Acid-Sensitive Sheddable PEGylated, Mannose-Modified Nanoparticles Increase the Delivery of Betamethasone to Chronic Inflammation Sites in a Mouse Model.

Inflammation is implicated in a host of chronic illnesses. Within these inflamed tissues, the pH of the microenvironment is decreased and immune cells, particularly macrophages, infiltrate the area. Additionally, the vascular integrity of these sites is altered with increased fenestrations between endothelial cells. These distinctive properties may be exploited to enhance targeted delivery of anti-inflammatory therapies. Using a mouse model of chronic inflammation, we previously showed that acid-sensitive sheddable PEGylation increases the distribution and retention of nanoparticles in chronic inflammation sites. Here we demonstrated that surface modification of the acid-sensitive sheddable PEGylated nanoparticles with mannose, a ligand to mannose receptors present in chronic inflammation sites, significantly increases the targeted delivery of the nanoparticles to these areas. Furthermore, we showed that the acid-sensitive sheddable PEGylated, mannose-modified nanoparticles are able to significantly increase the delivery of betamethasone-21-acetate (BA), a model anti-inflammatory compound, to chronic inflammation sites as compared to free BA. These results highlight the ability to engineer formulations to target chronic inflammation sites by exploiting the microenvironment of these regions.