(106e) Therapeutic Antioxidant Polymers as a Potential Polymeric Material for Coating Medical Devices

Biodegradable polymers (e.g. poly(lactic acid), polyurethanes, etc.) are used for coating variety of medical devices and implants [1]. Depending on the application, the purpose of the polymer coating can be to improve the surface properties of the device (e.g. orthopedic implants) or eluting drug from the surface of the implant (e.g. stents). While it is thought that degradable materials can evade long term compatibility issues through degradation, recent studies found that the local accumulation of acids, which are by-products of biodegradation, may trigger inflammatory response leading to further oxidative stress [2-4]. It has been shown that inflammatory response to the polymer and its degradation products is characterized by oxidative stress where an imbalance between the production of oxidative species and antioxidant defense mechanism leads to a net increase in the production of reactive oxygen species (ROS) (e.g. O2.-, OH., etc.) and reactive nitrogen species (RNS) (e.g. NO., ONOO., etc.). Hence, in addition to the mechanical and controlled drug release properties, the polymer is also expected to be biodegradable, have long-term biocompatibility and that it does not induce long-term inflammatory response. In our previous work, we have developed an antioxidant polymer having its own native antioxidant activity that upon biodegradation releases active antioxidant trolox and demonstrated its ability to suppress oxidative stress injury in vitro. It is believed that these polymers are excellent candidates for medical device coatings. In this work, we have synthesized antioxidant polymer poly(trolox) (PTx) with different molecular weights, PTx-1000 and PTx-2500 and evaluated their ability to form surface coatings, cell adhesive characteristics and ability to suppress oxidative stress. In vitro degradation of PTx nanoparticles, cytotoxicity of PTx nanoparticles and mechanical strength of PTx films is also presented. 1. Ratner, B.D., Biomaterials science : an introduction to materials in medicine. 2nd ed. 2004, Amsterdam ; Boston: Elsevier Academic Press. xii, 851 p. 2. Jiang, W.W., et al., Phagocyte responses to degradable polymers. J Biomed Mater Res A, 2007. 82(2): p. 492-7. 3. Matheson, L.A., J.P. Santerre, and R.S. Labow, Changes in macrophage function and morphology due to biomedical polyurethane surfaces undergoing biodegradation. J Cell Physiol, 2004. 199(1): p. 8-19. 4. Serrano, M.C., et al., Transitory oxidative stress in L929 fibroblasts cultured on poly(epsilon-caprolactone) films. Biomaterials, 2005. 26(29): p. 5827-34.