论文部分内容阅读
通过在水溶性的壳聚糖衍生物——羟丙基壳聚糖(HPCS)的氨基上引入具有光反应活性的叠氮基团(4-叠氮苯甲酸),制备了一种光可引发交联的叠氮化羟丙基壳聚糖(Az-HPCS).利用红外光谱、核磁共振及氨基滴定法对其结构和取代度进行了表征.通过离子交联和光交联两步交联法制备了壳聚糖纳米凝胶,用透射电镜观察了纳米凝胶的形貌和粒径,并研究了纳米凝胶在不同pH值溶液中的溶胀度、载药行为及释药性能.实验结果表明包封率与溶液pH值无关,而溶胀度及释药行为则主要受pH值的影响.在酸性条件(pH 2.60)下,溶胀度最大,突释现象也最明显,30 min内释药率可达80%;在碱性条件(pH 9.40)下,溶胀度最低,药物释放速度较慢,2 h内释药率仅为40%;而在中性条件(pH 7.38)下,该纳米凝胶溶胀度中等,有明显的缓控释效果.
By introducing a photoreactive azide group (4-azidobenzoic acid) into the amino group of the water-soluble chitosan derivative-hydroxypropylchitosan (HPCS), a photoinitiated Crosslinked azidohydroxypropyl chitosan (Az-HPCS) was synthesized by the method of IR, 1HNMR and amino titration.The structure and degree of substitution were characterized by two-step ionic crosslinking and photocrosslinking The chitosan nanogels were prepared and the morphology and particle size of nanogels were observed by transmission electron microscopy. The swelling degree, drug loading behavior and drug release properties of nanogels in different pH solutions were investigated. The results showed that the entrapment efficiency was not related to the pH value of the solution, while the swelling degree and drug release behavior were mainly affected by the pH value.Under the acidic condition (pH 2.60), the degree of swelling was the highest and the burst phenomenon was the most obvious. The rate of up to 80%; under alkaline conditions (pH 9.40), the lowest degree of swelling, slow drug release, drug release rate was only 40% within 2 h; under neutral conditions (pH 7.38), the nano Gel degree of swelling moderate, there is a clear controlled release effect.