Huo Weiqiang, Zhang Weixin, Wang Wei, Zhou Xiaohua
College of Science, South China Agricultural University, Guangzhou, China.
College of Life Science, South China Agricultural University, Guangzhou, China.
Int J Biol Macromol. 2014 Sep;70:257-65. doi: 10.1016/j.ijbiomac.2014.06.049. Epub 2014 Jul 8.
Two types of microcapsules (MCs) were prepared by the emulsion cross-linking method, where biguanidino chitosan (BGCS)and O-carboxymethyl chitosan (O-CMCS) served as the wall materials, and the antibacterial agent 2,4-diamino-6-(2-pyridyl)-1,3,5-triazine (PyTNH) served as a model water-soluble drug. The physicochemical performance of the MCs and their drug release behavior were investigated by Fourier transform infrared spectroscopy, thermogravimetric analysis/derivative thermogravimetric analysis, scanning electron microscopy, and swelling and in vitro drug release studies of the two MCs with unmodified chitosan-MCs (CS-MCs) used as the control. The results indicated that the degree of cross-linking, encapsulation efficiency, and thermal stability of the shell wall of the BGCS-microcapsules (BGCS-MCs) were much higher than those of the control and the O-CMCS-microcapsules (CMCS-MCs), owing to the reduction of steric hindrance and development of the conjugation effect in the cross-linking process. Studies on the swelling and in vitro drug-release behavior revealed a sustained release effect of the BGCS-MCs. Moreover, the CMCS-MCs were found to exhibit a pH-dependent drug release behavior, which can be attributed to the successive formation of H-bonds and repulsive forces with the change in the pH of the medium. Based on these results, the swelling-release models and the drug release kinetics of BGCS-MCs and CMCS-MCs are proposed.
采用乳液交联法制备了两种微胶囊（MCs），以双胍基壳聚糖（BGCS）和O-羧甲基壳聚糖（O-CMCS）为壁材，以抗菌剂2,4-二氨基-6-（2-吡啶基）-1,3,5-三嗪（PyTNH）为模型水溶性药物。通过傅里叶变换红外光谱、热重分析/微商热重分析、扫描电子显微镜以及对两种微胶囊与未改性壳聚糖微胶囊（CS-MCs）的溶胀和体外药物释放研究，考察了微胶囊的理化性能及其药物释放行为。结果表明，由于交联过程中空间位阻的降低和共轭效应的发展，BGCS微胶囊（BGCS-MCs）壳壁的交联度、包封率和热稳定性均高于对照和O-CMCS微胶囊（CMCS-MCs）。对溶胀和体外药物释放行为的研究揭示了BGCS-MCs的缓释效果。此外，发现CMCS-MCs表现出pH依赖性药物释放行为。这可归因于随着介质pH值的变化，氢键和排斥力的相继形成。基于这些结果，提出了BGCS-MCs和CMCS-MCs的溶胀-释放模型及药物释放动力学。
