Dermal Absorption of (14)C-Labeled 4,4'-Methylenedianiline (4,4'-MDA) in Rats, Guinea Pigs, and Monkeys

摘要

To help determine workplace exposure to 4,4'-MDA, studies were performed in male rats, guinea pigs and monkeys treated topically with a low (2 mg/kg) or high (20 mg/kg) dose of 14C-4,4'-MDA. Conditions of treatment (dosage, dose regimens, and occlusion) were assessed. The disposition of 4,4'-MDA was also examined after i.v. dosing. In rats, 43 and 10% of the low dose was recovered in urine and feces during a 96 h period; 2% remained in tissues and skin washing removed 25% of dose. The remainder (26%) was recovered by skin extraction and solubilization. The percent of dose absorbed decreased by increasing the dose, but the total amount absorbed (approx. 0.25 mg/rat) was similar after both doses. In g. pigs, 10 and 18% of the low dose was excreted in urine and feces; 1% was recovered in tissue, 41% in the skin wash and 29% from the application area. The percent of dose absorbed decreased following the high dose, but the amounts absorbed (in mg/animal) doubled.