Novel adhesion prevention membrane based on a bioresorbable copoly(ester-ether) comprised of poly-L-lactide and Pluronic (R): In vitro and in vivo evaluations

Block copolymers consisting of poly(L-lactide) (PLLA) and poly(oxyethylene- co-oxypropylene), with various compositions, were synthesized and character ized in vitro and in vivo for their application as postoperative adhesion p revention membranes. It was found that the flexibility and degradability of the cast films of the block copolymers grew with increasing Pluronic(R) F6 8 [PN; poly(oxyethylene-co-oxypropylene] composition. The receding contact angle of the copolymer films against water became lower than that of the PL LA film, because the surface was predominantly covered with more hydrophili c PN segments in a wet state. This surface property significantly affects t he cell attachment property of the copolymer films, and the fibroblasts cul tured on the films exhibit a spheroid like morphology. The copolymer films subcutaneously implanted in the back of rats induced milder tissue response s compared with PLLA homopolymers, because of the increased surface hydroph ilicity in the former. In vivo evaluation using a uterus horn model in rats revealed that the performance of these copolymer films as an adhesion-prev ention membrane is comparable to that of a conventionally utilized membrane of oxidized regenerated cellulose. These results indicate that the copolym er films are biocompatible materials with controllable mechanical propertie s and biodegradability as adhesion-prevention membranes. (C) 2000 John Wile y & Sons, Inc.