胆甾醇琥珀酰基壳聚糖锚定脂质体用作表阿霉素载体的体外实验

In vitro study of cholesterol succinyl chitosan anchored liposomes as a carrier for epirubicin

背景:多糖"锚定"脂质体在抗肿瘤药物、蛋白以及基因的传输领域有着极其重要的理论及应用价值,国外已有较多机构在进行相关的研究。目的:通过"锚定"的方式制备胆甾醇琥珀酰基壳聚糖锚定脂质体,并以表阿霉素作为模型药物,考察其对包载药物体外释放性质的影响。设计、时间及地点:体外实验,于2006-09/2008-05在天津市生物医学材料重点实验室完成。材料:以壳聚糖为原料,合成胆甾醇琥珀酰基壳聚糖,并采用胶体滴定法测定其胆甾醇基取代度。方法:采用pH梯度法制备表阿霉素脂质体,然后通过共孵育的方法合成了取代度为2.80%,5.58%和8.00%的载药胆甾醇琥珀酰基壳聚糖锚定脂质体。主要观察指标:荧光分光光度计检测药物浓度;透射电镜观察脂质体形态;亚微米粒度及电位分析仪检测脂质体的粒径大小、分布和电位;动态透析法考察包载药物表阿霉素在胆甾醇琥珀酰基壳聚糖锚定脂质体中的体外释放特征。结果:胆甾醇琥珀酰基壳聚糖锚定脂质体为规则球状形态,呈现典型的核壳结构,粒径为245.4~279.7nm,zeta电位为+21.09^+25.48mV;和载药脂质体及壳聚糖包衣脂质体相比,CHCS锚定脂质体能明显延缓表阿霉素的体外释放,在胆甾醇基取代度2.80%~5.85%范围内,表阿霉素的释放速度随着取代度的增加呈降低的趋势。结论:胆甾醇琥珀酰基壳聚糖锚定脂质体有着比普通脂质体及壳聚糖包衣脂质体更高的稳定性,能显著延缓包载药物的释放速度。

BACKGROUND： Polysaccharides anchored liposomes play an extremely important role in the fields of antitumor drug, protein and gene transmission. Related research is also present abroad. OBJECTIVE： To prepare cholesterol succinyl chitosan （CHCS） anchored liposomes, and to investigate the effect of CHCS anchored liposomes on the release property in vitro of loading drugs taking epirubicin as a model drug. DESIGN, TIME AND SETTING： A study in vitro was performed in the Key Laboratory of Biomedical Materials of Tianjin （China） from September 2006 to May 2008. MATERIALS： CHCS conjugates were synthesized and their substitution degree of cholesterol moiety was determined by colloidal titration method. METHODS： Epirubicin-loaded liposomes were prepared using pH gradient method, and then CHCS anchored liposomes with epirubicin loading were prepared by incubating method, harvesting the substitution degree of 2.80%, 5.58% and 8.00%. MAIN OUTCOME MEASURES： Drug concentration was detected by spectrofluorimeter; Liposomes were characterized by transmission electron microscopy; The particle size of liposomes was assayed by submicron particle size analyzer and zeta potential technologies; The release behavior of epirubicin from CHCS anchored liposomes in vitro was investigated by dynamic dialysis method. RESULTS： CHCS anchored liposomes were almost spherical in shape and had a classic shell-core structure. The sizes of CHCS anchored liposomes ranged from 245.4 nm to 279.7 nm and the zeta potential values were in the range of ＋21.09 mV to ＋25.48 mV. Compared to epirubicin-loaded liposomes and chitosan-coated liposomes, CHCS anchored liposomes significantly sustained the release of epirubicin in vitro, and the release rate decreased with substitution degree of cholesterol moiety increasing at a range of 2.80%-5.85%. CONCLUSION： CHCS anchored liposomes are more stable than common liposomes and chitosan-coated liposomes, and they can significantly sustain the release of loading drug.