A biodegradable and biocompatible drug-delivery system based on polyoxalate microparticles

Drug delivery using biodegradable polymeric microparticles is becoming an important means of delivering therapeutic agents. In this work, we describe polyoxalate microparticles as a biodegradable and biocompatible protein drug-delivery system. Polyoxalate was synthesized from a polycondensation reaction between oxalyl chloride and 1,4-cyclohexanedimethanol under basic conditions. Polyoxalate, in design, undergoes hydrolytic degradation to generate non-toxic low-molecular-weight compounds that can be easily excreted from a body. Polyoxalate was hydrophobic and had a half-life of 6.5 days at pH 7.4. This hydrophobic polyoxalate could be formulated into microparticles by a double emulsion method and encapsulate proteins with a loading efficiency of more than 80%. Cytotoxicity evaluation using RAW 264.7 cells indicated that polyoxalate microparticles exhibited a cytotoxicity profile superior to PLGA microparticles. The polyoxalate microparticles were taken up by macrophages in vitro as confirmed by confocal fluorescence microscopy. The ease of synthesis coupled with the physicochemical properties and excellent biocompatibility make this polyoxalate a promising candidate for protein-delivery applications.