Obtention of biocompatible hydrogels containing PEGs/silicon fatty blocks with potential use as A controlled release system

Abstract

Novel crosslinked polyesters were designed to obtain hydrogels friendly with the environment and able to display potential biologic applications. Through polycondensation reactions, the synthesis used polyethylene glycols (PEGs) of different molecular weights and a silylated fatty methyl ester obtained from methyl 10-undecenoate, a derivative of castor oil. Depending on the PEGs molecular weights, a series of crosslinked polyesters were obtained and characterized by spectroscopic methods. Thanks to double quantum coherence (DQ) proton experiments, the synthesis was optimized by determining the highest crosslink density achieved from the parameter “Constant residual dipole coupling” (Dres), which is proportional to the crosslink density. These amphiphilic polyesters showed biocompatible properties according to ISO 10993-5. Besides, they could form hydrogels structurally confirmed by scanning electron microscopy. The swelling capacity was remarkable, depending on the PEGs molecular weights. The studies of encapsulation and release using rhodamine as host molecules revealed very conclusive and promising results, demonstrating that it was possible to control the releasing time by modifying the molar mass of the PEGs used in the synthesis. This critical outcome could be considered an essential parameter for tailoring materials for different drug or fertilizer release applications.