Characterization, release, and antioxidant activity of caffeic acid-loaded collagen and chitosan hydrogel composites

Abstract

Collagen- and chitosan-based hydrogel composites were successfully prepared using a solvent casting technique. Tetraethyl orthosilicate was employed as a crosslinking agent. The loaded amount of caffeic acid (CA) was 5–30wt.% among the hydrogel composites. Fourier-transform infrared (FTIR) spectroscopy was used to study the structural properties of the hydrogel. The vibrations at 1650 and 1380cm−1 were attributed to CO and CN stretching, respectively, and they were involved in the molecular vibration of collagen, chitosan, and CA. The thermal decomposition of hydrogel is classified into three stages, and it did not significantly change during the experiment. In the presence of CA, the glass transition temperature was slightly shifted from 60–70°C to 70–90°C. CA can be an obstacle for the molecular chain movement of both chitosan and collagen. Morphological studies performed by scanning electron microscopy showed that the hydrogel cracked in the presence of CA. CA molecules diffused onto the hydrogel surface when it became dry. CA decreased the swelling properties and the degradation behavior. The aromatic structure of CA increased the dimensional stability of hydrogel when it was immersed in medium. The drug release study revealed gradual release profiles within 8h, and the release pattern was influenced by the loaded amount of CA. The release behavior was rapid within 60min, and it was stable for 8h. Antioxidant activities were investigated through DPPH·, ABTH·+, and FRAP assays, and the total phenolic content was also determined. The antioxidant properties of the CA loaded-chitosan and collagen composite hydrogel demonstrated potential usefulness for pharmaceutical and cosmetic research.