THE DEPENDENCE OF DEGRADATION AND RELEASE BEHAVIOR OF POLYESTERS ON MONOMER SEQUENCE

[摘要] Although Nature has taught us that sequence control can be used to control macromolecular properties, there is little systematic polymer research connecting sequence with properties.Poly(lactic-co-glycolic acid) (PLGA) copolymers are universally recognized as biodegradable polymers that can be used for in vivo bioengineering applications.Sequence control of PLGAs may allow the tuning of properties for specific drug delivery or cell scaffolding applications.A series of sequenced PLGAs were prepared and their hydrolysis rates, thermal properties and ability to sequester and deliver rhodamine B (RhB) were investigated. By monitoring both polymer molecular weight and lactic acid release, it was determined that sequenced copolymers hydrolyze more gradually than random copolymers.Data from thermal studies and from the size exclusion chromatography of these samples establish also that they maintain their initial morphology throughout and do not become heterogeneous as do the random controls. Differences in hydrolysis profile were also found for specific sequences.RhB encapsulation and release was also found to depend on sequence—the alternating copolymer had a lower loading capacity but a more gradual release rate than the random copolymer with the same lactic/glycolic unit composition.

[发布机构] the University of Pittsburgh