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https://www.readbyqxmd.com/read/28343348/process-analytical-techniques-for-hot-melt-extrusion-and-their-application-to-amorphous-solid-dispersions
#1
REVIEW
Patrick Hitzer, Tim Bäuerle, Tobias Drieschner, Edwin Ostertag, Katharina Paulsen, Holger van Lishaut, Günter Lorenz, Karsten Rebner
Newly developed active pharmaceutical ingredients (APIs) are often poorly soluble in water. As a result the bioavailability of the API in the human body is reduced. One approach to overcome this restriction is the formulation of amorphous solid dispersions (ASDs), e.g., by hot-melt extrusion (HME). Thus, the poorly soluble crystalline form of the API is transferred into a more soluble amorphous form. To reach this aim in HME, the APIs are embedded in a polymer matrix. The resulting amorphous solid dispersions may contain small amounts of residual crystallinity and have the tendency to recrystallize...
March 25, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28343346/molecularly-imprinted-polymer-prepared-with-polyhedral-oligomeric-silsesquioxane-through-reversible-addition-fragmentation-chain-transfer-polymerization
#2
Shu-Ping Gao, Xue Zhang, Li-Shun Zhang, Yan-Ping Huang, Zhao-Sheng Liu
Polyhedral oligomeric silsesquioxane (POSS) was utilized to prepare imprinted polymer through reversible addition-fragmentation chain transfer polymerization (RAFT) successfully. The imprinted polymer was made with a mixture of RAFT agent, 4-vinylpyridine (4-VP), POSS monomer [PSS-(1-propylmethacrylate)-heptaisobutyl substituted, MA 0702], and ethylene glycol dimethacrylate (EDMA), with ketoprofen (KET) as template. The influence of polymerization variables, the amount of RAFT agent and POSS monomer, the ratio of KET to 4-VP, and the ratio of 4-VP to EDMA, were investigated on the retention factor and imprinting effect...
March 25, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28343137/synthesis-of-novel-muramic-acid-derivatives-and-their-interaction-with-lysozyme-action-of-lysozyme-revisited
#3
Manas Jana, Anirban Ghosh, Abhishek Santra, Rajiv Kumar Kar, Anup Kumar Misra, Anirban Bhunia
HYPOTHESIS: The interaction of lysozyme with the N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) unit of peptidoglycan (PGN) polymer of the bacterial cell wall is of immense importance to understand the mechanism of lysozyme on PGN. EXPERIMENTS: The synthesis of three novel NAM derivatives containing fused oxazinone ring to the NAM moiety has been achieved. The synthesized compounds were evaluated for their potential as a glycomimetic acceptor of lysozyme using different biophysical and computational methods such as (1)H NMR, STD NMR, DOSY and Molecular docking...
March 16, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28343136/facile-microfluidic-production-of-composite-polymer-core-shell-microcapsules-and-crescent-shaped-microparticles
#4
Ekanem E Ekanem, Zilin Zhang, Goran T Vladisavljević
HYPOTHESIS: Core-shell microcapsules and crescent-shaped microparticles can be used as picolitre bioreactors for cell culture and microwells for cell trapping/immobilisation, respectively. RESULTS: Monodisperse polylactic acid (PLA) core-shell microcapsules with a diameter above 200μm, a shell thickness of 10μm, and 96% water entrapment efficiency were produced by solvent evaporation from microfluidically generated W/O/W emulsion drops with core-shell structure, and used to encapsulate Saccharomyces cerevisiae yeast cells in their aqueous cores...
March 18, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28343129/nano-sized-molecularly-imprinted-polymer-for-selective-ultrasound-assisted-microextraction-of-pesticide-carbaryl-from-water-samples-spectrophotometric-determination
#5
A A Bazrafshan, M Ghaedi, Z Rafiee, S Hajati, A Ostovan
Ultrasound-assisted dispersive solid phase microextraction followed by UV-Vis spectrophotometry (UA-DSPME UV-Vis) was designed for the extraction and preconcentration of Carbaryl using nano-sized molecularly-imprinted polymer (MIP-NP). Nano-sized Carbaryl-imprinted polymer was characterized by scanning electron microscopy. A preliminary Plackett-Burman design was applied for screening. Subsequently, central composite design under response surface methodology was used to investigate and model the Carbaryl adsorption as response as well as to optimize this response versus variables such as Carbaryl MIP-NP mass, sonication time, temperature, eluent volume, pH and vortex time...
