Temperature-responsive polymers have become increasingly attractive as carrier for the injectable drug delivery systems. In the present work, we have studied the preparation of poly(N-isopropylacrylamide-acrylamide-vinilpyrrolidone) (NIPAAm-AAm-VP terpolymer) nanoparticulated terpolymer and its blend with poly(lactide-co-glycolide, PLGA,; molar ratio of lactide/glycolid 1/3). Thermosensitive terpolymer, poly(NIPAAM-AAm-VP) was prepared by free-radical polymerization aqueous solution. The natioparticles of poly(NIPAAm-AAm-VP) and its blend with PLGA containing naltrexone were prepared using the evaporation and w/o emulsion-solvent evaporation methods, respectively. Narloparticles prepared from terpolymer-PLGA blend at low polymer concentration (5%) shows larger particle size (>300 nm) and higher drug content%. Various types of nanoparticles showed a burst release of less than 10%, after 24 h. The results suggest that by regulating different variables, desired release profiles of naltrexone can be achieved using a blend of PLGS-ploy(NIPAAm-AAm-VP) nano-particulate system. (c) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 1905-1910, 2009