Polylactic acid (PLA), also known as polylactide, is a type of aliphatic polyester polymerized with lactic acid as a monomer. Polyglycolic acid (PGA) is a synthetic polymer material with good biodegradability and biocompatibility. Generally, glycolide is used to make the intermediate product glycolide, and the glycolide is ring-opened and polymerized to form PGA.
Compared with PLA, PGA has one less methyl group in the main chain unit, so it has better hydrophilicity and faster hydrolysis than PLA. The copolymerization of PGA and PLA into poly(lactide-co-glycolide) (PLGA) can significantly improve PLA. The degradation rate.
At present, the preparation of PLGA mostly adopts the ring-opening polymerization method. Common ring-opening polymerization is to separately dehydrate and cyclize glycolic acid and lactic acid to synthesize two monomers of glycolide (GA) and lactide (LA), and then ring-opening polymerization of GA and LA to obtain a PLGA random copolymer.
The ratio of PGA and PLA in the PLGA copolymer is different, and the crystallinity is also different. The crystallinity of the copolymer is different, and the water absorption rate is different. Lactic acid is less hydrophilic than glycolic acid, so PLGA copolymers rich in lactide are more hydrophilic than copolymers rich in glycolide. Therefore, the degradation rate of the copolymer can be adjusted by changing the ratio of PLA and PGA in the copolymer.
In addition to its application as a conventional degradable plastic, PLGA is also widely used as a functional pharmaceutical excipient to control the release of parenteral drugs, as well as for the production of bioabsorbable implantable medical devices for orthopedics, cardiovascular and wound healing applications.
