A novel and simple oral colon-specific drug delivery system based on the pectin/modified nano-carbon sphere nanocomposite gel films.

The 3-aminopropyltriethoxysilane modified nano-carbon sphere (MNCS) was added into pectin-Ca2+ film to improve the controlled release properties of the pectin-based oral colon-specific drug delivery system (OCDDS). The FT-IR measurements indicated the successful modification of nano-carbon sphere via silylation reaction and the electrostatic interaction between the pectin molecules and MNCS in the composite film. The FE-SEM showed the pore structure when the MNCS was mingled with the pectin. The 5-fluorouracil (5-FU) was employed as the drug model and the controlled release properties of the corresponding OCDDSs were determined. The values of the encapsulation efficiency ranged from 30.1% to 52.6%. All composite film based OCDDSs presented higher encapsulation efficiency than single pectin-Ca2+ based OCDDS. The drug release studies emerged that almost all the OCDDSs from composite films presented better release properties than single pectin-Ca2+ based OCDDS. The sample C revealed best release performance with the cumulative release rate of 32.17%, 22.77% and 63.89% in the simulated gastric fluid, small intestinal fluid and colon fluid, respectively. In addition, the kinetics studies were performed to analyze the release data. The cytotoxicity assay indicated good biocompatibility of the composite carriers.