Sustained release drug delivery system based on MSNs dispersed in an injectable in-situ gelling chitosan hydrogel

Stimuli-responsive hydrogels offer unique advantages over traditional drug delivery systems regarding localized drug delivery and in situ release of anti-cancer drug molecules near the tumor site. In this work, mesoporous silica nanoparticles (MSNs) were synthesized and loaded by curcumin $(\mathbf{C U})$ and then dispersed in chitosan/beta-glycerol phosphate (CS/□GP) the solution, as an injectable thermo-responsive in situ forming hydrogel, to formulate a sustained release system, which could lead to drug delivery for a prolonged period in cancer therapy. CU-loaded MSNs (MSNs-CU) dispersed in CS/DGP hydrogel (CS/ $\mathbf{B G H} / \mathbf{M S N s}-\mathrm{CU}$) were characterized by FTIR, FESEM, and TEM analysis. The loading capacity and encapsulation efficiency of MSNs-CU were measured at $\mathbf{2 0 \%}$ and $78 \%$, respectively. In vitro drug release studies were performed in the simulated body fluid (SBF) and confirmed achieving the prolonged sustained release pattern for CU $\mathbf{9 0 \%}$ in 190h). TEM analysis displayed the successful uptake of nanoparticles by epithelial breast tumor cells (MCF-7).