Preparation and in vitro evaluation of novel poly(anhydride-ester)-based amphiphilic copolymer curcumin-loaded micelles.

Novel poly(anhydride-ester)-b-poly(ethylene glycol) copolymers (PAE-b-PEGs) were synthesized by esterization of methyl poly(ethylene glycol) and poly(anhydride-ester), which were obtained by the melt polycondensation of alpha,omega-acetic anhydride-terminated poly(L-lactic acid), and characterized by 1H-NMR and gel permeation chromatography. The two poly(anhydride-ester)-b-poly(ethylene glycols) (denoted as PAE-b-PEG2k and PAE-b-PEG5k) thus obtained can self-assemble in water to form micelles with hydrodynamic diameters of 92.5 and 97.5 nm above their critical micelle concentrations of 3.78 and 2.36 microg/mL, respectively. The curcumin-loaded PAE-b-PEG2k and PAE-b-PEG5k micelles were prepared by the solid dispersion method, and they could encapsulate approximately 7% (w/w) curcumin. The diameters of the micelles were stable for 5 days. Curcumin is released faster from the micelles at pH 5.0 than at pH 7.4. Curcumin is released from the micelles at a fast rate during the initial 12 h, followed by a zero-order release during the subsequent 200 h, both at pH 5.0 and 7.4. The IC50 values of the curcumin-loaded PAE-b-PEG2k and PAE-b-PEG5k micelles against HeLa cells are 12.41 and 15.31 microg/mL, respectively, which is lower than that of free curcumin (25.90 microg/mL). The PAE-b-PEG2k micelles are taken up faster than the PAE-b-PEG5k micelles by HeLa cells. Curcumin-loaded micelles can induce G2/M phase cell cycle arrest and apoptosis of HeLa cells.