EFFECT OF SODIUM LAURYL SULFATE (SLS) ON IN-VITRO PERCUTANEOUS PENETRATION OF WATER, HYDROCORTISONE AND NICKEL

The dose- and time-related effect of sodium lauryl sulfate (SLS) on in vitro percutaneous penetration was studied using 3 radiolabeled trace r compounds with different physicochemical properties: tritiated water , hydrocortisone and nickel. Human cadaver abdominal skin from caucasi an women was used as membrane in static in vitro penetration cells. Si multaneous application of SLS together with 1 of the tracer compounds showed, after 48 h, a significant dose-effect relationship between SLS concentration (0.25%, 2% and 10%) and penetration of tritiated water or nickel (p<0.001, Spearman), whereas SLS had no significant effect o n penetration of hydrocortisone. When 4% SLS was applied as pretreatme nt, a significant time-effect relationship, after 48 h, was found betw een pretreatment time (0.5, 2 and 8 h) and penetration of tritiated wa ter. A similar relationship was not found for penetration of nickel or hydrocortisone. Pretreatment of the skin with SLS for 2 h using 3 con centrations (0.25%, 4% and 10%) showed, after 48 h, a significant dose -effect relationship between SLS treatment and penetration of tritiate d water or nickel (p<0.001, Spearman). Pretreatment had no effect on p enetration of hydrocortisone. Pretreatment simulates a cleaning-washin g situation. The present in vitro skin penetration model, using human cadaver skin, described the dose-effect and time-effect relationships for SLS on the penetration profiles of 3 different compounds. The mode l may be extended to other compounds with suspected irritant/damaging effect on the skin barrier. It should be kept in mind that the model u ses a dead skin membrane without the barrier repair mechanisms of live skin.