Synthesis of Polyether-Polyoxazolidone Networks for the Design of Drug-Eluting Implants

Soft polymer networks are attractive for drug-eluting medical implants because their elasticity mimics soft tissues, and their swelling enables drug loading. Although polyurethanes (PUs) are widely used for long-term implantation, concerns over their toxic isocyanate precursors motivated the development of nonisocyanate alternatives. We report elastic poly(propylene glycol)-polyoxazolidone (PPG-POx) networks prepared from bis(α-alkylidene cyclic carbonate) (BisαCC) via a three-step, catalyst-free strategy: (i) step-growth polyaddition of BisαCC with PPG diamines, forming poly(hydroxy-oxazolidone)s, (ii) easy thermal dehydration to produce poly(alkylidene oxazolidone), and (iii) thiol-ene photo-cross-linking with a trithiol. By varying the BisαCC spacer, PPG molecular weight, dehydration degree, and cross-linker ratio, the properties of the networks were evaluated. The most promising candidate demonstrated biocompatibility with human fibroblasts, hemocompatibility, and sustained release under physiological conditions of acetylsalicylic acid (ASA), chosen for its widespread use in cardiovascular prevention and its antiplatelet activity. These results position BisαCC-derived PPG-POx networks as bio- and hemocompatible isocyanate-free alternatives to polyurethanes for drug-eluting implants.