DEGRADATION OF POLYURETHANE FOAMS USED IN THE MEME BREAST IMPLANT

The release of toluene diisocyanate derivatives from polyurethane foam covers that were removed from the Meme breast implant was studied. The polyurethane foam covers as retrieved from the implants were contaminated on average with 2,4- and 2,6-toluene diamine (TDA), 2,4- and 2,6-toluene diisocyanate (TDI), and toluene isocyanate amine (TIA) at the 1086 ppm level (combined TDA, TDI, and TIA). When cleaned foam was incubated in Ringer's solution at 37-degrees-C for periods ranging from 6-35 days, 4.6 ppm/day of TDA, TDI, and TIA (combined) was formed; the projected annual degradation rate of the foam under these conditions was estimated to be about 0.8%. When cleaned foam was incubated dry at 37-degrees-C, 1.5 ppm/day of TDA, TDI, and TIA (combined) was produced. Hence, the polyurethane foam covers used in the Meme breast implants are susceptible to both thermal and hydrolytic degradation under simulated physiological conditions.