COMPARISON OF EXAGGERATED AND NORMAL USE TECHNIQUES FOR ASSESSING THE MILDNESS OF PERSONAL CLEANSERS

A variety of exaggerated-exposure wash techniques have been used to evaluate the mildness of personal cleansing products in lieu of clinical evaluation during normal use. This study compares two exaggerated methods, a forearm wash method and a flex wash method, to home-use studies to determine how well the exaggerated methods approximate ad lib usage. The results indicate that the forearm wash method is a better predictor of product mildness under home-use conditions when soap bars are used. Both exaggerated methods yield similar mildness pictures when syndet bars are used, although the forearm wash method is more discriminating. The flex wash implement (sponge) induces greater damage to the stratum corneum than does the forearm wash implement (towel). However, this does not account for the total damage observed when product is applied in the flex wash method. A significant amount of damage is apparently due to product reaching arid interacting with lower layers of the skin once the barrier's integrity has been compromised by the sponge. The results indicate that the forearm and flex wash methods are based on different exposure models, and that the model on which the forearm wash is based is more predictive of actual consumer use conditions than is the model on which the flex wash is based.