biodegradable polymeric compositions that are liquids or pastes at temperatures below 37 ° c . are described . immersion of the compositions in aqueous medium , such as body fluids , increases the viscosity of the composition resulting in the formation of a semisolid material . the polymeric material is a hydroxyalkanoic acid polyester derived from the copolymerization of at least one unsaturated hydroxy fatty acid copolymerized with hydroxyalkanoic acids of 2 - 6 carbons .