RT Journal Article ID 3e1437fc2492d998 A1 Thrall, Karla A1 Soelberg, Jolen J. A1 Powell, Thomas E. A1 Corley, Richard A. T1 Physiologically Based Pharmacokinetic Modeling of the Disposition of Octamethylcyclotetrasiloxane (D4) Migration from Implants in Humans JF Journal of Long-Term Effects of Medical Implants JO JLT YR 2008 FD 2009-10-20 VO 18 IS 2 SP 133 OP 144 K1 D4 K1 implants K1 PBPK K1 migration K1 silicone. AB A physiologically based pharmacokinetic model was developed to describe the silicone constituent octamethylcyclotetrasiloxane (D4) and its migration from intact or ruptured silicone gel-filled breast implants into surrounding tissues. D4 is a representative low-molecular weight constituent of silicone gel that is soluble enough in biological fluids to migrate from the implant and into surrounding tissues. The simulations were based on a representative young adult (premenopausal) woman and a mature (postmenopausal) woman using worst-case exposure conditions (i.e., complete rupture of the largest implant available, maximum levels of D4 in silicone, equal solubility of D4 in breast tissue and gel, and a range of breast tissue fat contents). The results indicate that D4 is cleared primarily by exhalation with highest concentrations achieved briefly in breast tissues of a representative postmenopausal woman. Maximum D4 levels in breast tissues for this scenario were estimated to be approximately 750 ppb with over 90% cleared in about 20 days. Thus, it is unlikely that D4 would be detected in any tissue within a few weeks of receiving an implant, even if immediately ruptured, under the assumptions used in this model. PB Begell House LK https://www.dl.begellhouse.com/journals/1bef42082d7a0fdf,065c175e0dfcb87c,3e1437fc2492d998.html