolite membranes in separation or combined reaction and separation processes is very attractive. Advantages of using such a type of membranes include their ability to discriminate molecules based on the molecular size and their stability[1]. In the past ten years, most efforts were involved in the synthesis and permeation studies of MFI zeolite membrane[2, 3]. Recently, NaA zeolite membrane has attracted much attention because of its high potential in the dehydration of organic liquids[4]. However, few gas permeation results were reported[5]. Furthermore, most of the NaA zeolite membrane was synthesized from gel[4]. In this letter, the synthesis of NaA zeolite membrane from clear solution and its gas permeation properties are reported.

  9. ENHANCED PERVAPORATION SEPARATION EFFICIENCY VIA STAGED FRACTIONAL CONDENSATION (DEPHLEGMATION) OF PERMEATE VAPOR

    Science.gov (United States)

    In traditional pervaporation systems, the permeate vapor is completely condensed to obtain a liquid permeate stream. For example, in the recovery of ethanol from a 5-wt% aqueous stream (such as a biomass fermentation broth), the permeate from a silicone rubber pervaporation membr...

  10. Counter-diffusion and -permeation of deuterium and hydrogen through metals

    Energy Technology Data Exchange (ETDEWEB)

    Kizu, Kaname; Tanabe; Tetsuo [Nagoya Univ. (Japan)

    1998-03-01

    The first experiments for counter-diffusion and -permeation of deuterium and hydrogen through palladium were performed. Deuterium permeation rates against D{sub 2} pressure were measured under the condition where hydrogen permeated to opposite direction by supplying H{sub 2} gas at the permeated side of D{sub 2}. It was found that not a small amount of deuterium was clearly permeated even if the deuterium pressure was much smaller than the hydrogen pressure. Deuterium permeation rate was gradually reduced by increasing the counter H permeation. The deuterium permeation rate under the counter H permeation is well represented by a simple model in which the ratio of the deuterium permeation rates with and without the counter H permeation was proportional to the fractional concentration of deuterium in the bulk. As increasing the hydrogen counter flow, however, the deuterium permeation rate deviates from the model. This means that adsorption (absorption) of D{sub 2} from gas phase is inhibited and surface recombination of deuterium is blocked by hydrogen. (author)

  11. SYSTEMIC DELIVERY OF DICLOFENAC SODIUM AFTER TOPICAL APPLICATION OF GELS INCORPORATED WITH DRUG-LOADED SOLID LIPID NANOPARTICLES (SLN

    Directory of Open Access Journals (Sweden)

    NARESH GADDAM JITHAN AUKUNURU

    2013-09-01

    Full Text Available The aim of this study was to prepare and evaluate gels incorporating solid lipid nanoparticles (SLNs of diclofenac sodium for systemic delivery of the active after topical application. SLNs were prepared using hot homogenization followed by sonication technique and these were incorporated into freshly prepared carbopol gel. Three different gel formulations (DSL1, DSL2 and DSL3 were prepared and characterized for particle size, charge, viscosity, morphology, and drug-lipid compatibility. The gels were evaluated for in vitro drug release, ex vivo permeation studies and in vivo absorption. The gels enriched with SLN sustained the drug release for 24 h both in vitro and in vivo. The results suggest enhancement in systemic delivery of diclofenac sodium with gels incorporating SLNs.

  12. Determination of benzalkonium chloride concentration in tobramycin in-situ forming eye gel by high performance liquid chromatography%高效液相色谱法测定妥布霉素眼用即用型凝胶中苯扎氯铵的含量

    Institute of Scientific and Technical Information of China (English)

    刘修树; 汤国平

    2012-01-01

    目的:建立高效液相色谱(HPLC)法测定妥布霉素眼用即用型凝胶中苯扎氯铵的含量.方法:HPLC法色谱柱为Kromasil C18(250.0 mm×4.6 mm,5 μm),0.07 mol/L乙酸铵溶液(含1%三乙胺,冰乙酸调节pH值至5.0)-乙腈(70:30)为流动相;检测波长215 nm,柱温35 ℃,流速0.8 ml/min.结果:苯扎氯铵在16.22~81.10 μg/ml范围内呈良好的线性关系(r=0.999 8,n=5),回归方程为Y ∧=6 091.9X+10 114,平均回收率为99.85%,RSD为1.07%.结论:该法简便、灵敏、准确、重复性好,可用于妥布霉素眼用即用型凝胶中的苯扎氯铵的含量控制.%Objective: To establish a high performance liquid chromatography ( HPLC ) method for the determination of benzalkonium chloride in tobramycin in-situ forming eye gel. Methods:HPLC,the chromatographic column was Kromasil C18(250. 0 mm ×4. 6 mm, 5 (j,m) ,the mobile phase 0.07 mol/L ammonium acetate solution(including 1% triethylamine,adjusting with glacial acetic acid to pH 5. 0) -acetonitrile(70: 30). The detection wavelength 215 nm,the column temperature 35 ℃ ,the flow rate was 0. 8 ml/min. Results: The calibration curve was linear in the range of 16. 22 —81. 10 μg/ml for benzalkonium chloride ( r = 0. 999 8, n = 5 ) , the regression equation was Y =6 091. 9X + 10 114,the average recovery was 99. 85% ,RSD was 1. 07%. Conclusions: The method is convenient, sensitive and accurate with a good repeatability for the determination of benzalkonium chloride in tobramycin in-situ forming eye gel.

  13. GelTouch

    DEFF Research Database (Denmark)

    Miruchna, Viktor; Walter, Robert; Lindlbauer, David

    2015-01-01

    We present GelTouch, a gel-based layer that can selectively transition between soft and stiff to provide tactile multi-touch feedback. It is flexible, transparent when not activated, and contains no mechanical, electromagnetic, or hydraulic components, resulting in a compact form factor (a 2mm thin...... touchscreen layer for our prototype). The activated areas can be morphed freely and continuously, without being limited to fixed, predefined shapes. GelTouch consists of a poly(N-isopropylacrylamide) gel layer which alters its viscoelasticity when activated by applying heat (>32 C). We present three different...... a tablet with 6x4 tactile areas, enabling a tactile numpad, slider, and thumbstick. We show that the gel is up to 25 times stiffer when activated and that users detect tactile features reliably (94.8%)....

  14. Gas Chromatography

    Science.gov (United States)

    Qian, Michael C.

    Gas chromatography (GC) has many applications in the analysis of food products. GC has been used for the determination of fatty acids, triglycerides, cholesterol, gases, water, alcohols, pesticides, flavor compounds, and many more. While GC has been used for other food components such as sugars, oligosaccharides, amino acids, peptides, and vitamins, these substances are more suited to analysis by high performance liquid chromatography. GC is ideally suited to the analysis of volatile substances that are thermally stable. Substances such as pesticides and flavor compounds that meet these criteria can be isolated from a food and directly injected into the GC. For compounds that are thermally unstable, too low in volatility, or yield poor chromatographic separation due to polarity, a derivatization step must be done before GC analysis. The two parts of the experiment described here include the analysis of alcohols that requires no derivatization step, and the analysis of fatty acids which requires derivatization. The experiments specify the use of capillary columns, but the first experiment includes conditions for a packed column.

  15. Ion activated in situ gel of gellan gum containing salbutamol sulphate for nasal administration.

    Science.gov (United States)

    Salunke, Sneha R; Patil, Sanjay B

    2016-06-01

    Nasal delivery is the promising approach for rapid onset of action and avoids the first pass metabolism. The main aim of present study was to develop a novel mucoadhesive in situ gel of salbutamol sulphate using gellan gum and hydroxylpropyl methyl cellulose (HPMC) for nasal administration. The formulations were prepared so as to have gelation at physiological ion content after nasal administration. Developed formulations were evaluated for gelation, viscosity, drug content, in vitro mucoadhesion, in vitro drug release study, ex vivo permeation, and histopathology. Formulations showed pH in the range of nasal cavity and optimum viscosity for nasal administration. The mucoadhesive force depends upon concentration of HPMC and drug release was found to be 97.34% in 11h. The histopathology did not detect any damage during ex vivo permeation studies. Hence, in situ gel system of gellan gum may be a promising approach for nasal delivery of salbutamol sulphate for therapeutic improvement.

  16. A modified method using the SonoPrep ultrasonic skin permeation system for sampling human interstitial fluid is compatible with proteomic techniques.

    Science.gov (United States)

    Lecomte, Marie M J; Atkinson, Kelly R; Kay, Daniel P; Simons, Joanne L; Ingram, John R

    2013-02-01

    The use of biomarkers in skin is a novel diagnostic tool. Interstitial fluid (ISF) from skin provides a snapshot of proteins secreted at the time of sampling giving insights into the patient's health status. A minimally invasive technique for the transdermal collection of human ISF proteins. A low frequency ultrasonic skin permeation device (SonoPrep ultrasonic skin permeation system) was used to produce micropores in the stratum corneum through which ISF was extracted using a portable pulsed vacuum ISF collection device. On average, protein concentrations recovered ranged between 0.064 and 4.792 μg/μL (mean 1.258 μg/μL). Two-dimensional gel electrophoresis revealed that this sample type was amenable to this type of analysis. Gel images indicated that both highly abundant proteins and lower abundance proteins were isolated from the skin. Western blot analysis confirmed the presence of proteins commonly found in plasma and the epidermis. A minimally invasive method for the transdermal recovery of ISF proteins has been developed. We have demonstrated that ISF samples obtained using this approach can be analysed with proteomic techniques, such as two-dimensional gel electrophoresis and western blots, providing another tool for the identification of disease specific protein biomarkers. © 2012 John Wiley & Sons A/S.

  17. Mucus can change the permeation rank order of drug candidates

    DEFF Research Database (Denmark)

    Hagesaether, Ellen; Christiansen, Elisabeth; Due-Hansen, Maria Elisabeth

    2013-01-01

    The aim of the study was to test the effect of mucus on the permeability of newly developed structurally related free fatty acid receptor 1-agonists TUG-488, TUG-499 and TUG-424, which were compared to the more hydrophilic ketoprofen and the more hydrophobic testosterone as reference drugs...... out at a lower agitation. These results indicate that an experimental system without mucus can give a faulty rank order of permeation compared to mucous membranes when structurally related drug candidates are tested....... a minor influence. However, for one of the drug candidates, TUG-499, mucus had a clear impact, and this could not be explicitly related to the hydrophobicity of this compound. Secreted mucus thus changed the obtained rank order of permeation. This was especially apparent when the experiments were carried...

  18. A Novel Dense Mixed-Conducting Membrane for Oxygen Permeation

    Institute of Scientific and Technical Information of China (English)

    徐南平; 李世光; 金万勤; 时钧

    2000-01-01

    Perovskite type SrCo0.4Fe0.6O3-δ(SCF) membrane and a novel perovskite-related ZrO2 doped SrCo0.4Fe0.6O3-δ(SCFZ) membrane were successfully prepared by isostatic pressing. The sintered membranes were characterized by high-temperature X-ray diffraction (HTXRD) and energy dispersive spectroscopy (EDS). The oxygen permeabilities of membranes have been measured in the temperature range of 923 K to 1243 K. The oxygen permeation flux at 1123K and activation energy of SCFZ membrane with the thickness of 2mm are respectively 2.68×10-7 mol·cm-2·min-1 and 97.76 kJ·mol-1. The results of HTXRD in argon atmosphere and the oxygen permeation experiment indicate that the SCFZ membrane is stable at elevated temperature and low oxygen partial pressure.

  19. Wholly Endoscopic Permeatal Removal of a Petrous Apex Cholesteatoma

    Directory of Open Access Journals (Sweden)

    Todd Kanzara

    2014-01-01

    Full Text Available We report a case of a petrous apex cholesteatoma which was managed with a wholly endoscopic permeatal approach. A 63-year-old Caucasian male presented with a 10-year history of right-sided facial palsy and profound deafness. On examination in our clinic, the patient had a grade VI House-Brackmann paresis, otoscopic evidence of attic cholesteatoma behind an intact drum, and extensive scarring of the face from previous facial reanimation surgery. Imaging review was suggestive of petrous apex cholesteatoma. An initial decision to manage the patient conservatively was later reviewed on account of the patient suffering recurrent epileptic seizures. A wholly endoscopic permeatal approach was used with successful outcomes. In addition to the case report we also provide a brief description of the technique and a review of the relevant literature.

  20. Gas Permeation Characteristics across Nano-Porous Inorganic Membranes

    Directory of Open Access Journals (Sweden)

    M.R Othman, H. Mukhtar

    2012-10-01

    Full Text Available An overview of parameters affecting gas permeation in inorganic membranes is presented. These factors include membrane physical characteristics, operational parameters and gas molecular characteristics. The membrane physical characteristics include membrane materials and surface area, porosity, pore size and pore size distribution and membrane morphology. The operational parameters include feed flow rate and concentration, stage cut, temperature and pressure. The gas molecular characteristics include gas molecular weight, diameter, critical temperature, critical pressure, Lennard-Jones parameters and diffusion volumes. The current techniques of material characterization may require complementary method in describing microscopic heterogeneity of the porous ceramic media. The method to be incorporated in the future will be to apply a stochastic model and/or fractal dimension. Keywords: Inorganic membrane, surface adsorption, Knudsen diffusion, Micro-porous membrane, permeation, gas separation.

  1. A Novel Dense Mixed-Conducting Membranefor Oxygen Permeation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Perovskite typeSrCo0.4Fe0.6O3-δ(SCF) membrane and a novelperovskite-related ZrO2doped SrCo0.4Fe0.6O3-δ(SCFZ) membrane were successfully prepared by isostatic pressing. Thesintered membranes were characterized by high-temperature X-ray diffraction (HTXRD) and energydispersive spectroscopy (EDS). The oxygen permeabilities of membranes have been measured in thetemperature range of 923 K to 1243 K. The oxygen permeation flux at1123 K and activation energy ofSCFZ membrane with the thickness of 2 mm are respectively2.68×10-7 mol*cm-2*min-1 and97.76 kJ*mol-1. The results of HTXRD in argon atmosphere and the oxygen permeation experiment indicatethat the SCFZ membrane is stable at elevated temperature and low oxygen partial pressure.

  2. Study on low temperature plasma driven permeation of hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Takizawa, Masayuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    It is one of the most important problem in PWI of fusion devices from the point of view of tritium leakage that hydrogen diffuses in the wall of the device and permeates through it, which results in hydrogen being released to the coolant side. In this study, plasma driven permeation experiments were carried out with several kinds of metal membranes in the low temperature plasma where ionic and atomic hydrogen as well as electron existed in order to survey PDP mechanism from the many view points. In addition, incident flux rate from the plasma to the membrane surface was evaluated by calculation analysis. As a result the mechanism of low temperature PDP was found out and described as PDP models. The simulation of the membrane pump system was executed and the system performance was estimated with the models. (author). 135 refs.

  3. Permeation study of the potassium channel from streptomyces Lividans

    Institute of Scientific and Technical Information of China (English)

    XU Xiuzhi; ZHAN Yong; ZHAO Tongjun

    2004-01-01

    A three-state hopping model is established according to experiments to study permeation of an open-state potassium channel from Streptomyces Lividans (KcsA potassium channel). The master equations are used to characterize the dynamics of the system. In this model, ion conduction involves transitions of three states, with one three-ion state and two two-ion states in the selectivity filter respectively. In equilibrium, the well-known Nernst equation is deduced. It is further shown that the current follows Michaelis-Menten kinetics in steady state. According to the parameters provided by Nelson, the current-voltage relationship is proved to be ohmic and the current-concentration relationship is also obtained reasonably. Additional validation of the model in the characteristic time to reach the steady state for the potassium channel is also discussed. This model lays a possible physical basis for the permeation of ion channel, and opens an avenue for further research.

  4. MICROSTRUCTURAL EXAMINATION AND DEUTERIUM PERMEATION TESTING OF ADVANCED COATINGS FOR TRITIUM SERVICE

    Energy Technology Data Exchange (ETDEWEB)

    Korinko, P.

    2004-01-24

    A plant directed research and development task to develop and study new, improved, and low cost tritium permeation barriers was initiated in FY02. The project was intended to determine the permeation rate and permeation reduction factor of substrate materials and coated materials. The samples were characterized for microstructural and microchemical consistency. Permeation tests were also run. The sample geometry and sample sealing method selected for the coatings posed significant schedule and technical challenges. Diffusivity were consistent with published values but permeation data exhibited an unexpected sample to sample variation. The effort has lead to an improved sample design that will be used to support a Process Development task.

  5. Separation of Proteins by Electrophoretic Affinity Chromatography

    Institute of Scientific and Technical Information of China (English)

    邺韶骅; 刘铮; 丁富新; 袁乃驹

    1999-01-01

    A new kind of electrophoretic affinity chromatography (EAC) for bioseparation was proposed,Separation by EAC was conducted in a multicompartment electrolyzer in which the affinity gel media were packed in one of the central compartments.The presence of an electric field accelerated the migration of proteins inside the gel matrix during adsorption and descrption processes,This led to the increase of the overall speed of separation,The present study was focused on the effect of the strength of the electric field on adsorption and desorption processes.

  6. Isolation and Quantitative Assay of α-lactalbumin and β-lactoglobulin from Milk and Dairy Products by Gel Colume High Performance Liquid Chromatography%HPLC凝胶过滤色谱法测定牛奶及其乳制品中的α-乳白蛋白和β-乳球蛋白

    Institute of Scientific and Technical Information of China (English)

    王浩; 蒋利群; 石振华; 常彦忠; 段相林; 张志国

    2012-01-01

    建立了一种基于凝胶柱高效液相色谱的分析方法,可以一次性定量分离牛奶及乳制品中的α-乳白蛋白和β-乳球蛋白.组分分离度达到1.0,达到基线分离,回收率大于90%,相对标准偏差0.4%~3.1%.该方法不需对样品进行离心,简化了操作程序,减少了有效成分的流失,提高了蛋白质的回收率,具有准确、灵敏和迅速等特点,可用于牛奶及其乳制品的质量控制和定量检测.%To establish a method based on gel colume high performance liquid chromatography (HPLC). With this method,α-lactalbumin and β-lactoglobulin of milk and dairy products can be quantitatively analyzed. The chromatographic resolution of each component is near 1.0 and baseline separation is achieved . The recovery rate is more than 90 % and the value of relative standard deviation (RSD) is 0.4 %~3.1 % . The sample cen-trifuging process is not needed any more. Compared with previous methods,our method could simplify the experimental procedure,reduce the loss of active components and increase the recovery rate of protein. In conclusion, the method is sensitive,accurate and rapid and could be used for quality control and quantitative analysis of the milk or dairy productions.

  7. Selective permeation of hydrogen gas using cellulose nanofibril film.

    Science.gov (United States)

    Fukuzumi, Hayaka; Fujisawa, Shuji; Saito, Tsuguyuki; Isogai, Akira

    2013-05-13

    Biobased membranes that can selectively permeate hydrogen gas have been developed from aqueous dispersions of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (TOCN) prepared from wood cellulose: TOCN-coated plastic films and self-standing TOCN films. Compared with TOCNs with sodium, lithium, potassium, and cesium carboxylate groups, TOCN with free carboxyl groups (TOCN-COOH) had much high and selective H2 gas permeation performance. Because permeabilities of H2, N2, O2, and CO2 gases through the membranes primarily depended on their kinetic diameters, the gas permeation behavior of the various TOCNs can be explained in terms of a diffusion mechanism. Thus, the selective H2 gas permeability for TOCN-COOH was probably due to a larger average size in free volume holes present between nanofibrils in the layer and film than those of other TOCNs with metal carboxylate groups. The obtained results indicate that TOCN-COOH membranes are applicable as biobased H2 gas separation membranes in fuel cell electric power generation systems.

  8. Permeation Studies of Captopril Transdermal Films Through Human Cadaver Skin.

    Science.gov (United States)

    Nair, Rajesh Sreedharan; Nair, Sujith

    2015-01-01

    Mortality rate due to heart diseases increases dramatically with age. Captopril is an angiotensin converting enzyme inhibitor (ACE) used effectively for the management of hypertension. Due to short elimination half-life of captopril the oral dose is very high. Captopril is prone to oxidation and it has been reported that the oxidation rate of captopril in skin tissues is considerably low when compared to intestinal tissues. All these factors make captopril an ideal drug candidate for transdermal delivery. In this research work an effort was made to formulate transdermal films of captopril by utilizing polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) as film formers and polyethylene glycol 400 (PEG400) as a plasticizer. Dimethyl sulfoxide (DMSO) and dimethylformamide (DMF) were used as permeation enhancers. Physicochemical parameters of the films such as appearance, thickness, weight variation and drug content were evaluated. The invitro permeation studies were carried out through excised human cadaver skin using Franz diffusion cells. The in-vitro permeation studies demonstrated that the film (P4) having the polymer ratio (PVP:PVA = 80:20) with DMSO (10%) resulted a promising drug release of 79.58% at 24 hours with a flux of 70.0 µg/cm(2)/hr. No signs of erythema or oedema were observed on the rabbit skin as a result of skin irritation study by Draize test. Based on the stability report it was confirmed that the films were physically and chemically stable, hence the prepared films are very well suited for transdermal application.

  9. Silicon oxide permeation barrier coating of PET bottles and foils

    Science.gov (United States)

    Steves, Simon; Deilmann, Michael; Awakowicz, Peter

    2009-10-01

    Modern packaging materials such as polyethylene terephthalate (PET) have displaced established materials in many areas of food and beverage packaging. Plastic packing materials offer are various advantages concerning production and handling. PET bottles for instance are non-breakable and lightweight compared to glass and metal containers. However, PET offers poor barrier properties against gas permeation. Therefore, the shelf live of packaged food is reduced. Permeation of gases can be reduced by depositing transparent plasma polymerized silicon oxide (SiOx) barrier coatings. A microwave (2.45 GHz) driven low pressure plasma reactor is developed based on a modified Plasmaline antenna to treat PET foils or bottles. To increase the barrier properties of the coatings furthermore a RF substrate bias (13.56 MHz) is applied. The composition of the coatings is analyzed by means of Fourier transform infrared (FTIR) spectroscopy regarding carbon and hydrogen content. Influence of gas phase composition and substrate bias on chemical composition of the coatings is discussed. A strong relation between barrier properties and film composition is found: good oxygen barriers are observed as carbon content is reduced and films become quartz-like. Regarding oxygen permeation a barrier improvement factor (BIF) of 70 is achieved.

  10. GPC-HPLC法测定南极磷虾油中虾青素及校正因子计算%Determination of astaxanthin in antarctic krill oil by GPC-high performance liquid chromatography and calculation of correction factor

    Institute of Scientific and Technical Information of China (English)

    孙伟红; 冷凯良; 邢丽红; 朱敏; 翟毓秀; 苗均魁; 朱兰兰

    2013-01-01

    Taking health products, antarctic krill oil, as the object in the paper, an analytical method based on gel permeation chromatography-high performance liquid chromatography (GPC-HPLC ) has been developed for the determination of astaxanthin in antarctic krill oil. The sample was purified by gel permeation chromatography, saponified by sodium hydroxide-methanol solution, and separated by a C30 liquid chromatographic column. In this paper, we established the purification conditions of gel permeation chromatography, the collection time of astaxanthin and astaxanthin easter was 7. 48 ~ 12. 60 min. The conditions of saponification were researched by exploring the solvents, volume of sodium hydroxide-methanol solution and saponification time on saponification efficiency of astaxanthin in antarctic krill oil. The results show that methylene chloride: methanol as saponification solvent had the best effect than other solvents, the most suitable volume for 0. 2 mol/L sodium hydroxide-methanol solution was 1 mL, and the best saponification time was 12 h by comparing among 1~18h at 4℃. We also investigated the effect of pH on stability of astaxanthin in antarctic krill oil, the content of astaxanthin had less influence on neutral environment among 0 ~ 12 h, but the content in serious decline and isomerization on alkaline environment. The contents of isomers of astaxanthin in antarctic krill oil were calculated by calibration factor, the calibration factor of 13-cis-astaxanthin to trans-astaxanthin was 1.3, and 9-cis-astaxanthin to trans-astaxanthin was 1.1, so we got the quantitative method of astaxanthin in krill oil. The limits of quantification for astaxanthin in antarctic krill oil were 0. 5 mg/kg. There were good linear relationship between the chromatographic peak area and the concentration in the range of 0. 1 mg/L ~ 5 mg/L with correlation coefficient over 0.999. The average recoveries were between 96.0% and 98.5%, and the precision of the method were 3. 0% ~5. 6

  11. Penetratin-Mediated Transepithelial Insulin Permeation: Importance of Cationic Residues and pH for Complexation and Permeation

    DEFF Research Database (Denmark)

    Kristensen, Mie; Franzyk, Henrik; Klausen, M. T.

