Targeted delivery of flufenamic acid by V-amylose

2021 ◽  
Author(s):  
Rabab Fatima ◽  
Mousmee Sharma ◽  
Parteek Prasher
Keyword(s):  
Controlled Release ◽  
Targeted Delivery ◽  
Helical Structure ◽  
Xrd Analysis ◽  
Magic Angle Spinning ◽  
Flufenamic Acid ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
Acid Complex ◽  
Angle Spinning

Aim: Controlled release of flufenamic acid by helical V-amylose to achieve enzyme-responsive, targeted release of the cargo drug. Materials & methods: Solid-state cross-polarization magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS NMR), Fourier transform IR and x-ray diffraction (XRD) analysis validated the entrapment of flufenamic acid inside the helical structure of V-amylose. Scanning electron microscopy (SEM) investigations established the morphology of conjugates in simulated gastric environment (pH 1.2) and simulated intestine media (pH 7.2) containing hydrolyzing enzyme. Results & discussion: V-amylose–flufenamic acid complex displayed a sustained release of flufenamic acid for 12 h with a marked stability in simulated gastric pH, while showing a controlled release of drug in simulated intestine media. Conclusion: The V-amylose–flufenamic acid system achieves intestine-targeted delivery of flufenamic acid. The controlled release of flufenamic acid may ensure minimal ulcerogenicity and application as enteric coatings.

Synthesis of amorphous boron nitride from the molecular precursor ammonia-monochloroborane

1999 ◽  
Vol 14 (5) ◽  
pp. 1934-1938 ◽  
Author(s):  
Douglas R. Ketchum ◽  
Allison L. DeGraffenreid ◽  
Philipp M. Niedenzu ◽  
Sheldon G. Shore
Keyword(s):  
Xrd Analysis ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Gas Evolution ◽  
Amorphous Boron ◽  
X Ray Diffraction ◽  
Nmr Spectrum ◽  
X Ray ◽  
Molecular Precursor ◽  
Angle Spinning

Ammonia-monochloroborane, NH3BH2Cl, has been synthesized from the reaction of ammonia-borane with HCl in Et2O. Decomposition of the solid under NH3 to 600 °C produced amorphous BN in 97% yield. The 11B magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectrum of the amorphous BN is indicative of boron in the same environment as in hexagonal BN. Subsequent pyrolysis of the amorphous BN to 1000 °C produced turbostratic BN. Pyrolysis of NH3BH2Cl under vacuum to 1100 °C led to the formation of turbostratic BN as confirmed by x-ray diffraction (XRD) analysis. Gas evolution during this pyrolysis confirmed that the precursor loses H2 and HCl.

scholarly journals Slag Blended Cement Paste Carbonation under Different CO2 Concentrations: Controls on Mineralogy and Morphology of Products

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3404
Author(s):  
Wei Liu ◽  
Shifa Lin ◽  
Yongqiang Li ◽  
Wujian Long ◽  
Zhijun Dong ◽  
...  
Keyword(s):  
Blended Cement ◽  
Co2 Concentration ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Accelerated Carbonation ◽  
X Ray Diffraction ◽  
Cement Pastes ◽  
Co2 Concentrations ◽  
Angle Spinning ◽  
Natural Carbonation

To investigate the effect of different CO2 concentrations on the carbonation results of slag blended cement pastes, carbonation experiments under natural (0.03% CO2) and accelerated conditions (3, 20, and 100% CO2) were investigated with various microscopic testing methods, including X-ray diffraction (XRD), 29Si magic angle spinning nuclear magnetic resonance (29Si MAS NMR) and scanning electron microscopy (SEM). The XRD results indicated that the major polymorphs of CaCO3 after carbonation were calcite and vaterite. The values of the calcite/(aragonite + vaterite) (c/(a + v)) ratios were almost the same in all carbonation conditions. Additionally, NMR results showed that the decalcification degree of C-S-H gel exposed to 0.03% CO2 was less than that exposed to accelerated carbonation; under accelerated conditions, it increased from 83.1 to 84.2% when the CO2 concentration improved from 3% to 100%. In SEM observations, the microstructures after accelerated carbonation were denser than those under natural carbonation but showed minor differences between different CO2 concentrations. In conclusion, for cement pastes blended with 20% slag, a higher CO2 concentration (above 3%) led to products different from those produced under natural carbonation. A further increase in CO2 concentration showed limited variation in generated carbonation products.

scholarly journals Utilization of Calcium Carbide Residue Using Granulated Blast Furnace Slag

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3511 ◽  
Author(s):  
Joonho Seo ◽  
Solmoi Park ◽  
Hyun No Yoon ◽  
Jeong Gook Jang ◽  
Seon Hyeok Kim ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Calcium Carbide ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
Granulated Blast Furnace Slag ◽  
Calcium Carbide Residue ◽  
Angle Spinning ◽  
Furnace Slag

The solidification and stabilization of calcium carbide residue (CCR) using granulated blast furnace slag was investigated in this study. CCR binding in hydrated slag was explored by X-ray diffraction, 29Si and 27Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, and thermodynamic calculations. Mercury intrusion porosimetry and and compressive strength tests assessed the microstructure and mechanical properties of the mixtures of slag and CCR. C-A-S-H gel, ettringite, hemicarbonate, and hydrotalcite were identified as the main phases in the mixture of slag and CCR. The maximum CCR uptake by slag and the highest volume of precipitated solid phases were reached when CCR loading in slag is 7.5% by mass of slag, according to the thermodynamic prediction. This feature is also experimentally observed in the microstructure, which showed an increase in the pore volume at higher CCR loading.

