The project aims to improve the delivery of anti-cancer doxorubicin (DOX) drug by its encapsulation in two different polymer composites (the first polymer composite: the cross-linked methacrylic modified poly N-vinyl-pyrrolidone coated magnetic nanoparticle (PNVP@Fe3O4), and the second polymer composite: the cross-linked methacrylic modified poly N-isopropylacrylamide-co-N-vinylpyrrolidone coated magnetic nanoparticle [P(NIPAAM-co-NVP@Fe3O4)]). These two composites were synthesized by the radical copolymerization of the monomers without requiring any special conditions. Formations of these two composites were confirmed by FT-IR, UV, TGA-DTA, XRD, VSM and SEM. The results show the high drug loading and the low release time for the prepared composites. Furthermore, when N-isopropylacrylamide was used as a monomer, the composite showed a lower critical solution temperature property which can be beneficial in cancer drug delivery, since the temperature of cancer cells is higher than normal ones, and DOX can be released selectively in cancer cells. (C) 2014 Elsevier B.V. All rights reserved.