THE MECHANISMS OF OXIDATIVE-DEGRADATION OF BIOMEDICAL POLYMERS BY FREE-RADICALS

Degradation is an essential factor in polymer biocompatibility. The ph ysiological environment of the human body can be aggressive to polymer s. Most implanted polymers suffer degradation and the kinetics and mec hanisms of the processes can be significantly affected by various biol ogically active species, especially enzymes, lipids, peroxides, free r adicals, and phagocytic cells. Iron enhances the toxicity of oxygen fr ee radicals. Superoxide and hydrogen peroxide can interact to form the very toxic hydroxyl radical in the presence of iron. The data have sh own that the hydroxyl radical is likely to be one of the main causes o f polymer degradation in implementable devices. (C) 1994 John Wiley & Sons, Inc.