Phase separation-induced nanoprecipitation for making polymer nanoparticles with high drug loading

Increasing drug loading remains a critical challenge in the development and translation of nanomedicine. High drug-loading nanoparticles have demonstrated unique advantages such as less carrier material used, better-controlled drug release, and improved efficacy and safety. Herein, we report a simple and efficient salt concentration screening method for making polymer nanoparticles with exceptionally high drug loading (up to 66.5 wt%) based on phase separation-induced nanoprecipitation. Upon addition of salt, phase separation occurs in a miscible solvent-water solution delaying the precipitation time of drugs and polymers to different extents, facilitating their co-precipitation thus the formation of high drug-loading nanoparticles with high encapsulation efficiency (>90%) and excellent stability (>1 month). This technology is versatile and easy to be adapted to various hydrophobic drugs, different polymers, and solvents. This salt-induced nanoprecipitation strategy offers a novel approach to fabricating polymer nanoparticles with tunable drug loading, and opens great potentials for future nanomedicines.