Search results for "solubility"
showing 10 items of 681 documents
Thermo-oxidative resistant nanocomposites containing novel hybrid-nanoparticles based on natural polyphenol and carbon nanotubes
2015
Abstract Quercetin (Q), a natural antioxidant molecule, is physically immobilized onto multi-walled carbon nanotubes (CNTs) bearing covalently-linked long-chain alkyl functional groups, and the so obtained hybrid-nanoparticles are used to prepare Ultra High Molecular Weight PolyEthylene-based nanocomposite films with enhanced thermo-oxidation resistance. The effective immobilization of the Q molecules is confirmed by spectroscopic (micro-Raman, ATR-FTIR, and FTIR) and thermo-gravimetric analyses, and the influence of the nanoparticles on the rheological behaviour and thermo-oxidative stability of the nanocomposites are investigated. Rheological analyses (linear viscoelasticity and stress re…
Methyl cellulose-based edible films and coatings I. Effect of plasticizer content on water and 1-octen-3-ol sorption and transport
1995
Edible films were prepared from methyl cellulose with various concentrations of poly(ethylene glycol) 400 (PEG400) used as a plasticizer. Water vapour and 1-octen-3-ol (an aroma compound) were selected as hydrophilic and hydrophobic volatile penetrants respectively. Their solubility and permeability through methyl cellulose-based edible films were studied using gas chromatography methods. Whatever penetrant was used, the flux increased with the PEG400 content. Transfer behaviour, i.e., the order of increased magnitude of the transfer rate, strongly depends on the nature of the volatile compound. However, water sorption only depends on the PEG400 content whereas the aroma compound sorption i…
Effect of Polarity of Solvent on Silanization of Halloysite Nanoclay Using (3-Glycidyloxy propyl) Trimethoxy Silane
2021
Abstract: The grafting of silane groups on clay surfaces has been recently investigated in order to fabricate versatile compounds with new potential applications in materials science and ecological engineering. This work explored the influence of variety of solvents with variable polarity on the silanization of halloysite nanoclay (HNT) surface by (3-Glycidyloxy propyl) trimethoxy silane. To this purpose, the functionalization of HNT by 3-Glycidyloxypropyltrimethoxysilane (GOPTMS) has been conducted in Ethanol (polar protic solvent), Tetrahydrofuran (THF) and Acetonitrile (polar aprotic solvents), and Hexane, 1,4-Dioxane and Toluene (non polar solvents). The silane grafted materials were ch…
A one-pot method to enhance dissolution rate of low solubility drug molecules using dispersion polymerization in supercritical carbon dioxide
2009
The surfactant assisted polymerization of 1-vinyl-2-pyrrolidone in supercritical carbon dioxide in the presence of Piroxicam, selected as a model of a low aqueous solubility drug, was studied in order to prepare in a single step a polymeric composite to enhance the rate of dissolution of the pharmaceutical compound. Reactive entrapping was carried out at 65 degrees C in the P range 21-38MPa. Under proper operative conditions we obtained the composite under the form of sub-micron spherical particles with relatively narrow particle size distribution. Drug loadings higher than 12% (w/w) were obtained and XRD and Raman spectroscopy suggest that the anti-inflammatory agent is dispersed in the ma…
Evaluation of the interaction and drug release from alpha,beta-polyaspartamide derivatives to a biomembrane model
2005
This article reports on a comparative study on the ability of various polymers, containing hydrophilic and/or hydrophobic groups, to interact with a biomembrane model using the differential scanning calorimetry (DSC) technique. Multilamellar vesicles of mixed dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidic acid (DMPA) were chosen as a model of cell membranes. The investigated samples were a water soluble polymer, the alpha,beta-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) and its derivatives partially functionalized with polyethylene glycol (PEG2000) to obtain PHEA-PEG2000, with hexadecylamine (C16) to obtain PHEA-C16, and with both compounds to obtain PHEA-PEG2000-C16. Th…
Process parameters of microsphere preparation based on propylene carbonate emulsion-precursors.
2020
This study aimed for a detailed understanding of the impact of different process parameters involved during celecoxib-loaded microsphere preparation based on propylene carbonate emulsion-precursors.Microspheres were prepared by a modified emulsification-solvent extraction method. Performed investigations included polymer solubility and viscosity, microsphere size, morphology and stability, propylene carbonate content as well as celecoxib solid state, content and release.Rough-walled round microspheres with sizes between 21 µm and 122 µm and an internal sponge-like structure filled with residual propylene carbonate (content between 1.9 ± 0.1% and 6.7 ± 0.5% w/w) were obtained. Encapsulation …
Influence of Polyvinyl Alcohol (PVA) on PVA-Poly-N-hydroxyethyl-aspartamide (PVA-PHEA) Microcrystalline Solid Dispersion Films
2020
AbstractThis study was conducted to formulate buccal films consisting of polyvinyl alcohol (PVA) and poly-N-hydroxyethyl-aspartamide (PHEA), to improve the dissolution of the drug through the oral mucosa. Ibuprofen sodium salt was used as a model drug, and the buccal film was expected to enhance its dissolution rate. Two different concentrations of PVA (5% w/v and 7.5% w/v) were used. Solvent casting was used to prepare films, where a solution consisting of drug and polymer was cast and allowed to dry. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) were used to investigate the pr…
Liquid phase exfoliation of antimonene: systematic optimization, characterization and electrocatalytic properties
2019
Antimonene, a novel group 15 two-dimensional material, is attracting great attention due to its outstanding physical and chemical properties. Despite its thermodynamic stability, the pronounced covalent character of the interlayer interactions imposes severe limitations on its exfoliation into mono- and few-layer. Here, we develop a systematic study of liquid phase exfoliation (LPE) with the aim to optimize antimonene production in terms of concentration and dimensional anisotropy, investigating the most relevant experimental factors affecting the exfoliation: pre-processing of pristine antimony, solvent selection based on Hansen solubility parameters and ultrasound conditions. Moreover, ex…
Evaluation of microhardness, sorption, solubility, and color stability of bulk fill resins : a comparative study
2020
Background Due to the increasing popularity of bulk fill resins, there is a concern that their components can be leached; this is because these are inserted in a single 4-5 mm increment. This in vitro study evaluated the microhardness, sorption, solubility, and color stability of three restorative bulk fill resins, namely: Filtek Bulk Fill (FBF), Tetric N-Ceram Bulk Fill (TNC), and Opus Bulk Fill (OBF). Material and Methods Cylindrical samples were fabricated to be 15 mm in diameter and 1 mm thick (n = 10). For the microhardness test, three random indentations were formulated on the samples using a micro-durometer with a load of 300 gf for 15 s. Sorption and solubility were then evaluated (…
Rietveld refinement study of vanadium distribution in V+4–ZrSiO4 solid solutions obtained from gels
2002
Abstract Vanadium-containing zircon gel precursors with nominal compositions Vx–ZrSiO4 with x=0.0, 0.004, 0.01, 0.04 and 0.2 were prepared by a previously reported colloidal sol-gel technique and annealed for 30 h at 1400 °C. The Rietveld refinement of the structures by X-ray powder diffraction confirms previous results concerning the limit of solubility of V+4 in the zircon structure. The new finding regarding with the entry of V+4 in the Zr+4 site for zircon doped with high contents of vanadium is in accordance with reported results.