Department of Pharmaceutics and Analytical Chemistry, The Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
Int J Pharm. 2010 May 5;390(1):70-5. doi: 10.1016/j.ijpharm.2009.10.023. Epub 2009 Oct 15.
Synthetic short interfering RNA (siRNA) is promising for specific and efficient knockdown of disease-related genes. However, in vivo application of siRNA requires an effective delivery system. Commonly used siRNA carriers are based on polycations, which form electrostatic complexes with siRNA. Such poly- or lipoplexes are of limited use in vivo due to severe problems associated with toxicity, serum instability and non-specific immune-responses. The aim of the present study was to prepare uniformly sized nanoparticles (NPs) with a high load of siRNA by use of the safe and biodegradable poly-(DL-lactide-co-glycolide) (PLGA) polymer without including polycations. The siRNA was encapsulated in the core of NPs by the double emulsion solvent evaporation method. To optimize the NP formulation, the effects of important formulation and processing parameters were investigated systematically. Generally, spherical siRNA-loaded NPs (<300 nm, PDI<0.2, zeta potential -40 mV) were obtained. An encapsulation efficiency of up to 57% was achieved by adjusting the inner water phase volume, the PLGA concentration, the first emulsification sonication time, and stabilization of the water-oil interface with serum albumin. The integrity of siRNA was preserved during the preparation. Preparation of core-loaded siRNA-NPs based on PLGA and no cationic excipient seems possible and promising for delivery of siRNA.
合成短干扰 RNA（siRNA）是一种很有前途的方法，可以特异性和有效地敲低与疾病相关的基因。然而，siRNA 的体内应用需要有效的递送系统。常用的 siRNA 载体基于聚阳离子，它与 siRNA 形成静电复合物。由于毒性、血清不稳定性和非特异性免疫反应等严重问题，这种聚阳离子或脂质体在体内的应用受到限制。本研究旨在使用安全且可生物降解的聚（DL-丙交酯-共-乙交酯）（PLGA）聚合物，而不包含聚阳离子，制备具有高负载量 siRNA 的均匀大小的纳米颗粒（NPs）。通过双乳液溶剂蒸发法将 siRNA 包封在 NPs 的核心中。为了优化 NP 配方，系统研究了重要的配方和处理参数的影响。通常，可获得负载 siRNA 的 NPs（<300nm，PDI<0.2，zeta 电位-40mV）。通过调整内水相体积、PLGA 浓度、第一次乳化超声时间以及用血清白蛋白稳定油水界面，可以实现高达 57%的包封效率。在制备过程中保持了 siRNA 的完整性。基于 PLGA 且不含阳离子赋形剂的载有 siRNA 的核芯 NPs 的制备似乎是可行且有前途的，可用于 siRNA 的递药。
