Polyglycolides block copolymers

Absorbable suture materials are catgut (collagen derived from sheep intestinal submucosa), reconstituted collagen, polyglycolide (e.g., Dexon , Dexon II , Dexon S ), poly(glycolide/lactide) random copolymer (e.g.. Vicryl ), antimicrobial-coated Vicryl (Vicryl Plus ), poly-/ -dioxanone (e.g., PDS , PDSII PDS Plus), poly(glycolide/trimethylene carbonate) block copolymer (e.g., Maxon ), poly(glycolide/e-caprolactone) (e.g., Monocryl ,... 

Occasionally in the synthesis of the copolymers, insoluble material is produced. This results from polymer containing blocks of polyglycolide rather than the desired random structure. Obviously, such compositions would have considerable effect on the performance of controlled release formulations utilizing those polymers. This problem is particularly evident when one is seeking to utilize the 50 50 glycolide/lactide copolymer as a biodegradable excipient. However, with carefully controlled polymerization conditions, useful 50 50 polymer is readily produced. 

Block/segmented absorbable copolymers of high melting crystallizable polyesters such as polyglycolide with amorphous polyether-ester such as poly-l,5-dioxepane-2-one... 

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