Methotrexate (MTX),an antineoplastic agent,is routinely used in the treatment of acute lymphoblastic leukemia,psoriasis,choriocarcinoma and related trophoblastic tumors [1].However,it is reported to have toxic side effects to normal cells,drug resistance,and leucopoenia and nephrotoxicity.Hyperbranched polymers (HBPs) are nanoscale macromolecules extensively used for drug delivery owing to their biocompatibility and the presence of large number of peripheral functional groups that allow conjugation of multiple molecules.