Novel composite hydrogels prepared from carboxymethyl chitosan and polysaccharides extracted from Ononis natrix for controlled release of bioactive molecules

Composite hydrogels were synthesized using carboxymethyl chitosan (CMCh) and polysaccharides (PS) extracted from Ononis natrix through chemical cross-linking with genipin, a naturally derived cross-linker. Hydrogels with different PS/CMCh ratios were characterized in terms of their structural, morphological, thermal, rheological, and biological properties. The results showed that an increase in PS concentration enhanced both the swelling capacity and viscoelastic properties of the hydrogels. In vitro drug release was carried out using ascorbic acid (Aas) and curcumin (Cur) as model of hydrophilic and hydrophobic bioactive molecules, respectively. Drug loading was achieved by immersion of lyophilized hydrogel in a drug solution. The release profiles showed a higher release rate at physiological pH (7.4) compared to acidic pH (5.5) due to enhanced hydrogel swelling under neutral conditions. Modeling with Korsmeyer-Peppas equation revealed Fickian diffusion-controlled release for Aas and non-Fickian diffusion-controlled release for Cur. Moreover, the composite hydrogels displayed notable antioxidant activity, and Aas-loaded hydrogel exhibited antibacterial effects against Staphylococcus aureus, highlighting their promise in counteracting oxidative damage and microbial infection, two crucial factors in the wound healing process. Therefore, it is concluded that the PS/CMCh composite hydrogel presents great potential for the development of biomaterials from renewable resources for controlled drug delivery systems and wound care applications.