磁性纳米颗粒在顺铂脂质体结构中的组装
Assemble of magnetic nanoparticles into the structure of cisplatin liposome
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摘要:
通过探讨制备过程中磁性颗粒不同的加入顺序对其在脂质体结构中分布的影响, 制备了具有较高包封率的磁性顺铂 (cisplatin, CDDP) 脂质体。本研究采用改良水热合成方法一步制备了表面修饰的Fe3O4磁性纳米颗粒并采用薄膜超声法制备了CDDP磁性脂质体, 用石墨炉原子吸收分光光度法测定CDDP含量。在制备过程中考察两种不同制备程序对脂质体微观结构的影响, 即程序I: 将磁性颗粒先与磷脂结合再成膜制备脂质体; 程序II: 将磁性颗粒分散于药物溶液中水合制备脂质体。用透射电镜 (transmission electron microscope, TEM) 观察磁性脂质体形态。按正交实验设计筛选最优处方制备磁性脂质体, 以程序I制备的脂质体磁性颗粒分布于磷脂双层中, 包封率为34.90%, 而以程序II制备的脂质体磁性颗粒分布于脂质体中间水相, 包封率为28.34%。两者包封率均高于普通脂质体。3种不同脂质体体外释药均符合一级释药规律。程序I制备的磁性脂质体由于磁性颗粒分布于磷脂双层中, 改变了磷脂所形成的双层骨架, 使其释药t1/2为9 h, 比另外两者较短。结果表明, 采用程序I实现了纳米磁性颗粒在脂质体中的组装, 用此方法制备的磁性脂质体在药物包封率和磁性颗粒的含量上都优于程序II, 并且能保证一定的缓释效应。
Abstract:Effects of different procedures of magnetic nanoparticles into the liposome structure on the distribution of magnetic particles in the liposome were investigated. Magnetic liposomes with high-encapsulating rate of cisplatin (CDDP) were obtained. Fe3O4 magnetic nanoparticles which was modified by organic functional group on surface was synthesized by an one-step modified hydrothermal method. The CDDP magnetic liposomes were prepared by a film scattering-ultrasonic technique and the concentrations of CDDP in the liposomes were measured by graphite furnace atomic absorbance spectroscopy. Magnetic liposomes with different microstructure were prepared by the two different procedures, where the magnetic particles were combined with phospholipid before the film preparation to form liposome in procedure I, and drug solution and the magnetic particles were mixed before hydrating the lipids film to form liposome in procedure II. The liposome structure was observed by transmission electron microscope (TEM). The CDDP magnetic liposomes were prepared by the optimized method which was selected by orthogonal test. Encapsulation rate of the magnetic particles distributed in the phospholipid bilayer through the procedure I was 34.90%. While liposome, produced by the procedure II technique, contained magnetic particles in the interior aqueous compartment, which encapsulation rate was 28.34%. Encapsulation rates of both I and II were higher than that of conventional liposome. The release profile of all the three different liposomes in vitro fitted with a first-order equation. Because of distribution of magnetic particles in the phospholipid bilayer, the skeleton of phospholipid bilayer was changed. The releasing t1/2 of magnetic liposomes produced by the procedure I technique is 9 h, which is shorter than that of the other two liposomes. Assemble of magnetic nanoparticles into the structure of liposome was succeeded by the procedure I, which showed superiority than by procedure II whatever in CDDP liposome encapsulation efficiency and content of the magnetic particles and would ensure sustained-release character.
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