Development of creatine and arginine-6-oligomer for the ring-opening polymerization of cyclic esters

Natural creatine and arginine-6-oligomer have been effectively engaged as ring-opening polymerization initiators of poly( L -lactide) (PLLA) and poly( ɛ -caprolactone) (PCL) in bulk. The nonlinear structure and thermal properties of the resulted polymers were further elucidated by 1 H, 13 C nuclear magnetic resonance, and a modulated differencial scanning calorimetry (MDSC). Thermal analysis indicated that the synthesized polymers had lower melting points, glass-transition temperatures, fusion enthalpy, and crystallization temperature than those of linear PCL or PLLA due to the presence of the arginine-6-oligomer in the macromolecule and crystalline imperfections caused by the branched structure. This study provides an efficient and metal-free method for the synthesis of branched biodegradable polymers with incorporated compounds, which exhibit therapeutic properties, adequate for the drug carrier applications.