Suchergebnisse

This book is the first volume of two volumes on cyclodextrins published in the series Environmental Chemistry for a Sustainable World. After a brief description of the cyclodextrin fundamentals, the first chapter by Grégorio Crini et al. provides an overview of cyclodextrin research during the last 5 years. The second chapter by Michal Řezanka discusses the synthesis of novel cyclodextrin systems by selective modifications. Then Eric Monflier et al. describes the synthesis of nanostructured porous materials based on cyclodextrins, and applications in heterogeneous catalysis and photocatalysis. The use of thermal analyses for assessing cyclodextrin inclusion complexes is reviewed in chapter 4 by Daniel Hădărugă et al. Experimental methods for measuring binding constants of cyclodextrin inclusion compounds are presented by David Landy. The second volume reviews cyclodextrin applications in medicine, food, environment and liquid crystals

The formation of small hybrid aggregates between excipient and drug molecules is one of the mechanisms that contributes to the solubilization of active principles in pharmaceutical formulations. The characterization of the formation, governing interactions and structure of such entities is not trivial since they are highly flexible and dynamic, quickly exchanging molecules from one to another. In the case of cyclodextrins, this mechanism and the formation of inclusion complexes synergistically cooperate to favour the bioavailability of drugs. In a previous study we reported a detailed characterization of the possible formation of inclusion complexes with 1:1 stoichiometry between remdesivir, the only antiviral medication currently approved by the United States Food and Drug Administration for treating COVID-19, and sulphobutylether-β-cyclodextrins. Here we extend our study to assess the role of the spontaneous aggregation in the solubilization of the same drug, by molecular dynamics simulations at different relative concentrations of both compounds. The number of sulphobutylether substitutions in the cyclodextrin structure and two different protonation states of the remdesivir molecule are considered. We aim to shed light in the solubilization mechanism of sulphobutylether-β-cyclodextrins, broadly used as an excipient in many pharmaceutical formulations, in particular in the case of remdesivir as an active compound ; R.G.-F thanks to the Spanish Agencia Estatal de Investigación (AEI) and the ERDF (RTI2018-098795-A-I00) and for a "Ramón y Cajal" contract (RYC-2016-20335), to Xunta de Galicia (ED431F 2020/05) and Centro singular de investigación de Galicia accreditation 2019-2022, ED431G 2019/03) and the European Union (European Regional Development Fund - ERDF). Á. P. thanks to the Ministerio de Ciencia e Innovación (PID2019-111327 GB-I00) ; SI

19 Páginas; 2 Tablas; 2 Figuras ; Carotenoids refer to a wide class of lipophilic pigments synthesized by plants, exert photoprotective and antioxidant properties that are lost upon carotenoid degradation. Their inclusion into hydrophilic host-molecules could improve their stability. Cyclodextrins, provide a hydrophobic cavity in the core of their structure while the outer configuration is suitable with aqueous environments. Carotenoids can accommodate into the hydrophobic core of cyclodextrins and therefore, they are protected from exogenous stress. Literature reported that carotenoid structure could modulate stability of the complexes, however no conclusions can be drawn as the studies performed so far were not completely analogous. We describe the synthesis of several carotenoids/β-CDs inclusion complexes and provide experimental evidences that β-CDs inclusion renders these compounds more stability towards the oxidizing agents (2,2′-azobis, 2-methylpropionamidine dihydrochloride and hydrogen peroxide). Esterified carotenoids were also used in this work to screen the influence of this particular structural configuration of xanthophylls against oxidation. ; We would like to thank Dr. Ralf Wellinger for continuous support. Research of Dr Fernández-García was supported by Junta de Andalucía (P11-CTS-7962) and the European Union (FEDER). Financial support of the Spanish Government (Ministry of Economy and Competitiveness, project AGL2013-42757-R) is also acknowledged. ; Peer reviewed

[Image: see text] Recently, β-cyclodextrin (βCD)-based polymers with enhanced adsorption kinetics and high removal capacity of organic micropollutants (OMPs) and uptake rates have been synthesized and tested experimentally. Although the exact physical–chemical mechanisms via which these polymers capture the various types of OMPs are not yet fully understood, it is suggested that the inclusion complex formation of OMPs with βCD is very important. In this study, the inclusion complex formation of OMPs with βCD in an aqueous solution is investigated by using the well-established attach–pull–release method in force field-based molecular dynamics simulations. A representative set of OMPs is selected based on the measured occurrences in surface and ground waters and the directives published by the European Union. To characterize the formation of the inclusion complex, the binding free energies, enthalpies, and entropies are computed and compared to experimental values. It is shown that computations using the q4md-CD/GAFF/Bind3P force field combination yield binding free energies that are in reasonable agreement with the experimental results for all OMPs studied. The binding enthalpies are decomposed into the main contributing interaction types. It is shown that, for all studied OMPs, the van der Waals interactions are favorable for the inclusion complexion and the hydrogen bond formation of the guest with the solvent and βCD plays a crucial role in the binding mechanism. Our findings show that MD simulations can adequately describe the inclusion complex formation of βCD with OMPs, which is the first step toward understanding the underlying mechanisms via which the βCD-based polymers capture OMPs.