    2015-01-01

    Penetratin is a widely used carrier peptide showing promising potential for mucosal delivery of therapeutic proteins. In the present study, the importance of specific penetratin residues and pH was investigated with respect to complexation with insulin and subsequent transepithelial insulin...... permeation. Besides penetratin, three analogues were studied. The carrier peptide-insulin complexes were characterized in terms of size and morphology at pH 5, 6.5, and 7.4 by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. At pH 7.4 mainly very large complexes were...... present, while much smaller complexes dominated at pH 5. Presence of arginine residues in the carrier peptide proved to be a prerequisite for complexation with insulin as well as for enhanced transepithelial insulin permeation in vitro. Rearrangement of tryptophan residues resulted in significantly...

  12. Use of Curcuma longa in cosmetics: extraction of curcuminoid pigments, development of formulations, and in vitro skin permeation studies

    Directory of Open Access Journals (Sweden)

    Gisele Mara Silva Gonçalves

    2014-12-01

    Full Text Available Curcuma longais a ginger family aromatic herb (Zingiberaceae whose rhizomes contain curcuminoid pigments, including curcumin, a compound known for its anti-inflammatory effects. The objective of this study was to obtain curcuminoid-rich extracts, develop topical formulations thereof, and assess the stability and skin permeation of these formulations. Curcuma longa extracts were obtained and used to develop formulations. Skin permeation studies were conducted in a modified Franz diffusion cell system, and skin retention of curcuminoid pigments was quantified in pig ear membrane. Prepared urea-containing gel-cream formulations were unstable, whereas all others had satisfactory stability and pseudoplastic rheological behavior. The amount of curcuminoid pigments recovered from the receptor solution was negligible. The skin concentration of curcuminoid pigments retained was positive (>20 µg/g of skin, mostly in the stratum corneum, considering the low skin permeability of curcumin. We conclude that development of topical formulations containing curcumin or Curcuma longaextract is feasible, as long as adjuvants are added to improve preservation and durability. The formulations developed in this study enabled penetration of curcumin limited to the superficial layers of the skin and then possibly without a risk of systemic action, thus permitting local use as a topical anti-inflammatory.

  13. The development of Cutina lipogels and gel microemulsion for topical administration of fluconazole.

    Science.gov (United States)

    El Laithy, H M; El-Shaboury, K M F

    2002-01-01

    The influence of the vehicle on the release and permeation of fluconazole, a topical antifungal drug dissolved in Jojoba oil was evaluated. Series of Cutina lipogels (Cutina CPA [cetyl palmitate], CBS [mixture of glyceryl stearate, cetearyl alcohol, cetyl palmitate, and cocoglycerides], MD [glyceryl stearate], and GMS [glyceryl monostearate]) in different concentrations as well as gel microemulsion were prepared. In-vitro drug release in Sorensen's citrate buffer (pH 5.5) and permeation through the excised skin of hairless mice, using a modified Franz diffusion cell, were performed. The rheological behavior and the apparent viscosity values for different gel bases were measured before and after storage under freezing conditions at -4 degrees C and were taken as measures for stability of network structure. Candida albicans was used as a model fungus to evaluate the antifungal activity of the best formula achieved. The results of in vitro drug release and its percutaneous absorption showed that the highest values from gel microemulsion were assured. The rheological behavior of the prepared systems showed pseudoplastic (shear-thinning) flow indicating structural breakdown of the existing intermolecular interactions between polymeric chains. Moreover, the stability study revealed no significant difference between viscosity before and after storage for different formulae except for CPA Cutina lipogel (using analysis of variance [ANOVA] test at level of significance.05). The antifungal activity of fluconazole showed the widest zone of inhibition with gel microemulsion. The gel microemulsion is an excellent vehicle for fluconazole topical drug delivery.

  14. Statistical optimization of insulin-loaded Pluronic F-127 gels for buccal delivery of basal insulin.

    Science.gov (United States)

    Das, Nilanjana; Madan, Parshotam; Lin, Senshang

    2012-01-01

    The principle of statistical optimization was employed to fabricate insulin-loaded Pluronic F-127 (PF-127) gel formulations having the potential for buccal delivery of basal insulin. A two-level resolution III fractional factorial design was applied to simultaneously evaluate five independent formulation variables: PF-127 concentration, insulin concentration, sodium sulfate concentration, hydroxypropylmethyl cellulose (HPMC) concentration, and presence of sodium glycocholate. The amount of insulin released and permeated from gels as well as gelation time and mucoadhesion force of gels were measured and used as dependent response variables for formulation optimization. Optimization of a gel formulation was achieved by applying constrained optimization via regression analysis. In vitro permeation flux of insulin from the optimized formulation through procine buccal mucosa was 93.17 (±0.058, n = 3) μg/cm(2). Plasma insulin levels following buccal administration of the optimized formulation at 10, 25 and 50 IU/kg to healthy rats were found to be dose dependent and basal insulin levels were maintained at least for 8 h. Furthermore, continuous hypoglycemia for at least 8 h was observed with 89%, 51% and 25% of blood glucose reduction, respectively, for these three doses. The results of this investigation conclude the feasibility of development of optimized buccal insulin-loaded Pluronic F-127 gels for basal insulin delivery.

  15. Design and evaluation of microemulsion gel system of nadifloxacin

    Directory of Open Access Journals (Sweden)

    Ujwala Shinde

    2012-01-01

    Full Text Available Topical microemulsion systems for the antiacne agent, nadifloxacin were designed and developed to overcome the problems associated with the cutaneous delivery due to poor water solubility. The solubility of nadifloxacin in oils, surfactants and cosurfactants was evaluated to screen the components of the microemulsion. Various surfactants and cosurfactants were screened for their ability to emulsify the selected oily phase. The pseudoternary diagrams were constructed to identify the area of microemulsion existence. The influence of km (surfactant/cosurfactant ratio on the microemulsion existence region was determined and optimum systems were designed. The systems were assessed for drug-loading efficiency and characterised for optical birefringence, pH and refractive index, robustness to dilution, globule size, drug content and thermodynamic stability. Optimised microemulsion systems were formulated into gel form and evaluated for viscosity, spreadability, drug content, ex vivo skin permeation and antibacterial activity. The maximum solubility of nadifloxacin in the microemulsion system was found to be 0.25%. The nadifloxacin microemulsions had a small and uniform globule size (67.3-121.23 nm. The stability results revealed that all formulations showed a stable globule size and the polydispersity index under stress conditions. Incorporation of nadifloxacin in microemulsion gel increased the ex vivo skin permeation and antibacterial activity when compared to marketed cream.

  16. Design and evaluation of microemulsion gel system of nadifloxacin.

    Science.gov (United States)

    Shinde, Ujwala; Pokharkar, Sharda; Modani, Sheela

    2012-05-01

    Topical microemulsion systems for the antiacne agent, nadifloxacin were designed and developed to overcome the problems associated with the cutaneous delivery due to poor water solubility. The solubility of nadifloxacin in oils, surfactants and cosurfactants was evaluated to screen the components of the microemulsion. Various surfactants and cosurfactants were screened for their ability to emulsify the selected oily phase. The pseudoternary diagrams were constructed to identify the area of microemulsion existence. The influence of k(m) (surfactant/cosurfactant) ratio on the microemulsion existence region was determined and optimum systems were designed. The systems were assessed for drug-loading efficiency and characterised for optical birefringence, pH and refractive index, robustness to dilution, globule size, drug content and thermodynamic stability. Optimised microemulsion systems were formulated into gel form and evaluated for viscosity, spreadability, drug content, ex vivo skin permeation and antibacterial activity. The maximum solubility of nadifloxacin in the microemulsion system was found to be 0.25%. The nadifloxacin microemulsions had a small and uniform globule size (67.3-121.23 nm). The stability results revealed that all formulations showed a stable globule size and the polydispersity index under stress conditions. Incorporation of nadifloxacin in microemulsion gel increased the ex vivo skin permeation and antibacterial activity when compared to marketed cream.

  17. Development of transferosomal gel for trans-dermal delivery of insulin using iodine complex.

    Science.gov (United States)

    Marwah, Harneet; Garg, Tarun; Rath, Goutam; Goyal, Amit K

    2016-06-01

    The main object of this current research was to examine transferosomes as a transdermal delivery system for insulin, to overwhelm the difficulties related with its subcutaneous delivery. Transferosomal gel formulations were prepared by rotary evaporation sonication technique. The result revealed that insulin was successfully entrapped (78%) in optimized formulations (2.5 I.U. of the drug and 25% of sodium cholate) with cumulative percent drug release (83.11 ± 3.782). The glucose lowering study revealed that the transferosomal gel with chemical penetration enhancer showed better glucose lowering effect as compared to the control gel. Consequently, this study authenticated that the transferosomal gel can be used as a possible substitute to the conventional formulations of insulin with progressive permeation characteristics for transdermal application.

  18. Development of Curcumin loaded chitosan polymer based nanoemulsion gel: In vitro, ex vivo evaluation and in vivo wound healing studies.

    Science.gov (United States)

    Thomas, Lydia; Zakir, Foziyah; Mirza, Mohd Aamir; Anwer, Md Khalid; Ahmad, Farhan Jalees; Iqbal, Zeenat

    2017-03-16

    In the present study, various nanoemulsions were prepared using Labrafac PG+Triacetin as oil, Tween 80 as a surfactant and polyethylene glycol (PEG 400) as a co-surfactant. The developed nanoemulsions (NE1-NE5) were evaluated for physicochemical characterizations and ex-vivo for skin permeation and deposition studies. The highest skin deposition was observed for NE2 with 46.07% deposition amongst all developed nanoemulsions (NE1-NE5). Optimized nanoemulsion (NE2) had vesicle size of 84.032±0.023nm, viscosity 78.23±22.2 cps, refractive index 1.404. Nanoemulsion gel were developed by incorporation of optimized nanoemulsion (NE2) into 1-3% chitosan and characterized by physical evaluation and rheological studies. Chitosan gel (2%) was found to be suitable for gelation of nanoemulsion based on its consistency, feel and ease of spreadability. The flux of nanoemulsion gel was found 68.88μg/cm(2)/h as compared to NE2 (76.05μg/cm(2)/h) is significantly lower suggesting limited skin permeation of curcumin form gel. However, the retained amount of curcumin on skin by gel formulation (980.75±88μg) is significantly higher than NE2 (771.25±67μg). Enhanced skin permeation of NE2 (46.07%) was observed when compared to nanoemulsion gel (31.25%) and plain gel (11.47%). The outcome of this study evidently points out the potential of curcumin entrapped nanoemulsion gel in wound healing.

  19. Mechanically induced gel formation

    NARCIS (Netherlands)

    van Herpt, Jochem T.; Stuart, Marc C. A.; Browne, Wesley R.; Feringa, Ben L.

    2013-01-01

    Mechanical triggering of gelation of an organic solution by a carbazole-based bisurea organogelator is described. Both the duration of the mechanical stimulation and the gelator concentration control the gelation process and the characteristics of the gel obtained.

  20. Conformance Improvement Using Gels

    Energy Technology Data Exchange (ETDEWEB)

    Seright, Randall S.; Schrader, Richard; II Hagstrom, John; Wang, Ying; Al-Dahfeeri, Abdullah; Gary, Raven; Marin; Amaury; Lindquist, Brent

    2002-09-26

    This research project had two objectives. The first objective was to identify gel compositions and conditions that substantially reduce flow through fractures that allow direct channeling between wells, while leaving secondary fractures open so that high fluid injection and production rates can be maintained. The second objective was to optimize treatments in fractured production wells, where the gel must reduce permeability to water much more than that to oil.

  1. Crystallization from Gels

    Science.gov (United States)

    Narayana Kalkura, S.; Natarajan, Subramanian

    Among the various crystallization techniques, crystallization in gels has found wide applications in the fields of biomineralization and macromolecular crystallization in addition to crystallizing materials having nonlinear optical, ferroelectric, ferromagnetic, and other properties. Furthermore, by using this method it is possible to grow single crystals with very high perfection that are difficult to grow by other techniques. The gel method of crystallization provides an ideal technique to study crystal deposition diseases, which could lead to better understanding of their etiology. This chapter focuses on crystallization in gels of compounds that are responsible for crystal deposition diseases. The introduction is followed by a description of the various gels used, the mechanism of gelling, and the fascinating phenomenon of Liesegang ring formation, along with various gel growth techniques. The importance and scope of study on crystal deposition diseases and the need for crystal growth experiments using gel media are stressed. The various crystal deposition diseases, viz. (1) urolithiasis, (2) gout or arthritis, (3) cholelithiasis and atherosclerosis, and (4) pancreatitis and details regarding the constituents of the crystal deposits responsible for the pathological mineralization are discussed. Brief accounts of the theories of the formation of urinary stones and gallstones and the role of trace elements in urinary stone formation are also given. The crystallization in gels of (1) the urinary stone constituents, viz. calcium oxalate, calcium phosphates, uric acid, cystine, etc., (2) the constituents of the gallstones, viz. cholesterol, calcium carbonate, etc., (3) the major constituent of the pancreatic calculi, viz., calcium carbonate, and (4) cholic acid, a steroidal hormone are presented. The effect of various organic and inorganic ions, trace elements, and extracts from cereals, herbs, and fruits on the crystallization of major urinary stone and gallstone

  2. Preparation of chitosan gel

    Directory of Open Access Journals (Sweden)

    Lagerge S.

    2012-06-01

    Full Text Available Aerogel conditioning of the chitosan makes it possible to prepare porous solids of significant specific surface. The increase in the chitosan concentration or the degree of acetylation decreases the specific surface of the synthesized chitosan gel. Whereas drying with supercritical CO2 more effectively makes it possible to preserve the volume of the spheres of gel and to have a more significant specific surface in comparison with evaporative drying.

  3. PERMEATION OF POLYELECTROLYTES AND OTHER SOLUTES INTO THE PORE SPACES OF WATER-SWOLLEN CELLULOSE: A REVIEW

    Directory of Open Access Journals (Sweden)

    Ning Wu

    2009-08-01

    Full Text Available The rate and extent of transport of macromolecules and other solutes into cellulosic materials and fibers have important applications in such fields as papermaking, textiles, medicine, and chromatography. This review considers how diffusion and flow affect permeation into wood, paper, and other lignocellulosic materials. Because pore sizes within such materials can range from nanometers to millimeters, a broad perspective will be used, also considering some publications related to other porous materials. Factors that limit the rate or extent of polymer or other solute transport into pores can involve thermodynamics (affecting the driving motivation for permeation, kinetics (if there is insufficient time for the system to come to equilibrium, and physical barriers. Molecular flow is also affected by the attributes of the solute, such as molecular mass and charge, as well as those of the substrate, such as the pore size, interconnectedness, restricted areas, and surface characteristics. Published articles have helped to clarify which of these factors may have a controlling influence on molecular transport in different situations.

  4. 丁香酚键合硅胶液相色谱固定相的制备和色谱性能%Preparation and chromatographic performance of a eugenol-bonded silica gel stationary phase for high performance liquid chromatography

    Institute of Scientific and Technical Information of China (English)

    许丽丽; 衷明华; 陈小静

    2015-01-01

    采用固液相表面连续反应法,先将偶联剂γ-[(2,3)-环氧丙氧]丙基三甲氧基硅烷(KH-560)键合到球形硅胶表面,然后再将植物有效成分丁香酚与硅胶上的 KH-560活性基团反应,合成了丁香酚键合硅胶液相色谱固定相( EGSP)。采用元素分析、热重分析和红外光谱对该固定相的结构进行了表征。以萘作为溶质探针,乙腈-水(35:65,v/v)为流动相,流速为0.8 mL/min,测得 EGSP柱的柱效。以一系列的中性、碱性和酸性化合物为溶质探针, C18柱和苯基柱作参比,对该固定相的色谱性能及保留机理进行了研究。结果表明,硅胶表面成功键合上了丁香酚配体,键合量为0.28 mmol/g,EGSP柱理论塔板数约为24707 N/m。该固定相不仅具有良好的反相色谱性能,同时由于配体结构中含有芳环、烯基和甲氧基,还能与溶质发生π-π电荷转移、偶极-偶极和氢键作用。与传统的反相 C18柱和苯基柱相比,EGSP在极性芳香族化合物的快速、简便分离中占优势。%A eugenol-bonded silica gel stationary phase( EGSP ) for high performance liquid chromatography( HPLC)has been synthesized by the solid-liquid successive reaction method. The preparation process included two steps:firstly,γ-glycidoxypropyltrimethoxy-silane( KH-560)was covalently attached to the surface of spherical silica gel. Then the bonded silica gel continued to react with eugenol ligand,which was a plant active component,and obtained EGSP. The structure of EGSP was characterized by elemental analysis,thermogravimetric anal-ysis and Fourier transform infrared spectroscopy. Using naphthalene as a probe,the column efficiency was tested under the mobile phase of acetonitrile-water(35:65,v/v)at a flow rate of 0. 8 mL/min. The chromatographic properties and the retention mechanism of EGSP were evaluated by using neutral,basic and acidic analytes as solute probes. Meanwhile

  5. Purification of the envelope glycoproteins of western equine encephalitis virus by glass wool column chromatography.

    OpenAIRE

    Yamamoto, K.; Simizu, B

    1980-01-01

    Glass wool column chromatography was used for separation of the two glycoproteins of western equine encephalitis virus. Cross-contamination of each protein separated was confirmed to be negligible by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

  6. Determination of Mesotrione in Food by Liquid Chromatography Tandem Mass Spectrometry%高效液相色谱-串联质谱法测定食品中硝磺草酮

    Institute of Scientific and Technical Information of China (English)

    张代辉; 滕国生; 李正强; 李爱军; 康明芹; 牟峻

    2012-01-01

    A method for the determination of mesotrione in foods by liquid chromatography tandem mass spectrometry (LC-MS/MS) has been developed. The mesotrione in food samples was extracted with acetonitrile-water (3:1, V/V). The extract was cleaned up by gel permeation chromatography (GPC) and solid phase extraction cartridges (SPE), and then diluted to a certain volume with methanol. The mobile phase in LC was an acetonitrile-0.1% formic acid aqueous solution. Electrospray ionization (ESI) source in negative ionization mode as well as multiple reaction monitoring(MRM) mode was used in the detection. The final solution was determined and confirmed by LC-MS/MS, and quantified by the external standard method. While the fortified levels of mesotrione were in the range of 0. 01-0. 10 mg/kg, the recoveries were 85. 5% -98. 1% , and the RSDs were in the range of 3. 0%-6. 1%. The limit of determination was 0. 01 mg/kg. The method is highly sensitive and well repeatable for the determination of mesotrione in foods.

  7. Thin layer chromatography.

    Science.gov (United States)

    Santiago, Marina; Strobel, Scott

    2013-01-01

    In many experiments, it is important to be able to separate a mixture into its chemical components in order to isolate one compound or to assess the purity of the mixture. Thin layer chromatography (TLC) is one of the easiest and most versatile methods of doing this because of its low cost, simplicity, quick development time, high sensitivity, and good reproducibility. TLC is used by many industries and fields of research, including pharmaceutical production, clinical analysis, industrial chemistry, environmental toxicology, food chemistry, water, inorganic, and pesticide analysis, dye purity, cosmetics, plant materials, and herbal analysis. In its simplest form, glass plates are coated with a uniform layer of silica gel (SiO2). The dissolved sample is placed on the plate, and the plate is inserted into a screw-top jar containing the developing solvent and a piece of filter paper. When the solvent has risen to near the top of the plate, the plate is removed, dried, and visualized using UV light. Variations on this protocol are used for different purposes, including pretreating the sample, changing the sorbent, plate material, the solvent system, the development techniques, and method of detection and visualization or by coupling TLC to other techniques. © 2013 Elsevier Inc. All rights reserved.

  8. CONFORMANCE IMPROVEMENT USING GELS

    Energy Technology Data Exchange (ETDEWEB)

    Randall S. Seright

    2004-09-30

    This report describes work performed during the third and final year of the project, ''Conformance Improvement Using Gels.'' Corefloods revealed throughput dependencies of permeability reduction by polymers and gels that were much more prolonged during oil flow than water flow. This behavior was explained using simple mobility ratio arguments. A model was developed that quantitatively fits the results and predicts ''clean up'' times for oil productivity when production wells are returned to service after application of a polymer or gel treatment. X-ray computed microtomography studies of gels in strongly water-wet Berea sandstone and strongly oil-wet porous polyethylene suggested that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than gel-ripping or gel-displacement mechanisms. In contrast, analysis of data from the University of Kansas suggests that the gel-ripping or displacement mechanisms are more important in more permeable, strongly water-wet sandpacks. These findings help to explain why aqueous gels can reduce permeability to water more than to oil under different conditions. Since cement is the most commonly used material for water shutoff, we considered when gels are preferred over cements. Our analysis and experimental results indicated that cement cannot be expected to completely fill (top to bottom) a vertical fracture of any width, except near the wellbore. For vertical fractures with apertures less than 4 mm, the cement slurry will simply not penetrate very far into the fracture. For vertical fractures with apertures greater than 4 mm, the slurry may penetrate a substantial distance into the bottom part of the fracture. However, except near the wellbore, the upper part of the fracture will remain open due to gravity segregation. We compared various approaches to plugging fractures using gels, including (1) varying polymer content, (2) varying placement (extrusion) rate

  9. A Gas Chromatographic Analysis of Light Hydrocarbons on a Column Packed with Modified Silica Gel

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A one-meter long column packed with silica gel is used to separate light hydrocarbons. The silica gel has been modified with several kinds of gas chromatography stationary phases. Among these, PEG 2000 shows fairly good effect when using 80-100 meshes silica gel for the separation of mixture of methane, ethane, ethylene, acetylene, propane, propylene and n-, i-butane. The different behavior of silica gel between batch to batch is also found. When silica gel is coated with a small amount of Al2O3 prepared with sol-gel method, better resolution has been observed on a 2-meter column compared with the non-modified silica gel.

  10. INVESTIGATION OF THE INTERACTIONS BETWEEN WATER AND MODIFIED SILICA GEL BY IGC AND TPD

    Institute of Scientific and Technical Information of China (English)

    LI Xin; LI Zhong; XIA Qibin; XI Hongxia

    2006-01-01

    In this work, the thermodynamic parameters for the adsorption of water vapor on untreated silica gel and silica gel treated with hygroscopic salts and silane coupling agent were determined by Inverse Gas Chromatography (IGC) in the infinite dilution region. The desorption activation energies of the water vapor on virgin and modified silica gels were estimated by using the Temperature Programmed Desorption (TPD) technique. The interactions between the water and the virgin and modified silica gels were discussed. Results showed that the thermodynamic parameters and desorption activation energy of water vapour on the silica gels increase with decreasing pore size and increasing the surface hydrophilic properties. The desorption activation energy of virgin and modified silica gels was found to increase with increasing the thermodynamic parameters. The larger the adsorption parameters and the desorption activation energy were, the interactions between water and virgin and modified silica gels were.

