Dry Water for Delivery of Biologics to the Airways

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?