AN IN VITRO SYSTEM FOR PREDICTING SKIN IRRITATION OF LIQUID ANTIPERSPIRANTS.

This study by scientists at Procter & Gamble demonstrated the ability to use MatTek’s EpiDerm in vitro human tissue equivalent as a preclinical test to confirm the mildness of prototype liquid antiperspirant formulations prior to beginning human clinical evaluations. Topical skin care products differ substantially in their composition, yet all need to be acceptably mild to the skin. Small-scale clinical screening is often used to carefully evaluate the irritation potential of novel formulations prior to larger-scale clinical efficacy testing. Clinical testing is time and cost-intensive, and requires development of near finished formulations, often requiring resources to overcome formulation challenges that may not be justified prior to early evaluation of irritation potential. The goal of this Procter & Gamble study was to evaluate EpiDerm human skin equivalent cultures as a preclinical approach to characterize the skin irritancy of prototype liquid antiperspirant formulations. A set of prototype liquid antiperspirant formulations spanning a range of irritancy typical for this product type, based on historical clinical data, was selected for methods development and validation. An in vitro screening protocol was developed utilizing topical application of test formulations to the stratum corneum surface of EpiDerm three dimensional human skin equivalent cultures (MatTek Corp.). Cell viability (MTT metabolism) and inflammatory cytokine expression were measured as endpoints. Prototype formulations were tested blind using the in vitro protocol. The EpiDerm in vitro results correlated with historical in vivo clinical data. In addition, excellent reproducibility was obtained between independent experiments. These results indicate that in vitro testing of prototype liquid antiperspirant formulations in EpiDerm human skin equivalent cultures is a useful approach to confirm skin mildness prior to clinical evaluations.

Antiperspirants, Cell viability, Clinical irritation, EPI-200, EpiDerm, Erythema, Human skin equivalent cultures, In vitro screening protocol, Inflammation, Inflammatory, Inflammatory cytokine, Inflammatory cytokine expression, Irritation potential, MTT, MTT metabolism, Preclinical skin irritancy, Prototype liquid antiperspirant formulations, Redness, Reproducibility, Skin irritation, Skin mildness, Skin mildness confirmation, Stratum corneum surface, Topical application, Topical skin care products

IL-1-RA, IL-1a, IL-8, MTT