Development of chitosan–pectin hydrogels for controlled drug release

Hydrogels are promising materials for smart drug delivery systems due to their biocompatibility, high water absorption capacity, and structural similarity to biological tissues, mainly enabling controlled and localized drug release. In this work, chitosan–pectin composite hydrogels were developed through physical crosslinking at different ratios (1:1, 2:1, and 1:2) and pectin concentrations (1%, 2.5%, and 5% w/v), incorporating the drug sulfasalazine. The hydrogels were characterized in terms of their structure, porosity, swelling capacity, and mass loss. In addition, the hydrogels were analyzed using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). FTIR analysis confirmed the formation of the polyelectrolyte complex and efficient sulfasalazine incorporation, as evidenced by the presence of bands characteristic of the functional groups of both polymers and of the drug's bonds. SEM revealed a transition from porous to compact structures as the pectin concentration increased. Hydrogels with higher chitosan contents exhibited greater porosity and swelling capacity, which is consistent with the SEM observations. In general, it was observed that the influence of pectin on porosity depends on the molar ratio of the polymers. In vitro sulfasalazine release studies fitted both the Higuchi and zero-order models, suggesting that drug release is controlled by diffusion and polymer matrix relaxation. These results demonstrated the potential of chitosan–pectin hydrogels as effective vehicles for controlled drug delivery applications.