| Biodegradable polymer is a very important part of biomedical materials. In recent years, biodegradable aliphatic polycarbonates became one of the most attractive biomedical materials for its good properties. Biodegradable aliphatic polycarbonates are promising to be used in the biomedical fields.Poly-(trimethylene carbonate)(PTMC)has been used in surgical sutures for its excellent mechanical property, good biocompatibility and low toxicity. In other hand, this kind of polyester still have limitations of low drug loading, easy to lose activity and difficult to control, and so on, due to its intrinsic great hydrophobic. It's a good method to improve the properties of homopolymers that to synthesis block copolymer or random copolymer, by using different feed composition. The monomer of 5-benzyloxy-trimethylene carbonate (BTMC)was synthesized and the monomer of TMC was purified. The homopolymer of PBTMC and PTMC was synthesized by the catalyst of Sn(Oct)2. The compositions of copolymers were 1:5, 1:3, 1:2 and 1:1 of P (BTMC-co-TMC) were synthesized, the protected groups were effectively removed via catalytic hydrogenation, and the copolymer of P (HTMC-co-TMC) was obtained at last. The properties of the copolymers and homopolymers were assayed by 1HNMR, FT-IR, GPC, degradation behavior in vitro.The model protein BSA loaded microspheres of P (HTMC-co-TMC) and PTMC were prepared by improved double emulsion solvent evaporation technique (W1/O/W2). The microspheres size and size distribution, drug loading amount and encapsulation efficiency, in vitro release behavior were investigated. The BSA release behaviors were different with different polymer composition. The BSA release rate can be adjusted by varying the composition of the novel biodegradable polycarbonates. The novel biodegradable polycarbonates maybe have the potential to use as the controlled release carriers of protein and polypeptide drugs. |
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