In situ Crosslinking System of Gelatin with Acrylated β-cyclodextrin Towards the Fabrication of Hydrogels for Sustained Drug Release

Cyclodextrins (CDs) are of interest in fabrication of various polymeric platforms; especially the crosslinked networks that possess unique advantages in biomedical applications. Benefiting from the abilities of CDs to form inclusion complexes with hydrophobic drug molecules, hydrogel-based sustained drug platforms employ CDs as nano-buckets in the network structure. In the current study, we report on the fabrication of gelatin based hydrogels chemically crosslinked with acrylated β-cyclodextrin (β-CD) as sustained drug release platforms. A simple and practical synthesis of crosslinked networks was achieved by Michael addition reaction of gelatin amino functionalities onto acryloyl groups of modified β-CD. Tunable synthesis of hydrogels incorporating different amount of β-CD molecules were maintained by simple adjustment of the reaction stoichiometry between amine and acrylate groups. The resulting hydrogels were characterized by their equilibrium swelling ratios and rheological properties. Thus obtained hydrogels were evaluated in terms of their drug loading capacities and sustained release efficiencies. The results demonstrated that the amount of drug loading and prolonged release is dependent on the amount of β-CD in the gel network. Owing to their in situ gel forming abilities, these hydrogels can be used as injectable formulations for various biomedical applications.