Preparation and antibacterial activity of chitosan grafted cyclodextrin hydrogel loaded berberine hydrochloride using dual gelling agent

In this paper, cyclodextrin-grafted-chitosan (CD-g-CS) with different degrees of substitution (DS) was synthesized successfully by the reaction of O-p-toluenesulfonyl-β-cyclodextrin (TCD) and chitosan (CS), and a novel injectable thermosensitive hydrogel with rapid gelation was developed by physical cross-linking using dual gelling agents of αβ-glycerophosphate-sodium and hydrogen carbonate (GP-SHC). The results of 1H-NMR showed that the DS of CD-g-CS increased with the increase of TCD/CS (w/w). The influence of CD-g-CS with different DS, the concentration of SHC, and the ratio of CD-g-CS/GP-SHC (v/v) on gel time, swelling, drug release, degradation, and antibacterial activity of hydrogels prepared were studied. The results of FTIR indicated that the intermolecular interaction occurred in the hydrogel. And the hydrogel had a three-dimensional porous structure seen from SEM images. Compared with CS/GP hydrogel, the gel time of prepared hydrogel was shorter, which was less than 6 min, and the shortest gel time was 0.5 min. The prepared hydrogels had a good swelling ratio and degradable behavior. Berberine hydrochloride (BBH) was used as a model drug, and the gel showed a sustained drug release profile. In addition, the hydrogel had excellent antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Therefore the BBH@CD-g-CS/GP-SHC hydrogels had great potential in the development of biomedical drug delivery systems and antibacterial materials.