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Showing 1 to 20 of 36 for “"cellulose derivatives"”.
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Regioselective Synthesis of Cellulose Derivatives
Cellulose is the most abundant polysaccharide on earth and it is relatively a simple homopolymer with three hydroxyl groups, differing only subtly in reactivity. The position of substitution has a powerful influence on physical properties of cellulose derivatives. To better understand the structure …
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Synthesis and characterization of fluorinated cellulose derivatives
The synthesis of fluorinated cellulose derivatives was pursued for the purpose of investigating the effects of fluorine on the interfacial properties of cellulose derivatives, in multiphase materials. Synthetic approaches included: 1) the replacement of hydroxyl groups on cellulose with fluorine …
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The physiology and pharmacology of some cellulose derivatives
Increasing knowledge in physics and chemistry has stimulated research on high polymers, or to use another term, on macromolecules and on their applications in various fields. The definition of macromolecules given in 1922 by Staudinger and Fritschi states that a macromolecule is a compound with …
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Regioselective Synthesis of Novel Cellulose Derivatives for Drug Delivery
… the regioselective synthesis of new classes of cellulose derivatives with properties that could help improve the delivery of pharmaceutical drugs within the human body. The specific synthetic targets of this research were regioselectively carboxylated and regioselectively aminated cellulose …
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Synthesis and Applications of Cellulose Derivatives for Drug Delivery
In an effort to produce new derivatives of cellulose for drug delivery applications, methods were developed to regioselectively modify C-6 halo cellulose esters to produce cationic derivatives via nucleophilic substitution. Reaction of C-6 substituted bromo and iodo cellulose with trialkylated …
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Secondary interactions in blends of lignin and cellulose derivatives: composite morphology and properties
… the morphology of solvent cast hydroxypropyl cellulose (HPC) films. These techniques revealed the existence of three phases in the bulk material: 1) an amorphous phase, 2) a crystalline phase, and 3) a phase of intermediate order which arises as a consequence of liquid crystal mesophase …
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Regioselective Synthesis of Cellulose Esters
Cellulose is an extraordinarily abundant polymer that can be harvested and purified from trees and other renewable sources. Cellulose derivatives have been widely used as coatings, optical films, fibers, molded objects, and matrices for controlled release. The properties of cellulose derivatives …
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Synthesis and Structure-property Evaluation of Novel Cellulosic Polymers as Amorphous Solid Dispersion Matrices for Enhanced Oral Drug Delivery
… enhancement of hydrophobic drugs. Cellulose derivatives have strong potential as ASD polymers. We demonstrate herein design, synthesis and structure-property relationship characterization of a new series of organo-soluble cellulose omega-carboxyalkanoates for ASDs, by two different …
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Dielectric dispersion of poly(vinyl acetate) solutions
… type material possesses greater flexibility than cellulose derivatives in solution and, thus, the magnitude of capacitance changes over a frequency range is considerably reduced. Because of the very small changes in capacitance, reproducible results are difficult to obtain and definite conclusions …
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Synthesis and Characterization of Drug-Containing, Polysaccharide-Based Nanoparticles for Applications in Oral Drug Delivery
… were investigated. In this thesis, several novel cellulose derivatives and a pullulan derivative were studied. Among these polymers, carboxymethyl cellulose acetate butyrate (CMCAB)-drug nanoparticles were investigated in detail. Previous work has shown that the presence of different chemical …
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Effects of Methyl Cellulose on the Cellulolytic Bacterium, Ruminococcus Flavefaciens (Rumen, Anaerobe)
Cellulose degradation by Ruminococcus flavefaciens and other ruminal cellulolytic bacteria was strongly inhibited by highly substituted methyl celluloses (degree of substitution > 1.5 and mol wt > 12,000). The inhibitory response was concentration dependent with 0.1% (wt/vol) or methyl cellulose …
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Design and Synthesis of Complex and Fluorescent Labeled Cellulose-Based Derivatives for Orally Administered Drug Delivery Systems
Cellulose ethers are valuable matrices for drug-delivery systems (DDS), namely amorphous solid dispersions (ASD). ASD are efficient vehicles that can solubilize and stabilize poorly soluble drugs by increasing the time that it takes for drugs to crystallize, thereby allowing higher drug …
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Regioselective Synthesis of Glycosaminoglycan Analogs
… biological roles and biosynthesis modulation. Cellulose is an abundant and renewable natural polymer. Applications of cellulose and cellulose derivatives have drawn increasing attention in recent decades. Chemical modification is an efficient method to append new functionalities to the …
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The solvation of cellulose nitrate
… data concerning the state of solvation of cellulose derivatives dispersed in solvent-non solvent systems is rather limited. Since such derivatives possess a high commercial importance largely because of their ability to be dispersed and regenerated from solvent-non solvent systems by …
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Molecular Design and Structural Optimization of Nanocellulose-Based Functional Films
… design and structural optimization of nanocellulose-based functional films. Since nanocellulose can be modulated and designed at the molecular level, tunable chemistry and functionalization of nanocellulose can offer much richer materials properties and more possibilities to construct …
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Cellulose-based amorphous solid dispersions enhance rifapentine delivery characteristics and dissolution kinetics in vitro
… pH-responsive amorphous solid dispersions with cellulose derivatives including: hydroxypropylmethylcellulose acetate succinate (HPMCAS), cellulose acetate suberate (CASub), and 5-carboxypentyl hydroxypropyl cellulose (CHC). Most amorphous solid dispersions reduced rifapentine release at gastric …
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Regioselective chlorination of cellulose esters
Chemical modification of cellulose has been of growing interest, owing to the abundance and processing challenges of natural cellulose. To date, etherification and esterification are the most effective strategies to modify physicochemical properties of cellulose and append new functionalities. …
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Amorphous solid dispersion effects on in vitro solution concentrations of quercetin
… into amorphous solid dispersions (ASDs) with cellulose derivatives, eliminating crystallinity, and selectively releasing amorphous quercetin under simulated intestinal conditions (pH 6.8, 37C). Amorphous quercetin was dispersed in cellulose esters including 6-carboxycellulose acetate butyrate …
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Studies of Macromolecule/Molecule Adsorption and Activity at Interfaces
… Fenton (CMF) non-enzymatic degradations on cellulose and chitin thin films was studied by liquid-phase QCM-D and AFM. QCM-D is a powerful tool to monitor the kinetics of hydrolysis of regenerated cellulose and chitin model surfaces. Results from QCM-D and AFM showed that the majority of the …
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Pullulan w-carboxyalkanoates for Drug Nanodispersions
… pullulan is completely water soluble unlike cellulose. It has also been tested and shown to possess non-toxic, biodegradable, non-mutagenic and non-carcinogenic properties. Chemical modification of polysaccharides to increased hydrophobicity and increase functionality has shown great promise …
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