University of Copenhagen, Faculty of Pharmaceutical Sciences, Department of Pharmaceutics and Analytical Chemistry, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark.
J Control Release. 2012 Jan 10;157(1):141-8. doi: 10.1016/j.jconrel.2011.08.011. Epub 2011 Aug 12.
Matrix systems based on biocompatible and biodegradable polymers like the United States Food and Drug Administration (FDA)-approved polymer poly(DL-lactide-co-glycolide acid) (PLGA) are promising for the delivery of small interfering RNA (siRNA) due to favorable safety profiles, sustained release properties and improved colloidal stability, as compared to polyplexes. The purpose of this study was to design a dry powder formulation based on cationic lipid-modified PLGA nanoparticles intended for treatment of severe lung diseases by pulmonary delivery of siRNA. The cationic lipid dioleoyltrimethylammoniumpropane (DOTAP) was incorporated into the PLGA matrix to potentiate the gene silencing efficiency. The gene knock-down level in vitro was positively correlated to the weight ratio of DOTAP in the particles, and 73% silencing was achieved in the presence of 10% (v/v) serum at 25% (w/w) DOTAP. Optimal properties were found for nanoparticles modified with 15% (w/w) DOTAP, which reduced the gene expression with 54%. This formulation was spray-dried with mannitol into nanocomposite microparticles of an aerodynamic size appropriate for lung deposition. The spray-drying process did not affect the physicochemical properties of the readily re-dispersible nanoparticles, and most importantly, the in vitro gene silencing activity was preserved during spray-drying. The siRNA content in the powder was similar to the theoretical loading and the siRNA was intact, suggesting that the siRNA is preserved during the spray-drying process. Finally, X-ray powder diffraction analysis demonstrated that mannitol remained in a crystalline state upon spray-drying with PLGA nanoparticles suggesting that the sugar excipient might exert its stabilizing effect by sterical inhibition of the interactions between adjacent nanoparticles. This study demonstrates that spray-drying is an excellent technique for engineering dry powder formulations of siRNA nanoparticles, which might enable the local delivery of biologically active siRNA directly to the lung tissue.
基于生物相容和可生物降解聚合物的基质系统，如美国食品和药物管理局（FDA）批准的聚合物聚（DL-丙交酯-共-乙交酯酸）（PLGA），由于具有良好的安全性、缓释特性和提高的胶体稳定性，与多聚物相比，是递送小干扰 RNA（siRNA）的有前途的选择。本研究的目的是设计一种基于阳离子脂质修饰的 PLGA 纳米粒子的干粉制剂，通过肺部递送 siRNA 用于治疗严重肺部疾病。阳离子脂质二油酰基三甲基铵丙烷（DOTAP）被掺入 PLGA 基质中以增强基因沉默效率。体外基因敲低水平与颗粒中 DOTAP 的重量比呈正相关，在存在 10%（v/v）血清的情况下，25%（w/w）DOTAP 可达到 73%的沉默。在 15%（w/w）DOTAP 修饰的纳米粒子中发现了最佳性能，其将基因表达降低了 54%。该制剂与甘露醇一起喷雾干燥成适用于肺部沉积的空气动力学大小的纳米复合微球。喷雾干燥过程不影响易于再分散的纳米粒子的物理化学性质，最重要的是，在喷雾干燥过程中保持了体外基因沉默活性。粉末中的 siRNA 含量与理论载药量相似，siRNA 完整，表明 siRNA 在喷雾干燥过程中得到了保留。最后，X 射线粉末衍射分析表明甘露醇在与 PLGA 纳米粒子喷雾干燥时保持结晶状态，这表明糖赋形剂通过空间位阻抑制相邻纳米粒子之间的相互作用发挥其稳定作用。这项研究表明，喷雾干燥是一种构建 siRNA 纳米粒子干粉制剂的优秀技术，它可能使生物活性 siRNA 直接递送到肺部组织的局部给药成为可能。
