You are here:
IN VITRO DERMAL ABSORPTION OF FLAME RETARDANT CHEMICALS
Citation:
Hughes, M F., B C. Edwards, C T. Mitchell, AND B. Bhooshan. IN VITRO DERMAL ABSORPTION OF FLAME RETARDANT CHEMICALS. Presented at SOT, San Francisco, CA, March 25 - 29, 2001.
Description:
IN VITRO DERMAL ABSORPTION OF FLAME RETARDANT CHEMICALS. M F Hughes1, B C Edwards1, C T Mitchell1, and B Bhooshan2. 1US EPA, ORD, NHEERL, RTP, NC; 2US CPSC, LSC, Rockville, MD.
Two flame retardant chemicals that are candidates for treating furniture fabrics were evaluated for dermal penetration. The chemicals were [14C]-decabromodiphenyl oxide (DBDPO) and [14C]-tris(1,3-dichloro-2-propyl)phosphate (TDCP). Skin from the adult hairless female mouse was removed and placed in flow-through diffusion cells. DBDPO (6, 30, and 60 nmole) or TDCP (20, 100, and 200 pmole) were applied in a volatile vehicle (DBDPO: tetrahydrofuran; TDCP: acetone) and receptor fluid was collected for 24 hr. Then the skin was washed with tetrahydrofuran (DBDPO) or ethanol (TDCP) to remove unabsorbed chemical. The receptor fluid, skin wash, and skin were analyzed for [14C]. Extracts prepared from high dose group skin homogenates were analyzed by HPLC. For DBDPO, 0.07-0.34% of the dose was detected in the receptor fluid by 24 hr. The dose detected in the skin ranged from 2-20%. The lowest dose of DBDPO (6 nmole) had the highest percentage of the dose (20%) in the skin. The skin wash removed the major portion of the dose (77-92%) of DBDPO. HPLC analysis of the skin homogenate extract detected primarily DBDPO and a smaller percentage of an unknown peak. TDCP was readily detected in the receptor fluid; 39-57% of the dose of TDCP was in the receptor fluid by 24 hr. The skin wash removed 11-25% of the dose of TDCP and 28-35% remained in the skin. HPLC analysis of the skin homogenate extract and receptor fluid extract from the TDCP high dose treated samples detected primarily TDCP and a smaller percentage of an unknown peak. Thus, TDCP more readily penetrates hairless mouse skin and diffuses into the receptor fluid than DBDPO. The differences in absorption between these chemicals may be due to their distinct physico-chemical properties (TDCP, log P=3.8, MW=431; DBDPO, Log P=9.97, MW=960). These data do not provide information about the adverse effects of these chemicals, but they can be used to develop exposure or risk assessments. (This abstract does not necessarily reflect EPA or CPSC policy. Supported in part by CPSC-I-99-1167).