Synthesis, characterization, and in vitro 5-Fu release behavior of poly(2,2-dimethyltrimethylene carbonate)-poly(ethylene glycol)-poly(2,2-dimethyltrimethylene carbonate) nanoparticles.

Novel ABA-type amphiphilic triblock copolymers composed of poly (ethylene glycol) (PEG) as hydrophilic segment and poly (2,2-dimethyltrimethylene carbonate) (PDTC) as hydrophobic segment were synthesized by ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC) initiated by dihydroxyl PEG. The influence of introducing PEG block on crystalline behavior of PDTC segment was investigated by DSC. Polymeric micelles in aqueous medium were characterized by fluorescence spectroscopy and dynamic light scattering. The critical micelle concentration of these copolymers was in the range of 5.1-50.5 mg/L. Particle size was 80-280 nm. Core-shell-type nanoparticles were prepared by the dialysis technique. Zeta potential was measured by laser Doppler anemometry, and all nanoparticles had negative zeta potential. Transmission electron microscopy images demonstrated that these nanoparticles were spherical in shape. Anticancer drug 5-fluorouracil (5-Fu) as a model drug was loaded in the polymeric nanoparticles. X-ray powder diffraction demonstrated that 5-Fu was encapsulated into polymeric nanoparticles as molecular dispersion. In vitro cytotoxicity of nanoparticles was evaluated by MTT assay. In vitro release behavior of 5-Fu was investigated, and sustained drug release was achieved.