title: Degradation of polydispersed poly(L-lactic acid) to modulate lactic acid release.
abstract: Polydispersed poly(L-lactic acid) (PLLA) membranes comprised of blends of monodispersed PLLA of weight average molecular weight of 82,500 and 7600 were fabricated to investigate the effect of polydispersity on degradation characteristics. The PLLA blends exhibited large spherulites of high molecular weight chains embedded in a low molecular weight matrix. During degradation in phosphate buffer at pH 7.4 and 37 degrees C for 28 d, the release rate of lactic acid increased as the percentage of the low molecular weight component in the blend was increased. For low molecular weight compositions larger than 50%, voids were created in the degrading blends due to the degradation of low molecular weight chains and the concurrent dissolution of lactic acid, and also the release of undegraded particles of high molecular weight. These studies demonstrate the feasibility of modulating lactic acid release during in vivo degradation of PLLA implants by adjusting the polymer polydispersity.
authors.affiliation: Department of Chemical Engineering, Cox Laboratory for Biomedical Engineering, Rice University, Houston, TX 77251, USA.
authors.forename: H A
authors.initials: HA
authors.lastname: von Recum
authors.forename: R L
authors.initials: RL
authors.lastname: Cleek
authors.forename: S G
authors.initials: SG
authors.lastname: Eskin
authors.forename: A G
authors.initials: AG
authors.lastname: Mikos
mesh_terms: D002152:Calorimetry, Differential Scanning; D002850:Chromatography, Gel; D003692:Delayed-Action Preparations / Q000378:metabolism; D005240:Feasibility Studies; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000737:chemistry / Q000378:metabolism*; D019344:Lactic Acid; D008970:Molecular Weight; D011091:Polyesters; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D019736:Prostheses and Implants / Q000592:standards; D013696:Temperature
chemical_list: D003692:Delayed-Action Preparations; D007773:Lactates; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)