Thermal analysis of cyclodextrins and their inclusion compounds

Cyclodextrin-based aggregates and characterization by microscopy.

β-Cyclodextrin (β-CyD) was cross-linked by toluene 2,4-diisocyanate in the presence of various steroids in dimethyl sulfoxide, and the steroids were removed after the polymerization. The molecularly imprinted β-CyD polymer, obtained by using cholesterol or stigmasterol as the template, efficiently and reversibly bound the steroid in the mixtures of water and tetrahydrofuran. In these polymers, the mutual orientation of β-CyD molecules is regulated so that they cooperatively bind the target guests which are too large to be included in the cavity of one β-CyD molecule. When either the alkyl residue at the 17-position or the hydroxyl residue at the 3-position is absent from the template, however, the molecular imprinting is much less efficient. The mechanism for the imprinting and the structure of the guest-binding sites in the imprinted polymers have been proposed.

Molecularly Imprinted Cyclodextrins as Selective Receptors for Steroids1

Here, we demonstrated the electrospinning of polymer-free nanofibrous webs from inclusion complex (IC) between hydroxypropyl-β-cyclodextrin (HPβCD) and Vitamin E (Vitamin E/HPβCD-IC NF). The inclusion complexation between HPβCD and Vitamin E was prepared by using two different molar ratios (Vitamin E/HPβCD; 1:2 and 1:1), which correspond to theoretical value of ∼13% (w/w) and 26% (w/w) loading of Vitamin E in the nanofiber (NF) matrix. After electrospinning and storage, a very high loading of Vitamin E (up to ∼11% w/w, with respect to fiber matrix) was preserved in Vitamin E/HPβCD-IC NF. Because of the cyclodextrin inclusion complexation, only a minimal weight loss (only ∼2% w/w) was observed. While pure Vitamin E is insoluble in water, Vitamin E/HPβCD-IC NF web has displayed fast-dissolving behavior. Because of the greatly enhanced water-solubility of Vitamin E, Vitamin E/HPβCD-IC NF web has shown effective antioxidant activity. Additionally, Vitamin E/HPβCD-IC NF web has provided enhanced photostability...

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Antioxidant Vitamin E/Cyclodextrin Inclusion Complex Electrospun Nanofibers: Enhanced Water Solubility, Prolonged Shelf Life, and Photostability of Vitamin E

Preparation and spectral investigation on inclusion complex of β-cyclodextrin with rutin

Study and characterization of molecular complexes between cholesterol and beta cyclodextrin has been done using X-ray diffraction, thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and nuclear magnetic resonance spectroscopy (13C NMR). Whatever the value of the molar ratio cholesterol/βCD used during the preparation, the same compound is always obtained. Corresponding to a molar ratio 1/3 (cholesterol/βCD), this compound is a stable hydrate which, contrary toβCD, contains at room temperature a large amount of molecules of water. It can be dehydrated under low pressure but the thermal degradation occurs at 200°C (250°C forβCD). This implies that cholesterol is strongly bounded toβCD.

B. Gonzalez

Papers

Physicochemical characterization of cholesterol-beta cyclodextrin inclusion complexes