Studies on Synthesis of Block Copolymers Containing Polyester and Polypeptide for Drug Delivery System . Synthesis and Characterization of Copolymer of L-Lactic Acid and L-Glutamic Acid

摘要

As a possible biocompatible and biodegrable polymer skeleton for drug delivery system, block copolymers of L-lactic acid and L-glutamic acid with different composition were synthesized and characterized. Poly (L-lactide) was prepared by polymerization of L-lactide with zine oxide at 130?é for 72 hrs. 3-Amino-l-propanol was introduced to poly (L-lactide) by an ester linkage in order to initiate polymerization. Polymerization of ￥?-benzyl-L-glutamate-N-carboxyanhydride (￥?-BLG-NCA) utiliizing the amino group of modified poly (L-lactide) as an initiator gave rise to the block copoly (L-lactide-￥?-benzyl-L-glutamate). The NMR study of resulting block copolymers showed that the composition of L-lactic acid and ￥?-benzyl-L-glutamate in block copolymers was depended on the weight ratio of poly (L-lactide) and ￥?-BLG-NCA. The thermal properties of the resulting block copolymers were determined by the differential scanning calorimetry and by the thermogravimetry.