Nanoparticle drug delivery applications have predominantly focused on the entrapment and delivery of hydrophobic molecules with poor water solubility. However, benefits can also be obtained from nanoparticle-based delivery of hydrophilic therapeutics. This study reports on the development of a p(HEMA-ran-GMA)-based nanoparticle synthesized via a spontaneous water-in-oil inverse nanoemulsion to deliver doxorubicin, a water-soluble chemotherapeutic. High drug loading efficiency and sustained release of doxorubicin from Cy5-functionalized p(HEMA-ran-GMA) nanoparticles enabled effective inhibition of the MCF-7 human breast cancer derived cell line. Direct comparative analyses with a hydrophobic PGMA nanoparticle demonstrated enhanced capabilities of the p(HEMA-ran-GMA)-based nanoparticle in vitro. The results suggest that p(HEMA-ran-GMA)-based nanoparticles, which are better suited for hydrophilic drug loading and delivery, may have the potential for the improved therapeutic effect in vivo by enhanced permeation and retention of the nanoparticles by avoidance of off-site side effects of the chemotherapeutic.