A REVIEW OF THE BIOSTABILITY AND CARCINOGENICITY OF POLYURETHANES IN MEDICINE AND THE NEW-GENERATION OF BIOSTABLE POLYURETHANES

Polyurethanes are very versatile materials which have been used in the body for over 20 years. In fact, there are probably more scientific p apers describing these materials and modifications of these materials for medical use than any other material to dale. Unfortunately, some f ormulations of these polymers are subject to biodegradation and have l imited their application in the body. Extensive investigation of the b iodegradation mechanisms of these polymers by many researchers in the field has led to the development of a new generation of what are now c alled 'biostable' polyurethanes. This article reviews the history of p olyurethane in medicine, polyurethane nomenclature, the biodegradation of these materials, the proposed mechanisms of its degradation as wel l as the carcinogenicity associated with these materials. Included in the discussion are the polyurethanes used as pacemaker lead insulators as well as those used to coat breast implants. The article concludes with a review of the new generation of 'biostable' polyurethanes and t heir proposed formulations.