Baby care product development: Artificial urine in vitro assay is useful for cosmetic product assessment

•We report results obtained on a new model defined as artificial urine in vitro assay.•Tolerances of cosmetic products were tested in the presence of artificial urine.•Decrease of IL1-α production induced by artificial urine was assessed.•Results are useful for cosmetic risk assessment of baby care products.

As a result of infants' inability to control urination, the skin of the diaper area has special needs for protection from irritating effects of urine and prevention of diaper dermatitis such as products for cleansing and protection of the skin. Several in vitro models are currently available to assess tolerance. In vitro testing using artificial urine allows the protective effects of diaper-region cosmetics to be ascertained. Thus, a new model defined as “artificial urine in vitro assay” has been added to our traditional pre-clinical in vitro testing program. IL1-α is a highly active and pleiotropic pro-inflammatory cytokine. It plays a key role in inflammation and is the biological mirror of irritation induced by diaper dermatitis. This study determines, on human skin explants, if a cosmetic formula is (1) tolerated equally as well in the presence of artificial urine as in its absence and (2) is able to decrease IL1-α production induced by artificial urine or Sodium Dodecyl Sulfate. 31 tests including 17 in-house formulas, 10 bench-markers and 4 combinations of products were performed and data obtained are represented on a simple four-point scale (from practically non protective to very protective). It allows determination of formula-type groups that will have predictable protective properties in subsequent clinical trials and comparison with competitors' products. It is a useful aid in the formulation stage and provides readily-useable data for the cosmetic risk assessment.