  11. Chemical fingerprinting of petroleum biomarkers in biota samples using retention-time locking chromatography and multivariate analysis.

    Science.gov (United States)

    Bartolomé, Luis; Deusto, Miren; Etxebarria, Nestor; Navarro, Patricia; Usobiaga, Aresatz; Zuloaga, Olatz

    2007-07-20

    This work was conducted to study a new separation and evaluation approach for the chemical fingerprinting of petroleum biomarkers in biota samples. The final aim of this work was to study the correlation between the observed effects in the shore habitats (mussels and limpets) and one pollution source: the oil spill of the Prestige tanker. The method combined a clean-up step of the biota extracts (mussels and limpets), the retention-time locking of the gas chromatographic set up, and the multivariate data analysis of the chromatograms. For clean-up, solid-phase extraction and gel permeation chromatography were compared, and 5g Florisil cartridges assured the lack of interfering compounds in the last extracts. In order to assure reproducible retention times and to avoid the realignment of the chromatograms, the retention-time locking feature of our gas chromatography-mass spectrometry (GC-MS) set up was used. Finally, in the case of multivariate analysis, the GC-MS chromatograms were treated, essentially by derivatization and by normalization, and all the chromatograms at m/z 191 (terpenes), m/z 217-218 (steranes and diasteranes) and m/z 231 (triaromatic steranes) were treated by means of principal component analysis. Furthermore, slightly different four oil samples from the Prestige oil spill were analyzed following the Nordtest method, and the GC-MS chromatograms were considered as the reference chemical fingerprints of the sources. In this sense, the correlation between the studied samples, including sediments and biota samples, and the source candidate was completed by means of a supervised pattern recognition method. As a result, the method proposed in this work was useful to identify the Prestige oil spill as the source of many of the analyzed samples.

  12. Tritium permeation characterization of Al{sub 2}O{sub 3}/FeAl coatings as tritium permeation barriers on 321 type stainless steel containers

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Feilong; Xiang, Xin; Lu, Guangda; Zhang, Guikai, E-mail: zhangguikai@caep.cn; Tang, Tao; Shi, Yan; Wang, Xiaolin

    2016-09-15

    Accurate tritium transport properties of prospective tritium permeation barriers (TPBs) are essential to tritium systems in fusion reactors. By passing a temperature and rate-controlled sweeping gas over specimen surfaces to carry the permeated tritium to an ion chamber, the gas-driven permeation of tritium has been performed on 321 type stainless steel containers with Al{sub 2}O{sub 3}/FeAl barriers, to determine the T-permeation resistant performance and mechanism of the barrier. The tritium permeability of the Al{sub 2}O{sub 3}/FeAl coated container was reduced by 3 orders of magnitude at 500–700 °C by contrast with that of the bare one, which meets the requirement of the tritium permeation reduction factor (PRF) of TPBs for tritium operating components in the CN-HCCB TBM. The Al{sub 2}O{sub 3}/FeAl barrier resists the tritium permeation by the diffusion in the bulk substrate at a limited number of defect sites with an effective area and thickness, suggesting that the TPB quality is a very important factor for efficient T-permeation resistance. - Highlights: • T-permeation has been measured on bare and coated type 321 SS containers. • Al{sub 2}O{sub 3}/FeAl coating give a reduction of T-permeability of 3 orders of magnitude. • Mechanism of Al{sub 2}O{sub 3}/FeAl barrier resisting T-permeation has obtained. • Quality of TPB is a very important factor for efficient T-permeating reduction.

  13. Ethosomes Loaded with Cryptotanshinone for Acne Treatment through Topical Gel Formulation.

    Science.gov (United States)

    Yu, Zhenwei; Lv, Hongyan; Han, Gang; Ma, Ke

    2016-01-01

    The aim of this study was to develop ethosomes loaded with cryptotanshinone (CPT) and formulate them as a topical gel for the treatment of acne. Ethosomes were prepared and evaluated for vesicle size, CPT loading and encapsulation efficiency. Optimized ethosomes were formulated as Carbomer 974 gels and compared with conventional hydroethanolic gels for transdermal permeation and skin deposition in vitro. The anti-acne activity and skin irritation of the gel was investigated in rabbits. Optimized ethosomes had an average vesicle size of 69.1 ± 1.9 nm with CPT loading and encapsulation efficiency of 0.445 ± 0.007 mg/mL and 40.31 ± 0.67%, respectively. The transdermal flux and skin deposition of the optimized ethosomal gel were 2.5- and 2.1-times those of conventional gels. The ethosomal gel revealed better anti-acne effect with only slight skin irritation. This study demonstrates that ethosomal formulation is an effective dermal delivery system for CPT, and that CPT ethosomal gels are promising future acne treatments.

  14. Ethosomes Loaded with Cryptotanshinone for Acne Treatment through Topical Gel Formulation.

    Directory of Open Access Journals (Sweden)

    Zhenwei Yu

    Full Text Available The aim of this study was to develop ethosomes loaded with cryptotanshinone (CPT and formulate them as a topical gel for the treatment of acne. Ethosomes were prepared and evaluated for vesicle size, CPT loading and encapsulation efficiency. Optimized ethosomes were formulated as Carbomer 974 gels and compared with conventional hydroethanolic gels for transdermal permeation and skin deposition in vitro. The anti-acne activity and skin irritation of the gel was investigated in rabbits. Optimized ethosomes had an average vesicle size of 69.1 ± 1.9 nm with CPT loading and encapsulation efficiency of 0.445 ± 0.007 mg/mL and 40.31 ± 0.67%, respectively. The transdermal flux and skin deposition of the optimized ethosomal gel were 2.5- and 2.1-times those of conventional gels. The ethosomal gel revealed better anti-acne effect with only slight skin irritation. This study demonstrates that ethosomal formulation is an effective dermal delivery system for CPT, and that CPT ethosomal gels are promising future acne treatments.

  15. Formulation and Evaluation of Aceclofenac Loaded Cubosomal Topical Gel

    Directory of Open Access Journals (Sweden)

    K. Bhargavi

    2015-11-01

    Full Text Available The aim of present work was to formulate and evaluate sustained release formulation of Aceclofenac a Non -steroidal anti-inflammatory drug (NSAID, as cubosomal topical gel to reduce gastro intestinal effects and to improve the bioavailability of the drug. Different formulations of Aceclofenac cubosomes were prepared by Top down approach using GMO as lipid phase vehicle, Poloxamer 407 as stabilizer and distilled water as aqueous phase by varying the concentrations of GMO and Poloxamer 407. Resultant formulations were characterized for particle size, zeta potential, surface morphology, encapsulation efficiency and in-vitro drug release. Optimized formulation (F10 showed drug release of 83.25% in 8hours. Aceclofenac cubosomal gel was prepared by using optimized cubosomal formulation (F10, Carbopol 940,Carbopol 934, HPMC K4M and HPMC 15M.Gels were evaluated for pH, viscosity, drug content and in-vitro drug diffusion studies. Among all the preparations, formulation G2 was found to show entrapment efficiency of 96.85 and in vitro drug release of 78.5%. Ex-vivo permeation of optimized gel formulation (D2 was evaluated across rat epidermis.

  16. Instrumentation: Ion Chromatography.

    Science.gov (United States)

    Fritz, James S.

    1987-01-01

    Discusses the importance of ion chromatography in separating and measuring anions. The principles of ion exchange are presented, along with some applications of ion chromatography in industry. Ion chromatography systems are described, as well as ion pair and ion exclusion chromatography, column packings, detectors, and programming. (TW)

  17. Ionic Selectivity and Permeation Properties of Human PIEZO1 Channels.

    Science.gov (United States)

    Gnanasambandam, Radhakrishnan; Bae, Chilman; Gottlieb, Philip A; Sachs, Frederick

    2015-01-01

    Members of the eukaryotic PIEZO family (the human orthologs are noted hPIEZO1 and hPIEZO2) form cation-selective mechanically-gated channels. We characterized the selectivity of human PIEZO1 (hPIEZO1) for alkali ions: K+, Na+, Cs+ and Li+; organic cations: TMA and TEA, and divalents: Ba2+, Ca2+, Mg2+ and Mn2+. All monovalent ions permeated the channel. At a membrane potential of -100 mV, Cs+, Na+ and K+ had chord conductances in the range of 35-55 pS with the exception of Li+, which had a significantly lower conductance of ~ 23 pS. The divalents decreased the single-channel permeability of K+, presumably because the divalents permeated slowly and occupied the open channel for a significant fraction of the time. In cell-attached mode, 90 mM extracellular divalents had a conductance for inward currents carried by the divalents of: 25 pS for Ba2+ and 15 pS for Ca2+ at -80 mV and 10 pS for Mg2+ at -50 mV. The organic cations, TMA and TEA, permeated slowly and attenuated K+ currents much like the divalents. As expected, the channel K+ conductance increased with K+ concentration saturating at ~ 45 pS and the KD of K+ for the channel was 32 mM. Pure divalent ion currents were of lower amplitude than those with alkali ions and the channel opening rate was lower in the presence of divalents than in the presence of monovalents. Exposing cells to the actin disrupting reagent cytochalasin D increased the frequency of openings in cell-attached patches probably by reducing mechanoprotection.

  18. Ionic Selectivity and Permeation Properties of Human PIEZO1 Channels.

    Directory of Open Access Journals (Sweden)

    Radhakrishnan Gnanasambandam

    Full Text Available Members of the eukaryotic PIEZO family (the human orthologs are noted hPIEZO1 and hPIEZO2 form cation-selective mechanically-gated channels. We characterized the selectivity of human PIEZO1 (hPIEZO1 for alkali ions: K+, Na+, Cs+ and Li+; organic cations: TMA and TEA, and divalents: Ba2+, Ca2+, Mg2+ and Mn2+. All monovalent ions permeated the channel. At a membrane potential of -100 mV, Cs+, Na+ and K+ had chord conductances in the range of 35-55 pS with the exception of Li+, which had a significantly lower conductance of ~ 23 pS. The divalents decreased the single-channel permeability of K+, presumably because the divalents permeated slowly and occupied the open channel for a significant fraction of the time. In cell-attached mode, 90 mM extracellular divalents had a conductance for inward currents carried by the divalents of: 25 pS for Ba2+ and 15 pS for Ca2+ at -80 mV and 10 pS for Mg2+ at -50 mV. The organic cations, TMA and TEA, permeated slowly and attenuated K+ currents much like the divalents. As expected, the channel K+ conductance increased with K+ concentration saturating at ~ 45 pS and the KD of K+ for the channel was 32 mM. Pure divalent ion currents were of lower amplitude than those with alkali ions and the channel opening rate was lower in the presence of divalents than in the presence of monovalents. Exposing cells to the actin disrupting reagent cytochalasin D increased the frequency of openings in cell-attached patches probably by reducing mechanoprotection.

  19. CHARACTERIZATION OF MIXED GAS PERMEATION THROUGH HOLLOW FIBERS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    IntroductionWith the development of membrane science andtechnology' membrane-based gas separation processeshave been emeopd as an efficient effective and areliable alternative in some applications of gastreatmentS, such as the purification of ~l gas andII-31.the enricboeat of either OZ orNZ from air.Criteria to evaluate membrane modules involvein many factors. It is doubtless that the permutionand selectivity for interest6d gases are the most keyParameters in asseSsing the potential of a membrmePermeator fo...

  20. Effects of Substrate Permeation on Kinetics of Phenol Biodegradation

    Institute of Scientific and Technical Information of China (English)

    冀秀玲; 张金利; 李Wei; 韩振亭; 王一平

    2003-01-01

    Based on the theory of substrate permeation through the cytoplasmic membrane,and considering the effect of initial concentration of substrate,a new kinetic model of phenol degradation process was proposed,Comparing with the widely used Haldane model,which is greatly dependent on the initial phenol concentration,our model can be used to simulate the phenol degradation process in a wide range of initial phenol concentration by using only one set of model parameters ,Therefore,this new kinetic model has much more potential applications to industrial design and operation.

  1. Permeation mechanism of a two-state potassium channel

    Institute of Scientific and Technical Information of China (English)

    WANG Xiangqun; ZHAO Tongjun; SONG Yang; ZHAN Yong

    2007-01-01

    A two-state hopping model was proposed to study the permeation of ion channel.The Nemst equation in equilibrium and the Michaelis-Menten relation in steady state were derived from the two-state kinetic model.The currentvoltage relationship obtained in the symmetrical solutions case was linear when the applied potential was less than 100 mV,which met Ohm's law.The conductance-concentration relationship exhibited the saturation property.Moreover,the characteristic time reaching the steady state of the KcsA channel was also discussed.

  2. Modular synthesis of cell-permeating 2-ketoglutarate esters.

    Science.gov (United States)

    Zengeya, Thomas T; Kulkarni, Rhushikesh A; Meier, Jordan L

    2015-05-15

    Cell-permeating esters of 2-ketoglutarate (2-KG) have been synthesized through a convergent sequence from two modules in two and three steps, respectively. This route provides access to a full series of mono- and disubstituted 2-KG esters, enabling us to define the effect of regioisomeric masking on metabolite release and antihypoxic activity in cell-based assays. In addition to providing insight into the biological activity of cell permeable 2-KG esters, the straightforward and modular nature of this synthetic route may prove useful for the development of next-generation 2-KG analogues for diagnostic and therapeutic applications.

  3. Design of Autonomous Gel Actuators

    Directory of Open Access Journals (Sweden)

    Shuji Hashimoto

    2011-01-01

    Full Text Available In this paper, we introduce autonomous gel actuators driven by chemical energy. The polymer gels prepared here have cyclic chemical reaction networks. With a cyclic reaction, the polymer gels generate periodical motion. The periodic motion of the gel is produced by the chemical energy of the oscillatory Belouzov-Zhabotinsky (BZ reaction. We have succeeded in making synthetic polymer gel move autonomously like a living organism. This experimental fact represents the great possibility of the chemical robot.

  4. Thiomers in noninvasive polypeptide delivery: in vitro and in vivo characterization of a polycarbophil-cysteine/glutathione gel formulation for human growth hormone.

    Science.gov (United States)

    Leitner, Verena M; Guggi, Davide; Bernkop-Schnürch, Andreas

    2004-07-01

    This study was aimed at investigating the potential of a new polycarbophil-cysteine (PCP-Cys)/glutathione (GSH) gel formulation to enhance the permeation of the model drug human growth hormone (hGH) across nasal mucosa in vitro and in vivo. The aqueous nasal gel contained PCP-Cys, GSH, and hGH in a final concentration of 0.3%, 0.5%, and 0.6% (m/v), respectively. In vitro permeation studies were performed in Ussing chambers on freshly excised bovine nasal mucosa using fluorescence-labeled dextran (molecular mass: 4.3 kDa; FD-4) and hGH (FITC-hGH). The release profile of FITC-hGH from the gel formulation and an unmodified PCP control formulation was determined. Furthermore, in vivo studies in rats were performed comparing the PCP-Cys/GSH/hGH gel with PCP/hGH control gel and physiological saline. The permeation of FD-4 and FITC-hGH across the nasal mucosa was improved two-fold and three-fold, respectively, in the presence of PCP-Cys/GSH. The PCP-Cys/GSH/hGH gel and the PCP/hGH control gel showed the same biphasic and matrix-controlled drug release. The nasal administration of the PCP-Cys/GSH/hGH gel formulation to rats resulted in a significantly increased and prolonged hGH plasma concentration-time profile versus unmodified PCP gel and physiological saline. According to these results, PCP-Cys gels might represent a promising new strategy for systemic nasal polypeptide delivery.

  5. Zero order delivery of itraconazole via polymeric micelles incorporated in situ ocular gel for the management of fungal keratitis.

    Science.gov (United States)

    Jaiswal, Munmun; Kumar, Manish; Pathak, Kamla

    2015-06-01

    The aim of this article is to investigate the role of amphiphilic block copolymer-based polymeric micelles of itraconazole for the management of fungal keratitis to overcome the limitations of the conventional dosage form. The polymeric micelles were made using pluronics above critical micelle concentration. Itraconazole-loaded polymeric micelles prepared by rotary evaporation method were characterized and the optimized micellar formulation (M5) was selected on the basis of least micelle size (79.99 nm), maximum entrapment efficiency (91.32%±1.73%) and in vitro permeation (90.28%±0.31%) in 8h, that best fitted zero-order kinetics. M5 was developed as pH sensitive in situ gel and characterized for various parameters. The optimized in situ gel (F5) proved to be superior in its ex vivo transcorneal permeation when compared with Itral(®) eye drop and pure drug suspension, exhibiting 41.45%±0.87% permeation with zero-order kinetics (r(2)=0.994) across goat cornea. Transmission electron microscopy revealed spherical polymeric micelles entrapped in the gel matrix. A spectrum of tests revealed hydration capability, non-irritancy, and histologically safe gel formulation that had appropriate handling characteristics. Conclusively, a controlled release pH-sensitive ocular formulation capable of carrying drug to the anterior segment of the eye via topical delivery was successfully developed for the treatment of fungal keratitis.

  6. Study on Co-Permeation of Solid Rare Earth, Boron and Vanadium

    Institute of Scientific and Technical Information of China (English)

    陶小克; 董桂霞; 彭日升; 孙永昌

    2001-01-01

    The effect of rare earth compound of CeCl3 on the kinetic process, composition, microstructure and mechanical properties of co-permeating of solid powder boron-vanadium (B-V) was investigated. The results indicate that the addition of CeCl3 to permeating agent not only has obviously catalytic effect on permeating rate, which increases by more than 40%, but also greatly improves the hardness and abrasion resistant of the permeating layer owing to the formation of new phase of CeFe2 after Ce permeates into the layer of the part as an alloying ingredient. It is believed that rare earth elements accelerate the permeating rate of B and V by increasing the potentials of B and V of the agent, activating the surface of the workpiece, and decreasing the activation energy of diffusion of the B and V atoms.

  7. Design and tritium permeation analysis of China HCCB TBM port cell

    Energy Technology Data Exchange (ETDEWEB)

    Jiangfeng, S.; Guoqiang, H.; Zhiyong, H.; Chang' an, C.; Deli, L. [China Academy of Engineering Physics, Mianyang, Sichuan (China)

    2015-03-15

    China is planning to develop a helium-cooled ceramic breeder (HCCB) test blanket module (TBM) on ITER to test key blanket technologies. In this paper, the design and tritium permeation analysis of China HCCB TBM port cell are introduced. A theoretical model has been developed to estimate tritium permeation rates and leak rates from the components and pipes which China has scheduled to house in the port cell. It is shown that on normal working conditions, the permeation and leak rate of the systems in the port cell will be no higher than 1.58 Ci/d without the use of tritium permeation barriers, and 0.10 Ci/d with the use of tritium permeation barriers. It also appears that tritium permeation barriers are necessary for high temperature components such as the reduction bed and the heater.

  8. Formulation of cellulose film containing permeation enhancers for prolonged delivery of propranolol hydrocloride.

    Science.gov (United States)

    Bigucci, Federica; Abruzzo, Angela; Cerchiara, Teresa; Gallucci, Maria Caterina; Luppi, Barbara

    2015-06-01

    The aim of this study was to evaluate the capacity of cellulose films enriched with oleic acid and polysorbate 80 to enhance the transdermal permeation of propranolol hydrochloride. Polymeric films were prepared by casting and drying aqueous solutions of hydroxypropylmethylcellulose or carboxymethylcellulose and characterized in chemical-physical properties, such as drug content, thickness, morphology and water uptake capacity. In vitro transport experiments were performed in order to evaluate the permeation enhancing ability of oleic acid and polysorbate 80. All carboxymethylcellulose films showed lower cumulative amounts of drug permeated than hydroxypropylmethylcellulose. Moreover, films containing both oleic acid and polysorbate 80 provided a greater permeation in comparison to film without permeation enhancers or only with one of these. The results obtained confirm that propranolol hydrochloride permeation can be easily modulated by varying the cellulose and enhancer type used for film preparation.

  9. Tritium permeation characterization of Al2O3/FeAl coatings as tritium permeation barriers on 321 type stainless steel containers

    Science.gov (United States)

    Yang, Feilong; Xiang, Xin; Lu, Guangda; Zhang, Guikai; Tang, Tao; Shi, Yan; Wang, Xiaolin

    2016-09-01

    Accurate tritium transport properties of prospective tritium permeation barriers (TPBs) are essential to tritium systems in fusion reactors. By passing a temperature and rate-controlled sweeping gas over specimen surfaces to carry the permeated tritium to an ion chamber, the gas-driven permeation of tritium has been performed on 321 type stainless steel containers with Al2O3/FeAl barriers, to determine the T-permeation resistant performance and mechanism of the barrier. The tritium permeability of the Al2O3/FeAl coated container was reduced by 3 orders of magnitude at 500-700 °C by contrast with that of the bare one, which meets the requirement of the tritium permeation reduction factor (PRF) of TPBs for tritium operating components in the CN-HCCB TBM. The Al2O3/FeAl barrier resists the tritium permeation by the diffusion in the bulk substrate at a limited number of defect sites with an effective area and thickness, suggesting that the TPB quality is a very important factor for efficient T-permeation resistance.

  10. Permeation of Military Fuels Through Nitrile-Coated Fabrics Used for Collapsible Fuel Storage Containers

    Science.gov (United States)

    2014-03-01

    Permeation of Military Fuels Through Nitrile -Coated Fabrics Used for Collapsible Fuel Storage Containers by James M. Sloan ARL-TR-6881...March 2014 Permeation of Military Fuels Through Nitrile -Coated Fabrics Used for Collapsible Fuel Storage Containers James M. Sloan...Final 3. DATES COVERED (From - To) October 2012–October 2013 4. TITLE AND SUBTITLE Permeation of Military Fuels Through Nitrile -Coated Fabrics Used

  11. Dynamic dissolution-/permeation-testing of nano- and microparticle formulations of fenofibrate

    DEFF Research Database (Denmark)

    Sironi, Daniel; Rosenberg, Jörg; Bauer-Brandl, Annette

    2017-01-01

    The aim of the current study was to evaluate a dynamic dissolution-/permeation-system for prediction of gastrointestinal and absorption-behavior of two commercial fenofibrate formulations. To this end, both dissolution and barrier-flux were followed simultaneously for fenofibrate powder...... for the first time. Furthermore, the dissolution-/permeation-system introduced here allowed for in-depth mechanistic insights: Biomimetic media, despite enhancing the apparent solubility of fenofibrate via micellar solubilization, did not increase permeation rate, irrespective whether the micro...

  12. Articles of protective clothing adapted for deflecting chemical permeation and methods therefor

    Science.gov (United States)

    Vo-Dinh, Tuan

    1996-01-01

    Apparatus and methods for detecting the permeation of hazardous or toxic chemicals through protective clothing are disclosed. The hazardous or toxic chemicals of interest do not possess the spectral characteristic of luminescence. The apparatus and methods utilize a spectrochemical modification technique to detect the luminescence quenching of an indicator compound which upon permeation of the chemical through the protective clothing, the indicator is exposed to the chemical, thus indicating chemical permeation.

  13. Gel electrolytes and electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Fleischmann, Sven; Bunte, Christine; Mikhaylik, Yuriy V.; Viner, Veronika G.

    2017-09-05

    Gel electrolytes, especially gel electrolytes for electrochemical cells, are generally described. In some embodiments, the gel electrolyte layers comprise components a) to c). Component a) may be at least one layer of at least one polymer comprising polymerized units of: a1) at least one monomer containing an ethylenically unsaturated unit and an amido group and a2) at least one crosslinker. Component b) may be at least one conducting salt and component c) may be at least one solvent. Electrodes may comprise the components a), d) and e), wherein component a) may be at least one layer of at least one polymer as described herein. Component d) may be at least one electroactive layer and component e) may be at least one ceramic layer. Furthermore, electrochemical cells comprising component a) which may be at least one layer of at least one polymer as described herein, are also provided.

