Using casein and oxidized hyaluronic acid to form biocompatible composite hydrogels for controlled drug release.

To develop biocompatible polymeric hydrogels for the in-situ encapsulation and controlled release of hydrophilic drugs, the oxidized hyaluronic acid containing aldehyde groups was prepared by the reaction between hyaluronic acid and sodium periodate, and then used for the first time to crosslink casein protein in aqueous system. By changing its aldehyde group content or amount, we found that the gelation kinetics and the properties of resultant composite hydrogel could be modulated. Particularly, an increase of its aldehyde group content or amount was found to result in a shorten gelation time, an enhanced gel strength, a reduced swelling ratio and a prolonged drug release. In addition, the as obtained composite hydrogel was also evaluated for its in vitro cytotoxicity on L929 mouse fibroblast cells and was confirmed to have a good biocompatibility.