Penetration of Ammonium Perfluorooctanoate Through Rat and Human Skin In Vitro

• Published in: Drug and chemical toxicology (New York, N.Y. 1978) Vol. 28; no. 1; pp. 79 - 90
• Main Authors: Fasano, W J, Kennedy, G L, Szostek, B, Farrar, D G, Ward, R J, Haroun, L, Hinderliter, P M
• Format: Journal Article
• Language: English
• Published: 01-01-2005
• ISSN: 0148-0545
• DOI: 10.1081/DCT-200039707

Rat and human epidermal membranes were mounted onto in vitro diffusion cells with an exposure area of 0.64 cm super(2), and skin integrity was confirmed using electrical impedance. Following membrane selection, Fluorad FC-118, a 20% aqueous solution of ammonium perfluorooctanoate (AFPO), was applied to the epidermal surface of each skin replicate at approximately 150 mu L/cm super(2) and the donor chamber opening occluded with Parafilm. Serial receptor fluid samples were collected hourly from 1 to 6 h and at 12, 24, 30, and 48 h and analyzed by liquid chromatography-mass spectrometry (LC-MS) for APFO anion (PFO super(-)). For rat skin, the time to steady-state penetration (6500 plus or minus 3000 ng APFO times cm super(-2) times h super(-1)) occurred in less than 12 h, which was sustained until termination (48 h). Based on the concentration of the applied test material, the permeability coefficient (Kp) for APFO in rat skin was calculated to be 3.25 plus or minus 1.51 x 10 super(-5) cm/h. By end of the 48-h exposure period, only a small portion of the total APFO applied (1.44 plus or minus 1.13%) had penetrated through rat skin. For human skin, steady-state penetration of APFO (190 plus or minus 57 ng APFO times cm super(-2) times h super(-1)) was reached by 12 h. Based on the concentration of the applied test material, the permeability coefficient for APFO in human skin was calculated to be 9.49 plus or minus 2.86 x 10 super(-7) cm/h. By the end of the 48-h exposure period, only a negligible amount of the total APFO applied (0.048 plus or minus 0.01%) had penetrated through human skin. Thus, under infinite dose and occlusive conditions, the steady-state penetration of APFO from a 20% solution was approximately 34-fold faster through rat skin than human skin.