Dextran/PLGA double-layered microspheres for sustained release of doxorubicin

Biodegradable polymer microspheres have been extensively developed as drug carriers that alleviate burst release and control drug release profiles. In this study, we report a simple method to develop double-layered microspheres for controlled and sustained drug release. Double layered microspheres were prepared using PLGA and natural hydrophilic polymer dextran by a simple method based on an emulsion-solvent evaporation method. Microspheres had a double layered structure with dextran layer in the core and PLGA on the surface due to phase separation and encapsulated doxorubicin as a model drug in their core. The molecular weight and concentration of PLGA dominated the structure, in vitro degradation and drug release profiles of microspheres. Dextran/PLGA double-layered microspheres had a diameter about 200 m and alleviated initial burst release. Drug release profiles from dextran/PLGA double-layered microspheres can becontrolled by manipulating the thickness of shell of the microspheres. We anticipate great potential of dextran/PLGA double-layered microspheres for controlled and sustained drug delivery, given their simple formulation and the control of drug release profiles.