Carver, M.P., N.A. Monteiro-Riviere, R.A. Rogers, K.F. Bowman, and J.E. Riviere. Percutaneous Absorption Kinetics of Organophosphates, Steroids, Caffeine, and Benzoic Acid in the Isolated Perfused Porcine Skin Flap (IPPSF). The Toxicologist 1987. 7:244.

benzoic acid - 00065-85-0; caffeine - 00058-08-2; malathion - 00121-75-5; parathion - 00056-38-2; DFP - , testosterone - , progesterone -

The dynamics of percutaneous absorption may be investigated in the IPPSF, a unique experimental skin model recently developed in our laboratory. This study involves the absorption of ¹⁴C-benzoic acid (B), -caffeine (C), -malathion - (M), -parathion (P), -DFP (D), -testosterone (T), and -progesterone (R) applied topically in ethanol (40 ug/cm²), both in vivo and on the IPPSF. In vivo absorption (urinary excretion of ¹⁴C-) ranked accordingly: B > C > M = P > T > D, and was usually complete by 96 hr. Preliminary evaluation of IPPSF absorption profiles (0-10 hrs post-dosing) revealed 2 consistent patterns: a rapid early penetration followed by a 75-90% lower rate after 3-5 hrs (B,D,P), or a single linear rate (C,M,T,R). The mean time to reach 1% of absorbed dose and the time to reach maximum venous effluent flux were both compound-specific as follows: B < organophosphates = C < steroids. These results suggest that the IPPSF may be a valid and sensitive technique for collecting percutaneous absorption data for pharmacokinetic models that include skin.