Synthesis and characterization of PEG-PCL-PEG triblock copolymers as carriers of doxorubicin for the treatment of breast cancer

Triblock copolymers of monomethoxy poly(ethylene glycol) (mPEG) and e-caprolactone (CL) were prepared with varying lengths of poly(e-caprolactone) (PCL) compositions and a fixed length of mPEG segment. The molecular characteristics of triblock copolymers were characterized by 1H NMR, gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). These amphiphilic linear copolymers based on PCL hydrophobic chain and hydrophilic mPEG ending, which can self-assemble into nanoscopic micelles with their hydrophobic cores, encapsulated doxorubicin (DOX) in an aqueous solution. The particle size of prepared micelles was around 40–92 nm. The DOX loading content and DOX loading efficiency were from 3.7–7.4% to 26–49%, respectively. DOX-released profile was pH-dependent and faster at pH 5.4 than pH 7.4. Additionally, the cytotoxicity of DOX-loaded micelles was found to be similar with free DOX in drug-resistant cells (MCF-7/adr). The great amounts of DOX and fast uptake accumulated into the MCF-7/adr cells from DOX-loaded micelles suggest a potential application in cancer chemotherapy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010