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目的以硝酸毛果芸香碱为模型药,研究温度敏感型原位凝胶对药物眼部滞留和体外释放的影响。方法以泊洛沙姆407、188为凝胶剂,以卡波姆974P为增黏剂,制备眼用温敏型原位凝胶。考察原位凝胶的流变学性质;采用改良Franz扩散池法研究凝胶的体外释药行为。结果流变学测定结果显示原位凝胶在室温状态下为物理缠结的聚合物溶液,在眼表温度下转变为次级键网状结构。泊洛沙姆188、卡波姆974P的加入均可延缓药物的释放,二者对凝胶的黏性模量G“的影响不同。原位凝胶在4h内缓慢释放药物,释放曲线符合Higuchi方程(r=0.9923)。结论通过调节泊洛沙姆407和188的比例,可得到具有适宜溶液-凝胶转变温度和良好释药特性的原位凝胶。流变学结果提示原位凝胶的眼部滞留能力强于普通滴眼液,是一种具有研究前景的给药系统。
Objective To investigate the effect of temperature-sensitive in situ gel on drug eye retention and in vitro release using pilocarpine nitrate as a model drug. Methods Poloxamer 407,188 was used as gelling agent and carbomer 974P as adhesion promoter to prepare ophthalmic thermosensitive in situ gels. The rheological properties of the in-situ gels were investigated. The modified Franz diffusion cell method was used to study the gels release in vitro. Results Rheological measurements showed that the in situ gels were physically entangled polymer solutions at room temperature and were converted to secondary bond networks at ocular surface temperatures. Poloxamer 188 and Carbomer 974P both delayed the release of the drug, which had different effects on the gel’s viscous modulus G ”. The in-situ gel slowly released the drug within 4 h and the release curve was consistent Higuchi equation (r = 0.9923) .Conclusion By adjusting the ratio of Poloxamer 407 and 188, in situ gels with suitable solution-gel transition temperatures and good drug release properties can be obtained. Rheological results suggest that in situ condensation Gum eye retention capacity is stronger than ordinary eye drops, is a promising drug delivery system.