Search results for " Cyclodextrin"

Functionalized halloysite nanotubes: Efficient carrier systems for antifungine drugs

2018

Abstract Halloysite-cyclodextrin hybrid was employed as carrier for sustained release of clotrimazole for vaginal or buccal treatment of Candidiasis. The nanocarrier was obtained by functionalization of halloysite surface with cyclodextrin moieties by means of microwave irradiation, with the final goal to obtain a scaffold for the covalent linkage of cysteamine hydrochloride. The interaction between clotrimazole and the pristine components, namely cyclodextrin and halloysite, was thoroughly investigated by several techniques such as DSC, TGA, UV–vis spectroscopy and some adsorption studies were, also, carried out. The release of the antifungine molecule was finally investigated in a medium …

Use of 2 hydroxypropyl-beta-cyclodextrin therapy in two adult Niemann Pick Type C patients

2016

Stabilization of unilamellar catanionic vesicles induced by β-cyclodextrins: A strategy for a tunable drug delivery depot.

2018

The limited stability of catanionic vesicles has discouraged their wide use for encapsulation and controlled release of active substances. Their structure can easily break down to form lamellar phases, micelles or rearrange into multilamellar vesicles, as a consequence of small changes in their composition. However, despite the limited stability, catanionic vesicles possess an attractive architecture, which is able to efficiently encapsulate both hydrophobic and hydrophilic molecules. Therefore, improving the stability of the vesicles, as well as the control on unilamellar structures, are prerequisites for their wider application range. This study focuses on the impact of β-cyclodextrins fo…

On the formation of inclusion complexes at the solid/liquid interface of anchored temperature-responsive PNIPAAM diblock copolymers with γ-cyclodextr…

2017

The thermal responsive behavior of adsorbed layers of diblock copolymers of poly(N-isopropylacrylamide) (PNIPAAM) and poly((3-acrylamidopropyl)trimethylammonium chloride) (PAMPTMA(+)) with γ-cyclodextrin (γ-CD) at the solid/liquid interface has been investigated using three in situ techniques: null ellipsometry, quartz–crystal microbalance with dissipation monitoring, and neutron reflectometry. The measurements provided information about the adsorbed amounts, the layer thickness, hydration and viscoelastic properties, and the interfacial structure and composition. The copolymers adsorb to silica with the cationic PAMPTMA(+) blocks sitting as anchors in a flat conformation and the PNIPAAM ch…

Highly Sensitive Detection of Naphthalene in Solvent Vapor Using a Functionalized PBG Refractive Index Sensor

2012

We report an optical refractive index sensor system based on a planar Bragg grating which is functionalized by substituted γ-cyclodextrin to determine low concentrations of naphthalene in solvent vapor. The sensor system exhibits a quasi-instantaneous shift of the Bragg wavelength and is therefore capable for online detection. The overall shift of the Bragg wavelength reveals a linear relationship to the analyte concentration with a gradient of 12.5 ± 1.5 pm/ppm. Due to the spectral resolution and repeatability of the interrogation system, this corresponds to acquisition steps of 80 ppb. Taking into account the experimentally detected signal noise a minimum detection limit of 0.48 ± 0.05 pp…

Host—Guest Interactions Involving Cyclodextrins: Useful Complementary Insights Achieved by Polarimetry.

2007

Abstract By means of simple polarimetry, we studied the binding abilities of native α-, β-, and γ-cyclodextrins toward a group of suitably chosen model guests. We were able to get reliable estimations of the binding constants K, spread over a wide range (from 3.7 to 12,300 M−1), allowing us to carry on interesting comparisons. A comprehensive discussion of polarimetric data, and in particular a detailed analysis of the variations ΔΘ of molar optical activities consequent to inclusion, offered us the opportunity to get useful insights into the structure and dynamic behavior of host–guest complexes.

Solubility and solvation features of native cyclodextrins in 1-ethyl-3-methylimidazolium acetate

2022

The comprehension of the mechanism entailing efficient solvation of cyclodextrins (CD) by green solvents is of great relevance to boost environmentally sustainable usages of smart supramolecular systems. Here, 1-ethyl-3- methylimidazolium acetate, an ecofriendly ionic liquid (IL), is considered as an excellent solvent for native CDs. This IL efficiently dissolves up to 40 wt.% β- and γ-CD already at ambient temperature and X-ray scattering indicates that CDs do not tend to detrimental flocculation under these drastic concentration conditions. Simu- lation techniques reveal the intimate mechanism of CD solvation by the ionic species: while the strong hydrogen bonding acceptor acetate anion i…

Two components hydrogels formed by host-guest interactions

Interesterification of triglycerides with methyl acetate for biodiesel production using a cyclodextrin-derived SnO@γ-Al2O3 composite as heterogeneous…

2022

International audience; Particle morphology and surface properties of metal oxides are topics of great importance in the field of heterogeneous catalysis. Herein, we have developed a molecular-colloidal coassembly approach combined with an ultrasonic-assisted precipitation method to fabricate SnO@γ-Al2O3 composites with tuneable pore size and well-defined octahedral-shape crystal structure. The supramolecular assemblies formed between the randomly methylated β-cyclodextrin (RaMeβCD) and Pluronic F127 were employed as template to tailor the size and shape of γ-Al2O3 nanoparticles and direct their assembly almost exclusively on the surface of micrometer-sized SnO single …

Two-Component Hydrogels Formed by Cyclodextrins and Dicationic Imidazolium Salts

2014

In the framework of our recent interest in studying the gelling behaviour of imidazolium salts, we took into account the possibility of obtaining two-component hydrogels by combining cyclodextrins and dicationic imidazolium salts. In particular, we used diimidazolium salts differing in the alkyl chain length and in the size, shape, and coordination ability of the anion, namely the 3,3′-di-n-decyl- and 3,3′-di-n-dodecyl-1,1′-(1,4- phenylenedimethylene)diimidazolium dibromide, and 3,3′-di-n-dodecyl-1, 1′-(1,4-phenylenedimethylene)diimidazolium ditetrafluoroborate and dihexafluorophosphate. As far as cyclodextrins are concerned, to gain information on the effects of different sized cyclic olig…