Castor oil-citric acid copolyester for tissue augmentation

Biodegrable polyesters derived from hydroxy acids have a broad clinical use. The aim of the study was to synthesize polymer compositions based on citric acid and castor oil for use as soft tissue augmentation. Two polymers were synthesized, a branched viscous polyester with a monomer ratio of 93.5:6.5 w/w and an apparent molecular weight of 11,000Da and a crosslinked semisolid polymer with a monomer ratio of 92.5:7.5 w/w. The branched polymer lost less than 10% of its weight during a 30-day degradation study. In vivo biocompatibility study in rats showed 20% formulation weight loss 9months post-subcutaneous administration. These results were in accordance with the in vitro hydrolytic degradation of the polymer. The in vivo study revealed good tolerability of the copolymer.