Ultrafine Nanoparticles of Ibuprofen-Poly(methyl methacrylate) by a Polymerization-Loading Method

Herein reported is a novel and versatile method to prepare drug-carrying polymeric nanoparticles of less than 50 nm in mean diameter and very narrow polydispersity. The process starts with the preparation of ultrafine poly(methyl methacrylate) nanoparticles by a technique termed as semicontinuous heterophase polymerization. Then, the obtained polymeric nanoparticles are loaded with hydrophobic drugs, where Ibuprofen being used as a model compound, by addition of an organic solution of the drug in a water immiscible low boiling point solvent; diffusion of the solution into the polymer nanoparticles allowed loading contents up to 18% IB/dry basis nanoparticles by weight. Analyzed by scanningtransmission electron microscopy, the prepared nanoparticles showed number-average diameters around 18 nm with 1.06- 1.07 polydispersity determined as the ratio weight-average to number-average diameter. Ibuprofen-loaded polymeric nanoparticles with sizes significantly smaller than those obtained by the typical methods reported in the specialized literature can conveniently be prepared by this method, which also permits the use of diverse monomers to synthesize a variety of different polymeric nanoparticles. It is expected that the ease of production, control of size and polydispersity and drug loading will help the polymeric nanoparticles thus prepared emerge as useful drug carriers in the present arsenal for disease control.