Glycine microparticles loaded with functionalized nanoparticles for pulmonary delivery.

The use of nanoparticles for pulmonary delivery poses challenges such as the presence of anatomical barriers and the loss of bioactive components. Excipients are often used to facilitate delivery. Excipients suitable for nanoparticle delivery are still being explored. Herein we introduce for the first time, spray-dried glycine microparticle-based excipients loaded with nanoparticles of the size range known to be taken up by alveolar macrophages. Using a microfluidic jet spray dryer, we produced glycine microparticles-based excipients which are spherical, uniform, cenospheric (hollow at core), and "coral-like" with average diameter of 60 ± 10 μm, 29 ± 0.8% porosity, and showed their effective loading with glycine coated iron oxide superparamagnetic nanoparticles (GSPIONs). Our loading protocol with nanoparticles further increased microsphere porosity and improved aerodynamic performance unlike the dense, solid commercial excipient, Lactohale200™. This demonstrates a feasible approach for delivery of such nanoparticles in the lung.