超临界流体技术在水体系中制备药用蛋白质及复合微粒的应用基础研究

Supercritical fluid assisted atomization (SAA) is a novel technique for fabricating microparticles which was developed in the recent decade. SAA process is highlighted with its availability for processing aqueous solution of water-soluble drugs, combined with its mild operation conditions and favorable control over particle size, which will be very promising in micronization of therapeutic proteins and peptides. The present work will focus on the preparation of therapeutic proteins and protein/polymer composite microparticulate formulations using the SAA-HCM technique (SAA with a hydrodynamic cavitation mixer), in which insulin and parathyroid hormone (PTH) are used as therapeutic agents while chitosan and its derivatives and sodium cellulose sulfate as the carriers. The influences of operation conditions on the particle morphology, particle size and particle size distribution will be elucidated. Protein tertiary structure and bioactivity will be characterized and the absorption enhancing effect during trans-mucosal drug delivery will be demonstrated. Meanwhile, mechanism of protein/polymer composite particle formation will also be studied. Furthermore, an apparatus coupling the SAA-HCM process with the self-assembly of polyelectrolyte in aqueous solution will be set up to prepare multicomponent microparticles with controlled/sustained- release profiles. Based upon that, functional materials like Fe3O4 nanopowder will be added in the initial solution to attain drug-loaded functional microparticles with targeted drug delivery performance. We will explore the interactions between the polymers and proteins, and understand the mechanisms of the self-assembly process and the drying process of composite microparticles. This multidisciplinary work will serve to expand the application of SAA-HCM to fabrication of protein and protein/polymer composite particulate systems, and will be meaningful to particle design and further improvement of this green micronization process.

超临界流体辅助雾化（SAA）是近年来发展起来的一种基于超临界流体的新型微粒化技术，其突出特点是可直接用于水体系的微粒化，在蛋白质及多肽类药物微粒制备中具有广阔的应用前景。本研究以胰岛素、甲状旁腺激素等药用蛋白质为研究对象，壳聚糖及其衍生物、纤维素硫酸钠等为聚合物载体，采用改进的SAA技术（SAA-HCM）制备药物微粒，考察操作条件对蛋白质微粒的形貌、粒径及其分布的影响，对蛋白质结构和活性进行表征；研究蛋白质/聚合物复合微粒成球机理及药物的跨黏膜吸收促进作用；建立SAA-HCM与聚电解质自组装耦合装置，制备多组分聚合物包裹的具有缓控释行为的复合微粒；加入四氧化三铁纳米粒等磁性材料，获得兼具靶向性的功能性复合微粒。探讨蛋白质与聚合物的相互作用，复合微粒自组装及干燥过程原理。该研究将拓展SAA技术在制备蛋白质及多肽类药物复合微粒中的应用，对微粒设计及发展绿色造粒技术具有重要意义。

建立了水力空化强化混合超临界流体辅助雾化过程，将其用于胰蛋白酶、胰岛素和甲状旁腺激素等蛋白质复合微粒的制备。考察了操作条件对微粒形貌、粒径和粒径分布以及载药效率等的影响，提出了蛋白质溶液液滴干燥到微粒形成的成壳机理，表征了蛋白质与聚合物的相互作用及蛋白质在复合微粒中的分布，研究了粉体的引湿性、密度、休止角等理化性质。制备得到的胰岛素复合微粒具有良好的空气动力学性能，质量中值空气动力学直径MMAD在1-3μm内，可吸入比高达60%以上，大鼠体内经气管给药试验表明该配方可以明显促进胰岛素的肺部吸收，提高其生物利用度至57.2%，展示了该新型胰岛素DPI制剂的优越性及其在肺部吸入式给药领域的应用前景。在此基础上，将该技术拓展到纳米载药系统，以满足实际应用中不同的给药系统和靶向部位的需求，并极大地丰富了超临界流体技术在生物医药领域的应用。