From the 2003 FDA Science Forum
M.E.Kraeling, J.J.Yourick, R.L.Bronaugh, Office of Cosmetics and Colors, CFSAN, FDA, Laurel, MD 20708
Diethanolamine (DEA) is contained in pharmaceuticals and various cosmetic and personal care products. The National Toxicology Program (NTP) raised concerns about the safety of DEA. Therefore, studies were conducted to measure the extent of DEA absorption in human skin relevant to exposures from consumer products. DEA penetration was determined from three different product classes: shampoos, hair dyes and body lotions. Two commercial products from each class were spiked with [14C]DEA and applied to excised viable and non-viable human skin in flow-through diffusion cells. Products remained on the skin for 5 min, 30 min and 24 hours for shampoos, hair dyes and body lotions, respectively. At the end of 24 hours, most of the DEA that penetrated was found in skin with only small amounts absorbed into the receptor fluid: 0.08%, 0.09% and 0.9% for shampoos, hair dyes and body lotions, respectively. In 72-hour studies, only small amounts of additional DEA were absorbed into the receptor fluid. In repeat dose studies with a lotion, DEA appeared to accumulate in skin (29.2%) with very little diffusing out into the receptor fluid. Therefore, skin levels of DEA should not be included in estimates of systemic absorption used in exposure assessments.