PCL(2k)-PEG(1k)-SPDP constitutes two block of polymers with different hydrophobicity, i.e. polycaprolactone (PCL)as a hydrophobic block and PEG as a hydrophilic block. It can react with thiol via thiol exchange reaction to form a disulfide bond. The polymer can self-assemble in aqueous media and be used as strategies for sustained drug delivery using micellar nanocarriers. Reagent grade, for research purpose.