Mice and rabbit models for oral and percutaneous absorption and disposition of amphoteric surfactant C31G.

A topical antimicrobial agent (C31G), composed of amphoteric surfactants (alkyl betaines and alkyl amine oxides), had a significant (P less than 0.001) and concentration dependent rate of percutaneous absorption in mice and rabbits. Percutaneous absorption studies (3 concentrations for 3 exposure periods) in mice indicated that dermal interaction resulted in nonlinear changes for rate of penetration and transport as a function of exposure and concentration. Kinetic studies of absorption and disposition after oral dosing in mice with [3H]C31G were used to determine the body burden (0.21 g/kg of body weight) at a no effect level. Dermal penetration (P) and transport (T) resulting from percutaneous exposure at variations of time and dosage concentrations were shown to fit the equation T = a + k ln t. The regression coefficient k represents the characteristic change of T with exposure time (t). For low concentrations k equaled 1.89 and at the high concentration k equaled 2.68. This increase of T indicated the interaction of the agent with the dermal barrier at high concentrations. Dermal transport in the rabbit was less than one-fourth of that in the mouse. Excretion of C31G after oral or dermal dosing was predominantly renal at higher dosage levels, whereas fecal excretion dominated at the lowest dosage levels. The half-life of [3H]C31G in the mouse was 68 hours and 86 hours in the rabbit. Data and statistical methods allowed prediction of the effects of daily exposures