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本文用透析法制备了新型温度/pH双敏自组装嵌段共聚物聚组氨酸-聚乳酸羟基乙酸-聚乙二醇-聚乳酸羟基乙酸-聚组氨酸(OLH-b-PLGA-b-PEG-b-PLGA-b-OLH)胶束,采用荧光探针技术测定其不同温度下临界胶束浓度(CMC);用透析法测定共聚物胶束的包封率和载药量;对胶束的粒径、形态和表面电位进行考察,并对阿霉素胶束的体外释药和pH敏感性进行了研究。CMC介于0.0224～0.0017μg.mL-1,胶束包封率为92.8%,载药量为15.7%;载药胶束粒径为(61.7±13.4)nm,zeta电位为-9.88 mV;阿霉素的体外释药速率随pH降低(pH 7.4～5.0)而增加。结果表明,胶束的CMC随温度升高而降低,体外释药具有明显的pH敏感性,该载体材料作为抗肿瘤药物的靶向传递系统具有较好的应用前景。
In this paper, a new temperature / pH bi-sensitive self-assembled block copolymer polyhistidine-polylactic acid glycolic acid-polyethylene glycol-polylactic acid glycolic acid-polyhistidine (OLH-b-PLGA-b -PEG-b-PLGA-b-OLH) micelles, and the critical micelle concentration (CMC) at different temperatures was measured by fluorescence probe technique. The encapsulation efficiency and drug loading of copolymer micelles were determined by dialysis method. The particle size, morphology and surface potential of micelles were investigated. The in vitro drug release and pH sensitivity of doxorubicin micelles were also investigated. CMC ranged from 0.0224 to 0.0017 μg · mL-1, the micelle encapsulation efficiency was 92.8% and drug loading was 15.7%. The diameter of drug-loaded micelles was (61.7 ± 13.4) nm and the zeta potential was -9.88 mV. In vitro release rate of ADM increased with pH (pH 7.4 ~ 5.0). The results showed that the CMC of micelles decreased with increasing temperature, and the in vitro release had obvious pH sensitivity. The carrier material has better application prospect as a target delivery system of antitumor drugs.