Preparation, characterization and biodegradable characteristics of poly(D,L-lactide-co-1,3-trimethylene carbonate)

Poly(D,L-lactide-co-1,3-trimethylene carbonate) (PLCA) has been synthesized by ring-opening polymerization of 1,3-trimethylene carbonate (CA) and D,L-lactide (LA) using stannous octoate as catalyst. The copolymers were characterized by H-1 nuclear magnetic resonance (NMR), C-13 NMR and differential scanning calorimetry. Water content and static contact angle of distilled water on the polymer surface were used to evaluate hydrophobicity of the polymers. It was found that the hydrophobicity increased with increasing CA fractions in the copolymers. Biodegradation experiments were conducted in vitro and in vivo. The results indicated that the biodegradation behaviour changed from surface to bulk degradation when the LA content exceeded 30 mol% in the copolymers. These properties of PLCA may be useful in protein delivery systems.