In order to improve the release properties of water-insoluble drugs from polymeric micelles, we develop polymeric micelles stabilized by polyethylenimine–copper (C₂H₅N–Cu) coordination between the amino groups in ABC triblock copolymer poly(ethylene glycol)-block-linear polyethylenimine-block-poly(ε-caprolactone) (PEG-PEI-PCL) and divalent copper cations.