Abstract：
Spray-drying of nucleic acid-based drugs designed for gene therapy or gene knockdown is associated with many advantages including storage stability and handling as well as the possibility of pulmonary application. The encapsulation of nucleic acids in nanoparticles prior to spray-drying is one strategy for obtaining efficient formulations. This, however, strongly relies on the definition of optimal nanoparticles, excipients and spray-drying conditions. Among polymeric nanoparticles, polyethylenimine (PEI)-based complexes with or without chemical modifications have been described previously as very efficient for gene or oligonucleotide delivery. The tyrosine-modification of linear or branched low molecular weight PEIs, or of polypropylenimine (PPI) dendrimers, has led to high complex stability, improved cell uptake and transfection efficacy as well as high biocompatibility. In this study, we identify optimal spray-drying conditions for PEI-based nanoparticles containing large plasmid DNA or small siRNAs, and further explore the spray-drying of nanoparticles containing chemically modified polymers. Poly(vinyl alcohol) (PVA), but not trehalose or lactose, is particularly well-suited as excipient, retaining or even enhancing transfection efficacies compared to fresh complexes. A big mesh size is critically important as well, while the variation of the spray-drying temperature plays a minor role. Upon spray-drying, microparticles in a ∼ 3.3 - 8.5 µm size range (laser granulometry) are obtained, dependent on the polymers. Upon their release from the spray-dried material, the nanoparticles show increased sizes and markedly altered zeta potentials as compared to their fresh counterparts. This may contribute to their high efficacy that is seen also after prolonged storage of the spray-dried material. We conclude that these spray-dried systems offer a great potential for the preparation of nucleic acid drug storage forms with facile reconstitution, as well as for their direct pulmonary application as dry powder.
摘要：
设计用于基因治疗或基因敲低的基于核酸的药物的喷雾干燥与许多优点相关,包括储存稳定性和处理以及肺部应用的可能性。在喷雾干燥之前将核酸封装在纳米颗粒中是获得有效制剂的一种策略。这个,然而,强烈依赖于最佳纳米粒子的定义，赋形剂和喷雾干燥条件。在聚合物纳米粒子中，先前已经描述了具有或不具有化学修饰的基于聚乙烯亚胺(PEI)的复合物对于基因或寡核苷酸递送非常有效。线性或支化低分子量PEIs的酪氨酸修饰，或聚丙烯亚胺（PPI）树枝状聚合物，导致了高度复杂的稳定性，改善细胞摄取和转染效率以及高生物相容性。在这项研究中,我们确定了含有大质粒DNA或小siRNA的基于PEI的纳米颗粒的最佳喷雾干燥条件，并进一步探索含有化学修饰聚合物的纳米颗粒的喷雾干燥。聚乙烯醇(PVA),但不是海藻糖或乳糖，特别适合作为赋形剂，与新鲜复合物相比，保留或甚至增强转染效力。大的网眼尺寸也至关重要，而喷雾干燥温度的变化起着次要的作用。喷雾干燥后，获得了约3.3-8.5微米尺寸范围(激光粒度)的微粒，取决于聚合物。一旦它们从喷雾干燥的材料中释放出来，与新鲜的纳米粒子相比，纳米粒子显示出增加的尺寸和显著改变的zeta电位。这可能有助于它们的高功效,这在延长喷雾干燥的材料的储存之后也可以看到。我们得出的结论是，这些喷雾干燥系统为制备易于重建的核酸药物储存形式提供了巨大的潜力，以及作为干粉直接肺部应用。
