Increased release time of diclofenac loaded into a cross-linked hyaluronic acid hydrogel

Hyaluronic acid from Bacillus subtilis was cross-linked with divinyl sulfone to produce hydrogels for controlled release formulations of diclofenac. Release studies show a significant increase in release time when diclofenac was loaded into the cross-linked hyaluronic acid hydrogel compared with commercial diclofenac formulations. Finally it was demonstrated that cross-linked hyaluronic acid hydrogels can be injected when mimicking subcutaneous injections with an injection force below 20 N.