Dry Water for Delivery of Biologics to the Airways

泡沫，空气在水中的分散体，在日常生活中随处可见：从消防到消费者剃须产品。这种分散体可以通过不可逆地结合到空气-水界面的胶体颗粒来稳定。最近，人们对通过改变胶体稳定剂化学来使这些材料发生过渡相转化产生了兴趣。这导致了一种非常罕见的现象-水在空气中的稳定分散，称为“干水”。这些材料表现为自由流动的干燥粉末，但其可以>98%的水，得到约lg/cm 3的密度。这是气雾剂科学的一大机遇：将稳定、干燥、单分散的粉末输送到气道，这些粉末在其天然溶液结构中含有敏感的治疗蛋白质。粉末的递送具有很大的优点，包括简单的“绿色”致动，而无需推进剂和一致的粒度，用于精确靶向靶部位。此外，“干水”在递送生物制剂如蛋白质、全细胞和RNA方面具有显著的优势，这些生物制剂在没有水存在的情况下不能稳定。然而，仍有几个问题：我们如何为这种应用制备合适粒径的干水？有效管理的最佳方法是什么？给药后，生物制剂如何从干燥的水中释放出来？

Foams, dispersions of air in water, are seen in everyday life: from fire-fighting to consumer shaving products. Such dispersions may be stabilised by colloidal particles which are irreversibly bound to the air-water interface. There has been recent interest in the transitional phase inversion of these materials by alteration of colloidal stabiliser chemistry. This leads to an exceedingly uncommon phenomenon - stable dispersions of water in air, known as "dry water". These materials appear as a free-flowing dry powder but which may >98% water, giving a density of ~1g/cm3. Therein lies a big opportunity in aerosol science: the delivery of stable, dry, monodisperse powders to the airways which contain sensitive therapeutic proteins in their native solution structure. Delivery of powders has great advantages including simple "green" actuation without propellant and consistent particle size for precision targeting of the target site. Furthermore, "dry water" has significant advantages in delivering biologics such as proteins, whole cells, and RNA, which cannot be stabilised without water present. However, several questions remain: How can we prepare dry water of the right particle size for this application? What are the best devices to allow effective administration? How can the biologic be liberated from the dry water after administration?