  14. Active Polymer Gel Actuators

    Directory of Open Access Journals (Sweden)

    Shuji Hashimoto

    2010-01-01

    Full Text Available Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of heart muscles. Here we show a novel biomimetic gel actuator that can walk spontaneously with a wormlike motion without switching of external stimuli. The self-oscillating motion is produced by dissipating chemical energy of oscillating reaction. Although the gel is completely composed of synthetic polymer, it shows autonomous motion as if it were alive.

  15. Methods of Analysis - Determination of Pyrethroid Insecticides in Water and Sediment Using Gas Chromatography/Mass Spectrometry

    Science.gov (United States)

    Hladik, Michelle; Smalling, Kelly L.; Kuivila, Kathryn

    2009-01-01

    A method for the determination of 14 pyrethroid insecticides in environmental water and sediment samples is described. The method was developed by the U.S. Geological Survey in response to increasing concern over the effects of pyrethroids on aquatic organisms. The pyrethroids included in this method are ones that are applied to many agricultural and urban areas. Filtered water samples are extracted for pyrethroids using solid-phase extraction (SPE) with no additional cleanup steps. Sediment and soil samples are extracted using a microwave-assisted extraction system, and the pyrethroids of interest are separated from co-extracted matrix interferences by passing the extracts through stacked graphitized carbon and alumina SPE cartridges, along with the use of high-performance liquid chromatography and gel-permeation chromatography (HPLC/GPC). Quantification of the pyrethroids from the extracted water and sediment samples is done using gas chromatography with mass spectrometry (GC/MS) or gas chromatography with tandem mass spectrometry (GC/MS/MS). Recoveries in test water samples fortified at 10 ng/L ranged from 83 to 107 percent, and recoveries in test sediment samples fortified at 10 ug/kg ranged from 82 to 101 percent; relative standard deviations ranged from 5 to 9 percent in the water samples and 3 to 9 percent in the sediment samples. Method detection limits (MDLs), calculated using U.S. Environmental Protection Agency procedures (40 CFR 136, Appendix B), in water ranged from 2.0 to 6.0 ng/L using GC/MS and 0.5 to 1.0 ng/L using GC/MS/MS. For sediment, the MDLs ranged from 1.0 to 2.6 ug/kg dry weight using GC/MS and 0.2 to 0.5 ug/kg dry weight using GC/MS/MS. The matrix-spike recoveries for each compound, when averaged for 12 environmental water samples, ranged from 84 to 96 percent, and when averaged for 27 environmental sediment samples, ranged from 88 to 100 percent.

  16. Gas Permeation through Polystyrene-Poly(ethylene oxide) Block Copolymers

    Science.gov (United States)

    Hallinan, Daniel, Jr.; Minelli, Matteo; Giacinti-Baschetti, Marco; Balsara, Nitash

    2013-03-01

    Lithium air batteries are a potential technology for affordable energy storage. They consist of a lithium metal anode and a porous air cathode separated by a solid polymer electrolyte membrane, such as PEO/LiTFSI (PEO = poly(ethylene oxide), LiTFSI = lithium bis-trifluoromethane sulfonimide). For extended operation of such a battery, the polymer electrolyte must conduct lithium ions while blocking electrons and gases present in air. In order to maintain a pressure difference the membrane must be mechanically robust, which can be achieved by incorporating the PEO into a block copolymer with a glassy block such as PS (PS = polystyrene). To protect the lithium electrode, the membrane must have low permeability to gases in air such as CO2, N2, and O2. We have therefore studied the permeation of pure gases through a PS-PEO block copolymer. A high molecular weight, symmetric block copolymer with a lamellar morphology was used to cast free-standing membranes. Gas permeability was measured through these membranes with a standard, pressure-based technique. A model was developed to account for transport through the polymer membrane consisting of semi-crystalline PEO lamellae and amorphous PS lamellae. PEO crystallinity was extracted from the permeation model and compares well with values from differential scanning calorimetry measurements.

  17. Permeation of Calcium through Purified Connexin 26 Hemichannels*

    Science.gov (United States)

    Fiori, Mariana C.; Figueroa, Vania; Zoghbi, Maria E.; Saéz, Juan C.; Reuss, Luis; Altenberg, Guillermo A.

    2012-01-01

    Gap junction channels communicate the cytoplasms of two cells and are formed by head to head association of two hemichannels, one from each of the cells. Gap junction channels and hemichannels are permeable to ions and hydrophilic molecules of up to Mr 1,000, including second messengers and metabolites. Intercellular Ca2+ signaling can occur by movement of a number of second messengers, including Ca2+, through gap junction channels, or by a paracrine pathway that involves activation of purinergic receptors in neighboring cells following ATP release through hemichannels. Understanding Ca2+ permeation through Cx26 hemichannels is important to assess the role of gap junction channels and hemichannels in health and disease. In this context, it is possible that increased Ca2+ influx through hemichannels under ischemic conditions contributes to cell damage. Previous studies suggest Ca2+ permeation through hemichannels, based on indirect arguments. Here, we demonstrate for the first time hemichannel permeability to Ca2+ by measuring Ca2+ transport through purified Cx26 hemichannels reconstituted in liposomes. We trapped the low affinity Ca2+-sensitive fluorescent probe Fluo-5N into the liposomes and followed the increases in intraliposomal [Ca2+] in response to an imposed [Ca2+] gradient. We show that Ca2+ does move through Cx26 hemichannels and that the permeability of the hemichannels to Ca2+ is high, similar to that for Na+. We suggest that hemichannels can be a significant pathway for Ca2+ influx into cells under conditions such as ischemia. PMID:23048025

  18. Asymmetric osmotic water permeation through a vesicle membrane

    Science.gov (United States)

    Su, Jiaye; Zhao, Yunzhen; Fang, Chang; Shi, Yue

    2017-05-01

    Understanding the water permeation through a cell membrane is of primary importance for biological activities and a key step to capture its shape transformation in salt solution. In this work, we reveal the dynamical behaviors of osmotically driven transport of water molecules across a vesicle membrane by molecular dynamics simulations. Of particular interest is that the water transport in and out of vesicles is highly distinguishable given the osmotic force are the same, suggesting an asymmetric osmotic transportation. This asymmetric phenomenon exists in a broad range of parameter space such as the salt concentration, temperature, and vesicle size and can be ascribed to the similar asymmetric potential energy of lipid-ion, lipid-water, lipid-solution, lipid-lipid, and the lipid-lipid energy fluctuation. Specifically, the water flux has a linear increase with the salt concentration, similar to the prediction by Nernst-Planck equation or Fick's first law. Furthermore, due to the Arrhenius relation between the membrane permeability and temperature, the water flux also exhibits excellent Arrhenius dependence on the temperature. Meanwhile, the water flux shows a linear increase with the vesicle surface area since the flux amount across a unit membrane area should be a constant. Finally, we also present the anonymous diffusion behaviors for the vesicle itself, where transitions from normal diffusion at short times to subdiffusion at long times are identified. Our results provide significant new physical insights for the osmotic water permeation through a vesicle membrane and are helpful for future experimental studies.

  19. Omniphobic low moisture permeation transparent polyacrylate/silica nanocomposite.

    Science.gov (United States)

    Hsu, Sheng-Hao; Chang, Yuan-Ling; Tu, Yu-Chieh; Tsai, Chieh-Ming; Su, Wei-Fang

    2013-04-24

    We report the development of low moisture permeation and transparent dense polyacrylate/silica nanocomposite material that can exhibit both superhydrophobic and oleophobic (omniphobic) properties. The material was prepared by a three-step process. The first step involved the preparation of UV polymerizable solventless hybrid resin and the fabrication of nanocomposite. The hybrid resin consisted of a mixture of acrylate monomer, initiator, and acrylate-modified different size silica nanoparticles. The second step was to roughen the surface of the nanocomposite with unique nanotexture by oxygen plasma. In the third step, we applied a low surface tension fluoro monolayer on the treated surface. The nanocomposite exhibits desired superhydrophobicity and oleophobicity with a water contact angle of 158.2° and n-1-octadecene contact angle of 128.5°, respectively; low moisture permeation of 1.44 g·mm/m(2)·day; and good transparency (greater than 82% at 450-800 nm for ~60 μm film). The material has potential applications in optoelectronic encapsulation, self-cleaning coating, etc.

  20. QSAR model for blood-brain barrier permeation.

    Science.gov (United States)

    Toropov, Andrey A; Toropova, Alla P; Beeg, Marten; Gobbi, Marco; Salmona, Mario

    2017-05-02

    Predicting blood-brain barrier permeability for novel compounds is an important goal for neurotherapeutics-focused drug discovery. It is impossible to determine experimentally the blood-brain barrier partitioning of all possible candidates. Consequently, alternative evaluation methods based on computational models are desirable or even necessary. The CORAL software (http://www.insilico.eu/coral) has been checked up as a tool to build up quantitative structure - activity relationships for blood-brain barrier permeation. The Monte Carlo technique gives possibility to build up predictive model of an endpoint by means of selection of so-called correlation weights of various molecular features. Descriptors calculated with these weights are basis for correlations "structure-endpoint". The approach gives good models for three random splits into the training and validation sets. The best model characterized by the following statistics for the external validation set: the number of compounds is 41, determination coefficient is equal to 0.896, root mean squared error is equal to 0.175. The suggested approach can be applied as a tool for prediction of blood-brain barrier permeation. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Hydrogen permeation through protected steel in open seawater and marine mud

    Energy Technology Data Exchange (ETDEWEB)

    Benson, J. [BNFL, Springfields (United Kingdom); Edyvean, R.G.J. [Univ. of Sheffield (United Kingdom). Dept. of Chemical and Process Engineering

    1998-09-01

    Hydrogen permeation through cathodically protected and unprotected BS 4360, grade 50D with various surface finishes and coatings was measured over a 12-month period in open seawater and for a subsequent 6 months in marine mud. Cathodically protected, uncoated steel showed the greatest hydrogen permeation, and coated steels showed the least. Nonantifouling coatings showed a rapid deterioration when buried in marine mud, with a significant increase in hydrogen permeation. Overall, the antifouling coating gave the lowest hydrogen permeation in both environments. Results were discussed in relation to possible hydrogen-induced cracking in the use of moveable jack-up offshore oil and gas platforms.

  2. A Modern Apparatus for Performing Flash Chromatography: An Experiment for the Organic Laboratory

    Science.gov (United States)

    Naumiec, Gregory R.; Del Padre, Angela N.; Hooper, Matthew M.; Germaine, Alison St.; DeBoef, Brenton

    2013-01-01

    A modern apparatus for performing flash chromatography using commercially available, prepacked silica cartridges has been developed. The key advantage of this system, when compared to traditional flash chromatography, is its use of commercially available silica cartridges, which obviates the need for students to handle silica gel. The apparatus…

  3. Determination of Vinyl Chloride at ug/l. Level in Water by Gas Chromatography

    Science.gov (United States)

    Bellar, Thomas A.; And Others

    1976-01-01

    A quantitative method for the determination of vinyl chloride in water is presented. Vinyl chloride is transfered to the gas phase by bubbling inert gas through the water. After concentration on silica gel or Carbosieve-B, determination is by gas chromatography. Confirmation of vinyl chloride is by gas chromatography-mass spectrometry. (Author/BT)

  4. Mucoadhesive Gels Designed for the Controlled Release of Chlorhexidine in the Oral Cavity

    Directory of Open Access Journals (Sweden)

    Adamo Fini

    2011-09-01

    Full Text Available This study describes the in vitro/ex vivo buccal release of chlorhexidine (CHX from nine mucoadhesive aqueous gels, as well as their physicochemical and mucoadhesive properties: CHX was present at a constant 1% w/v concentration in the chemical form of digluconate salt. The mucoadhesive/gel forming materials were carboxymethyl- (CMC, hydroxypropylmethyl- (HPMC and hydroxypropyl- (HPC cellulose, alone (3% w/w or in binary mixtures (5% w/w; gels were tested for their mucoadhesion using the mucin method at 1, 2 and 3% w/w concentrations. CHX release from different formulations was assessed using a USP method and newly developed apparatus, combining release/permeation process in which porcine mucosa was placed in a Franz cell. The combination of HPMC or HPC with CMC showed slower drug release when compared to each of the individual polymers. All the systems proved suitable for CHX buccal delivery, being able to guarantee both prolonged release and reduced transmucosal permeation. Gels were compared for the release of previously studied tablets that contained Carbopol and HPMC, alone or in mixture. An accurate selection and combination of the materials allow the design of different pharmaceutical forms suitable for different purposes, by simply modifying the formulation compositions.

  5. Optimization and formulation design of carbopol loaded Piroxicam gel using novel penetration enhancers.

    Science.gov (United States)

    Chaudhary, Hema; Rohilla, Ajay; Rathee, Permender; Kumar, Vikash

    2013-04-01

    The aim of the study was to develop and optimize Piroxicam transdermal gel formulation using three-factor, three-level Box-Behnken design by deriving a second-order polynomial equation to construct contour plots for prediction of responses as three selected independent variables with ratio of carbopol 974 (X1), ratio of propylene glycol (PG) (X2) and ratio of ethanol (X3). The dependent variables studied were the skin permeation rate of piroxicam (Y1), viscosity of the gel (Y2) and pH of the gel (Y3). Response surface plots were drawn, statistical validity of the polynomials was established to find the compositions of optimized formulation which was evaluated using the vertical Franz-type diffusion cell. The permeation rate of piroxicam increased proportionally with ethanol concentration but decreased with polymer concentration. The design demonstrated the role of the derived polynomial equation and contour plots in predicting the values of dependent variables for the preparation and optimization of gel formulation.

  6. gonarthrosis; therapy; Karmolis gel.

    Directory of Open Access Journals (Sweden)

    B. V. Zavodovsky

    2014-01-01

    Full Text Available Objective: to evaluate the efficacy, tolerance, and safety of Carmolis topical gel in patients with gonarthrosis. Subjects and methods. The investigation enrolled 60 patients with knee osteoarthrosis (OA who were divided into two groups: 1 40 patients received Carmolis topical gel in addition to nonsteroidal anti-inflammatory drugs (NSAIDs; 2 20 patients took NSAIDS only (a control group. The treatment duration was 2 weeks. In both groups, therapeutic effectiveness was evaluated from changes in the WOMAC index, pain intensity at rest and during movement by the visual analog scale (VAS. The disease activity was also assessed by a physician and a patient (a Likert scale, local swelling and hyperthermia of the affected joint, the efficiency of treatment, and daily needs for NSAIDs were deter- mined. Results. The performed treatment in both patent groups showed positive clinical changes. Combination therapy involving Carmolis gel displayed greater reductions in WOMAC pain and resting and movement pain than in the con- trol group (as assessed by VAS. On completion of the investigation, considerable improvement was, in the physicians' opinion, noted in 38 (95% patients using Carmolis, which coincided with self-evaluations of the patients. During Carmolis application, the starting dose of NSAIDs could be reduced in 18 (45% patients. Adverse reactions occurred infrequently and required no therapy discontinuation. Conclusion. Carmolis topical gel is effective in relieving clinical symptoms in patients with gonarthrosis, well tolerated, and safe, which can recommend its use in the combination treatment of knee OA.

  7. Droplet spreading and permeating on the hybrid-wettability porous substrates: a lattice Boltzmann method study

    Directory of Open Access Journals (Sweden)

    Ge Wen-Kai

    2016-01-01

    Full Text Available The spreading and permeation of droplets on porous substrates is a fundamental process in a variety of applications, such as coating, dyeing, and printing. The spreading and permeating usually occur synchronously but play different roles in the practical applications. The mechanisms of the competition between spreading and permeation is significant but still unclear. A lattice Boltzmann method is used to study the spreading and permeation of droplets on hybrid-wettability porous substrates, with different wettability on the surface and the inside pores. The competition between the spreading and the permeation processes is studied in this work from the effects of the substrate and the fluid properties, including the substrate wettability, the porous parameters, as well as the fluid surface tension and viscosity. The results show that increasing the surfacewettability and the porosity contact angle both inhibit the spreading and the permeation processes. When the inside porosity contact angle is larger than 90° (hydrophobic, the permeation process does not occur. The droplets suspend on substrates with Cassie state. The droplets are more easily to permeate into substrates with a small inside porosity contact angle (hydrophilic, as well as large pore sizes. Otherwise, the droplets are more easily to spread on substrate surfaces with small surface contact angle (hydrophilic and smaller pore sizes. The competition between droplet spreading and permeation is also related to the fluid properties. The permeation process is enhanced by increasing of surface tension, leading to a smaller droplet lifetime. The goals of this study are to provide methods to manipulate the spreading and permeation separately, which are of practical interest in many industrial applications.

  8. [Use of column and thin layer chromatography for detection of vanillyl mandelic acid in urine].

    Science.gov (United States)

    Riabichenko, V V; Barchukov, V G; Chernyĭ, A V; Salenko, Iu A

    2002-03-01

    The excretion of vanillylmandelic acid was measured by column chromatography of urinary samples on aluminum oxide with subsequent thin-layer chromatography on silica gel. Use of aluminum oxide allowed application of greater urine samples (up to 0.1% of 24-h diuresis) onto chromatographic plates and essentially improved the quality of separation of vanillylmandelic acid from other phenylcarbonic acids by thin-layer chromatography, as well as the specificity and reproducibility of measurements.

  9. A comparative in vitro study of the digestibility of heat- and high pressure-induced gels prepared from industrial milk whey proteins

    Science.gov (United States)

    He, Jin-Song; Mu, Tai-Hua; Wang, Juan

    2013-06-01

    We undertook this study to compare the digestibility of heat- and high pressure-induced gels produced from whey protein isolate (WPI). To simulate in vivo gastrointestinal digestion of WPI gels, a pepsin-trypsin digestion system was used. The in vitro protein digestibility of WPI gels induced by high pressure (400 MPa and 30 min; P-gel) and those induced by heat (80°C and 30 min; H-gel) was compared using a protein concentration of 0.14 g mL-1. The in vitro protein digestibility of P-gels was significantly greater than that of H-gels (p<0.05). The size-exclusion chromatography profiles of the hydrolysates showed that the P-gel generated more and smaller peptides than natural WPI and H-gels. Furthermore, Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed some soluble disulfide-mediated aggregation in the P-gel, while there was more insoluble aggregation in the H-gel than the P-gel. The P-gel was more sensitive to proteinase than the H-gel, which was related to the content of S-S bonds, and this in turn could be attributed to the differences in the gelation mechanism between the H-gel and P-gel.

  10. Sol-Gel Synthesis of Non-Silica Monolithic Materials

    Directory of Open Access Journals (Sweden)

    Bartłomiej Gaweł

    2010-04-01

    Full Text Available Monolithic materials have become very popular because of various applications, especially within chromatography and catalysis. Large surface areas and multimodal porosities are great advantages for these applications. New sol-gel preparation methods utilizing phase separation or nanocasting have opened the possibility for preparing materials of other oxides than silica. In this review, we present different synthesis methods for inorganic, non-silica monolithic materials. Some examples of application of the materials are also included.

  11. An Oxygen-Permeation Treatment for Hardening Titanium Alloys

    Institute of Scientific and Technical Information of China (English)

    MA Hong-yan; WANG Mao-cai; WEI Zheng; XIN Gong-chun

    2004-01-01

    In this paper, the characterization of oxygen permeation (OP) in titanium alloy TC11 at high temperature and the influence of oxygen solution layer on performances of substrate were characterized with the help of apparatus, such as TGA,SEM/EDAX, XRD, EPMA, Micro-hardness Tester, Two-body Abrasion Tester, Amsler Wear Test Machine, Potentiostat/Galvanostat Model 273 system. The results showed that there was a little shift in X-ray diffraction peaks of α and β phase during the OPT process as a result of oxygen solution. The OP treatment can significantly increase the surface hardness of titanium alloys and, accordingly, the abrasive wear resistance was improved. Titanium alloys with oxygen solution layer exhibited improved corrosion resistance both in 3.5 % NaCl and in 5 % HCl solution. Oxidation resistance of TC11 with oxygen solution layer at high temperature was also enhanced. The solution and hardening mechanisms were discussed based on the experimental results.

  12. Distinct permeation profiles of the connexin 30 and 43 hemichannels

    DEFF Research Database (Denmark)

    Hansen, Daniel Bloch; Braunstein, Thomas Hartig; Nielsen, Morten Schak;

    2014-01-01

    , lactate, and glucose, did not permeate the pore whereas ATP did. In contrast, permeability of glutamate, glucose and ATP was observed in oocytes expressing Cx30. Exposure to divalent cation free solutions induced a robust membrane conductance in Cx30-expressing oocytes but none in Cx43-expressing oocytes......Connexin 43 (Cx43) hemichannels may form open channels in the plasma membrane when exposed to specific stimuli, e.g. reduced extracellular concentration of divalent cations, and allow passage of fluorescent molecules and presumably a range of smaller physiologically relevant molecules. However......, the permeability profile of Cx43 hemichannels remains unresolved. Exposure of Cx43-expressing Xenopus laevis oocytes to divalent cation free solution induced a gadolinium-sensitive uptake of the fluorescent dye ethidium. In spite thereof, a range of biological molecules smaller than ethidium, such as glutamate...

  13. Structural and functional significance of water permeation through cotransporters

    DEFF Research Database (Denmark)

    Zeuthen, Thomas; Gorraitz, Edurne; Her, Ka

    2016-01-01

    and mutated residues lining the sugar transport pathway to cysteine. The mutants were expressed in Xenopus oocytes, and the unitary water and urea permeabilities were determined before and after modifying the cysteine side chain with reversible methanethiosulfonate reagents. The results demonstrate that water......Membrane transporters, in addition to their major role as specific carriers for ions and small molecules, can also behave as water channels. However, neither the location of the water pathway in the protein nor their functional importance is known. Here, we map the pathway for water and urea...... through the intestinal sodium/glucose cotransporter SGLT1. Molecular dynamics simulations using the atomic structure of the bacterial transporter vSGLT suggest that water permeates the same path as Na+ and sugar. On a structural model of SGLT1, based on the homology structure of vSGLT, we identified...

  14. An automated dynamic water vapor permeation test method

    Science.gov (United States)

    Gibson, Phillip; Kendrick, Cyrus; Rivin, Donald; Charmchii, Majid; Sicuranza, Linda

    1995-05-01

    This report describes an automated apparatus developed to measure the transport of water vapor through materials under a variety of conditions. The apparatus is more convenient to use than the traditional test methods for textiles and clothing materials, and allows one to use a wider variety of test conditions to investigate the concentration-dependent and nonlinear transport behavior of many of the semipermeable membrane laminates which are now available. The dynamic moisture permeation cell (DMPC) has been automated to permit multiple setpoint testing under computer control, and to facilitate investigation of transient phenomena. Results generated with the DMPC are in agreement with and of comparable accuracy to those from the ISO 11092 (sweating guarded hot plate) method of measuring water vapor permeability.

  15. Passive drug permeation through membranes and cellular distribution.

    Science.gov (United States)

    Scott, D O; Ghosh, A; Di, L; Maurer, T S

    2017-03-01

    Although often overlooked, passive mechanisms can lead to significant accumulation or restriction of drugs to intracellular sites of drug action. These mechanisms include lipoidal diffusion of ionized species and pH partitioning according to the electrochemical potential and to pH gradients that exist across subcellular compartments, respectively. These mechanisms are increasingly being exploited in the design of safe and effective drugs for the treatment of a wide variety of diseases. In this work, the authors review these efforts and the associated passive mechanisms of cellular drug permeation. A generic mathematical model of the cell is provided and used to illustrate concepts relevant to steady-state intracellular distribution. Finally, the authors review methods for estimating determinant parameters and measuring the net effect at the level of unbound intracellular drug concentrations.

