[Behavior of external adjuvants in human skin. In vitro penetration of various polyethylene glycols].

Polyethylene glycols (PEG), which serve as vehicles or additives in salves, sometimes appear to cause contact allergies, depending on their molecular weight. Whether this can be determined quantitatively should be proven. To this end we investigated the penetrative behavior of various PEG (mol. wts. 400 to 4000) on intact and damaged (stripped) human skin in vitro. It is shown here that in the course of time liquid PEG (mol. wt. 400) makes the intact horny layer more permeable than solid PEG does. The concentrations found in the intact epidermal horny layer were clearly dependent on molecular weight, indicating that liquid PEG penetrates better than solid high-molecular PEG. If the horny layer is damaged - as is the case with most dermatitis patients - all PEGs penetrate the dermis and epidermis independent of molecular weight. The allergological consequences, in particular for epicutaneous testing, are discussed briefly.