March 18, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28343119/synergistically-enhanced-stability-of-laccase-immobilized-on-synthesized-silver-nanoparticles-with-water-soluble-polymers
#6
M N M Cunha, H P Felgueiras, I Gouveia, A Zille
Silver nanoparticles (AgNPs) were synthesized by citrate reduction method in the presence of polymers, poly(ethylene glycol) (PEG), poly(vinyl alcohol) (PVA) and chitosan, used as stabilizing agents, and an oxidoreductase enzyme, laccase (Lac), with the goal of expanding the NPs antimicrobial action. AgNPs were characterized by UV-vis spectrometry, dynamic light scattering and transmission electron microscopy. As protecting agents, PEG and PVA promoted the formation of spherical uniformly-shaped, small-sized, monodispersed AgNPs (≈20nm)...
March 12, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28343005/development-of-a-uv-crosslinked-biodegradable-hydrogel-containing-adipose-derived-stem-cells-to-promote-vascularization-for-skin-wounds-and-tissue-engineering
#7
Gozde Eke, Naside Mangir, Nesrin Hasirci, Sheila MacNeil, Vasif Hasirci
The aim of this study was to design a dermal substitute containing adipose derived stem cells (ADSC) that can be used to improve the regeneration of skin on difficult wound beds by stimulating rapid neovascularization. This was achieved by first synthesizing methacrylated gelatin (GelMA) and methacrylated hyaluronic acid (HAMA) precursors which could be stored at -80 (o)C after lyophilisation. Polymer precursors were then dissolved in media (in 15:1 ratio), ADSCs added together with the photoinitiator and crosslinked with 40 s of UV...
March 18, 2017: Biomaterials
https://www.readbyqxmd.com/read/28343004/actively-controlled-release-of-dexamethasone-from-neural-microelectrodes-in-a-chronic-in%C3%A2-vivo-study
#8
C Boehler, C Kleber, N Martini, Y Xie, I Dryg, T Stieglitz, U G Hofmann, M Asplund
Stable interconnection to neurons in vivo over long time-periods is critical for the success of future advanced neuroelectronic applications. The inevitable foreign body reaction towards implanted materials challenges the stability and an active intervention strategy would be desirable to treat inflammation locally. Here, we investigate whether controlled release of the anti-inflammatory drug Dexamethasone from flexible neural microelectrodes in the rat hippocampus has an impact on probe-tissue integration over 12 weeks of implantation...
March 13, 2017: Biomaterials
https://www.readbyqxmd.com/read/28342981/mechanisms-of-in-vivo-release-of-triamcinolone-acetonide-from-plga-microspheres
#9
Amy C Doty, David G Weinstein, Keiji Hirota, Karl F Olsen, Rose Ackermann, Yan Wang, Stephanie Choi, Steven P Schwendeman
Little is known about the underlying effects controlling in vitro-in vivo correlations (IVIVCs) for biodegradable controlled release microspheres. Most reports of IVIVCs that exist are empirical in nature, typically based on a mathematical relationship between in vitro and in vivo drug release, with the latter often estimated by deconvolution of pharmacokinetic data. In order to improve the ability of in vitro release tests to predict microsphere behavior in vivo and develop more meaningful IVIVCs, the in vivo release mechanisms need to be characterized...
March 22, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/28342878/3d-printing-for-the-design-and-fabrication-of-polymer-based-gradient-scaffolds
#10
Laura G Bracaglia, Brandon T Smith, Emma Watson, Navein Arumugasaamy, Antonios G Mikos, John P Fisher
To accurately mimic the native tissue environment, tissue engineered scaffolds often need to have a highly controlled and varied display of three-dimensional (3D) architecture and geometrical cues. Additive manufacturing in tissue engineering has made possible the development of complex scaffolds that mimic the native tissue architectures. As such, architectural details that were previously unattainable or irreproducible can now be incorporated in an ordered and organized approach, further advancing the structural and chemical cues delivered to cells interacting with the scaffold...
