载羟基喜树碱叶酸-壳聚糖微球制备及其缓释性

以羟基喜树碱为药物模型,壳聚糖为药物载体,叶酸为肿瘤靶向配体,利用静电相互作用的原理,通过离子交联法合成载羟基喜树碱的叶酸-壳聚糖(FA-CTS/HCPT)微球.利用动态光散射、扫描电镜、以及红外等技术对微球的结构、平均粒径及粒径分布、形态特征、对药物的包封率及载药量、体外释放等特点进行了初步研究.结果表明,所制得的微球平均粒径为32.65μm.扫描电镜下观察其形态圆整,大小均匀,无粘连.对羟基喜树碱包封率最高为90.9%,载药量为20.9%.在人工胃液pH值1.2及人工小肠液pH值6.8条件下具有很好的缓释作用且无突释现象.

Preparation and characterization of hydroxycamptothecin loaded folate-chitosan microspheres as a sustained-release drugs carrier

Hydroxycamptothecin(HCPT) has been shown to have activity against a broad spectrum of cancers.In order to enhance its tumor-targeting and anticancer activity,hydroxycamptothecin-loaded microspheres made from folate(FA)-decorated chitosan(CTS) were prepared and their release characteristics in vitro was evaluated.FA-CTS/HCPT microspheres were prepared by the ionic crosslinking method through the electrostatic interaction between the protonated amino of chitosan in acidic conditions and the deprotonation of carboxyl of folic acid in alkaline conditions.The morphological characteristics of microspheres were examined using a scanning electron microscope(SEM).The average diameter of microspheres and size distribution were determined by dynamic light scattering.The drug encapsulation efficiency(EE),loading capacity(LC),and in vitro release characteristics were determined using ultraviolet spectrophotometer.It indicated that the microspheres are uniform spherical and regular,with a size of 32.65 μm.Optimized preparation parameters lead to the successful preparation of 10-hydroxycamptothecin-loaded folate-conjugated chitosan microspheres characterized with encapsulation efficiency and loading capacity up to 90.9% and 20.9 % respectively.About 90% of hydroxycamptothecin was released from microspheres in 8 h at artificial gastric juice and artificial small intestinal fluid.It indicates the microspheres have good delayed release effect without burst-releasing phenomena.