Degradation study of copolymers of pllga to be used as potential polymeric matrix in coronary stents

In this work, three types of poly(L-lactic-co-glycolic acid) copolymers (PLLGA) with di_erent lactide to glycolide ratio (70:30, 80:20 and 90:10%wt.L-LA:%wt.GA) were synthesized. The materials were characterized by known techniques. The degradation study of PLLGA was made in saline solution and followed by molecular weight change and mass loss percentage. The results showed that PLLGA degradation followed pseudo-first order kinetics. Prednisone (immunosuppressive drug) was incorporated into polymeric matrix. The release process was quantified by drug concentration change in the saline solution using UV spectroscopy at 240nm. The results showed that prednisone release process was governed by two phenomena: diffusion and degradation. The drug release processes were analyzed kinetically using zero order, first order, Higuchi and Korsmeyer- Peppas models. The cytotoxicity assay evidenced that PLLGA copolymers and PLLGA degradation products were not toxic in endothelial cells. Finally, a 3D printer was built and programmed to develop a procedure for the fabrication of a potential coronary stent based on polymeric matrix.