Chitosan Conjugated-Ordered Mesoporous Silica: a Biocompatible Dissolution Enhancer for Promoting the Antidiabetic Effect of a Poorly Water-Soluble Drug of Repaglinide

The oral pathway is the preferred drug administration route in pharmaceutical sciences, however, the most employed ‘highly active’ drug candidates suffer from poor water solubility. The aim of this study was to develop repaglinide (RL)-loaded chitosan-grafted mesoporous silica material (MSM) to enhance drug dissolution. Such enhanced dissolution was investigated in in vitro and in vivo conditions. Our results showed successful grafting of chitosan (CN) on the surface of the MSM and the loading of RL into the mesopores of the silica host. Furthermore, the obtained drug dissolution profiles were fitted to mathematical models to characterize and compare drug dissolution profiles. Cytotoxicity evaluation against the human colorectal adenocarcinoma (Caco-2) cell line showed concentration-dependent toxicity for the MSN-based particles. Various liver and kidney mitochondrial functional parameters including lipid peroxidation assay, complex II activity, mitochondrial glutathione (GSH) level assay, ferric reducing antioxidant power (FRAP) assay, protein carbonyl level, and reactive oxygen species (ROS) formation, were used to investigate the biosafety of the silica-based dissolution enhancer. A significant reduction in blood glucose was observed after oral administration of the biocomposites for 24 h. The histopathological studies of the kidney and liver indicated no MSM-related adverse effects. We believed that our achievements can help the use of the hybrid organic–inorganic MSMs in improving the bioavailability of PWSDs in the one hand and, on the other hand, open a novel avenue to develop biocompatible and nontoxic MSMs in oral bioavailability of PWSDs.