• Macromolecular Research
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• v.17 no.3
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• pp.156-162
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• 2009

Supramolecular hydrogels were instantaneously fabricated by mixing aqueous solutions of $\alpha$-cyclodextrins ($\alpha$-CDs) and amphiphilic methoxy (polyethylene glycol) (MPEG)-$\varepsilon$-caprolactone (CL) oligomer, which was synthesized via the ring-opening polymerization of the CL monomer using low-molecular-weight MPEG ($M_n$ of MPEG=2,000 g/mol) as an initiator. The supramolecular structure of the hydrogels was revealed by X-ray diffraction (XRD) analyses. Rheological studies of the hydrogels revealed an elastic character when the number of CL units in the oligomer was more than 2, and the obtained hydrogels showed high storage modulus but relatively low shearing viscosity due to the low-molecular-weight character of the oligomer, which was more preferable for use as an injectable delivery system. The physical properties of the hydrogels could be modulated by controlling the chain morphology and concentration of the oligomers, as well as the feed molar ratio of the oligomer to $\alpha$-CD. The components of the supramolecular hydrogels are biocompatible and can readily be eliminated from the body. These features render the supramolecular hydro gels suitable as drug delivery systems and tissue engineering scaffolds.

• Bulletin of the Korean Chemical Society
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• v.34 no.7
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• pp.2016-2022
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• 2013

Ionically modified ${\beta}$-cyclodextrins, which have excellent water-solubility, have been interested in purification technology as well as drug carrier system. The present study summarizes the synthesis and characterization of cationic and anionic ${\beta}$-cyclodextrin (${\beta}$-CyD) products using by polycondensation. The oligo (${\beta}$-CyD)s are synthesized from ${\beta}$-CyD, epichlorohydrin (EP) and choline chloride (CC; for cationic polymer) or chloroacetic acid (CAA; for anionic polymer) through one step polycondenstaion process. Unlike the previous studies, we successfully purified the ionic ${\beta}$-CyD condensation products from the ${\beta}$-CyD reaction mixtures and accomplished a great level of structural analysis. The detailed structural analysis of these ionic ${\beta}$-CyD compounds is done by $^1H$ NMR, MALDI-TOF as well as GPC analysis and confirms the formation of oligomers with a few units of ${\beta}$-CyD. We found that the sequence of reactant addition also could effect on the molecular weight of the resulting product as well as the molar ratio of the reactants. Finally, we used the cationic and anionic ${\beta}$-CyD oligomers for fabricating multilayer films by layer-layer process.