Petrolatum prevents irritation in a human cumulative exposure model in vivo.

BACKGROUND Protective creams (PCs) have been studied in different models indicating a protective effect of some products. In order to compare PCs in different studies, a generic reference standard should be available. OBJECTIVE The purpose of this study was to investigate if petrolatum prevents epidermal barrier disruption induced by various irritants in a repetitive irritation test (RIT) and to assess its potential as a standard reference product. METHODS White petrolatum was evaluated against a set of 4 irritants [10% sodium lauryl sulphate (SLS), 1% sodium hydroxide (NaOH), 30% lactic acid (LA) and undiluted toluene (TOL)] in the RIT. Twenty subjects were tested on the paravertebral skin of the midback. Irritation was assessed by visual scoring, transepidermal water loss and colorimetry. RESULTS Petrolatum was very effective against SLS, NaOH and LA irritation, and it provided a moderate protection against TOL. CONCLUSION Petrolatum can be recommended as a standard reference substance against which PCs may be compared as it is effective against water-soluble and water-insoluble irritants in a standardized test procedure.