新型可注射温敏水凝胶的制备及其释药性能

采用改性壳聚糖作为药物载体制备了一种可注射温敏水凝胶。将单甲氧基醚聚乙二醇2000（mPEG2000）接枝到壳聚糖(CS)上制备壳聚糖接枝产物（mPEG-g-CS）；将接枝产物在一定浓度下配制成凝胶溶液，测定其温敏性能；以温敏水凝胶为载体，以布洛芬为模型药物进行体外释放研究。结果表明，mPEG-g-CS水凝胶在体温37℃附近发生溶胶到凝胶的转变，具有良好的温敏性能，在一定的浓度范围内提高mPEG-g-CS浓度可降低相变温度，缩短胶凝时间。体外释药结果表明mPEG-g-CS水凝胶对模型药物具有缓释作用，有望用作可注射温敏型药物控释载体。

Preparation and characterization of a new injectable thermosensitive hydrogel for sustained drug release

An injectable thermosensitive hydrogel (PEG-g-CS), based on chemically modified chitosan, has been prepared by grafting different amounts of PEG onto chitosan. The sol-to-gel transition of the PEG-g-CS hydrogel was shown to occur atabout body temperature (～37℃) which indicates it has optimum thermosensitivity for use as a drug carrier. Increasing the grafting ratio results in a reduction in the phase transition temperature. A higher concentration of mPEG-g-CS leads to a lower phase transition temperature and a shorter response time of the thermosensitive gel. In vitro drug release from the gel was studied using ibuprofen as a model drug. The results indicated that the injectable gel is a promising carrier for sustained drug delivery.