Porous hydrophilic core/hydrophobic shell nanoparticles for particle size and drug release control

Polymeric nanoparticle has been developed for drug delivery during the past decades. However, the size of hydrophilic nanoparticles would increase in the aqueous environment due to water absorption, and then influence the in vivo biodistribution and drug release behavior. In the present study, the metronidazole-loaded porous Eudragit® RS (ERS)/poly(methyl methacrylate) (PMMA) core/shell nanoparticles were prepared by coaxial electrospray. Compared to the hydrophilic ERS nanoparticles, the porous hydrophilic core/hydrophobic shell nanoparticles displayed a slower drug release, and the release rate can be adjusted to change the surface area and particle size. In addition, the porous core/shell nanoparticles could maintain a stable particle size distribution in simulated body fluid for 8 h, which can be attributed to the bioinert nature of PMMA coating. And porous core/shell nanoparticles showed slight in vitro cytotoxicity and good cellular internalization property. The results demonstrated that the prepared porous hydrophilic core/hydrophobic shell nanoparticles is a potential candidate for delivering drugs, which can also be used as a platform and further modified into targeted drug delivery systems for clinical application.