Confinement and controlled release of quinine on chitosan-montmorillonite bionanocomposites

To accomplish the controlled-release systems based on layered clay minerals, one of the best ways is to intercalate organic molecules into the interlayer gallery of clay minerals. Into a series of chitosan (CS) intercalated montmorillonite (MMT) nanocomposites, prepared via ion-exchange route, antimalarial drug [quinine (QUI)] was loaded to act as effective drug delivery systems. Among the CS-MMT nanocomposites, higher drug adsorption with decreasing CS concentration was observed. CS-MMT and CS-MMT/QUI intercalated compounds were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, and thermal analysis. The synthesized nanocomposites, filled in the gelatin capsules followed by coating of Eudragit® L 100, were tested for in vitro drug release performance in the sequential buffer environments at 37 ± 0.5 °C. As no drug release (0%) was observed in the gastric fluid, the coating of Eudragit® L 100 to the capsules is highly adequate. However, the drug release rate was comparatively faster from the CS intercalated clay with compare with pure clay. The drug release kinetic data revealed that the release of QUI from the nanocomposites can be explained by modified Freundlich model. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 A series of chitosan (CS) intercalated montmorillonite (MMT) bionanocomposites were prepared via ion-exchange, followed by adsorption of quinine (QUI). Chitosan has a good miscibility with MMT due to its hydrophilic and polycationic nature in acidic media. As a result, it can easily intercalate with MMT by means of cation exchange process. The adsorption of QUI on CS-MMT was mainly attributed to the interaction between functional groups of the QUI and CS, and to some extent the interaction with clay -OH groups present at the clay surface.