[Preparation and in-vitro degradation of polylactide and poly(L-lactide-co-glycolide)]

In this paper, DL-lactide, L-lactide and glycolide were synthesized from DL-lactic acid, L-lactic acid and glycolic acid respectively. A set of homopolymerizations of lactide with stannous octoate as initiator and laurly alcohol as co-initiator was carried out; a series of copolymers of poly (L-lactide-co-glycolide) (PLGA) were prepared via ring-opening polymerization of DL-lactide or L-lactide and glycolide with stannous octoate in high vacuum. The structure and properties of homopolymers and copolymers were characterized by 1H-NMR spectroscopy, differential scanning calorimetry and gel permeation chromatography. The in vitro degradation behavior of polylactide (PLA) and PLGA films in Hank's solution was investigated. The hydrolytic degradation of the PLA and PLGA was monitored by measuring the changes of inherent viscosity and weight loss of the resulting samples. The degradation rate of PLGA could be adjusted by changing the composition of the copolymer and be enhanced with the glycolide content increasing. It is suggested that the PLGA copolymer is a potential material as drug elusion coating on coronary stents.