Trimethylene Carbonate - Lactide Ester Copolymer Synthesis, Characterization And Drug Control Release System

Biodegradable polymer is a very important part of biomedical materials.Polylactide has been widely used in medical applications,such as surgical sutures,bone-fixed materials,drug controlled release,scaffold,and so on,for its excellent mechanical property,good biocompatibility and low toxicity.In recent years,biodegradable polycarbonate became one of the most attractive biomedical materials for its some good properties.Biodegradable polycarbonate,Polyester and their copolymer are promising to be used in the biomedical fields.This article focused on the TMC,LA and their polymerization.To improve the properties of homopolymers,it's a good method that to synthsis block copolymer or random copolymer,by using different feed composition.Firstly,the monomers,Trimethylene carbonate and D,L-Lactide,were synthesized and purified with the modified methods of literature.Copolymers and homopolymers were synthesized via ring-opening polymerization.Sn(Oct)₂ has been chosen to start the homopolymerization of TMC and D,L-LA and their random copolymerization.PTMC,PDLLA and PTMC-co-LA were obtained with Sn(Oct)₂ as catalyst at high yield.Secondary,Polymers were to be characterized.The feed compositions of copolymers were 75/25,50/50 and 25/75.The actual compositions of the copolymers were measured by ¹HNMR.The results showed that the feed compositions were near the compositions of copolymers.The properties of the copolymers and homopolymers were assayed by DSC,GPC,Degradation in vitro.Finally,the model drug release behavior and degradation behavior of systems based on the mentioned above copolymers and homopolymers were investigated.The microballoon loading Levonorgestrel were prepared by O/W solvent evaporation method.The microballons immersed in 15%(V/V)ethanol/water mixsolvent were put into incubater at 37℃.The immersion solvent was refreshed regularly and its absorbance at 248nm on UV spectra was recorded.The results showed that the burst effect of all the microballoons was very low,To som extent The LNG release rate was related with the compositions of copolymers.The degradation rates of all the microballoons are rather slow.