Use of hydroxypropyl β-cyclodextrin as a dual functional component in xanthan hydrogel for sustained drug release and antibacterial activity

A hydrogel of xanthan gum (XG) was improved by crosslinking hydroxypropyl β-cyclodextrin (HPCD) physically to construct a novel drug delivery system. This hydrogel was full of the textures due to directional self-aggregations of XG helixes observed by optical microscopy and scanning electron microscopy. Rheological measurements indicated that HPCD added into XG hydrogel affected the dynamic behaviors of the hydrogel system, and the melting point of the hydrogels also rose from 117.5 °C up to 125.8 °C due to the enhancement of the supramolecular interactions. The XG/HPCD hydrogel with mass ratios 4:3 presented more elastic network than other XG/HPCD hydrogels did, which was more suitable for drug delivery. The supramolecular interactions in the gel network were mainly hydrogen bonding by the results of Fourier transform infrared spectroscopy. X-ray powder diffraction showed the XG/HPCD xerogel with amorphous characters to the benefit of loading drugs. The drug hydrogel loading anticancer methotrexate performed an effective controlled release, reflecting a host of HPCD molecule enhanced binding of drug methotrexate. And the hydrogel loading levofloxacin also exhibited fair antibacterial effects with inhibition zone method. Hence, this XG/HPCD hydrogel obtained would be a novel and interesting drug delivery system indeed.