Biocompatible and Biodegradable Hydrogels Based on Chitosan and Gelatin with Potential Applications as Wound Dressings

Abstract

Hydrogels based on chitosan and gelatin, were prepared by freeze-drying and ionic crosslinking with sodium tripolyphosphate. The anionic crosslinker interact with the protonated amino groups of chitosan and gelatin via electrostatic attractions. The hydrogels with a three-dimensional structure are macroporous with elongated or spherical pores, randomly or uniformly distributed as a function of the crosslinking degree; the uniformity increases by increase the time of crosslinking. The hydrogels absorb large quantities of phosphate buffered solution and simulated wound fluid. They are degraded by collagenase, the specific enzyme for collagens. Antimicrobial drug, Norfloxacin was loaded with good efficiency into hydrogel network and kinetics studies for drug release were carried out in phosphate buffered solutions. The drug release data analysis by mathematical models suggested a combination of swelling and matrix relaxation as major drug release mechanisms. Cytotoxicity assays were performed in order to establish the possibility to use the hydrogels in contact with human body; the prepared hydrogels are biocompatible and stimulate the cells proliferation.