Characterization of chitin and chitosan extracted from shrimp shells by two methods

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Carmiña Gartner ◽  
Carlos Alberto Peláez ◽  
Betty Lucy López
Keyword(s):  
Low Cost ◽  
Magic Angle Spinning ◽  
Chemical Extraction ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
Shrimp Shells ◽  
Before And After ◽  
Chitin Extraction ◽  
Angle Spinning ◽  
Chitin And Chitosan

AbstractShrimp shells from Penaeus Vannamei species were hydrolyzed for chitin extraction by a chemical and a papain enzymatic method. Composition of shells was analyzed and their microstructure was characterized before and after hydrolysis by microscopy. Chitin fibers arrangement in the tissue was preserved after chemical extraction, but after papain hydrolysis the tissue presented structural disarrangement indicating that papain reacts indistinctly with peptidic and N-acetyl linkages. Although chemical purification is very effective, by-products are not recoverable. Conversely, papain hydrolysis yields partially purified chitosan but permits aminoacids isolation, which is important in food industry. This method has other advantages such as low cost and easy accessibility of papain. Chitin and chitosan were characterized by thermogravimetric analysis, infrared spectrophotometry and capillary electrophoresis. Degree of N-acetylation (DA) was determined by cross-polarization magic angle spinning nuclear magnetic resonance (CPMAS 13CNMR) or potentiometry and crystallinity was measured by X ray diffraction.

scholarly journals Structure of nanocrystalline calcium silicate hydrates: insights from X-ray diffraction, synchrotron X-ray absorption and nuclear magnetic resonance

2016 ◽  
Vol 49 (3) ◽  
pp. 771-783 ◽  
Author(s):  
Sylvain Grangeon ◽  
Francis Claret ◽  
Cédric Roosz ◽  
Tsutomu Sato ◽  
Stéphane Gaboreau ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Calcium Silicate ◽  
Electron Probe ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Silicate Hydrates ◽  
Angle Spinning ◽  
X Ray Absorption

The structure of nanocrystalline calcium silicate hydrates (C–S–H) having Ca/Si ratios ranging between 0.57 ± 0.05 and 1.47 ± 0.04 was studied using an electron probe micro-analyser, powder X-ray diffraction,29Si magic angle spinning NMR, and Fourier-transform infrared and synchrotron X-ray absorption spectroscopies. All samples can be described as nanocrystalline and defective tobermorite. At low Ca/Si ratio, the Si chains are defect free and the SiQ3andQ2environments account, respectively, for up to 40.2 ± 1.5% and 55.6 ± 3.0% of the total Si, with part of theQ3Si being attributable to remnants of the synthesis reactant. As the Ca/Si ratio increases up to 0.87 ± 0.02, the SiQ3environment decreases down to 0 and is preferentially replaced by theQ2environment, which reaches 87.9 ± 2.0%. At higher ratios,Q2decreases down to 32.0 ± 7.6% for Ca/Si = 1.38 ± 0.03 and is replaced by theQ1environment, which peaks at 68.1 ± 3.8%. The combination of X-ray diffraction and NMR allowed capturing the depolymerization of Si chains as well as a two-step variation in the layer-to-layer distance. This latter first increases from ∼11.3 Å (for samples having a Ca/Si ratio <∼0.6) up to 12.25 Å at Ca/Si = 0.87 ± 0.02, probably as a result of a weaker layer-to-layer connectivity, and then decreases down to 11 Å when the Ca/Si ratio reaches 1.38 ± 0.03. The decrease in layer-to-layer distance results from the incorporation of interlayer Ca that may form a Ca(OH)2-like structure, nanocrystalline and intermixed with C–S–H layers, at high Ca/Si ratios.

Synthesis, X-ray diffraction and solid-state 31P magic angle spinning NMR study of ?-tricalcium orthophosphate

1996 ◽  
Vol 7 (7) ◽  
pp. 457-463 ◽  
Author(s):  
M. Bohner ◽  
J. LeMa�tre ◽  
A. P. LeGrand ◽  
J.-B. D'Espinose de la Caillerie ◽  
P. Belgrand
Keyword(s):  
Solid State ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nmr Study ◽  
Angle Spinning

Synthesis and characterization of montmorillonite-type phyllosilicates in a fluoride medium

Clay Minerals ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 177-190 ◽  
Author(s):  
M. Reinholdt ◽  
J. Miehé-Brendlé ◽  
L. Delmotte ◽  
R. Le Dred ◽  
M.-H. Tuilier
Keyword(s):  
Atomic Ratio ◽  
Magic Angle Spinning ◽  
Crystallization Time ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Angle Spinning ◽  
Mg Content ◽  
Fluoride Medium

AbstractThe fluorine route is thoroughly investigated for the hydrothermal synthesis of montmorillonite in the Na2O-MgO-Al2O3-SiO2-H2O system. Using the optimal conditions suggested by Reinholdt et al. (2001) for the crystallization of pure montmorillonites with the formula Na2x(Al2(1-x)Mg2x☐)Si4O10(OH)2, several parameters (x, Mg content, duration of crystallization, F/Si atomic ratio, pH, nature of counterbalance cation) are varied independently from their ideal values. The products are analysed by various techniques (X-ray diffraction, thermogravimetric analysis-differential thermal analysis, 29Si, 27Al and 19F magic angle spinning-nuclear magnetic resonance). It appears that a pure montmorillonite can only be obtained within a narrow x range (0.10 ≤ x ≤ 0.20). The presence of F in the starting hydrogel and the crystallization time also have significant effects on the purity of the final products. It is shown that a small amount of fluorine is needed for the crystallization of pure montmorillonite phyllosilicates.

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