Chitosan-alginate hydrogels for simultaneous and sustained releases of ciprofloxacin, amoxicillin and vancomycin for combination therapy

A set of chitosan-alginic acid hydrogels were prepared for multiple encapsulation and release of antibiotics for future application in combination therapy. Vancomycin, ciprofloxacin and amoxicillin were used as models, as widely used in therapy, either individually and in combination. The hydrogels were prepared by a simple, low cost and solventfree approach based on complexation between chitosan and alginic acid followed by crosslinking with CaCl2 to enhance structural properties. The antibiotics were loaded during the gelification process to maximize efficiency, and to reduce the loss of material. All the formulations were analyzed by scanning electron microscope to investigate the surface morphology, the inner structure, and the effect of the drugs loading. The swelling behavior, the cytotoxicityand the antibacterial activity, were evaluated. The investigation of the impact of simultaneous loading of the antibiotics along with the variation in the surrounding pH, on the release trend, represents a key part of work. The results revealed that the physicochemical properties of the combination of the drugs-loaded play an essential role in the morphology, structural changes and release profile.