PERCUTANEOUS PENETRATION OF N-NITROSO-N-METHYLDODECYLAMINE THROUGH HUMAN SKIN IN-VITRO - APPLICATION FROM COSMETIC VEHICLES

The human skin penetration of N-nitroso-N-methyidodecylamine (NDOMA) f rom isopropyl myristate (IPM) and two vehicles representative of cosme tic/personal. care formulations was determined in vitro. When applied as an infinite dose in IPM (1 mu g/mu l) the average total absorption over 48 hr was 0.10 +/- 0.01% of the applied dose fall data are expres sed as means +/- SE). When applied as a finite dose in a representativ e oil-in-water emulsion formulation the average total absorption over 48 hr was 4.66 +/- 0.76% of the applied dose. When applied as a finite dose in a representative shampoo formulation for 10 min, followed by rinsing (to represent in-use exposure conditions), the average total a bsorption over 48 hr was 0.75 +/- 0.17% of the applied dose. Approxima tely 72% of the NDOMA in the applied shampoo formulation was removed b y rinsing. The overall data indicated that NDOMA could penetrate the s kin but that penetration was low. The rate and extent of absorption, h owever, could be affected by differences in the vehicle of application , time of exposure and whether the formulation is (and the conditions are designed to mimic) a rinse-off or leave-on product. (C) 1997 Elsev ier Science Ltd.