  16. Ion Permeation and Mechanotransduction Mechanisms of Mechanosensitive Piezo Channels.

    Science.gov (United States)

    Zhao, Qiancheng; Wu, Kun; Geng, Jie; Chi, Shaopeng; Wang, Yanfeng; Zhi, Peng; Zhang, Mingmin; Xiao, Bailong

    2016-03-16

    Piezo proteins have been proposed as the long-sought-after mechanosensitive cation channels in mammals that play critical roles in various mechanotransduction processes. However, the molecular bases that underlie their ion permeation and mechanotransduction have remained functionally undefined. Here we report our finding of the miniature pore-forming module of Piezo1 that resembles the pore architecture of other trimeric channels and encodes the essential pore properties. We further identified specific residues within the pore module that determine unitary conductance, pore blockage and ion selectivity for divalent and monovalent cations and anions. The non-pore-containing region of Piezo1 confers mechanosensitivity to mechano-insensitive trimeric acid-sensing ion channels, demonstrating that Piezo1 channels possess intrinsic mechanotransduction modules separate from their pore modules. In conclusion, this is the first report on the bona fide pore module and mechanotransduction components of Piezo channels, which define their ion-conducting properties and gating by mechanical stimuli, respectively.

  17. Basic Principles of Chromatography

    Science.gov (United States)

    Ismail, Baraem; Nielsen, S. Suzanne

    Chromatography has a great impact on all areas of analysis and, therefore, on the progress of science in general. Chromatography differs from other methods of separation in that a wide variety of materials, equipment, and techniques can be used. [Readers are referred to references (1-19) for general and specific information on chromatography.]. This chapter will focus on the principles of chromatography, mainly liquid chromatography (LC). Detailed principles and applications of gas chromatography (GC) will be discussed in Chap. 29. In view of its widespread use and applications, high-performance liquid chromatography (HPLC) will be discussed in a separate chapter (Chap. 28). The general principles of extraction are first described as a basis for understanding chromatography.

  18. Transdermal permeation of Zanthoxylum bungeanum essential oil on TCM components with different lipophilicity

    Directory of Open Access Journals (Sweden)

    Yi Lan

    2016-07-01

    Conclusion: Z. bungeanum oil facilitated transdermal permeation of drugs with different lipophilicity, including the extremely hydrophilic and lipophilic drugs, whereas it exhibited greater enhancement activity for strongly hydrophilic drugs. The mechanisms of transdermal permeation enhancement by the oil could be explained with SC/vehicle partition coefficient, saturation solubility, and the interactions with SC lipids.

  19. Performances of AlN coatings as hydrogen isotopes permeation barriers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jie; Li, Qun; Xiang, Qing-Yun; Cao, Jiang-Li, E-mail: perov@sina.com

    2016-01-15

    Highlights: • The D-PRF of AlN-HIPB was studied. • The morphologies of AlN-HIPB remained compact after deuterium permeation tests. • The diffraction peaks maintained stable. • The nano-hardness increased after the deuterium permeation tests. - Abstract: Hydrogen isotope permeation barriers (HIPB) have great potential applications in the fields of hydrogen energy and thermonuclear fusion. In this study, the AlN-HIPB were prepared on 316 L stainless steel by RF magnetron sputtering. The properties of AlN-HIPB were studied, including the deuterium permeation reduced factor (D-PRF), structures and nano-hardness. The D-PRF of 0.4 μm AlN-HIPB could reach 36 at 600 °C, and gradually rise with decreasing permeation temperature. The D-PRF reached 53 at 400 °C and 144 at 250 °C, respectively. The coatings remained dense and the grains were spherical after the deuterium permeation test. The AlN (1 0 0) diffraction peaks appeared and maintained stable during the deuterium permeation process. The nano-hardness of the coatings increased from 5.96 GPa to 7.41 GPa and the elasticity modulus also increased from 156.6 GPa to 210.6 GPa after the deuterium permeation.

  20. Modeling benzene permeation through drinking water high density polyethylene (HDPE) pipes.

    Science.gov (United States)

    Mao, Feng; Ong, Say Kee; Gaunt, James A

    2015-09-01

    Organic compounds such as benzene, toluene, ethyl benzene and o-, m-, and p-xylene from contaminated soil and groundwater may permeate through thermoplastic pipes which are used for the conveyance of drinking water in water distribution systems. In this study, permeation parameters of benzene in 25 mm (1 inch) standard inside dimension ratio (SIDR) 9 high density polyethylene (HDPE) pipes were estimated by fitting the measured data to a permeation model based on a combination of equilibrium partitioning and Fick's diffusion. For bulk concentrations between 6.0 and 67.5 mg/L in soil pore water, the concentration-dependent diffusion coefficients of benzene were found to range from 2.0×10(-9) to 2.8×10(-9) cm2/s while the solubility coefficient was determined to be 23.7. The simulated permeation curves of benzene for SIDR 9 and SIDR 7 series of HDPE pipes indicated that small diameter pipes were more vulnerable to permeation of benzene than large diameter pipes, and the breakthrough of benzene into the HDPE pipe was retarded and the corresponding permeation flux decreased with an increase of the pipe thickness. HDPE pipes exposed to an instantaneous plume exhibited distinguishable permeation characteristics from those exposed to a continuous source with a constant input. The properties of aquifer such as dispersion coefficients (DL) also influenced the permeation behavior of benzene through HDPE pipes.

  1. Thickness dependence of oxygen permeation through erbia-stabilized bismuth oxide-silver composites

    NARCIS (Netherlands)

    Chen, C.S.; Kruidhof, H.; Bouwmeester, H.J.M.; Verweij, H.; Burggraaf, A.J.

    1997-01-01

    Oxygen permeation measurements were performed on erbia-stabilized bismuth oxide-silver (40 v/o) composite membranes in the range of thickness of 1.60–0.23 mm and temperature of 850–650 °C. Air was fed at one side of the membranes while permeated oxygen on the other side was swept away with helium. A

  2. Time-dependent permeation of carbon dioxide through a polyimide membrane above the plasticization pressure

    NARCIS (Netherlands)

    Wessling, M.; Huisman, I.; Boomgaard, van den Th.; Smolders, C.A.

    1995-01-01

    The time-dependent permeation behavior of a glassy polyimide is studied above and below the plasticization pressure with carbon dioxide as the permeating gas. The work particularly focuses on the quantification of the slow increase in permeability at feed pressures above the plasticization pressure.

  3. Physicochemical characterization of the human nail: solvent effects on the permeation of homologous alcohols.

    Science.gov (United States)

    Walters, K A; Flynn, G L; Marvel, J R

    1985-11-01

    To assess how vehicles might influence permeation through human nail, the diffusion of homologous alcohols (methanol to decanol) administered as neat liquids through finger nail plate has been studied using in-vitro diffusion cell methods and compared with permeation data for the same compounds in aqueous media. Permeation rates of the homologous alcohols through lipid depleted nail plate have also been assessed and the influences of dimethylsulphoxide (DMSO) and isopropyl alcohol on permeation rates of methanol and hexanol have been examined. With the exception of methanol, permeability coefficients are uniformly about five-fold smaller when the alcohols are undiluted than when they are applied in water. Overall parallelism in the permeability profiles under these separate circumstances of application is an indication that the external concentrations of the alcohols themselves are a determinant of their permeation velocities through the nail plate matrix. The even separation of the profiles suggests a facilitating role of water within the nail matrix. Chloroform/methanol delipidization of the nail led to increased penetration rates of water, methanol, ethanol and butanol. On the other hand, it caused a six-fold decrease in the permeation rate of decanol. Application of methanol and hexanol in DMSO somewhat retards their rates of permeation. Isopropyl alcohol also slows the permeation rate of hexanol but has little influence on that of methanol. Thus it appears that solvents which tend to promote diffusion through the skin horny layer have little promise as accelerants of nail plate permeability.

  4. Design, performance and manufacturing analysis for a compact permeator

    Energy Technology Data Exchange (ETDEWEB)

    Sacristan, R., E-mail: mrosa.sacristan@sener.es [SENER Ingenieria y Sistemas, Provenza 392, 5a 08025 Barcelona (Spain); Veredas, G. [EURATOM-CIEMAT Fusion Assoc., BBTU, Av. Complutense 22, 28040, Madrid (Spain); Bonjoch, I. [SENER Ingenieria y Sistemas, Provenza 392, 5a 08025 Barcelona (Spain); Fernandez, I. [EURATOM-CIEMAT Fusion Assoc., BBTU, Av. Complutense 22, 28040, Madrid (Spain); Martin, G. [SENER Ingenieria y Sistemas, Provenza 392, 5a 08025 Barcelona (Spain); Sanmarti, M. [b-FUS, Jardins de les Dones de Negre, 08930 Santa Adria de Besos, Barcelona (Spain); Sedano, L. [EURATOM-CIEMAT Fusion Assoc., BBTU, Av. Complutense 22, 28040, Madrid (Spain)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Not a single manufacturing option fulfills fully all the requirements that the PAV needs due to complicated manufacturing geometry and materials. Black-Right-Pointing-Pointer To avoid permeation in piping joints is a challenge. Black-Right-Pointing-Pointer CFD sensibility analysis and efficiency analysis show that the aim of the experiment can be accomplished. - Abstract: A fast and efficient recovery of bred tritium is a major milestone of tritium breeding technologies R and D for the demonstration of a fusion reactor tritium self-sufficiency. Permeator against vacuum (PAV) runs as a single-step process for tritium on-line recovery, acts as passive systems allowing to be thermally governed can be easily in-pipe integrated in LiPb loop systems and can be conceived with high compactness. An optimal PAV design is proposed with detailed design parameterization of tritium recovery efficiency at different velocity ranges from numerical simulation based on properly developed Openfoam{sup Registered-Sign} CFD code BelFoam{sup Registered-Sign} customized solver. Diverse structural design options are being considered to manufacture the PAV component that presents diverse manufacturing concerns. Fabrication options are exploring rolling of thin plate with internal armor in the vacuum gap up to the coating of a porous controlled thick wall. The aim of this paper is to emphasize on the advanced performance of the PAV proposed concept, to present and discuss the different technical solutions that have been studied as well as the fabrication tests carried out.

  5. Drug precipitation-permeation interplay: supersaturation in an absorptive environment.

    Science.gov (United States)

    Bevernage, Jan; Brouwers, Joachim; Annaert, Pieter; Augustijns, Patrick

    2012-10-01

    The present study investigated the interplay between supersaturation, absorption, precipitation, and excipient-mediated precipitation inhibition by comparing classic precipitation assessment in a non-absorption environment with precipitation/permeation assessment in an absorption environment. Loviride and HPMC-E5 were selected as poorly soluble model drug and precipitation inhibitor, respectively. To investigate supersaturation in an absorptive environment, supersaturation was induced at different degrees (DS), using a solvent shift method, in shaken Caco-2 Transwell® inserts containing fasted state simulated intestinal fluid (FaSSIF); to simulate a non-absorption environment, the inserts were parafilm-sealed and did not contain a cell monolayer. Donor and acceptor compartments were sampled as a function of time to determine precipitation kinetics and transport, respectively. In absence of precipitation, loviride transport increased proportionally with the initial DS; however, precipitation limited the supersaturation-induced transport enhancement. Loviride precipitation was found to be less extensive in an absorption environment compared to a non-absorption environment. As a result, the optimal DS obtained in a non-absorption environment (highest amount maintained in solution) did not correlate with the highest transport in an absorption environment. In addition, the impact of HPMC-E5 on loviride transport was inferior to its precipitation inhibitory capacity observed in a non-absorption environment. For the first time, the present study explicitly demonstrated that implementation of permeation in precipitation assays is critical to predict the impact of supersaturation, precipitation, and precipitation inhibition on the absorption of poorly soluble drugs. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Tritium permeation barrier based on self-healing composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Gao Jifeng; Zhang Dan [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Suo Jinping, E-mail: jpsuo@yahoo.com.cn [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2010-12-15

    Pores and cracks in ceramic coatings is one of the most important problems to be solved for the thermally sprayed tritium permeation barriers (TPBs) in fusion reactor. In this work, we developed a self-healing composite coating to address this problem. The coating composed of TiC + mixture(TiC/Al{sub 2}O{sub 3}) + Al{sub 2}O{sub 3} was deposited on martensitic steels by means of atmospheric plasma spraying (APS). Before and after heat treatment, the morphology and phase of the coating were comparatively investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). In the experiment, NiAl + Al{sub 2}O{sub 3}, mixture(TiC/Al{sub 2}O{sub 3}) + Al{sub 2}O{sub 3} and NiAl + TiC + mixture(TiC/Al{sub 2}O{sub 3}) + Al{sub 2}O{sub 3} films were also fabricated and studied, respectively. The results showed that the TiC + mixture(TiC/Al{sub 2}O{sub 3}) + Al{sub 2}O{sub 3} coating exhibited the best self-healing ability and good thermal shock resistance among the four samples after heat treatment under normal atmosphere. The SEM images analyzed by Image Pro software indicated that the porosity of the TiC + mixture(TiC/Al{sub 2}O{sub 3}) + Al{sub 2}O{sub 3} coating decreased more than 90% in comparison with the sample before heat treatment. This self-healing coating made by thermal spraying might be a good candidate for tritium permeation barrier in fusion reactors.

  7. Xanthan production by Xanthomonas campestris using whey permeate medium.

    Science.gov (United States)

    Savvides, A L; Katsifas, E A; Hatzinikolaou, D G; Karagouni, A D

    2012-08-01

    Xanthan gum is a polysaccharide that is widely used as stabilizer and thickener with many industrial applications in food industry. Our aim was to estimate the ability of Xanthomonas campestris ATCC 13951 for the production of xanthan gum by using whey as a growth medium, a by-product of dairy industry. X. campestris ATCC 13951 has been studied in batch cultures using a complex medium for the determination of the optimal concentration of glucose, galactose and lactose. In addition, whey was used under various treatment procedures (de-proteinated, partially hydrolyzed by β-lactamase and partially hydrolyzed and de-proteinated) as culture medium, to study the production of xanthan in a 2 l bioreactor with constant stirring and aeration. A production of 28 g/l was obtained when partially hydrolysed β-lactamase was used, which proved to be one of the highest xanthan gum production reported so far. At the same time, an effort has been made for the control and selection of the most appropriate procedure for the preservation of the strain and its use as inoculant in batch cultures, without loss of its viability and its capability of xanthan gum production. The pre-treatment of whey (whey permeate medium hydrolyzed, WPH) was very important for the production of xanthan by the strain X. campestris ATCC 13951 during batch culture conditions in a 2 l bioreactor. Preservation methods such as lyophilization, cryopreservation at various glycerol solution and temperatures have been examined. The results indicated that the best preservation method for the producing strain X. campestris ATCC 13951 was the lyophilization. Taking into account that whey permeate is a low cost by-product of the dairy industry, the production of xanthan achieved under the studied conditions was considered very promising for industrial application.

  8. Polyimide and polyimide/silica composites membranes for applications in gas separation: effects of preparation conditions on the structure and the permeation properties; Membranes polyimide et composites polyimide/silice pour des applications de separation gazeuse: effets des conditions de preparation sur la structure et les proprietes de permeation

    Energy Technology Data Exchange (ETDEWEB)

    Goizet, S.

    1997-03-01

    Polyimides have been largely studied in gaseous permeation for their high selectivities and thermo-stability. Correlatively, their permeabilities are low. The aim of this work has been to study the effect of the introduction of silica particles on the gaseous permeation properties of these polymers. The studied polyimides are the ODA-PMDA (with the same chemical structure of the Kapton), a fluorinated polyimide, the 6FDA-mPDA and the Ultem. The chosen way to introduce silica in these polymers is the sol-gel process. Polyimide/silica composites containing different proportions of silica have been carried out. The materials alone and in presence of silica have been characterized by different techniques (NMR, FTIR, light diffusion, TGA, DSC, viscosimetry, X-ray diffraction, SEM and density). Auto-supported membranes (films) and membranes supported on porous materials (thin layers) have been carried out. The gas permeation tests (He, H{sub 2}, CO{sub 2}, O{sub 2}, N{sub 2}, CH{sub 4}) of these membranes and their static characterization (thickness, density, chains organization) have led us to establish correlations between the preparation of such materials, their structure and their properties. The introduction of silica allows to increase the permeabilities. Selectivities are in some case improved too. This phenomenon has been explained by the structural changes occurring during the preparation of materials, due to the used preparation mode and to the presence of silica. (O.M.)

  9. Analysis of protein composition using multidimensional chromatography and mass spectrometry.

    Science.gov (United States)

    Link, Andrew J; Washburn, Michael P

    2014-11-03

    Multidimensional liquid chromatography of peptides produced by protease digestion of complex protein mixtures followed by tandem mass spectrometry can be coupled with automated database searching to identify large numbers of proteins in complex samples. These methods avoid the limitations of gel electrophoresis and in-gel digestions by directly identifying protein mixtures in solution. One method used extensively is named Multidimensional Protein Identification Technology (MudPIT), where reversed-phase chromatography and strong cation-exchange chromatography are coupled directly in a microcapillary column. This column is then placed in line between an HPLC and a mass spectrometer for complex mixture analysis. MudPIT remains a powerful approach for analyzing complex mixtures like whole proteomes and protein complexes. MudPIT is used for quantitative proteomic analysis of complex mixtures to generate novel biological insights.

  10. The Potent In Vitro Skin Permeation of Archaeosome Made from Lipids Extracted of Sulfolobus acidocaldarius

    Directory of Open Access Journals (Sweden)

    Eskandar Moghimipour

    2013-01-01

    Full Text Available Archaeosomes are a new generation of liposomes that exhibit higher stabilities under different conditions, such as high temperatures, alkaline or acidic pH, and presence of bile salts in comparison with liposomes, and can be used in biotechnology including drug, gene, and vaccine delivery. The objective of this study was to prepare archaeosomes using lipid extracted from Sulfolobus acidocaldarius and evaluate their physicochemical properties. The lipids were extracted from S. acidocaldarius and assayed by High Performance Thin-Layer Chromatography (HPTLC. Archaeosomes were prepared using film method and methylene blue was used as drug model. They were characterized for their vesicle size and Differential Scanning Calorimetry (DSC was used to investigate changes in their thermal behavior. The released amount of methylene blue was determined using a dialysis membrane and rat skin. HPTLC analysis of the extracted lipids showed that glycerol ether may be the major lipid with more than 78 percent probability. Results of particle size determination showed a mean size of 158.33 nm and the results of DSC indicated the possible interaction of methylene blue with lipids during the preparation of archaeosome. The addition of cholesterol significantly improved the encapsulation of methylene blue in the archaeosome so that the encapsulation efficiency was 61.66 ± 2.88%. The result of in vitro skin permeation showed that methylene blue could pass through skin model according to Peppas model and there was about 41.66% release after 6 h, whereas no release was observed through dialysis membrane. According to the results of the study, it is concluded that archaeosome may be successfully used as drug delivery system.

  11. The potent in vitro skin permeation of archaeosome made from lipids extracted of Sulfolobus acidocaldarius.

    Science.gov (United States)

    Moghimipour, Eskandar; Kargar, Mohammad; Ramezani, Zahra; Handali, Somayeh

    2013-01-01

    Archaeosomes are a new generation of liposomes that exhibit higher stabilities under different conditions, such as high temperatures, alkaline or acidic pH, and presence of bile salts in comparison with liposomes, and can be used in biotechnology including drug, gene, and vaccine delivery. The objective of this study was to prepare archaeosomes using lipid extracted from Sulfolobus acidocaldarius and evaluate their physicochemical properties. The lipids were extracted from S. acidocaldarius and assayed by High Performance Thin-Layer Chromatography (HPTLC). Archaeosomes were prepared using film method and methylene blue was used as drug model. They were characterized for their vesicle size and Differential Scanning Calorimetry (DSC) was used to investigate changes in their thermal behavior. The released amount of methylene blue was determined using a dialysis membrane and rat skin. HPTLC analysis of the extracted lipids showed that glycerol ether may be the major lipid with more than 78 percent probability. Results of particle size determination showed a mean size of 158.33 nm and the results of DSC indicated the possible interaction of methylene blue with lipids during the preparation of archaeosome. The addition of cholesterol significantly improved the encapsulation of methylene blue in the archaeosome so that the encapsulation efficiency was 61.66 ± 2.88%. The result of in vitro skin permeation showed that methylene blue could pass through skin model according to Peppas model and there was about 41.66% release after 6 h, whereas no release was observed through dialysis membrane. According to the results of the study, it is concluded that archaeosome may be successfully used as drug delivery system.

  12. Cavamax W7 composite ethosomal gel of clotrimazole for improved topical delivery: development and comparison with ethosomal gel.

    Science.gov (United States)

    Akhtar, Nida; Pathak, Kamla

    2012-03-01

    The present research work was aimed to formulate clotrimazole encapsulated Cavamax W7 composite ethosomes by injection method for improved delivery across epidermis. 3(2) factorial design was used to design nine formulations (F1-F9) and compared with ethosomal formulations (F10-F12). F9 with vesicle size of 202.8 ± 4.8 nm, highest zeta potential (-83.6 ± 0.96 mV) and %EE of 98.42 ± 0.15 was selected as optimized composite ethosome and F12 as reference ethosomal formulation. As revealed by transmission electron microscopy F9 vesicles were more condensed, uniformly spherical in shape than F12 vesicles. Vesicular stability studies indicated F9 to be more stable as compared to F12. Both F9 and F12 were incorporated in carbopol 934 gel base to get G1-G8 gel formulations and evaluated for in vitro skin permeability. Cavamax W7 composite ethosomal optimized gel (G5) showed higher in vitro percent cumulative drug permeation (88.53 ± 2.10%) in 8 h and steady state flux (J(ss)) of 3.39 ± 1.45 μg/cm(2)/min against the J(ss) of 1.57 ± 0.23 μg/cm(2)/min for ethosomal gel (G1) and 1.13 ± 0.06 μg/cm(2)/min for marketed formulation. The J(ss) flux of G5 was independent of amount of drug applied/unit area of skin. In vivo confocal laser scanning microscopic study of G5 depicted uniform and deeper penetration of rhodamine B (marker) in epidermis from Cavamax W7 composite ethosomal gel in comparison to G1. Finally, G5 demonstrated better (p ethosomes present a superior stable and efficacious vesicular system than ethosomal formulation for topical delivery of clotrimazole.

  13. Active Polymer Gel Actuators

    OpenAIRE

    Shuji Hashimoto; Ryo Yoshida; Yusuke Hara; Shingo Maeda

    2010-01-01

    Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of he...

  14. Extension of the selection of protein chromatography and the rate model to affinity chromatography.

    Science.gov (United States)

    Sandoval, G; Shene, C; Andrews, B A; Asenjo, J A

    2010-01-01

    The rational selection of optimal protein purification sequences, as well as mathematical models that simulate and allow optimization of chromatographic protein purification processes have been developed for purification procedures such as ion-exchange, hydrophobic interaction and gel filtration chromatography. This paper investigates the extension of such analysis to affinity chromatography both in the selection of chromatographic processes and in the use of the rate model for mathematical modelling and simulation. Two affinity systems were used: Blue Sepharose and Protein A. The extension of the theory developed previously for ion-exchange and HIC chromatography to affinity separations is analyzed in this paper. For the selection of operations two algorithms are used. In the first, the value of η, which corresponds to the efficiency (resolution) of the actual chromatography and, Σ, which determines the amount of a particular contaminant eliminated after each separation step, which determines the purity, have to be determined. It was found that the value of both these parameters is not generic for affinity separations but will depend on the type of affinity system used and will have to be determined on a case by case basis. With Blue Sepharose a salt gradient was used and with Protein A, a pH gradient. Parameters were determined with individual proteins and simulations of the protein mixtures were done. This approach allows investigation of chromatographic protein purification in a holistic manner that includes ion-exchange, HIC, gel filtration and affinity separations for the first time.