March 22, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28342789/enhanced-gastric-stability-of-esomeprazole-by-molecular-interaction-and-modulation-of-microenvironmental-ph-with-alkalizers-in-solid-dispersion
#11
Hien Van Nguyen, Namhyun Baek, Beom-Jin Lee
Due to the instability of esomeprazole magnesium dihydrate (EPM), a proton pump inhibitor, in gastric fluid, enteric-coated dosage form is commonly used for therapeutic application. In this study, we prepared new gastric fluid resistant solid dispersions (SDs) containing alkalizers. Then, new mechanistic evidence regarding the effects of pharmaceutical alkalizers on the aqueous stability of EPM in simulated gastric fluid was investigated. The alkalizer-loaded SD were prepared by dissolving or dispersing EPM, hydroxypropyl methylcellulose (HPMC) 6 cps, and an alkalizer, in ethanol 50% (v/v) followed by spray drying...
March 22, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28342783/effect-of-storage-on-the-physical-stability-of-thin-polymethacrylate-perphenazine-films
#12
Kristiina Korhonen, Elina Smolander, Ossi Korhonen, Jarkko Ketolainen, Riikka Laitinen
We evaluated the physical stability of thin polymethacrylate-drug films under three different storage conditions by X-ray powder diffraction, differential scanning calorimetry, scanning electron microscopy, polarized light microscopy, and Fourier transform infrared spectroscopy. Mechanical properties i.e. elongation, mechanical strength, and in vitro drug release from the thin films were also determined during storage. The films consisted of ammonium methacrylate copolymer (RLPO)/dimethylaminoethyl methacrylate copolymer (EPO), polyvinylpyrroline (PVP)/polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus) and perphenazine (PPZ)...
March 22, 2017: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28342356/heterogeneous-oxidative-desulfurization-of-diesel-fuel-catalyzed-by-mesoporous-polyoxometallate-based-polymeric-hybrid
#13
Huawei Yang, Bin Jiang, Yongli Sun, Luhong Zhang, Zhaohe Huang, Zhaoning Sun, Na Yang
In this work, the simple preparation of novel polymer supported polyoxometallates (POMs) catalysts has been reported. Soluble task-specific cross-linked poly (ionic liquid) (PIL) was prepared with N,​N-​dimethyl-​dodecyl-​(4-​vinylbenzyl) ammonium chloride and divinylbenzene as co-monomers. The as-prepared cationic PILs were assembled with different commercial POMs to form the interlinked mesoporous catalysts, and the formation mechanism was provided. The catalytic oxidation activities of the catalysts were closely related to the formation pathway of their corresponding peroxide active species...
March 10, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28342354/integrated-ion-imprinted-polymers-paper-composites-for-selective-and-sensitive-detection-of-cd-ii-ions
#14
Kai Huang, Ying Chen, Feng Zhou, Xiaoya Zhao, Jiafa Liu, Surong Mei, Yikai Zhou, Tao Jing
Paper-based sensor is a new alternative technology to develop a portable, low-cost, and rapid analysis system in environmental chemistry. In this study, ion imprinted polymers (IIPs) using cadmium ions as the template were directly grafted on the surface of low-cost print paper based on the reversible addition-fragmentation chain transfer polymerization. It can be applied as a recognition element to selectively capture the target ions in the complex samples. The maximum adsorption capacity of IIPs composites was 155...
March 18, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28340527/synthesis-and-adsorption-properties-of-4-vinylpyridine-and-styrene-copolymer-in-situ-immobilized-on-silica-surface
#15
E S Yanovska, L O Vretik, O A Nikolaeva, Y Polonska, D Sternik, O Yu Kichkiruk
Copolymer of 4-vinylpyridine with styrene was in situ immobilized on silica gel surface via the heterogeneous radical polymerization. Anchorage of the copolymer on the surface layer was confirmed by IR spectroscopy. The quantity of copolymer on the silica gel surface was evaluated as 25.73 wt.% by TG and DSC-MS analysis. "Islet" location of polymer layer on the silica surface was confirmed by the scanning electron microscopy. A high adsorption activity of silica gel with immobilized copolymer towards microquantitatives of Cu(II), Cd(II), Pb(II), Fe(III), and Ni(II) ions in steady state conditions as well as of Ni(II) ions in dynamic regime was found...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28340464/a-review-on-various-electrochemical-techniques-for-heavy-metal-ions-detection-with-different-sensing-platforms
#16
REVIEW
BabanKumar Bansod, Tejinder Kumar, Ritula Thakur, Shakshi Rana, Inderbir Singh
Heavy metal ions are non-biodegradable and contaminate most of the natural resources occurring in the environment including water. Some of the heavy metals including Lead (Pb), Mercury (Hg), Arsenic (As), Chromium (Cr) and Cadmium (Cd) are considered to be highly toxic and hazardous to human health even at trace levels. This leads to the requirement of fast, accurate and reliable techniques for the detection of heavy metal ions. This review presents various electrochemical detection techniques for heavy metal ions those are user friendly, low cost, provides on-site and real time monitoring as compared to other spectroscopic and optical techniques...
