Abstract: A star-shaped polymer adamantane-[poly(ε-caprolactone)-b-poly(2-(diethylamino)ethyl methacrylate)-b-poly(poly(ethylene glycol) methyl ether methacrylate)]₄ (Ad-(PCL-b-PDEAEMA-b-PPEGMA)₄) and its pH-responsive self-assembled polymeric micelles were developed for adriamycin (DOX) delivery. This star-shaped polymer was synthesized via ring-opening polymerization (ROP) and activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP), and characterized by ¹H NMR spectroscopy, gel permeation chromatograph (GPC), fluorescence spectra and dynamic light scattering (DLS). The resulting polymer had a definite structure with a narrow molecular weight distribution (PDI<1.3); the critical micelle concentration (CMC) of the polymer was very low (3.4 mg/L), which indicated that the polymeric micelles would keep stable in blood circulation system; resulting from the protonation of the tertiary amine group of PDEAEMA, the release performance of micelles at pH=5.0 were rapider than that at pH=7.4 and pH=6.8. The results shows that pH-responsive Ad-(PCL-b-PDEAEMA-b-PPEGMA)₄ micelles could be a potential carrier for targeted delivery of anti-cancer drugs with controlled and sustained release behavior.

Key words: star-shaped polymer, pH-responsive, micelles