Preparation, characterization, and cytotoxicity studies of niclosamide loaded mesoporous drug delivery systems

Recent reports on the anticancer potential of niclosamide have opened new avenues for anticancer treatment. Niclosamide belongs to the BCS class II, which is indicative of poor solubility and dissolution rate limited absorption. The aim of this study was to improve the dissolution rate of the drug by mesoporous drug delivery system. Porous silica grades (ordered and nonordered) with different pore size, pore volume and surface area were used in the study. The drug was loaded on silica carriers by the solvent evaporation method and characterized by BET surface area analysis, SEM, P-XRD, DSC, and FTIR. A discriminatory dissolution medium was developed for performing the in vitro dissolution of niclosamide. In comparison to the plain drug, all silica based formulations showed improvement in the dissolution rate. Maximum enhancement in the dissolution rate was observed in 1:2 drug:carrier loading ratio when compared to 1:1 ratio. Different properties of mesoporous silica like structural geometry, pore size and microenvironment pH demonstrated a significant impact on drug release from the formulations. Cytotoxicity of the optimized mesoporous formulations of niclosamide was explored in HCT-116, HCT-15, NCI, MDA-MB-231 and A549 cancer cell lines. Nearly 3 fold and 2 fold increase in% cytotoxicity of drug loaded Syloid-244 and Sylysia 350 at 1:2 ratio respectively, were observed when compared to the plain drug.