Preparation of ROS-responsive drug-loaded hydrogels applied in wound dressings using supercritical solvent impregnation

Drug-loaded hydrogels with wound environment stimuli-responsive property can significantly promote wound healing and are widely applied in dressings. Two natural polymers, i.e. sodium alginate and sodium hyaluronate, were modified by 3-aminophenylboric acid and then cross-linked with polyvinyl alcohol to prepare ROS responsive hydrogels. Doxycycline hydrochloride was loaded onto hydrogels using supercritical solvent impregnation (SSI) technology, and the effects of immersion time, pressure and temperature on drug loading capacity (DLC) were investigated. DLC firstly increased and then decreased with the elevation of supercritical CO2 pressure, and maximum value was up to 11 mg/g at 15 MPa and 50 °C. In the in vitro drug release study, doxycycline hydrochloride was controllably released from hydrogels for 10 h via the sensitivity of boronate ester bonds to ROS. This work expands the application of SSI in wound dressing, which provides a new approach for the design of composite hydrogel formulations with uniform drug distribution.