Synthesis and characterization of amphiphilic biodegradable copolymer, poly(aspartic acid-co-lactic acid)

An amphiphilic biodegradable polymer, poly(aspartic acid-co-lactic acid) (PAL), was synthesized by simply heating a mixture of aspartic acid (Asp) and L-lactide without additional catalysts or solvents. The unique branched architecture comprising succinimide units and lactic acid units was confirmed by IR and NMR spectroscopy. A copolymer of sodium aspartate and lactic acid (PALNa) was prepared by reacting PAL with an aqueous sodium hydroxide solution. The PAL was soluble in many organic solvents, while the PALNa was soluble in methanol and water. The hydrolytic degradation behavior of PAL varied with the copolymer composition. A, higher Asp content resulted in a faster molecular weight decrease, and introducing glycolic acid units accelerated the degradation rate.