Amphoteric Polymer-Clay Nanocomposites with Drug-Controlled Release Property

Quaternized carboxymethyl chitosan (QCMC) is a novel derivative of chitosan with great potential in clinical medicine application. In this study, in order to widen its application, QCMC was used to intercalate into organic rectorite (OREC) to prepare polymer/ layered silicate nanocomposite. XRD and TEM results showed that QCMC had been inserted into the interlayer of layered silicate; the largest interlayer distance was 4.7nm when the mass ratio of QCMC to OREC was 2:1. FTIR, XRD, 27Al-NMR, 29Si-NMR and Zeta potential analyses indicated that there was strong interaction between QCMC and OREC. Thermal study demonstrated that the introduction of OREC improved the thermal stability of QCMC. QCMC and nanocomposite nanoparticles with size aound 400nm were prepared via crosslinking with calcium alginate, and their drug-controlled release properties were investigated. It was found that the incorporation of OREC had important effect on the drug-delivery property of QCMC. In comparison with the nanoparticles made of pure QCMC, the nanoparticles obtained from the nanocomposites could encapsulate BSA more effectively and release the drug more slowly. Therefore, it can be confirmed that QCMC/OREC nanocomposites are more suitable to be used in the biomedicine field than single QCMC.