LAUSR

Abstract The hydrogel was constructed via self-assembly of a commercially available α-CD and amphiphilic phytosterol ethoxylates (BPS-n) based on the host-guest interaction. The gel formation mechanism and microstructure were investigated by nuclear magnetic resonance, scanning electron microscopy, small angle X-ray scattering and rheological measurements. It was found that the oxyethyl chain of BPS-n could spontaneously form the channel-type inclusion complexes with several α-CDs to produce the hydrogel with a lamellar structure, which was distinguished from the previously reported usual morphologies like randomly cross-linked network formed by CDs and polyoxyethylene containing molecules. The H-bonds between α-CD molecules and the hydrophobic interaction between steroid nuclei of BPS-n mainly dominated the formation of hydrogel. Its gel-sol transition temperature, morphology and mechanical strength could be controlled by changing the oxyethyl chain length and α-CD concentration. In addition, this lamellar hydrogel exhibited good shear-thinning behavior comparing with the hydrogels with fibrous structure, and the gel-sol transition temperatures (30 ˜ 45 °C) were close to body temperature. These characteristics and such a simple preparation method make these hydrogels be useful in controlled drug release systems.