  15. Systematic Development of Transethosomal Gel System of Piroxicam: Formulation Optimization, In Vitro Evaluation, and Ex Vivo Assessment.

    Science.gov (United States)

    Garg, Varun; Singh, Harmanpreet; Bhatia, Amit; Raza, Kaisar; Singh, Sachin Kumar; Singh, Bhupinder; Beg, Sarwar

    2017-01-01

    Piroxicam is used in the treatment of rheumatoid arthritis, osteoarthritis, and other inflammatory diseases. Upon oral administration, it is reported to cause ulcerative colitis, gastrointestinal irritation, edema and peptic ulcer. Hence, an alternative delivery system has been designed in the form of transethosome. The present study describes the preparation, optimization, characterization, and ex vivo study of piroxicam-loaded transethosomal gel using the central composite design. On the basis of the prescreening study, the concentration of lipids and ethanol was kept in the range of 2-4% w/v and 0-40% v/v, respectively. Formulation was optimized by measuring drug retention in the skin, drug permeation, entrapment efficiency, and vesicle size. Optimized formulation was incorporated in hydrogel and compared with other analogous vesicular (liposomes, ethosomes, and transfersomes) gels for the aforementioned responses. Among the various lipids used, soya phosphatidylcholine (SPL 70) and ethanol in various percentages were found to affect drug retention in the skin, drug permeation, vesicle size, and entrapment efficiency. The optimized batch of transethosome has shown 392.730 μg cm(-2) drug retention in the skin, 44.312 μg cm(-2) h(-1) drug permeation, 68.434% entrapment efficiency, and 655.369 nm vesicle size, respectively. It was observed that the developed transethosomes were found superior in all the responses as compared to other vesicular formulations with improved stability and highest elasticity. Similar observations were noted with its gel formulation.

  16. Determination of Alkylphenol Ethoxylates in Textiles by GelFiltration Chromatography-Tandem Mass Spectrometry%凝胶过滤色谱-串联质谱法测定纺织品中的烷基酚聚氧乙烯醚

    Institute of Scientific and Technical Information of China (English)

    马强; 王超; 白桦; 刘茜; 王烨; 席海为

    2012-01-01

    A comprehensive analytical method based on gel filtration chromatography-tandem quadrupole mass spectrometry has been developed for the determination of alkylphenol ethoxylates in textiles. The textile samples were extracted with ethanol by accelerated solvent extraction method. The extract was cleaned by a Sep-Pak Carbon/NH2 solid phase extraction cartridge. Qualitative and quantitative analyses were carried out for alkylphenol ethoxylates under the multiple reaction monitoring (MRM) mode after the chromatographic separation on Shodex MSpak GF-310 2D column (150×2. 0 mm). The limits of quantitation (LOQs) for nonylphenol ethoxylates and octylphenol ethoxylates were 0. 2 mg/kg. At the spiked levels of 0. 2~5 mg/kg,the mean recoveries for nonylphenol ethoxylates were 84. 2%~93. 5% with the relative standard deviations (RSDs) of 3. 9%~7. 5%,and the mean recoveries for octylphenol ethoxylates were 85. 5%~96. 1% with the relative standard deviations (RSDs) of 3. 4%~8. 1%. The method is suitable for the determination of alkylphenol ethoxylates in textiles.%建立了纺织品中烷基酚聚氧乙烯醚的凝胶过滤色谱-串联质谱(GFC-MS/MS)分析方法.纺织品样品采用加速溶剂萃取法,以无水乙醇为提取溶剂进行提取,提取液经Sep-Pak Carbon/NH2石墨化碳黑/氨基复合型固相萃取柱净化.烷基酚聚氧乙烯醚经Shodex MSpak GF-310 2D色谱柱(150×2.0 mm)分离后,在多反应监测(MRM)模式下进行串联质谱定性及定量分析.方法对壬基酚聚氧乙烯醚(NPnEO)和辛基酚聚氧乙烯醚(OPnEO)的定量眼均为0.2mg/kg,在0.2~5 mg/kg的3个添加水平范围内,NPnEO的平均回收率为84.2%~93.5%,相对标准偏差(RSD)为3.9%~7.5%;OPnEO的平均回收率为85.5%~96.1%,RSD为3.4%~8.1%.该方法能够满足纺织品中烷基酚聚氧乙烯醚的检测要求.

  17. Lecithin-based nanostructured gels for skin delivery: an update on state of art and recent applications.

    Science.gov (United States)

    Elnaggar, Yosra S R; El-Refaie, Wessam M; El-Massik, Magda A; Abdallah, Ossama Y

    2014-04-28

    Conventional carriers for skin delivery encounter obstacles of drug leakage, scanty permeation and low entrapment efficiency. Phospholipid nanogels have recently been recognized as prominent delivery systems to circumvent such obstacles and impart easier application. The current review provides an overview on different types of lecithin nanostructured gels, with particular emphasis on liposomal versus microemulsion gelled systems. Liposomal gels investigated encompassed classic liposomal hydrogel, modified liposomal gels (e.g. Transferosomal, Ethosomal, Pro-liposomal and Phytosomal gels), Microgel in liposomes (M-i-L) and Vesicular phospholipid gel (VPG). Microemulsion gelled systems encompassed Lecithin microemulsion-based organogels (LMBGs), Pluronic lecithin organogels (PLOs) and Lecithin-stabilized microemulsion-based hydrogels. All systems were reviewed regarding matrix composition, state of art, characterization and updated applications. Different classes of lecithin nanogels exhibited crucial impact on transdermal delivery regarding drug permeation, drug loading and stability aspects. Future perspectives of this theme issue are discussed based on current laboratory studies. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Development and comparison of two multi-residue methods for the analysis of select pesticides in honey bees, pollen, and wax by gas chromatography-quadrupole mass spectrometry.

    Science.gov (United States)

    Li, Yuanbo; Kelley, Rebecca A; Anderson, Troy D; Lydy, Michael J

    2015-08-01

    One of the hypotheses that may help explain the loss of honey bee colonies worldwide is the increasing potential for exposure of honey bees to complex mixtures of pesticides. To better understand this phenomenon, two multi-residue methods based on different extraction and cleanup procedures have been developed, and compared for the determination of 11 relevant pesticides in honey bees, pollen, and wax by gas chromatography-quadrupole mass spectrometry. Sample preparatory methods included solvent extraction followed by gel permeation chromatography (GPC) cleanup and cleanup using a dispersive solid-phase extraction with zirconium-based sorbents (Z-Sep). Matrix effects, method detection limits, recoveries, and reproducibility were evaluated and compared. Method detection limits (MDL) of the pesticides for the GPC method in honey bees, pollen, and wax ranged from 0.65 to 5.92 ng/g dw, 0.56 to 6.61 ng/g dw, and 0.40 to 8.30 ng/g dw, respectively, while MDLs for the Z-Sep method were from 0.33 to 4.47 ng/g dw, 0.42 to 5.37 ng/g dw, and 0.51 to 5.34 ng/g dw, respectively. The mean recoveries in all matrices and at three spiking concentrations ranged from 64.4% to 149.5% and 71.9% to 126.2% for the GPC and Z-Sep methods, with relative standard deviation between 1.5-25.3% and 1.3-15.9%, respectively. The results showed that the Z-Sep method was more suitable for the determination of the target pesticides, especially chlorothalonil, in bee hive samples. The Z-Sep method was then validated using a series of field-collected bee hive samples taken from honey bee colonies in Virginia.

  19. DIMETILSULFOKSID SEBAGAI ENHANCER TRANSPOR TRANSDERMAL TEOFILIN SEDIAAN GEL

    Directory of Open Access Journals (Sweden)

    Resty Annisa Damayanti

    2013-05-01

    Full Text Available Dimethylsulfoxide (DMSO has been intensively studied the 19th century. This substance is used as a medicine and solve. It can also be used as an absorption enhancer of various drugs, either synthetical or herbal medicines. This study conducted with DMSO as transdermal absorption enhancer of theophylline, which often used as an anti-cellulite dosage forms. The experiments studied in vitro transdermal absorption of theophylline in gel dosage forms, containing 7% theophylline dan various concentration of DMSO i.e. 0% , 3%, 5% and 7% DMSO respectively. These studies used skin membrane of Wistar strain male rats in a vertical type diffusion Cell. The results indicated that DMSO was very potential as a permeation enhancer theophylline, the formula containing 7% DMSO increased the theophylline transport from 17,9 µg to 139,1 µg.

  20. Purification of transferrins and lactoferrin using DEAE affi-gel blue.

    Science.gov (United States)

    Chung, M C; Chan, S L; Shimizu, S

    1991-01-01

    1. A simple method for purifying transferrins and lactoferrin is described. 2. The method consists of a preliminary step of dye-ligand chromatography using DEAE Affi-Gel Blue as the gel matrix at pH 7.5. In this chromatographic step, the transferrins and lactoferrin were readily separated from the bulk of the other proteins by start buffer elution. 3. Differences in the chromatographic behaviour of the various serum transferrins (monkey, human, rabbit, pig, chicken and duck) and ovotransferrin upon DEAE Affi-Gel Blue chromatography can be attributed to differences in the anionic charge of the transferrins in 0.02 M potassium phosphate buffer, pH 7.5, thus resulting in the differential retardation of these protein molecules by the gel matrix. 4. The result of DEAE Affi-Gel Blue chromatography of human lactoferrin is different from that for the transferrins. This may possibly reflect the differences in the strength of interaction between lactoferrin and transferrin with this gel matrix.

  1. Determination of membrane degradation products in the product water of polymer electrolyte membrane fuel cells using liquid chromatography mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zedda, Marco

    2011-05-12

    accelerated laboratory stress test procedure. Liquid chromatographic separation of the three possible isomers on a C18 stationary phase was used for identification of 4-HBA in all samples. Finally, this degradation product could be assigned to a monomer of the tested membrane. In conjunction with gel permeation chromatography (GPC) analysis a degradation mechanism for 4-HBA could be proposed. (orig.)

  2. Behavior of tritium permeation induced by water corrosion of alpha iron around room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, T.; Hashizume, K. [Kyushu University, Kasuga, Fukuoka (Japan)

    2015-03-15

    Tritium (T) permeation leakage to surroundings is a great safety concern in fission and fusion reactor systems. T permeation potentially occurs from T contaminated water through cooling tubes or storage tank made of metals which dissolve some T evolved by water corrosion. In order to understand behaviors of hydrogen uptake and permeation in pure α-iron (αFe) during water corrosion around room temperature, hydrogen permeation experiments for an αFe membrane have been conducted by means of tritium tracer techniques. The present study suggests that hydrogen produced by water corrosion of αFe is trapped in product oxide layers to delay hydrogen uptake in αFe for a moment. However, the oxide layers do not work as a sufficient barrier for hydrogen uptake. Some of hydrogen dissolved in αFe normally diffuses and permeates through the bulk in the early stage of permeation. In a later stage, hydrogen permeation could be apparently stopped by the disappearance of concentration difference of tritium. Hydrogen partial pressure at the water/αFe interface could be ranged from 0.7 to 9.5 kPa around room temperature.

  3. Effect of formulation factors on in vitro transcorneal permeation of voriconazole from aqueous drops

    Directory of Open Access Journals (Sweden)

    Biswaranjan Mohanty

    2013-01-01

    Full Text Available The purpose of this research was to evaluate the effect the formulation factors on in vitro permeation of voriconazole through freshly isolated goat and sheep corneas. An increase in the pH of the drops from 4.0 to 8.0 resulted in significant (P < 0.05 increase drug permeation. Raising concentration of the drops from 0.05% to 0.2% (w/v significantly, (P < 0.05 increased drug permeation, but decreased the percent permeation. Corneal transport of voriconazole is both pH and concentration dependent. Eye drops containing disodium edetate (ethylenediaminetetraacetic acid alone or combination with benzalkonium chloride showed significantly (P < 0.05 higher permeation as compared with control formulation. Addition of beta-cyclodextrin to the formulation enhanced corneal permeation of voriconazole. Compared with control formulation, voriconazole 0.2% (w/v drop containing viscosity modifier produced significant (P < 0.05 decrease in permeation. Most of the formulations showed higher zone of inhibition against Candida albicans.

  4. SONOPHORESIS EFFECT ON THE PERMEATION OF METRONIDAZOLE USING 3D SKIN EQUIVALENT

    Directory of Open Access Journals (Sweden)

    Mai Aldwaikat*, Mohammed Alarjah , Jacki Willis and Timothy Mason

    2013-01-01

    Full Text Available Transdermal drug delivery is highly advantageous method for drug administration, yet the compact structure of stratum corneum is an effective barrier which limited the use of this route to very few drug molecules. Ultrasound enhances the permeation through the skin by altering this barrier function in a phenomenon named sonophoresis. This study aimed to evaluate the effect of variable ultrasonic conditions on the permeation of Metronidazole (ML. This involved validating the applicability of utilizing a three dimensional skin equivalent as human skin models for sonophoresis studies. A Franz diffusion cell was used to study the effect of therapeutic ultrasound at 1 MHz and power ultrasound at 20 KHz on the permeation of Metronidazole across the 3D skin equivalent EpiDerm™. HPLC methods were used for the determination of the concentration of Metronidazole in the receiving compartment. Utilizing therapeutic ultrasound at 1 MHz frequency has enhanced the permeation of Metronidazole through the EpiDerm™, as about double the permeation of the ML was obtained with no apparent damage to the membrane. The results indicated significant permeation enhancement with low frequency sonophoresis at 20 KHz frequency treatments through EpiDerm™ skin equivalent. Up to five fold enhancement was measured with the permeation of investigated molecules through EpiDerm™. The mechanism of action observed seemed highly dependent on the ultrasonic conditions.

  5. Long-term permeator experiment PETRA at the tritium laboratory Karlsruhe: commissioning tests with tritium

    Energy Technology Data Exchange (ETDEWEB)

    Penzhorn, R.D.; Berndt, U.; Kirste, E.; Hellriegel, W.; Jung, W.; Pejsa, R.; Romer, O. [Research Center Karlsruhe (Germany)

    1995-10-01

    During the commissioning of the PETRA facility, the PETRA PdAg permeator was characterized using hydrogen isotopes by determining the hydrogen curves for H{sub 2}, D{sub 2} and DT as well as He curves for various H{sub 2}/D{sub 2}/He gas mixtures at 300 and 400{degree}C. A method was developed to verify the mechanical integrity of the permeator during runs with the tritium. The H{sub 2} and D{sub 2} permeation losses into the isolation vacuum of the permeator were quantified. Hydrogen permeation into the isolation vacuum could be kept at levels low enough to permit an undisturbed continuous operation of the permeator using a ZrCo tritium storage vessel. It was shown that the combination of the PETRA facility with a Normetex scroll pump, it is possible to extract at <320{degree}C >98% of the hydrogen isotopes from the ZrCo storage vessel with (a) negligible permeation losses, (b) without the danger of disproportionation of the intermetallic compound and (c) with the minimization of the tritium inventory in the facility. 5 refs., 13 figs., 1 tab.

  6. Rapid permeation measurement system for the production control of monolayer and multilayer films

    Science.gov (United States)

    Botos, J.; Müller, K.; Heidemeyer, P.; Kretschmer, K.; Bastian, M.; Hochrein, T.

    2014-05-01

    Plastics have been used for packaging films for a long time. Until now the development of new formulations for film applications, including process optimization, has been a time-consuming and cost-intensive process for gases like oxygen (O2) or carbon dioxide (CO2). By using helium (He) the permeation measurement can be accelerated from hours or days to a few minutes. Therefore a manometric measuring system for tests according to ISO 15105-1 is coupled with a mass spectrometer to determine the helium flow rate and to calculate the helium permeation rate. Due to the accelerated determination the permeation quality of monolayer and multilayer films can be measured atline. Such a system can be used to predict for example the helium permeation rate of filled polymer films. Defined quality limits for the permeation rate can be specified as well as the prompt correction of process parameters if the results do not meet the specification. This method for process control was tested on a pilot line with a corotating twin-screw extruder for monolayer films. Selected process parameters were varied iteratively without changing the material formulation to obtain the best process parameter set and thus the lowest permeation rate. Beyond that the influence of different parameters on the helium permeation rate was examined on monolayer films. The results were evaluated conventional as well as with artificial neuronal networks in order to determine the non-linear correlation between all process parameters.

  7. Changes in chemical permeation of disposable latex, nitrile, and vinyl gloves exposed to simulated movement.

    Science.gov (United States)

    Phalen, Robert N; Le, Thi; Wong, Weng Kee

    2014-01-01

    Glove movement can affect chemical permeation of organic compounds through polymer glove products. However, conflicting reports make it difficult to compare the effects of movement on chemical permeation through commonly available glove types. The aim of this study was to evaluate the effect of movement on chemical permeation of an organic solvent through disposable latex, nitrile, and vinyl gloves. Simulated whole-glove permeation testing was conducted using ethyl alcohol and a previously designed permeation test system. With exposure to movement, a significant decrease (p ≤ 0.001) in breakthrough time (BT) was observed for the latex (-23%) and nitrile gloves (-31%). With exposure to movement, only the nitrile glove exhibited a significant increase (p ≤ 0.001) in steady-state permeation rate (+47%) and cumulative permeation at 30 min (+111%). Even though the nitrile glove provided optimum chemical resistance against ethyl alcohol, it was most affected by movement. With exposure to movement, the latex glove was an equivalent option for overall worker protection, because it was less affected by movement and the permeation rate was lower than that of the nitrile glove. In contrast, the vinyl glove was the least affected by movement, but did not provide adequate chemical resistance to ethyl alcohol in comparison with the nitrile and latex gloves. Glove selection should take movement and polymer type into account. Some glove polymer types are less affected by movement, most notably the latex glove in this test. With nitrile gloves, at least a factor of three should be used when attempting to assign a protection factor when repetitive hand motions are anticipated. Ultimately, the latex gloves outperformed nitrile and vinyl in these tests, which evaluated the effect of movement on chemical permeation. Future research should aim to resolve some of the observed discrepancies in test results with latex and vinyl gloves.

  8. In vitro permeation and in vivo anti-inflammatory and analgesic properties of nanoscaled emulsions containing ibuprofen for topical delivery

    Directory of Open Access Journals (Sweden)

    et al

    2011-02-01

    Full Text Available Ghassan Z Abdullah1*, Muthanna F Abdulkarim1*, Ibrahim M Salman1, Omar Z Ameer1, Mun F Yam1,2, Ahmed F Mutee1, Mallikarjun Chitneni3, Elrashid S Mahdi1, Mahiran Basri4, Munavvar A Sattar1, Azmin M Noor11School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, Malaysia; 2Faculty of Medicine and Health Science, Universiti Putra Malaysia, Selangor, Malaysia; 3School of Pharmacy and Health Sciences, International Medical University, Kuala Lumpur, Malaysia; 4Faculty of Science, Universiti Putra Malaysia, Selangor, Malaysia; *The first and second authors have contributed equally to this work.Introduction: As a topical delivery system, a nanoscaled emulsion is considered a good carrier of several active ingredients that convey several side effects upon oral administration, such as nonsteroidal anti-inflammatory drugs (NSAIDs.Objective: We investigated the in vitro permeation properties and the in vivo pharmacodynamic activities of different nanoscaled emulsions containing ibuprofen, an NSAID, as an active ingredient and newly synthesized palm olein esters (POEs as the oil phase.Methodology: A ratio of 25:37:38 of oil phase:aqueous phase:surfactant was used, and different additives were used for the production of a range of nanoscaled emulsions. Carbopol® 940 dispersion neutralized by triethanolamine was employed as a rheology modifier. In some circumstances, menthol and limonene were employed at different concentrations as permeation promoters. All formulae were assessed in vitro using Franz diffusion cell fitted with full-thickness rat skin. This was followed by in vivo evaluation of the anti-inflammatory and analgesic activities of the promising formulae and comparison of the effects with that of the commercially available gel.Results and discussion: Among all other formulae, formula G40 (Carbopol® 940-free formula had a superior ability in transferring ibuprofen topically compared with the reference. Carbopol® 940 significantly

  9. Study on hydrogen isotope permeation in the HTTR hydrogen production system. 2. Effectiveness of reducing the amount of permeated deuterium by oxidized film. Contract research

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Tetsuaki; Nishihara, Tetsuo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Iwatsuki, Jin [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    2002-11-01

    The Japan Atomic Energy Research Institute (JAERI) has performed a research and development (R and D) program on nuclear production of hydrogen as a study consigned by Ministry of Education, Culture, Sports, Science and Technology. Permeation of hydrogen isotope through a high-temperature alloy as used a heat transfer pipe of an intermediate heat exchanger and a steam reformer is an important problem in the hydrogen production system connected to be the high-temperature engineering test reactor (HTTR). In order to obtain detailed data for safety review and development of analytical codes, a test of permeation of hydrogen isotope was carried out as one of essential tests. The objective of this study is to obtain a permeability of hydrogen isotope through Hastelloy XR and other high temperature alloys and to evaluate quantitatively an effect of oxidized film on reducing the amount of permeated hydrogen through the pipe. From the results obtained in this experiment, it is supposed that the oxidized film produced on the surface of the heat transfer pipe during an early stage of the reactor operation will reduce the amount of tritium permeated from the primary circuit of the HTTR to the utilization system. This report describes the amount of permeated hydrogen and deuterium through Hastelloy XR with oxidized film on the tube surface and state for production of oxidized film. (author)

  10. Development of long-acting bioadhesive vaginal gels of oxybutynin: formulation, in vitro and in vivo evaluations.

    Science.gov (United States)

    Tuğcu-Demiröz, Fatmanur; Acartürk, Füsun; Erdoğan, Deniz

    2013-11-30

    Overactive bladder (OAB) and vaginal dryness are common problems after menopause. Oxybutynin (OXY) is an antimuscarinic agent that has been available for more than 30 years in the treatment of OAB patients. The aim of the work reported in this paper was to develop long acting mucoadhesive gel formulations of OXY and to investigate their effects on blood levels compared to those of oral OXY immediate release tablets, in rabbits. Mucoadhesive gels were prepared with chitosan, hydroxypropyl methylcellulose (HPMC K100M) and Poloxamer 407 (Pluronic F 127). The physicopharmaceutical properties of gels were evaluated. The gel formulation which was prepared with HPMC K100M, exhibited the highest viscosity, the greatest adhesiveness, cohesiveness and mucoadhesion values. The formulation which was prepared from HPMC K100M showed suitable permeation characteristics across the vaginal mucosa. Comparative bioavailability studies were carried out on rabbits with vaginal HPMC gel, vaginal chitosan gel, vaginal OXY solution and commercially available oral Üropan tablets. It was concluded that the highest AUC and relative bioavailability values were obtained for the bioadhesive vaginal gel formulation prepared with HPMC K100M. Therefore, the mucoadhesive vaginal gels of OXY can be a promising and innovative alternative therapeutic system for the treatment of OAB. It can be safely used in cases of overactive bladder and as well as vaginal dryness after menopause.

  11. Factors influencing alginate gel biocompatibility.

    Science.gov (United States)

    Tam, Susan K; Dusseault, Julie; Bilodeau, Stéphanie; Langlois, Geneviève; Hallé, Jean-Pierre; Yahia, L'Hocine

    2011-07-01

    Alginate remains the most popular polymer used for cell encapsulation, yet its biocompatibility is inconsistent. Two commercially available alginates were compared, one with 71% guluronate (HiG), and the other with 44% (IntG). Both alginates were purified, and their purities were verified. After 2 days in the peritoneal cavity of C57BL/6J mice, barium (Ba)-gel and calcium (Ca)-gel beads of IntG alginate were clean, while host cells were adhered to beads of HiG alginate. IntG gel beads, however, showed fragmentation in vivo while HiG gel beads stayed firm. The physicochemical properties of the sodium alginates and their gels were thoroughly characterized. The intrinsic viscosity of IntG alginate was 2.5-fold higher than that of HiG alginate, suggesting a greater molecular mass. X-ray photoelectron spectroscopy indicated that both alginates were similar in elemental composition, including low levels of counterions in all gels. The wettabilities of the alginates and gels were also identical, as measured by contact angles of water on dry films. Ba-gel beads of HiG alginate resisted swelling and degradation when immersed in water, much more than the other gel beads. These results suggest that the main factors contributing to the biocompatibility of gels of purified alginate are the mannuronate/guluronate content and/or intrinsic viscosity.

