Alginate-Based pH-Sensitive Hydrogels Encoated with Chitosan as a Bioactive Cargo Carrier with Caffeic Acid as a Model Biomolecule
Ifra Hassan, Adil Gani
Abstract
pH-responsive hydrogel beads as delivery systems for caffeic acid were fabricated by ionic cross-linking with calcium chloride encompassing chitosan as a coating material. Hydrogel beads were characterized for size aspects, polyphenol content, and Fourier transform infrared, antioxidant, in vitro release, and nutraceutical properties. The coating of chitosan in calcium alginate hydrogels modified the release profile of polyphenols in acidic medium. The recovery of encapsulated polyphenols occurred mainly in simulated gastric fluid by an erosion and diffusion mechanism, thereby providing a good small-intestinal-targeted release. Additionally, the release profile of caffeic acid revealed that the porosity of alginate beads could not efficiently retard the diffusion of caffeic acid from the beads. Electrostatic interaction between alginate and chitosan provided an effective barrier against caffeic acid release and significantly reduced swelling of the particles. Furthermore, the nutraceutical and antioxidant capacity evaluation demonstrated that caffeic acid encapsulated in hydrogel beads could provide good protection against degradation and enhance its antioxidant and nutraceutical capacity. These findings suggested that hydrogels could be used as a promising delivery system for encapsulating bioactive ingredients.