Synthesis, characterization, and application of amino-terminated poly(ethylene glycol)-block-poly(epsilon-caprolactone) copolymer for paclitaxel.

In this paper, we successfully synthesized amino-terminated poly(ethylene glycol)-block-poly (epsilon-caprolactone) (NH2-PEG-PCL) block copolymer from polyethylene glycol 2000, epsilon-caprolactone (epsilon-CL) and hydrazine hydrate. The obtained copolymer was characterized by nuclear magnetic resonance (1H-NMR), the molecular weight and distribution of NH2-PEG-PCL were characterized by Gel permeation chromatography (GPC). The NH2-PEG-PCL copolymer could self-assemble into micelles in water. Paclitaxel (PTX) loaded NH2-PEG-PCL (PNPP) micelles were prepared by solid dispersion technique without organic solvent. The micelles were characterized by XRD, TEM and Malvern laser particle size. The results of this work indicated that PNPP micelles were uniform and spherical shapes in solution. The average size and zeta potential of PNPP (DL = 8%) in water was about 97.1 +/- 1.2 nm, +13.9 +/- 0.6 mV, respectively. The in vitrodrug release profile of PNPP micelles showed a clear slow-release effect. The results suggested that NH2-PEG-PCL copolymer might be an excellent carrier for hydrophobic drugs such as PTX. In particular, the NH2-PEG-PCL polymer has potential value for modifying with ligands to work as active targeting drug delivery carriers, which has great significance for cancer therapeutics.