Pluronic® F127 grafted poly (methyl vinyl ether-alt-maleic acid) copolymer was synthesized using dicyclohexylcarbodiimide and dimethylaminopyridine to prepare a suitable micellar carrier for delivery of doxorubicin (DOX) in breast cancer. The copolymer structure was confirmed by 1 H NMR and FTIR. Critical micelle concentration (CMC) of the copolymer was determined by pyrene as a fluorescent probe. DOX was loaded in micelles by direct dissolution method, and the physical properties of micelles; including particle size, zeta potential, drug loading efficiency and drug release profiles were studied. The cytotoxicity of micelles loaded with DOX in different concentrations was studied in MCF-7 cells using MTT assay. FTIR and 1 H NMR spectra confirmed successful production of the copolymeric micelles with CMC of 390μg/ml. Optimized micelles were obtained using 6mg of DOX per 24mg of copolymer, a temperature of 45.7°C, stirring time of 1h and stirring rate of 400RPM. This produced micelles with a particle size of 419.1±38.2nm, zeta potential of −13.3±1.2mV, an acceptable drug loading efficiency of 93.5±2.7% and the release efficiency of 29.0±3.1%. The release test at 4h showed a sustained release property. The drug release from copolymer was pH dependent and was faster in pH 5.5 compared to 7.4. The synthesized copolymer was not cytotoxic. Its micelles, when loaded with 0.21μM of DOX could kill about 48.9±1.7% of MCF-7 cells compared to free DOX; which killed 36.4±1.1% of these cells at the same concentration. This significant difference in cytotoxicity (p<0.05) seems promising in reducing drug resistance in breast cancer.