  12. Photoacoustic study of percutaneous absorption of Carbopol and transdermic gels for topic use in skin

    Science.gov (United States)

    Rossi, R. C. P.; de Paiva, R. F.; da Silva, M. D.; Barja, P. R.

    2008-01-01

    Topical medicine application has been used to treat a good number of pathological processes. Its efficacy is associated to an efficient penetration of the drug in the internal skin layers, promoting systemic effects and excluding the possibility of drug degradation by the digestive tract and hepatic elimination. This work analyzes the penetration kinetics of two soluble bases employed as vehicles for topic application: superficial gel (Carbopol 940) and transdermic (transdermal) gel. Analysis was performed with the photoacoustic technique, based upon the absorption of modulated light by a sample with subsequent conversion of the absorbed energy in heat, generating acoustic waves in the air layer adjacent to the sample. Each of the two vehicles was evaluated through in vivo (human skin) and in vitro application. Measurements in vitro employed samples of VitroSkin (synthetic material with properties similar to those of real skin, employed in the pharmaceutical industry research). Results show that the permeation was faster for the transdermal gel, both for in vivo and in vitro measurements, indicating that in vitro measurements may be utilized in qualitative, comparative permeation studies.

  13. Practical experience of backwashing with SWRO permeate for UF fouling control

    KAUST Repository

    Li, Sheng

    2013-01-01

    Effectiveness of seawater reverse osmosis (SWRO) permeate backwash on fouling control of seawater ultrafiltration was investigated at a pilot scale. A standard membrane module was used in this pilot to represent full-scale desalination plants. Results of the pilot show a good reproducibility. When the UF permeate was used for backwash, the frequency of chemically enhanced backwash (CEB) was around once per day. However, results of the pilot show that SWRO permeate backwashing could significantly reduce the CEB frequency. © 2013 Desalination Publications.

  14. Gas-driven permeation of deuterium through tungsten and tungsten alloys

    Energy Technology Data Exchange (ETDEWEB)

    Buchenauer, Dean A., E-mail: dabuche@sandia.gov [Sandia National Laboratories, Energy Innovation Department, Livermore, CA 94550 (United States); Karnesky, Richard A. [Sandia National Laboratories, Energy Innovation Department, Livermore, CA 94550 (United States); Fang, Zhigang Zak; Ren, Chai [University of Utah, Department of Metallurgical Engineering, Salt Lake City, UT 84112 (United States); Oya, Yasuhisa [Shizuoka University, Graduate School of Science, Shizuoka (Japan); Otsuka, Teppei [Kyushu University, Department of Advanced Energy Engineering Science, Fukuoka (Japan); Yamauchi, Yuji [Hokkaido University, Third Division of Quantum Science and Engineering, Faculty of Engineering, Sapporo (Japan); Whaley, Josh A. [Sandia National Laboratories, Energy Innovation Department, Livermore, CA 94550 (United States)

    2016-11-01

    Highlights: • We have designed and performed initial studies on a high temperature gas-driven permeation cell capable of operating at temperatures up to 1150 °C and at pressures between 0.1–1 atm. • Permeation measurements on ITER grade tungsten compare well with past studies by Frauenfelder and Zahkarov in the temperature range from 500 to 1000 °C. • First permeation measurements on Ti dispersoid-strengthened ultra-fine grained tungsten show higher permeation at 500 °C, but very similar permeation with ITER tungsten at 1000 °C. Diffusion along grain boundaries may be playing a role for this type of material. - Abstract: To address the transport and trapping of hydrogen isotopes, several permeation experiments are being pursued at both Sandia National Laboratories (deuterium gas-driven permeation) and Idaho National Laboratories (tritium gas- and plasma-driven tritium permeation). These experiments are in part a collaboration between the US and Japan to study the performance of tungsten at divertor relevant temperatures (PHENIX). Here we report on the development of a high temperature (≤1150 °C) gas-driven permeation cell and initial measurements of deuterium permeation in several types of tungsten: high purity tungsten foil, ITER-grade tungsten (grains oriented through the membrane), and dispersoid-strengthened ultra-fine grain (UFG) tungsten being developed in the US. Experiments were performed at 500–1000 °C and 0.1–1.0 atm D{sub 2} pressure. Permeation through ITER-grade tungsten was similar to earlier W experiments by Frauenfelder (1968–69) and Zaharakov (1973). Data from the UFG alloy indicates marginally higher permeability (< 10×) at lower temperatures, but the permeability converges to that of the ITER tungsten at 1000 °C. The permeation cell uses only ceramic and graphite materials in the hot zone to reduce the possibility for oxidation of the sample membrane. Sealing pressure is applied externally, thereby allowing for elevation

  15. Time-dependent water permeation behavior of concrete under constant hydraulic pressure

    Institute of Scientific and Technical Information of China (English)

    Fang Yonghao; Wang Zhongli; Zhou Yue

    2008-01-01

    In the present work, a concrete permeability testing setup was designed to study the behavior of hydraulic concrete subjected to constant hydraulic pressure. The results show that when concrete is subjected to high enough constant hydraulic pressure, it will be permeated, and after it reaches its maximum permeation rate, the permeability coefficient will gradually decrease towards a stable value. A time-dependent model of permeability coefficient for concrete subjected to hydraulic pressure is proposed. It is indicated that the decrease of the permeability coefficient with permeation time conforms well to the negative-exponential decrease model.

  16. Calcipotriol delivery into the skin as emulgel for effective permeation.

    Science.gov (United States)

    Naga Sravan Kumar Varma, V; Maheshwari, P V; Navya, M; Reddy, Sharath Chandra; Shivakumar, H G; Gowda, D V

    2014-12-01

    The objective of this work is to formulate and evaluate an emulgel containing calcipotriol for treatment of psoriasis. Emulgels have emerged as a promising drug delivery system for the delivery of hydrophobic drugs. Isopropyl alcohol and polyethylene glycol have been employed as permeation enhancers. Formulation chart is made with seven formulations, evaluated for physical parameters, drug content, viscosity, thixotropy, spreadability, extrudability, mucoadhesion, diffusion studies, skin irritation test along with short term stability studies. Carbopolis is reported to have a direct influence on appearance and viscosity of final formulation. The photomicroscopic evaluations showed the presence of spherical globules in size range of 10-15 μm. Rheograms revealed that all the formulations exhibited pseudoplastic flow. Optimized formulation (F6) had shown 86.42 ± 2.0% drug release at the end of 8 h study. The release rate through dialysis membrane and rat skin is higher when compared to commercial calcipotriol ointment. Hence it is concluded that calcipotriol can be delivered topically with enhanced penetration properties when formulated as emulgel.

  17. Water and Ion Permeation through Electrically Charged Nanopore

    Institute of Scientific and Technical Information of China (English)

    ZENG Li; ZUO Guang-Hong; GONG Xiao-Jing; LU Hang-Jun; WANG Chun-Lei; WU Ke-Fei; WAN Rong-Zheng

    2008-01-01

    @@ The behaviour of water and small solutes in confined geometries is important to a variety of chemical and nanofluidic applications. Here we investigate the permeation and distribution of water and ions in electrically charged carbon cylindrical nanopore during the osmotic process using molecular dynamics simulations. In the simulations, charges are distributed uniformly on the pores with diameter of 0.9 nm. For nanopores with no charge or a low charge, ions are difficult to enter. With the increasing of charge densities on the pores, ions will appear inside the nanopores because of the large electronic forces between the ions and the charged pores. Different ion entries induce varying effects on osmotic water flow. Our simulations reveal that the osmotic water can flow through the negatively charged pore occupied by K+ ions, while water flux through the positively charged pores will be disrupted by Cl- ions inside the pores. This may be explained by the different radial distributions of K+ions and Cl- ions inside the charged nanopores.

  18. PEP Support: Laboratory Scale Leaching and Permeate Stability Tests

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L.; Peterson, Reid A.; Rinehart, Donald E.; Buchmiller, William C.

    2010-05-21

    This report documents results from a variety of activities requested by the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The activities related to caustic leaching, oxidative leaching, permeate precipitation behavior of waste as well as chromium (Cr) leaching are: • Model Input Boehmite Leaching Tests • Pretreatment Engineering Platform (PEP) Support Leaching Tests • PEP Parallel Leaching Tests • Precipitation Study Results • Cr Caustic and Oxidative Leaching Tests. Leaching test activities using the PEP simulant provided input to a boehmite dissolution model and determined the effect of temperature on mass loss during caustic leaching, the reaction rate constant for the boehmite dissolution, and the effect of aeration in enhancing the chromium dissolution during caustic leaching. Other tests were performed in parallel with the PEP tests to support the development of scaling factors for caustic and oxidative leaching. Another study determined if precipitate formed in the wash solution after the caustic leach in the PEP. Finally, the leaching characteristics of different chromium compounds under different conditions were examined to determine the best one to use in further testing.

  19. Exploring unsaturated fatty acid cholesteryl esters as transdermal permeation enhancers.

    Science.gov (United States)

    Rambharose, Sanjeev; Kalhapure, Rahul S; Jadhav, Mahantesh; Govender, Thirumala

    2017-04-01

    The intrinsic protective barrier property of skin, one of the major challenges in the design of transdermal drug delivery systems, can be overcome through the use of chemical permeation enhancers (CPEs). Herein, we explore the potential of unsaturated fatty acid (UFA) esters of cholesterol (Chol) viz., oleate, linoleate and linolenate, as transdermal CPEs using tenofovir (TNF) as a model drug. All Chol UFA esters at 1% w/w were found to be more effective enhancers when compared to their respective parent fatty acids (FAs) and saturated FA counterparts. Cholesteryl linolenate (Chol-LLA) showed the most superior performance (enhancement ratio (ER) = 3.71). The greatest ER for Chol-LLA (5.93) was achieved at a concentration of 2% w/w. The histomorphological and transepithelial electrical resistance (TEER) evaluations supported the results of the permeability studies. These findings showed no significant loss in the integrity of the epidermis, with drug and enhancer treatment having temporary effects on the barrier property of the epidermis. Chol UFA esters can therefore be considered as new CPEs for exploitation in topical formulations for various classes of drugs.

  20. Partial characterization of hog renin purified by affinity chromatography.

    Science.gov (United States)

    Devaux, C; Ménard, J; Sicard, P; Corvol, P

    1976-05-01

    A method has been set up to purify renin on a large scale by affinity chromatography using Pepstatin, a potent inhibitor of renin, as a ligand. Pepstatin was covalently coupled to Sepharose via six different spacer 'arms'. The Sepharose-hexamethylenediamino-Pepstatin appeared to be the better derivative for renin purification even at a concentration as low as 160 nmol of Pepstatin/ml of moist gel. Renin was extracted from 100 kg of hog kidneys and semi-purified by ammonium sulfate precipitations and chromatography on DEAE-cellulose. The active fraction (48.5 g of proteins) was applied on a 500-ml affinity column. Renin was eluted in the starting buffer containing 6 M urea. Renin was purified 120-fold by the affinity chromatography step with a 79% recovery. Physico-chemical characterization of highly purified renin was performed. Isoelectrofocusing on a pH gradient from 3 to 6 showed a major peak with an isoelectric point (pI) of 4.95 and a minor peak (pI = 4.70). Polyacrylamide gel electrophoresis, pH 7.8, at different gel concentrations, showed a single peak of renin activity which was found in the major protein band. Molecular size estimated on agarose-acrylamide gel filtration was 40 000. All these physical parameters were similar before and after purification.

  1. Chromatography resin support

    Science.gov (United States)

    Dobos, James G.

    2002-01-01

    An apparatus and method of using an improved chromatography resin support is disclosed. The chromatography support platform is provided by a stainless steel hollow cylinder adapted for being inserted into a chromatography column. An exterior wall of the stainless steel cylinder defines a groove for carrying therein an "O"-ring. The upper surface of the stainless steel column is covered by a fine stainless steel mesh welded to the edges of the stainless steel cylinder. When placed upon a receiving ledge defined within a chromatography column, the "O"-ring provides a fluid tight seal with the inner edge wall of the chromatography cylinder. The stainless steel mesh supports the chromatography matrix and provides a back flushable support which is economical and simple to construct.

  2. THE PROPERTIES OF CARRAGEENAN GELS

    Directory of Open Access Journals (Sweden)

    Grubnik I.M., Gladukh Ye.V., Chernyaev S.V.

    2012-04-01

    Full Text Available The article presents the results of studies on the functional properties of carrageenan, depending on the concentration of sodium chloride and xanthan in gels. It is established that the main factors in the syneresis of carrageenan gels are its concentration, the presence of ions and gums in solution. If using sodium chloride there is a change in the structure of mesh of the resulting gel, which leads to an increase in syneresis.

  3. Thermoresponsive polymeric gel as an on-demand transdermal drug delivery system for pain management.

    Science.gov (United States)

    Indulekha, S; Arunkumar, P; Bahadur, D; Srivastava, R

    2016-05-01

    The main aim of this work is to design a heat triggered transdermal drug delivery system (TDDS) using a thermoresponsive polymer, poly (N-vinyl caprolactam) [PNVCL] based gel, where in patients can themselves administer a pulse of drug on mere application of heat pad over the TDDS, whenever pain is experienced. The phase transition temperature of PNVCL was tuned to 35 °C by grafting it onto a pH sensitive biopolymer, Chitosan, to synthesize Chitosan-g-PNVCL (CP) co-polymer which render the gel both thermo- and pH-responsive property. The application of triggered delivery was explored by loading acetamidophenol (a model hydrophilic drug) and etoricoxib (a model hydrophobic drug). In vitro drug release experiments were performed at three different temperatures (25, 32 and 39 °C) at two different pH (5.5 and 7) to study its drug release with response to temperature and pH. Drug release profiles obtained were found to have enhanced release for both the drugs respectively at 39 °C (above LCST) and pH5.5 when compared to other release conditions. In vitro skin permeation of both the drugs performed in rat abdominal skin using Franz diffusion cell showed enhanced drug release when the skin was subjected to higher temperature (39 °C). Moreover, it was also found that skin permeation for hydrophobic drug was better than that of hydrophilic drug. The in vivo biocompatibility studies of the CP gel in rat skin proved that the gel is biocompatible. The results obtained demonstrated the potential use of the thermoresponsive CP gel as an on-demand localized drug delivery system.

  4. Separation techniques: Chromatography

    Science.gov (United States)

    Coskun, Ozlem

    2016-01-01

    Chromatography is an important biophysical technique that enables the separation, identification, and purification of the components of a mixture for qualitative and quantitative analysis. Proteins can be purified based on characteristics such as size and shape, total charge, hydrophobic groups present on the surface, and binding capacity with the stationary phase. Four separation techniques based on molecular characteristics and interaction type use mechanisms of ion exchange, surface adsorption, partition, and size exclusion. Other chromatography techniques are based on the stationary bed, including column, thin layer, and paper chromatography. Column chromatography is one of the most common methods of protein purification. PMID:28058406

  5. Fun with Paper Chromatography.

    Science.gov (United States)

    Coleman, Dava; Hounshell, Paul B.

    1982-01-01

    Discusses paper chromatographic techniques and provides examples of typical classroom activities. Includes description of retardation values obtained during chromatography exercises and suggests using them for math lessons. (JN)

  6. Gel polymer electrolytes for batteries

    Science.gov (United States)

    Balsara, Nitash Pervez; Eitouni, Hany Basam; Gur, Ilan; Singh, Mohit; Hudson, William

    2014-11-18

    Nanostructured gel polymer electrolytes that have both high ionic conductivity and high mechanical strength are disclosed. The electrolytes have at least two domains--one domain contains an ionically-conductive gel polymer and the other domain contains a rigid polymer that provides structure for the electrolyte. The domains are formed by block copolymers. The first block provides a polymer matrix that may or may not be conductive on by itself, but that can soak up a liquid electrolyte, thereby making a gel. An exemplary nanostructured gel polymer electrolyte has an ionic conductivity of at least 1.times.10.sup.-4 S cm.sup.-1 at 25.degree. C.

  7. Efficient mucus permeation and tight junction opening by dissociable "mucus-inert" agent coated trimethyl chitosan nanoparticles for oral insulin delivery.

    Science.gov (United States)

    Liu, Min; Zhang, Jian; Zhu, Xi; Shan, Wei; Li, Lian; Zhong, Jiaju; Zhang, Zhirong; Huang, Yuan

    2016-01-28

    Oral administration of protein drugs is greatly impeded by the lack of drug carriers that can efficiently overcome the absorption barriers of mucosa tissue, which consists of not only epithelium but also a blanket of mucus gel. We herein report a novel self-assembled nanoparticle (NP) platform for oral delivery of insulin by facilitating the efficient permeation through both of these two barriers. The NP possesses a core composed of insulin and trimethyl chitosan (TMC), and a dissociable "mucus-inert" hydrophilic coating of N-(2-hydroxypropyl) methacrylamide copolymer (pHPMA) derivative. The NPs exhibited free Brownian motion and excellent permeability in mucus, which enabled the access of the NP core to the epithelial cell surface underneath the mucus. Moreover, investigation of NP behavior showed that the pHPMA molecules started to dissociate as the NP permeates through mucus, and the TMC NP core was then exposed to facilitate transepithelial transport via paracellular pathway. The pHPMA coating significantly improved transepithelial transport of TMC-based NP and their ability to open tight junctions between the mucus-secreting epithelial cells. Moreover, in diabetic rats, pHPMA coated NPs generated a prominent hypoglycemic response following oral administration, and exhibited a relative bioavailability 2.8-fold higher than that of uncoated TMC-based NPs. Our study provided the evidence of using pHPMA as "mucus-inert" agent to enhance mucus permeation of TMC-based NPs, and validated a novel strategy to overcome the multiple absorption barriers using NP platform with dissociable hydrophilic coating and TMC-based core possessing tight junction-opening ability.

  8. Alteration of skin hydration and its barrier function by vehicle and permeation enhancers: a study using TGA, FTIR, TEWL and drug permeation as markers.

    Science.gov (United States)

    Shah, D K; Khandavilli, S; Panchagnula, R

    2008-09-01

    Vehicles and permeation enhancers (PEs) used in transdermal drug delivery (TDD) of a drug can affect skin hydration, integrity and permeation of the solute administered. This investigation was designed to study the effect of the most commonly used vehicles and PEs on rat skin hydration, barrier function and permeation of an amphiphilic drug, imipramine hydrochloride (IMH). An array of well-established techniques were used to confirm the findings of the study. Thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy were used to determine changes in skin hydration. Alteration of the stratum corneum (SC) structure was investigated using FTIR studies. To monitor the barrier function alteration, transepidermal water loss (TEWL) measurement and permeation studies were performed. Our findings indicate that with hydration, there was an increase in the bound water content of the skin, and pseudoequilibrium of hydration (a drastic decrease in hydration rate) was achieved at around 12 h. Hydration increased the ratio between amide-I and amide-II peaks in FTIR and reduced the C-H stretching peak area. Both propylene glycol (PG) and ethanol (EtOH) dehydrated skin, with the latter showing a predominant effect. Furthermore, it was confirmed that PG and EtOH decreased the bound water content due to alteration in the protein domains and extraction of SC lipids, respectively. The effect of hydration on the SC was found to be similar to that reported for temperature. Permeation studies revealed that the dehydration caused by vehicles decreased IMH flux, whereas the flux was enhanced by PEs. The role of partition was predominant for the permeation of IMH through dehydrated skin. A synergistic effect was observed for PG and menthol in the enhancement of IMH. Further findings provided strong evidence that PG affects protein domains and EtOH extracts lipids from the bilayer. Both PG and EtOH, with or without PEs, increased TEWL. Initial TEWL was well

  9. Experimental Validation of Hybrid Distillation-Vapor Permeation Process for Energy Efficient Ethanol-Water Separation

    Science.gov (United States)

    The energy demand of distillation-based systems for ethanol recovery and dehydration can be significant, particularly for dilute solutions. An alternative separation process integrating vapor stripping with a vapor compression step and a vapor permeation membrane separation step,...

  10. IVIVR in oral absorption for fenofibrate immediate release tablets using dissolution and dissolution permeation methods.

    Science.gov (United States)

    Buch, P; Holm, P; Thomassen, J Q; Scherer, D; Kataoka, M; Yamashita, S; Langguth, P

    2010-10-01

    In a previous study it has been demonstrated that a dissolution/permeation (D/P) system can discriminate between different immediate release fenofibrate formulations. The fractions permeated were correlated with fenofibrate's in vivo exposure in rats following p.o. administration. In the present study more detailed investigations are presented using data from six fenofibrate tablets tested in vivo in humans. In these pharmacokinetic studies no significant differences between formulations in AUC but in Cmax were found. Differences between the Cmax values were not explained by the dissolution characteristics of the tablets but were rationalized on the basis of micellar entrapment and diminished mobility of the active ingredient by surfactants in the formulations. This was demonstrated by a permeation system using dialysis membranes. Thus a permeation step in addition to dissolution measurement may significantly improve the establishment of an IVIV relationship.

  11. Water vapor permeation and dehumidification performance of poly(vinyl alcohol)/lithium chloride composite membranes

    KAUST Repository

    Bui, Duc Thuan

    2015-10-09

    Thin and robust composite membranes comprising stainless steel scaffold, fine and porous TiO2 and polyvinyl alcohol/lithium chloride were fabricated and studied for air dehumidification application. Higher hydrophilicity, sorption and permeation were observed for membranes with increased lithium chloride content up to 50%. The permeation and sorption properties of the membranes were investigated under different temperatures. The results provided a deeper insight into the membrane water vapor permeation process. It was specifically noted that lithium chloride significantly reduces water diffusion energy barrier, resulting in the change of permeation energy from positive to negative values. Higher water vapor permeance was observed for the membrane with higher LiCl content at lower temperature. The isothermal air dehumidification tests show that the membrane is suitable for dehumidifying air in high humid condition. Additionally, results also indicate a trade-off between the humidity ratio drop with the water vapor removal rate when varying air flowrate.

  12. Meloxicam transdermal delivery: effect of eutectic point on the rate and extent of skin permeation

    Directory of Open Access Journals (Sweden)

    Soliman Mohammadi-Samani

    2014-02-01

    Conclusion: This study set out to determine that thymol plays as a skin permeation enhancer and increases the meloxicam skin absorption and this enhancement is significant at the eutectic point of drug-enhancer mixture.

  13. Experimental Validation of Hybrid Distillation-Vapor Permeation Process for Energy Efficient Ethanol-Water Separation

    Science.gov (United States)

    The energy demand of distillation-based systems for ethanol recovery and dehydration can be significant, particularly for dilute solutions. An alternative separation process integrating vapor stripping with a vapor compression step and a vapor permeation membrane separation step,...

  14. A fragment-based approach for the in silico prediction of blood-brain barrier permeation

    OpenAIRE

    Moda, Tiago L.; Carrara, Alexandre E.; Andricopulo, Adriano Defini

    2012-01-01

    Blood-brain barrier (BBB) permeation is an essential property for drugs that act in the central nervous system (CNS) for the treatment of human diseases, such as epilepsy, depression, Alzheimer's disease, Parkinson disease, schizophrenia, among others. In the present work, quantitative structure-property relationship (QSPR) studies were conducted for the development and validation of in silico models for the prediction of BBB permeation. The data set used has substantial chemical diversity an...

