Abstract
In this in vivo human study we assessed the influence of skin damage by sodium lauryl sulphate (SLS) on percutaneous penetration of polyethylene glycols (PEGs) of different molecular weights (MW). Percutaneous penetration of PEGs was determined using tape stripping of the stratum corneum (SC). The forearm skin of volunteers was pretreated with 5% w/w SLS for 4 h, and 24 h later patches with PEGs were applied for 6 h. The penetration parameters were deduced by data regression to Fick's law for unsteady-state diffusion. The trans-epidermal water loss (TEWL) increased after SLS treatment from 6.3 +/- 2.1 to 17.9 +/- 8.7 g/m(2)/h. The diffusion coefficient for all PEGs was increased in the SLS-damaged skin. The increase was smaller for higher MW. In addition, the partition coefficient of PEGs between SC and water was larger in the SLS-compromised skin and showed a tendency to increase with MW. The permeability coefficient decreased gradually with increasing MW of PEGs in both control and SLS-compromised skin. SLS caused a threefold increase in the permeability coefficient for all MWs ranging in control skin from 0.34 to 0.70 x 10(-5) cm/h and in the SLS-compromised skin from 1.20 to 2.09 x 10(-5) cm/h for MW of 590-282 Da. The results of this study show the deleterious effect of SLS on the skin barrier for hydrophilic PEGs. A defective skin barrier will facilitate absorption of other chemicals and local skin effects.
