Enzymatically catalyzed degradation of poly (thioether-ester) nanoparticles

Abstract

Biodegradable synthetic polymeric materials have shown promising results in sustained release of drugs. The knowledge of the in vitro degradation mechanisms of these materials and the evaluation of the parameters that affect it are crucial to make the delivery system more effective. Herein, hydrolytic degradation and enzymatic hydrolysis of poly (thioether-ester) nanoparticles synthesized via thiol-ene polymerization in miniemulsion using α,ω-diene diester monomer from renewable resources were examined. The in vitro degradation was carried out at 37 °C, in an acid solution, containing hydrochloric acid (HCl) (0.01 M, pH 2.8) and phosphate buffer solution (PBS) (0.2 M, pH 7.4), with or without 5% (w/w) of Candida Antarctica Lipase B. The change in molar mass, particle size and size distribution, morphology and functional groups during the degradation process were evaluated. The enzymatic degradation of the polymeric nanoparticles was accentuated, showing the hydrolysis of the ester bond with 90% of molar mass reduction in 240 h, while in the acidic solution this reduction was only 37% after 3 months of degradation. In PBS solution, no alteration was observed up to 3 months.