黄芪甲苷脂质体原位凝胶眼部给药系统的研究

Ocular drug delivery system for astragalosideⅣliposome in situ gel

目的制备黄芪甲苷(ASⅣ)脂质体原位凝胶(ASⅣlips gel),对ASⅣlips gel进行制剂学表征及细胞学评价,探讨ASⅣlips gel在眼部给药系统的应用潜力。方法采用乙醇注入法制备黄芪甲苷脂质体(ASⅣlips),以包封率为考察指标进行ASⅣlips处方及制备工艺优化,对最优处方及工艺制得的ASⅣlips进行表征;以壳聚糖(CS)和甘油磷酸钠(GP)为凝胶基质,通过物理交联制备CS/GP凝胶,对CS/GP凝胶进行表征;将ASⅣlips载入CS/GP凝胶构建ASⅣlips gel,并对ASⅣlips gel进行稳定性研究、体外释放研究、细胞毒性及细胞摄取考察。结果最优处方及工艺制得的ASⅣlips平均粒径为(75.09±0.65)nm,与透射电镜观察到的粒子大小接近,且粒径分布均匀;包封率可达71.68%,对ASⅣ具有较好的包载效率。红外光谱与X射线衍射分析可知已成功制得CS/GP凝胶;CS/GP凝胶在扫描电镜下呈明显的三维网状结构,35℃下胶凝时间为3 min。ASⅣlips gel连续7 d粒径基本无明显变化,稳定性良好;体外释放结果表明,与黄芪甲苷滴眼液相比,ASⅣlips gel有明显的缓释作用。细胞毒性结果显示ASⅣlips gel对人视网膜色素上皮细胞毒性较低,细胞相容性较好。分别用荧光显微镜定性观察、流式细胞仪定量分析制剂的细胞摄取情况,结果表明,脂质体原位凝胶制剂比滴眼液更易被人视网膜色素上皮细胞摄取。结论制备的ASⅣlips gel在眼部温度下可自发成胶,具有明显的缓释作用,更易被人视网膜色素上皮细胞摄取,有作为眼部给药系统的潜力。

Objective To prepare astragalosideⅣ(ASⅣ)liposome in situ gel(ASⅣlips gel),characterize the formula and evaluate the cytology of ASⅣlips gel,and determine the potential application of ASⅣlips gel in ocular drug delivery system.Methods Astragaloside-Ⅳliposome(ASⅣlip)was prepared by ethanol injection.ASⅣlips formula and preparation process were optimizaed with encapsulation efficiency as the evaluation index.ASⅣlips with the best formula and process were charactered.Chitosan(CS)and sodium glycerophosphate(GP)were used as the gel matrix,CS/GP gel was prepared by physical crosslinking,and the properties of CS/GP gel were characterized.The ASⅣlips were loaded into CS/GP gel to obtain ASⅣlips gel,the stability,in vitro release,cytotoxicity and cell uptake of ASⅣlips gel were determined.Results The average particle size of optimized ASⅣlips was(75.09±0.65)nm,which was consistent with the particle size by transmission electron microscopy and the distribution was uniform.The encapsulation efficiency of ASⅣlips prepared by the optimal formula and process reached 71.68%,indicating good encapsulation efficiency for ASⅣ.The CS/GP gel was successfully prepared by infrared spectroscopy and X-ray diffraction.The CS/GP gel showed obvious three-dimensional network structure under scanning electron microscope,and the gelling time was 3 min at 35℃.ASⅣlips gel showed no obvious change in the particle size for 7 consecutive days,suggesting good stability.The in vitro release showed that compared with ASⅣeye drops,ASⅣlips gel had an obvious sustained-release effect.The cytotoxicity showed that ASⅣlips gel had low toxicity to human retinal pigment epithelial cells and good cell compatibility.Liposome in situ gel was more easily absorbed by human retinal pigment epithelial cells than did eye drops.Conclusion The prepared ASⅣlips gel can spontaneously form gel at eye temperature and has a fair sustained-release effect.It is more easily taken up by human retinal pigment epithelial cells and indicating possible ocular drug delivery system.