The synthesis and biodegradability of poly(lactide-random-depsipeptide)-PEG-Poly(lactide-random-depsipeptide) ABA-type triblock copolymers

Amphiphilic ABA-type triblock copolymers were synthesized to develop a biodegradable anti-adhesive membrane. In this particular synthesis, poly[L-lactide(LA)-co-depsipeptideI (poly[LA-co-(Glc-Leu)]: PLGL) was used as the A segment, and the poly(ethylene glycol)s (PEG)s, Mn = 10,000 and Mn = 20,500 were used as the B segment. The synthesis of the triblock copolymer (PLGL-PEG-PLGL) was carried out via a ring-opening copolymerization of L-lactide and cyclo(Glc-Leu) in the presence of hydroxytelechelic poly(ethylene glycol) using tin 2-ethylhexanoate as a catalyst. To evaluate the copolymer films as candidates for biodegradable anti-adhesive membranes, physicochemical properties such as degradation on behavior under physiological conditions and water absorption were investigated. The degradation rate of the PLGL-PEG-PLGL films varied with changes in the molecular architecture; specifically, the molecular weight of the hydrophilic B segment and the depsipeptide unit content in the A segment were more prominent. The biocompatibility and resorption of the PLGL-PEG-PLGL films were also evaluated. The PLGL-PEG-PLGL films were degraded and depleted gradually in vivo without inflammation.