Drug Delivery to Respiratory Mucosa using Fusogenic Liposomes and its Molecular Design.

本研究的目的是评估融合脂质体（FL）的有用性和特性，其中有包膜糖蛋白的仙台病毒在其表面上，在呼吸道mucosal.After鼻给药的FL和单层脂质体（Lips）含有FITC-葡聚糖（FD）作为模型大分子化合物，FD在血浆中没有检测到在任何时间的大分子传递。经鼻和气管给药后，FLS的FD恢复率显著低于FD溶液或Lips。经时程分析，鼻内15 min、气管内30 min可检测到FL与黏膜的快速融合，鼻内30 min、气管内60 min融合最快。FD的分子量不影响FL与粘膜的结合和融合。通过共聚焦激光扫描荧光显微镜评价，摄取研究显示上皮细胞中的细胞内荧光。DTT和唾液酸酶预处理均能降低FLs与粘膜的结合和融合。这些结果表明，FLs可能在结合融合过程中识别唾液酸。阳离子荧光素与鼻粘膜的结合量大于阴离子荧光素，但两者的融合量基本相同。蛋白酶抑制剂如唾液酸酶抑制剂、胰蛋白酶抑制剂和chamostat可增加FL与粘膜的结合和融合量，而杆菌肽则无此作用。从这些结果来看，FLs可能有助于将大分子定位于鼻粘膜。

The objective of the present investigation was to evaluate the usefulness and characterization of fusogenic liposomes (FLs), which have envelope glycoproteins of the Sendai virus on their surface, on a delivery of macromolecules to respiratory mucosa.After nasal administration of FLs and unilaminar liposomes (Lips) containing FITC-dextran (FD) as a model macromolecular compound, FD was not detected in plasma at any times. The recovery of FD after administration of Fls to nose and trachea was significantly lower than that of FD solution or Lips. Time course analysis showed that the rapid fusion to the mucosa in FLs was detectable within 15 min in nose and 30 min in trachea, and reached a maximum value at 30 min in nose and 60 min in trachea. The molecular weights of FD did not affect the binding and fusion of FLs to the mucosa. As evaluated by confocal laser scanning fluorescence microscopy, uptake studies revealed intracellular fluorescence in the epithelial cells. The binding and fusion of FLs to the mucosa were decreased with the coadministration of DTT and pretreatment of sialidase. These results suggested that FLs may recognize sialic acid in the process of the binding and fusion. The binding amount of cationic FLs to nasal mucosa was larger than of anionic FLs, but the fusion amount was almost same between cationic and anionic FLs. Protease inhibitors, such as sialidase inhibitor, typsin inhibitor and chamostat, increased the binding and fusion amount of FLs to the mucosa, but bacitracin did not. From these results, FLs may be useful in localizing macromolecules to nasal mucosa.