聚乳酸羟基乙酸CXCR4-miRNA纳米微粒的制备及其特征

背景：有关研究表明聚乳酸羟基乙酸能够有效包裹反义寡核苷酸、小的干扰 RNA、微小RNA等，可以较好地保护其在体内不受各种酶的破坏，并可以起到缓慢释放药物的作用，从而可以减少药物的给药次数，达到长期、有效的治疗效果。 目的：制备聚乳酸羟基乙酸CXCR4-miRNA纳米微粒，并研究纳米微粒的特性。 方法：运用二次超声乳化溶剂挥发法制备聚乳酸羟基乙酸CXCR4-miRNA纳米微粒，采用紫外分光光度法测定纳米微粒的载药量及包封率，透射电镜观察微粒形态，激光粒径仪测定纳米微粒的大小和分布；将纳米微粒悬浮于磷酸盐缓冲液中观察其缓释特性。 结果与结论：制备的纳米微粒形态呈圆形，表面光滑，分散性好，不粘连，其粒径分布在143-502 nm，平均粒径为280 nm，平均载药量为（0.515±0.023）%，平均包封率为50.2%，批间差异小。纳米微球在体外可以缓慢释放，经过前几天的快速释放后，在第14天进入平台期。结果充分表明运用二次超声乳化溶剂挥发法制备聚乳酸-羟基乙酸CXCR4-miRNA纳米微粒的工艺过程简单，粒子性状符合要求且具有缓释性。

Preparation and characterization of poly D,L-lactide-co-glycolide CXCR4-miRNA nanoparticles

BACKGROUND：Related studies have showed that poly D,L-lactide-co-glycolide can effectively package antisense oligonucleotides, smal interfering RNA, microRNA. Poly D,L-lactide-co-glycolide can better protect them against the destruction of the enzymes in vivo and have slow the drug release. Therefore, the number of drug administration can be reduced to achieve a long-term and effective therapeutic effect. OBJECTIVE：To prepare poly D,L-lactide-co-glycolide-CXCR4-miRNA-nano-particles and to research the characteristics of the prepared nanoparticles. METHODS：Poly D,L-lactide-co-glycolide-CXCR4-miRNA nanoparticles were prepared by double emulsion-evaporation process. Ultraviolet spectrophotometry was utilized for measurement of encapsulation efficiency and drug-loading rate, observing the shape of nanoparticles by transmission electron microscope, and measuring the size and distribution of nanoparticles by laser particle size analyzer. Sustained-release characteristics of nanoparticle suspension were observed in phosphate buffer. RESULTS AND CONCLUSION：The prepared nanoparticles were spherical-shaped, smooth, evently distributed and inadhesive. The particle size was mainly distributed within 143-502 nm, with an average diameter of 280 nm. The average drug loading was （0.515±0.023）%, the average encapsulation ratio was 50.2%and difference＆amp;nbsp;between batches was smal . The nanoparticles could slowly release in vitro and the process initial y experienced the fast-release stage, and then reached a basical y stable platform stage at day 14. These finding indicate that the process to prepare poly D,L-lactide-co-glycolide CXCR4-miRNA-nanoparticles by double emulsion-evaporation is simple. The prepared nanoparticles are wel targeted and exhibit sustained-release effects.