Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark.
Inhalation Sciences Sweden AB, Hälsovägen 7, 141 57 Huddinge, Sweden; Institute of Environmental Medicine, Karolinska Institutet, Nobels väg 13, Solna, 171 77 Stockholm, Sweden.
Int J Pharm. 2022 Jun 10;621:121758. doi: 10.1016/j.ijpharm.2022.121758. Epub 2022 Apr 26.
Thermostable dry powder inhaler (DPI) formulations with high aerosol performance are attractive inhalable solid dosage forms for local treatment of inflammatory lung diseases. We recently demonstrated that lipidoid-polymer hybrid nanoparticles (LPNs) loaded with small interfering RNA (siRNA) directed against tumor necrosis factor alpha (TNF-α) mediate efficient intracellular siRNA delivery and reduce inflammation in vivo. Here, we show that mixtures of the stabilizing excipients trehalose (Tre) and dextran (Dex), in combination with the shell-forming dispersion enhancer leucine (Leu), stabilize TNF-α siRNA-loaded LPNs during spray drying into nanocomposite microparticles, and result in DPI formulations with high aerosol performance. At low Leu content (0 to 10%, w/w), the DPI formulations were amorphous, and exhibited poor aerosol performance. When the Leu content was increased from 20 to 60% (w/w), the surface content of Leu increased from 39.2 to 68.1 mol%, and the flowability was significantly improved. Microscopy analysis suggest that the improved powder dispersibility is the result of a wrinkled surface morphology, which reduces the surface area available for interparticle interactions. Increasing the Leu content further (to above 10%, w/w) did not influence the aerosol performance, and the aerosol yield was maximal at 30-40% Leu (w/w). Formulations containing 40% Leu and a Tre:Dex ratio of 10:90 (w/w) displayed a high fine particle fraction and aerosol properties suitable for inhalation. The chemical integrity of TNF-α siRNA was preserved in the solid state, and biodistribution studies in mice showed that pulmonary administration of DPI formulations with high aerosol performance resulted in homogenous deep lung deposition. Our results demonstrate that at optimal ratios, ternary excipient mixtures of Leu, Tre and Dex protect TNF-α siRNA-loaded LPNs during spray drying. Hence, this study shows that microparticles with an amorphous Tre/Dex matrix and a crystalline Leu shell efficiently stabilize the nanocomposite LPNs in the solid state, and ensure aerosol properties suitable for inhalation.
具有高气溶胶性能的热稳定干粉吸入剂（DPI）制剂是局部治疗炎症性肺病的有吸引力的可吸入固体制剂。我们最近证明，负载针对肿瘤坏死因子-α（TNF-α）的小干扰 RNA（siRNA）的脂质-聚合物杂化纳米颗粒（LPN）介导有效的细胞内 siRNA 递送至体内并减轻炎症。这里，我们表明，稳定赋形剂海藻糖（Tre）和葡聚糖（Dex）的混合物，与形成壳的分散增强剂亮氨酸（Leu）一起，在喷雾干燥成纳米复合微球时稳定负载 TNF-α siRNA 的 LPN，并且导致具有高气溶胶性能的 DPI 制剂。在低 Leu 含量（0 至 10％，w / w）下，DPI 制剂为无定形，表现出较差的气溶胶性能。当 Leu 含量从 20 增加到 60％（w / w）时，表面 Leu 含量从 39.2 增加到 68.1mol％，流动性得到显著改善。显微镜分析表明，改善的粉末分散性是皱缩表面形态的结果，其减少了用于颗粒间相互作用的表面积。进一步增加 Leu 含量（至超过 10％，w / w）不会影响气溶胶性能，并且在 30-40％Leu（w / w）时气溶胶产率最大。含有 40％Leu 和 Tre：Dex 比为 10：90（w / w）的制剂显示出高的细颗粒分数和适合吸入的气溶胶性质。TNF-α siRNA 的化学完整性在固态中得以保留，并且在小鼠中的体内分布研究表明，具有高气溶胶性能的 DPI 制剂的肺部给药导致均相深肺沉积。我们的结果表明，在最佳比例下，亮氨酸，海藻糖和葡聚糖的三元赋形剂混合物在喷雾干燥过程中保护负载 TNF-α siRNA 的 LPN。因此，该研究表明，具有无定形 Tre / Dex 基质和结晶 Leu 壳的微粒有效地在固态中稳定纳米复合 LPN，并且确保适合吸入的气溶胶性质。
