Poly(ester anhydride)/mPEG amphiphilic block co-polymer nanoparticles as delivery devices for paclitaxel

This work focused on the preparation and characterization of a novel amphiphilic block co-polymer and paclitaxel-loaded co-polymer nanoparticles (NPs) and in vitro evaluation of the release of paclitaxel and cytotoxicity of NPs. mPEG-b-P(OA-DLLA)-b-mPEG was prepared via melt polycondensation of methoxy poly(ethylene glycol) (mPEG), octadecanedioic acid (OA) and D,L-lactic acid (DLLA) and characterized by FT-IR, (1)H-NMR, (13)C-NMR, GPC, DSC and XRD. The paclitaxel-loaded mPEG-b-P(OA-DLLA)-b-mPEG NPs were prepared by nanoprecipitation and then characterized by LPSA, TEM and (1)H-NMR. In vitro release behaviors of the paclitaxel-loaded NPs were investigated by HPLC. In vitro cytotoxicity of NPs was evaluated by MTT assay with normal mouse lung fibroblast cells (L929) as model cells. The composition of mPEG-b-P(OA-DLLA)-b-mPEG is consistent with that of the designed co-polymer. The paclitaxel-loaded NPs are of spherical shape with core/shell structure and size smaller than 300 nm. Paclitaxel can be continuously released from the paclitaxel-loaded NPs and the in vitro release rate of paclitaxel decreases with increasing the content of the P(OA-DLLA) segments in the co-polymer. The mPEG-b-P(OA-DLLA)-b-mPEG NPs are non-toxic to L929. The results suggest that mPEG-b-P(OA-DLLA)-b-mPEG NPs are a potential candidate carrier material for the controlled delivery of paclitaxel and other hydrophobic compounds.