PCL(2k)-PEG(3k)-NH2 is an amphiphilic block copolymer containing a hydrophobic polycaprolactone (PCL) block chemically attached to a hydrophilic PEG block. The polymer is reactive with an active ester (NHS) in water at pH 7-9 to form a stable amide bond. Upon dispersion in water, the polymer self assembles to form micelles which can encapsulate drugs for sustained drug delivery. Reagent grade, for research purpose.