The incorporated hydrogel of chitosan-oligoconjugated linoleic acid vesicles and the protective sustained release for curcumin in the gel

Assemblies of as called "chitosan hydrogel-liposome" are expected for overcoming the burst effect in drug release from chitosan (CS) hydrogels. Herein, a hydrogel delivery system made of chitosan incorporated fatty acid vesicles was constructed for protective sustained release of curcumin (Cur). The curcumin was encapsulated in the prepared oligo-conjugated linoleic acid vesicles (OCLAVs), and then the drug-embedded vesicles were constructed to Cur-OCLAVs-CS hydrogels with CS solution. The fabricated Cur-OCLAVs-CS hydrogel was fluidic at room temperature and could be rapidly gelled at 37 °C. Morphology study proves that the OCLAVs stayed as nano-vesicles in the gel. The Cur-OCLAVs-CS hydrogels effectively declined the burst effect with enhanced antioxidant activity. The Cur (400 μM)-OCLAVs-CS gel presented a cumulative release rate of 51.23 % of curcumin in 96 h, comparing to 93.37 % of that from the Cur-CS gel. Moreover, the corporation of OCLAVs and CS made the gel exhibited strong synergistic effect on the antioxidant activity, with an enhancement of up to 148.1 % on the ferric reducing power. Therefore, the hydrogel carrier made of incorporated fatty acid vesicles-chitosan can be served as an injectable or 3D printable drug delivery system, which may provide a hint to overcome the burst effect that existed in chitosan and other polysaccharide-based gels.