  15. Comparative evaluation of selected vegetable oils and Terpenes on Transdermal permeation of Ketorolac Tromethamine

    Directory of Open Access Journals (Sweden)

    Goudanavar Prakash

    2011-12-01

    Full Text Available A reservoir type transdermal patch for delivery of ketorolac tromethamine (KT, a potent analgesic agent was studied. Studies were carried out to investigate the effect of permeation enhancers on the in vitro permeation of KT across rat skin. Films were prepared by using hydroxy propyl methyl cellulose (HPMC and polyvinylalcohol (PVA polymers by incorporating glycerine as plasticizers using solvent casting method. A total of fourteen formulations were prepared by using same drug polymer ratio of 1:1 and incorporated different terpenes and vegetable oils as permeation enhancers in same concentrations. The prepared systems released the drug in the following order: FP2 > FP3 > FH2 > FP5 > FH3 > FP4 > FH5 > FH4 > FH6 > FP6 > FH7 > FP7 > FH1 > FH1. The various permeation parameters such as enhancement ratio and percent of drug permeated were determined for all the formulations. The maximum percent of drug permeation was observed with PVA monolithic system containing 10% d-limonene. Permeation enhancement of KT with different enhancers followed the order: d-limonene > cineole > olive oil > menthol >linseed oil > sunflower oil. The in vitro release studies revealed that terpenes showed better permeation enhancement than vegetable oils and the release was sustained up to 24 h and it follows zero-order kinetics. All the films were found to be stable at 37°C and 45°C with respect to their physical parameters. A reservoir type transdermal patch for delivery of KT thus appears to be feasible of delivering KT across skin.

  16. Factors that restrict intestinal cell permeation of cyclic prodrugs of an opioid peptide (DADLE)

    DEFF Research Database (Denmark)

    Ouyang, Hui; Chen, Weiqing; Andersen, Thomas E;

    2009-01-01

    The objective of this study was to determine the relative importance of metabolism by cytochrome P450 (CYP) enzymes versus efflux by P-glycoprotein (P-gp) in restricting the intestinal mucosal permeation of cyclic prodrugs (AOA-DADLE, CA-DADLE, OMCA-DADLE) of the opioid peptide DADLE (H......-gp), not metabolic enzymes (e.g., CYP 3A, esterases), restrict the permeation of peptide prodrugs across the rat intestinal mucosa....

  17. Formation and growth model of B-Al permeation layer of Steel 45

    Institute of Scientific and Technical Information of China (English)

    吉泽升; 李庆芬; 李冬华

    2002-01-01

    The B-Al permeation layers of Steel 45 were studied by means of SEM, TEM and XRD. The formation and growth model of permeation layer was proposed. The layer formation, growth and the migration behaviors of B were discussed. It is suggested that the diffusion of Al is deferred when the surface was covered by borides and aluminize compounds are surrounded by borides with the further growing of borides.

  18. Effect of membrane environment on proton permeation through gramicidin A channels.

    Science.gov (United States)

    Qin, Zhen; Tepper, Harald L; Voth, Gregory A

    2007-08-23

    Multistate empirical valence bond simulations were employed to study proton transport through gramicidin A channels embedded in two different lipid bilayers, glycerol 1-monooleate (GMO) and diphytanolphosphatidylcholine (DiPhPC). Free energy barriers to proton permeation were derived using a new internal reaction coordinate describing the proton permeation process. The large quantitative and qualitative differences between the two systems are discussed in terms of local bilayer structures, ordering of interfacial water, and channel flexibility in the two environments.

  19. Design of experiment approach for the optimization of polybrominated diphenyl ethers determination in fine airborne particulate matter by microwave-assisted extraction and gas chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Beser, Maria Isabel; Beltrán, Joaquim; Yusà, Vicent

    2014-01-03

    A sensitive and selective procedure for the determination of 12 polybrominated diphenyl ethers (BDE-28, BDE-49, BDE-47, BDE-66, BDE-100, BDE-119, BDE-99, BDE-155, BDE-154, BDE-153, BDE-139 and BDE-183) in airbone particulate matter (PM2.5) at trace level has been developed. The proposed method includes extraction PM2.5-bound PBDEs by microwave-assisted extraction (MAE) followed by gel permeation chromatography (GPC) clean-up and determination by GC-MS/MS using a programmed temperature vaporizer (PTV) in large volume injection (LVI) mode to introduce the sample to the chromatographic system. A design of experiment (DoE) approach was used for the optimization of large volume injection and microwave-assisted extraction parameters to improve these techniques efficiency. Other conditions of the method were studied: GC-MS/MS parameters, extraction solvent and matrix effect. The limit of quantification ranged from 0.063pgm(-3) to 0.210pgm(-3) when air volumes of 723m(3) were collected. Recoveries ranged from 80% to 106%. The method was successfully applied to eight real samples collected from a residential area of the monitoring network of the Region of Valencia Government (Spain) during April-August 2012. BDE-47 and BDE-99 were quantified in six and five samples respectively. The concentrations were ranged from 0.063 to 0.112pgm(-3) for BDE-47, and from 0.107 to 0.212pgm(-3) for BDE-99.

  20. Comprehensive multiresidue method for the simultaneous determination of 74 pesticides and metabolites in traditional Chinese herbal medicines by accelerated solvent extraction with high-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Jia, Zhengwei; Mao, Xiuhong; Chen, Ke; Wang, Ke; Ji, Shen

    2010-01-01

    In this paper, a multiresidue method for the simultaneous target analysis of 74 pesticides and metabolites in traditional Chinese herbal medicines (TCHMs) was developed using accelerated solvent extraction (ASE) coupled with HPLC/MS/MS. Pesticide residues were extracted from the different samples using ASE, then purified by gel permeation chromatography and graphitized carbon black/primary, secondary amine SPE. Gradient elution was used in conjunction with positive mode electrospray ionization MS/MS to detect 74 pesticides and metabolites from Cortex Cinnamomi, Flos Carthami, Folium Ginkgo, Herba Pogostemonis, Radix Ginseng, and Semen Ginkgo using a single chromatographic run. The analytical performance was demonstrated by the analysis of extracts spiked at three concentration levels ranging from 0.005 to 0.125 mg/kg for each pesticide and metabolite. In general, recoveries ranging from 70 to 110%, with RSDs better than 15%, were obtained. The recovery and repeatability data were in good accordance with European Union guidelines for pesticide residue analysis. The LOD for most of the targeted pesticides and metabolites tested was below 0.01 mg/kg.

  1. Enhanced skin permeation of naltrexone by pulsed electromagnetic fields in human skin in vitro.

    Science.gov (United States)

    Krishnan, Gayathri; Edwards, Jeffrey; Chen, Yan; Benson, Heather A E

    2010-06-01

    The aim of the present study was to evaluate the skin permeation of naltrexone (NTX) under the influence of a pulsed electromagnetic field (PEMF). The permeation of NTX across human epidermis and a silicone membrane in vitro was monitored during and after application of the PEMF and compared to passive application. Enhancement ratios of NTX human epidermis permeation by PEMF over passive diffusion, calculated based on the AUC of cumulative NTX permeation to the receptor compartment verses time for 0-4 h, 4-8 h, and over the entire experiment (0-8 h) were 6.52, 5.25, and 5.66, respectively. Observation of the curve indicated an initial enhancement of NTX permeation compared to passive delivery whilst the PEMF was active (0-4 h). This was followed by a secondary phase after termination of PEMF energy (4-8 h) in which there was a steady increase in NTX permeation. No significant enhancement of NTX penetration across silicone membrane occurred with PEMF application in comparison to passively applied NTX. In a preliminary experiment PEMF enhanced the penetration of 10 nm gold nanoparticles through the stratum corneum as visualized by multiphoton microscopy. This suggests that the channels through which the nanoparticles move must be larger than the 10 nm diameter of these rigid particles.

  2. Effects of Vehicles and Enhancers on the Skin Permeation of Phytoestrogenic Diarylheptanoids from Curcuma comosa.

    Science.gov (United States)

    Tuntiyasawasdikul, Sarunya; Limpongsa, Ekapol; Jaipakdee, Napaphak; Sripanidkulchai, Bungorn

    2017-04-01

    Curcuma comosa (C. comosa) is widely used in traditional medicine as a dietary supplement for health promotion in postmenopausal women in Thailand. It contains several diarylheptanoids, which are considered to be a novel class of phytoestrogens. However, the diarylheptanoids isolated from the plant rhizome are shown to have low oral bioavailability and faster elimination characteristics. The aim of this study was to investigate the permeation behavior of the active compounds of diarylheptanoids. The effects of binary vehicle systems and permeation enhancers on diarylheptanoids permeation and accumulation within the skin were studied using side-by-side diffusion cells through the porcine ear skin. Among the tested binary vehicle systems, the ethanol/water vehicle appeared to be the most effective system for diarylheptanoids permeation with the highest flux and shortest lag time. The presence of transcutol in the vehicle system significantly increased diarylheptanoid's permeation and accumulation within the skin in a concentration-dependent manner. Although the presence of terpenes in formulation decreased the flux of diarylheptanoids, it raised the amount of diarylheptanoids retained within the skin substantially. Based on the feasibility of diarylheptanoid permeation, C. comosa extract should be further developed into an effective transdermal product for health benefits and hormone replacement therapy.

  3. Study on hydrogen isotopes permeation in fluidized state of liquid lithium-lead

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, S.; Yoshimura, R.; Okada, M.; Fukada, S.; Edao, Y. [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-shi, Fukuoka (Japan)

    2015-03-15

    Lithium-lead (Li-Pb) is one of the most promising candidate materials for the liquid blanket of fusion reactors. Hydrogen transfer under a fluidized condition of Li-Pb is investigated experimentally to design a Li-Pb blanket system. Li-Pb eutectic alloy flows inside a Ni tube in the experimental system, where H{sub 2} permeates into and out of the forced Li-Pb flow. The overall H{sub 2} permeation rate is analyzed using a mass balance model. Hydrogen atoms diffuse in Ni and Li-Pb. The steady-state H{sub 2} permeation rate obtained by this experiment is smaller than the result of the calculation model. A resistance factor is introduced to the present analysis in order to evaluate the influence of other H{sub 2} transfer mechanisms, such as diffusion in Li-Pb and dissolution reaction between Ni and Li-Pb. The contribution of the resistance to the overall H{sub 2} permeation rate becomes large when the flow rate of Li-Pb is low. This is because the boundary layer thickness between Ni and Li-Pb affects the overall H{sub 2} permeation rate. When the flow velocity of Li-Pb increases, the thickness of the boundary layer becomes thin, and the driving force of H{sub 2} permeation through the Ni wall becomes bigger. (authors)

  4. Evaluation of the transdermal permeation of different paraben combinations through a pig ear skin model.

    Science.gov (United States)

    Caon, Thiago; Costa, Ana Carolina Oliveira; de Oliveira, Marcone Augusto Leal; Micke, Gustavo Amadeu; Simões, Cláudia Maria Oliveira

    2010-05-31

    Although parabens have several features of ideal preservatives, different studies have shown that they may affect human health due to their estrogenic activity. Therefore, various strategies have been applied to reduce their skin penetration. However, the effect of paraben combinations on transdermal permeation has not yet been investigated. Thus, the objective of this study was to evaluate paraben permeation in pig ear skin using a Franz diffusion cell system with capillary electrophoresis detection, in order to identify which paraben combinations (defined by a factorial design) have the lowest skin permeation. The permeation of isolated parabens was also evaluated and the permeation characteristics, obtained by the Moser model, confirmed that lipophilicity and molecular weight may influence the systemic absorption of these compounds. In previous tests using isolated parabens, methyl and ethyl parabens presented greater retention in the epidermis compared to the dermis, while propyl and butyl parabens had similar retention profiles in these layers. An increase in ethanol concentration and experimental time promoted greater parabens retention in the dermis compared to the epidermis. The binary combinations of methyl and ethyl parabens as well as of methyl and propyl parabens (added to several cosmetic products in order to increase the antimicrobial spectrum) reduced significantly their permeation rates through pig ear skin (with the exception of EP), probably due to the high retention of these parabens in the epidermis and dermis.

  5. Compensation effect in H 2 permeation kinetics of PdAg membranes

    KAUST Repository

    Zeng, Gaofeng

    2012-08-30

    Knowledge about the (inter)dependence of permeation kinetic parameters on the stoichiometry of H 2-selective alloys is still rudimentary, although uncovering the underlying systematic correlations will greatly facilitate current efforts into the design of novel high-performance H 2 separation membranes. Permeation measurements with carefully engineered, 2-7 μm thick supported Pd 100-xAg x membranes reveal that the activation energy and pre-exponential factor of H 2 permeation laws vary systematically with alloy composition, and both kinetic parameters are strongly correlated for x ≤ 50. We show that this permeation kinetic compensation effect corresponds well with similar correlations in the hydrogen solution thermodynamics and diffusion kinetics of PdAg alloys that govern H 2 permeation rates. This effect enables the consistent description of permeation characteristics over wide temperature and alloy stoichiometry ranges, whereas hydrogen solution thermodynamics may play a role, too, as a yet unrecognized source of kinetic compensation in, for example, H 2-involving reactions over metal catalysts or hydrogenation/ dehydrogenation of hydrogen storage materials. © 2012 American Chemical Society.

  6. Scoping Analyses on Tritium Permeation to VHTR Integarted Industrial Application Systems

    Energy Technology Data Exchange (ETDEWEB)

    Chang H. Oh; Eung S. Kim

    2011-03-01

    Tritium permeation is a very important current issue in the very high temperature reactor (VHTR) because tritium is easily permeated through high temperature metallic surfaces. Tritium permeations in the VHTR-integrated systems were investigated in this study using the tritium permeation analysis code (TPAC) that was developed by Idaho National Laboratory (INL). The INL TPAC is a numerical tool that is based on the mass balance equations of tritium containing species and hydrogen (i.e. HT, H2, HTO, HTSO4, TI) coupled with a variety of tritium sources, sink, and permeation models. In the TPAC, ternary fission and thermal neutron caption reactions with 6Li, 7Li 10B, 3He were taken into considerations as tritium sources. Purification and leakage models were implemented as main tritium sinks. Permeation of tritium and H2 through pipes, vessels, and heat exchangers were considered as main tritium transport paths. In addition, electroyzer and isotope exchange models were developed for analyzing hydrogen production systems including high temperature electrolysis (HTSE) and sulfur-iodine processes.

  7. Dynamic dissolution-/permeation-testing of nano- and microparticle formulations of fenofibrate.

    Science.gov (United States)

    Sironi, Daniel; Rosenberg, Jörg; Bauer-Brandl, Annette; Brandl, Martin

    2017-01-01

    The aim of the current study was to evaluate a dynamic dissolution-/permeation-system for prediction of gastrointestinal and absorption-behavior of two commercial fenofibrate formulations. To this end, both dissolution and barrier-flux were followed simultaneously for fenofibrate powder, a microparticle formulation (Lipidil® 200mg) and a nanoparticle formulation (LIPIDIL 145 ONE®) using a pair of side-by side diffusion cells separated by a cellulose hydrate membrane. Under such dynamic conditions, transient supersaturation arising from the nanoparticle formulation could be demonstrated for the first time. Furthermore, the dissolution-/permeation-system introduced here allowed for in-depth mechanistic insights: Biomimetic media, despite enhancing the apparent solubility of fenofibrate via micellar solubilization, did not increase permeation rate, irrespective whether the micro-/ or nanoparticle-formulation was tested. Nondissolved nano-/microparticles served as a reservoir helping to maintain high levels of molecularly dissolved drug, which in turn caused high and constant permeation rates. The micelle-bound drug may also serve as a drug-reservoir, yet of subordinate importance as long as there are nano-/microparticles present. Despite the limitations of the current experimental set-up, combined dissolution-/permeation-testing appears a valuable new tool to promote mechanistic understanding during formulation development. Last but not least, the in vitro dissolution and permeation behavior revealed here was in good qualitative agreement with human duodenal and plasma values reported in literature for the same formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Differential permeation of piroxicam-loaded PLGA micro/nanoparticles and their in vitro enhancement

    Science.gov (United States)

    Shankarayan, Raju; Kumar, Sumit; Mishra, Prashant

    2013-03-01

    Piroxicam is a non-steroidal anti-inflammatory drug used for the treatment of musculoskeletal pain. The main problem encountered when piroxicam is administered orally is its gastric side-effect (ulcer, bleeding and holes in the stomach). Transmucosal delivery and encapsulation of piroxicam in biodegradable particles offer potential advantages over conventional oral delivery. The present study was aimed to develop an alternative to piroxicam-delivery which could overcome the direct contact of the drug at the mucosal membrane and its permeation through the mucosal membrane was studied. To achieve this, the piroxicam was encapsulated in Poly (lactide- co-glycolide) (PLGA) microparticles (size 1-4 μm, encapsulation efficiency 80-85 %) and nanoparticles (size 151.6 ± 28.6 nm, encapsulation efficiency 92.17 ± 3.08 %). Various formulation process parameters were optimised for the preparation of piroxicam-loaded PLGA nanoparticles of optimal size and encapsulation efficiency. Transmucosal permeability of piroxicam-loaded PLGA micro- and nanoparticles through the porcine oesophageal mucosa was studied. Using fluorescently labelled PLGA micro- and nanoparticles, size-dependent permeation was demonstrated. Furthermore, the effect of different permeation enhancers on the flux rate and permeability coefficient for the permeation of nanoparticles was investigated. The results suggested that amongst the permeation enhancers used the most efficient enhancement of permeation was observed with 10 mM sodium dodecyl sulphate.

  9. Differential permeation of piroxicam-loaded PLGA micro/nanoparticles and their in vitro enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Shankarayan, Raju; Kumar, Sumit; Mishra, Prashant, E-mail: pmishra@dbeb.iitd.ac.in [Indian Institute of Technology Delhi, Department of Biochemical Engineering and Biotechnology (India)

    2013-03-15

    Piroxicam is a non-steroidal anti-inflammatory drug used for the treatment of musculoskeletal pain. The main problem encountered when piroxicam is administered orally is its gastric side-effect (ulcer, bleeding and holes in the stomach). Transmucosal delivery and encapsulation of piroxicam in biodegradable particles offer potential advantages over conventional oral delivery. The present study was aimed to develop an alternative to piroxicam-delivery which could overcome the direct contact of the drug at the mucosal membrane and its permeation through the mucosal membrane was studied. To achieve this, the piroxicam was encapsulated in Poly (lactide-co-glycolide) (PLGA) microparticles (size 1-4 {mu}m, encapsulation efficiency 80-85 %) and nanoparticles (size 151.6 {+-} 28.6 nm, encapsulation efficiency 92.17 {+-} 3.08 %). Various formulation process parameters were optimised for the preparation of piroxicam-loaded PLGA nanoparticles of optimal size and encapsulation efficiency. Transmucosal permeability of piroxicam-loaded PLGA micro- and nanoparticles through the porcine oesophageal mucosa was studied. Using fluorescently labelled PLGA micro- and nanoparticles, size-dependent permeation was demonstrated. Furthermore, the effect of different permeation enhancers on the flux rate and permeability coefficient for the permeation of nanoparticles was investigated. The results suggested that amongst the permeation enhancers used the most efficient enhancement of permeation was observed with 10 mM sodium dodecyl sulphate.

  10. Permeation barrier coating and plasma sterilization of PET bottles and foils

    Science.gov (United States)

    Steves, Simon; Deilmann, Michael; Bibinov, Nikita; Awakowicz, Peter

    2009-10-01

    Modern packaging materials such as polyethylene terephthalate (PET) offer various advantages over glass or metal containers. Beside this they only offer poor barrier properties against gas permeation. Therefore, the shelf-live of packaged food is reduced. Additionally, common sterilization methods like heat, hydrogen peroxide or peracetic acid may not be applicable due to reduced heat or chemical resistance of the plastic packaging material. For the plasma sterilization and permeation barrier coating of PET bottles and foils, a microwave driven low pressure plasma reactor is developed based on a modified Plasmaline antenna. The dependencies of important plasma parameters, such as gas mixture, process pressure, power and pulse conditions on oxygen permeation through packaging foil are investigated. A residual permeation as low as J = 1.0 ±0.3 cm^3m-2day-1bar-1 for 60 nm thick silicon oxide (SiOx) coated PET foils is achieved. To discuss this residual permeation, coating defects are visualized by capacitively coupled atomic oxygen plasma etching of coated substrate. A defect density of 3000 mm-2 is revealed responsible for permeation. For plasma sterilization, optimized plasma parameters based on fundamental research of plasma sterilization mechanisms permit short treatment times of a few seconds.

  11. Bacterial adhesion onto nanofiltration and reverse osmosis membranes: effect of permeate flux.

    Science.gov (United States)

    Semião, Andrea J C; Habimana, Olivier; Casey, Eoin

    2014-10-15

    The influence of permeate flux on bacterial adhesion to NF and RO membranes was examined using two model Pseudomonas species, namely Pseudomonas fluorescens and Pseudomonas putida. To better understand the initial biofouling profile during NF/RO processes, deposition experiments were conducted in cross flow under permeate flux varying from 0.5 up to 120 L/(h m(2)), using six NF and RO membranes each having different surface properties. All experiments were performed at a Reynolds number of 579. Complementary adhesion experiments were performed using Pseudomonas cells grown to early-, mid- and late-exponential growth phases to evaluate the effect of bacterial cell surface properties during cell adhesion under permeate flux conditions. Results from this study show that initial bacterial adhesion is strongly dependent on the permeate flux conditions, where increased adhesion was obtained with increased permeate flux, until a maximum of 40% coverage was reached. Membrane surface properties or bacterial growth stages was further found to have little impact on bacterial adhesion to NF and RO membrane surfaces under the conditions tested. These results emphasise the importance of conducting adhesion and biofouling experiments under realistic permeate flux conditions, and raises questions about the efficacy of the methods for the evaluation of antifouling membranes in which bacterial adhesion is commonly assessed under zero-flux or low flux conditions, unrepresentative of full-scale NF/RO processes.

  12. Crystallization and deuterium permeation behaviors of yttrium oxide coating prepared by metal organic decomposition

    Directory of Open Access Journals (Sweden)

    Takumi Chikada

    2016-12-01

    Full Text Available Yttrium oxide coatings were fabricated on reduced activation ferritic/martensitic steels by metal organic decomposition with a dip-coating technique, and their deuterium permeation behaviors were investigated. The microstructure of the coatings varied with heat-treatment temperature: amorphous at 670ºC (amorphous coating and crystallized at 700ºC (crystallized coating. Deuterium permeation flux of the amorphous coating was lower than the uncoated steel by a factor of 5 at 500ºC, while that of the crystallized coating was lower by a factor of around 100 at 400‒550ºC. The permeation fluxes of both coatings were drastically decreased during the measurements at higher temperatures by a factor of up to 790 for the amorphous coating and 1000 for the crystallized one, indicating a microstructure modification occurred by an effect of test temperature with hydrogen flux. Temperature dependence of deuterium diffusivity in the coatings suggests that the decrease of the permeation flux has been derived from a decrease of the diffusivity. Characteristic permeation behaviors were observed with different annealing conditions; however, they can be interpreted using the permeation mechanism clarified in the previous erbium oxide coating studies.

  13. pH-controllable water permeation through a nanostructured copper mesh film.

    Science.gov (United States)

    Cheng, Zhongjun; Du, Ming; Fu, Kewei; Zhang, Naiqing; Sun, Kening

    2012-11-01

    Water permeation is an important issue in both fundamental research and industrial applications. In this work, we report a novel strategy to realize the controllable water permeation on the mixed thiol (containing both alkyl and carboxylic acid groups) modified nanostructured copper mesh films. For acidic and neutral water, the film is superhydrophobic, and the water cannot permeate the film because of the large negative capillary effect resulting from the nanostructures. For basic water, the film shows superhydrophilic property, and thus the water can permeate the film easily. The permeation process of water can be controlled just by simply altering the water pH. A detailed investigation indicates that nanostructures on the