PREDICTIVE TESTING: UNDERSTANDING THE ROLE OF IN VITRO AND IN VIVO TESTING.

Understanding predictive in vitro testing of topically applied materials is especially important to the pharmacologist who works with the skin since this technology is applied for basic research and product development. This exhibit presents information and data on traditional and relatively new in vitro assays, i.e. both human clinical data and innovative three dimensional, artificially produced human skin, along with human clinical data. So that the information might be more generally interpretable, we have emphasized the use of materials which are commonly applied topically and are familiar. The four in vitro methods used were: the Dermal Toxicity Time Course Assay; the Keratinocyte Neutral Red Uptake Bioassay; Keratinocyte the Neutral Red Release Assay; the Cytosensor Microphysiometer Assay. Good correlation was observed between the 1/ET (50) obtained from the Dermal Toxicity Time Course Assay using human epidermal construct (EpiDerm) and the in vivo scores. A weaker correlation was observed between the Neutral Red Uptake NRU(50) and the in vivo scores. This system lacks any barrier properties but does expose the cells to the test agent for an extended period. The Neutral Red Release assay showed no correlation between the toxicity induced in a very short (5 minute) exposure and the erythema scores. This assay is normally used to predict ocular irritation potential of surfactant products. The Cytosensor Microphysiometer showed an inverted relationship between toxicity in vitro and the erythema scores. This assay has proven effective in the prediction of ocular irritation potential of surfactant materials. These data point to the importance of modeling both the cellular components and barrier properties of the skin.

Barrier properties, EpiDerm, Neutral Red, Neutral Red, Skin irritancy testing, Skin irritation, Skin irritation testing, Surfactants, Surfactants, irritancy, Surfactants, irritancy potential