Drug Nanoparticle Isolation by Hydrogen Bonding Coacervation

To ensure long term stability most nanoparticle dispersions need to be prepared in dry form. The drying step is either costly as in the case of freeze drying, or results in aggregation as in the case of pan drying. We present a novel drying process that involves the unique hydrogen bonding complex between polyethylene glycol and poly carboxylic acid compounds. These interactions, triggered at low pH result in rapid floccualation of the nanoparticle dispersion. The resulting precipitate can be dried and redispersed back to the original particle size. The redisolution is triggered by breaking the complex via ionization of the acid groups by neutralizing the solution to a neutral pH.