IN-VITRO PERCUTANEOUS-ABSORPTION OF SODIUM ARSENATE IN B6C3F(1) MICE

We report the investigation of the percutaneous absorption of sodium [ As-73]arsenate through skin of female B6C3F(1) mice under various cond itions of exposure. In vitro diffusion experiments were conducted for 24 hr using previously clipped full-thickness dorsal skin in a flow-th rough system with HEPES-buffered Hanks' balanced salt solution as the receptor fluid. Doses of 5, 50, 500 or 5000 ng were applied to the ski n surface (area = 0.64 cm(2)) as the solid compound, in aqueous vehicl e (100 and 250 mu l) or in sail (23 mg/cm(2)). Dermal absorption was q uantified by summing the amounts of arsenate-derived radioactivity in the receptor fluid and skin following washing of the skin surface to r emove unpenetrated compound. Absorption of sodium arsenate increased l inearly with the applied dose from all exposure vehicles, with a const ant fraction of the dose being absorbed. Maximum absorption (62% of th e applied dose) was obtained from the 100-mu l aqueous vehicle and the skin contained a higher level of the compound than the receptor fluid . Soil provided the least (<0.3% of the applied dose) absorption of th e chemical, with the major portion (68%) of the absorbed dose residing within the skin. Even short-term (1 hr) dermal exposure to arsenate i n water resulted in the passage of the chemical into the skin, which, on further perfusion (23 hr), passed into the receptor fluid. Thus, th e exposure vehicle plays an important role in the in vitro dermal abso rption of sodium arsenate in B6C3F, mice, with the aqueous vehicle pro viding greater absorption than the soil.