N-acetylcysteine side-chain functionalization of poly(globalide-co-ε-caprolactone) through thiol-ene reaction

N-Acetykysteine (NAC) is a drug well known for its antimucolytic action, antioxidant activity and ability to protect cells from oxidative stress. Conjugation of NAC with double bonds in the main polymer chain of poly (globalide-co-epsilon-caprolactone) (PGlCL) through thiol-ene reaction is reported. Different globalide (Gl) (an unsaturated macrolactone) to epsilon-caprolactone (CL) ratios were employed for PGICL synthesis. The polymeric materials (PGICL-NAC) were evaluated in terms of the number of functionalized double bonds, thermal properties, affinity for water and antioxidant potential. PGlCL-NAC containing more globalide repeating units presented higher degree of functionalization, due to the higher number of double bonds available to react through thiolene coupling. For high globalide contents (Gl/CL ratios above 50/50), NAC coupling in PGICL chains resulted in completely amorphous copolymers with a more hydrophilic character, which should enhance bioresorption and cell adhesion characteristics. Functionalization also gave rise to a thioether linkage, conferring to PGICL-NAC an antioxidant character, important for biomedical applications, where the material could combat cellular oxidative-stress.