Resorbable materials of poly(L-lactide). VII. In vivo and in vitro degradation.
In vivo and in vitro degradation of high molecular weight poly(L-lactide) used for internal bone fixation has been investigated. Within 3 months as-polymerized, microporous PLLA (Mv = 6.8-9.5 X 10(5] exhibited a massive strength-loss (sigma b = 68-75 MPa to sigma b = 4 MPa) and decrease of Mv (90-95%). At week 39, the first signs of resorption were evident (mass-loss 5 wt%). Except for dynamically loaded bone plates no differences between in vivo and in vitro degradation of PLLA were observed. The increase of crystallinity of PLLA upon degradation (up to 83%) is likely to be attributed to recrystallization of tie-chain segments. A more ductile PLLA exhibiting a lower rate of degradation was prepared by extraction of low molecular weight compounds with ethyl acetate.
Leenslag
J W
JW
Department of Polymer Chemistry, University of Groningen, The Netherlands.
Pennings
A J
AJ
Bos
R R
RR
Rozema
F R
FR
Boering
G
G
D000818:Animals; D001672:Biocompatible Materials / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001860:Bone Plates; D001863:Bone Screws; D004285:Dogs; D008422:Materials Testing; D008970:Molecular Weight; D011091:Polyesters / Q000378:metabolism*; D051381:Rats; D013718:Tensile Strength
D001672:Biocompatible Materials; D011091:Polyesters; C033616:poly(lactide)