In vitro percutaneous absorption of sodium lauryl sulfate (SLS) in human skin decreased by quaternium-18 bentonite gels

Penetration of [(35)S]-sodium lauryl sulfate (SLS) into and through human skin, with and without quaternium-18 bentonite (Q-18B) gel coating, was measured over 24 h. SLS was applied to human cadaver skin, dermatomed to 500 mu m, from three subjects, and fastened on diffusion cells. Liquid scintillation counting in receptor cell fluid was measured after 24-h penetration. Residual SLS on and in skin was also determined. Results indicated that SLS penetration through skin precoated with three different formulations was inhibited from 65% to 88%. This in vitro model may be capable of predicting the protective efficacy of chemical agents applied to human skin in vivo.