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目的:以维生素A棕榈酸酯(VAP)为主药,制备阳离子脂质体原位凝胶,并对其兔角膜滞留性进行考察。方法:采用薄膜分散法制备VAP脂质体(VAPL),并用不同季铵化程度的NC-三甲基壳聚糖(TMC)包衣制备CAP阳离子脂质体(TMCVAPL),再以泊洛沙姆407为基质,制备VAP阳离子脂质体原位凝胶(TMC-VAPL-ISG)。采用荧光示踪法对其兔角膜的滞留时间进行考察。结果:透射电镜显示VAP脂质体粒径分布均匀,未包衣时平均粒径为(62.98±0.078)nm,Zeta电位为(-11.2±0.57)mV,平均包封率为(70.62±0.66)%(n=3);TMC包衣后,脂质体粒径明显增大(P<0.05),平均包封率为(69.49±0.79)%,随着TMC季铵化程度的增大,Zeta电位显著增大(P<0.05)。与未包衣和包衣的CAPL相比,TMC-CAPLISG兔角膜的滞留时间延长2倍,且随着TMC季铵化程度的提高,滞留效果逐渐增强(P<0.05)。结论:TMC-VAPL-ISG具有阳离子脂质体和原位凝胶的优势,能明显延长兔角膜滞留时间。
OBJECTIVE: To prepare cationic liposomes in situ gel with vitamin A palmitate (VAP) as the main drug and observe the rabbit corneal retentivity. Methods: VAP liposomes (VAPL) were prepared by membrane dispersion method. CAP cationic liposomes (TMCVAPL) were prepared by coating with different degree of quaternization on NC-trimethyl chitosan (TMC) M 407 as a matrix to prepare VAP cationic liposome in situ gels (TMC-VAPL-ISG). Fluorescent tracer method was used to examine the corneal retention time in rabbits. Results: Transmission electron microscopy showed that the average size of VAP liposomes was (62.98 ± 0.078) nm and the Zeta potential was (-11.2 ± 0.57) mV, the average entrapment efficiency was (70.62 ± 0.66) (P <0.05). The average encapsulation efficiency was (69.49 ± 0.79)%. With the increase of the quaternization degree of TMC, Zeta Potential increased significantly (P <0.05). Compared with uncoated and coated CAPL, the retention time of TMC-CAPLISG rabbit cornea was prolonged by 2 times, and with the increase of TMC quaternization, the retention effect was enhanced (P <0.05). Conclusion: TMC-VAPL-ISG possesses the advantages of cationic liposomes and in situ gel, which can significantly prolong the corneal retention time in rabbits.