March 18, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28339813/microstructural-observation-of-fuel-cell-catalyst-inks-by-cryo-sem-and-cryo-tem
#17
Junichi Shimanuki, Shinichi Takahashi, Hajime Tohma, Atsushi Ohma, Ayumi Ishihara, Yoshiko Ito, Yuri Nishino, Atsuo Miyazawa
In order to improve the electricity generation performance of fuel cell electric vehicles, it is necessary to optimize the microstructure of the catalyst layer of a polymer electrolyte fuel cell. The catalyst layer is formed by a wet coating process using catalyst inks. Therefore, it is very important to observe the microstructure of the catalyst ink. In this study, the morphology of carbon-supported platinum (Pt/C) particles in catalyst inks with a different solvent composition was investigated by cryogenic scanning electron microscopy (cryo-SEM)...
February 9, 2017: Microscopy
https://www.readbyqxmd.com/read/28339485/chronic-parp-1-inhibition-reduces-carotid-vessel-remodeling-and-oxidative-damage-of-the-dorsal-hippocampus-in-spontaneously-hypertensive-rats
#18
Krisztian Eros, Klara Magyar, Laszlo Deres, Arpad Skazel, Adam Riba, Zoltan Vamos, Tamas Kalai, Ferenc Gallyas, Balazs Sumegi, Kalman Toth, Robert Halmosi
Vascular remodeling during chronic hypertension may impair the supply of tissues with oxygen, glucose and other compounds, potentially unleashing deleterious effects. In this study, we used Spontaneously Hypertensive Rats and normotensive Wistar-Kyoto rats with or without pharmacological inhibition of poly(ADP-ribose)polymerase-1 by an experimental compound L-2286, to evaluate carotid artery remodeling and consequent damage of neuronal tissue during hypertension. We observed elevated oxidative stress and profound thickening of the vascular wall with fibrotic tissue accumulation induced by elevated blood pressure...
2017: PloS One
https://www.readbyqxmd.com/read/28339190/luminescent-zn-ii-coordination-polymers-for-highly-selective-sensing-of-cr-iii-and-cr-vi-in-water
#19
Tian-Yi Gu, Ming Dai, David James Young, Zhi-Gang Ren, Jian-Ping Lang
Three photoluminescent zinc coordination polymers (CPs), {[Zn2(tpeb)2(2,5-tdc)(2,5-Htdc)2]·2H2O}n (1), {[Zn2(tpeb)2(1,4-ndc)(1,4-Hndc)2]·2.6H2O}n (2), and {[Zn2(tpeb)2(2,3-ndc)2]·H2O}n (3) (tpeb = 1,3,5-tri-4-pyridyl-1,2-ethenylbenzene, 2,5-tdc = 2,5-thiophenedicarboxylic acid, 1,4-ndc = 1,4-naphthalenedicarboxylic acid, and 2,3-ndc = 2,3-naphthalenedicarboxylic acid) were prepared from reactions of Zn(NO3)2·6H2O with tpeb and 2,5-H2tdc, 1,4-H2ndc, or 2,3-H2ndc under solvothermal conditions. Compound 1 has a two-dimensional (2D) grid-like network formed from bridging 1D [Zn(tpeb)]n chains via 2,5-tdc dianions...
March 24, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28339186/quantum-chemical-strain-analysis-for-mechanochemical-processes
#20
Tim Stauch, Andreas Dreuw
The use of mechanical force to initiate a chemical reaction is an efficient alternative to the conventional sources of activation energy, i.e., heat, light, and electricity. Applications of mechanochemistry in academic and industrial laboratories are diverse, ranging from chemical syntheses in ball mills and ultrasound baths to direct activation of covalent bonds using an atomic force microscope. The vectorial nature of force is advantageous because specific covalent bonds can be preconditioned for rupture by selective stretching...
March 24, 2017: Accounts of Chemical Research
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