Study on montmorillonite/insulin/TiO2 hybrid nanocomposite as a new oral drug-delivery system.

This study was conducted in two main stages. In the first stage, drug-loaded montmorillonite nanocomposites were prepared by intercalation of insulin into the montmorillonite layers in acidic deionized (DI) water. In the second stage, to increase the release of insulin from the prepared nanocomposites they were coated with TiO2, an inorganic porous coating, by using titanium (IV) butoxide, as precursor. The prepared nanocomposites were characterized by FT-IR, XRD, FE-SEM, BET, DLS and Zeta potential analysis. After investigating the release behaviour of the nanocomposites by UV-Vis absorbance technique, the results revealed that incorporation of porous TiO2 coating increased the drug entrapment noticeably, and decreased the amount of drug release, so that nanocomposites without and with TiO2 coating released the drug after 60min and 22h in pH7.4, respectively. These results could be used in converting the insulin utilization from injection to oral.

Synthesis and characterization of insulin/zirconium phosphate@TiO2 hybrid composites for enhanced oral insulin delivery applications.

In this work, a series of composites of insulin (Ins)/zirconium phosphate (ZrP) were synthesized by intercalation method, then, these composites were coated with TiO2 by sol-gel method to prepare Ins/ZrP@TiO2 hybrid composites and the drug release of the composites was investigated by using UV-Vis spectroscopy. Ins/ZrP (10, 30, 60 wt%) composites were prepared by intercalation of insulin into the ZrP layers in water. Then Ins/ZrP composites were coated with different amounts of TiO2 (30, 50, 100 wt %) by using titanium tetra n-butoxide, as precursor. Formation of intercalated Ins/ZrP and Ins/ZrP@TiO2 hybrid composites was characterized by FT-IR, FE-SEM, BET and XRD analysis. Zeta potential of the optimized Ins/ZrP@TiO2 hybrid composite was determined -27.2 mV. Cytotoxic effects of the optimized Ins/ZrP@TiO2 hybrid composite against HeLa and Hek293T cell lines were evaluated using MTT assay and the results showed that designed drug delivery system was not toxic in biological environment. Compared to the Ins/ZrP composites, incorporation of TiO2 coating enhanced the drug entrapment considerably, and reduced the drug release. The Ins/ZrP composites without TiO2 coating released the whole drug after 30 min in pH 7.4 (phosphate buffer solution) while the TiO2-coated composites released the entrapped drug after 20 h. In addition to increasing the shelf life of hormone, this nanoencapsulation and nanocoating method can convert the insulin utilization from injection to oral and present a painless and more comfortable treatment for diabetics.