IRAG WORKING GROUP 3 - CELL FUNCTION-BASED ASSAYS

Cell function-based tests measure responses of cells at sublytic conce ntrations of test agents. The fluorescein leakage assay measures effec ts of substances on the barrier function of epithelial monolayers or m ultilayers (MDCK or NHEK cells) as in vitro models of corneal epitheli al function. Two IRAG data submissions suggest that the fluorescein le akage assay shows promise as a screening test for surfactants and alco hols. The test method requires further optimization, standardization a nd evaluation to fully determine its utility as an in vitro ocular irr itancy test. The silicon microphysiometer test measures effects of tes t substances on the metabolic rate of cells; although a large number o f cell types have been evaluated, L929 cells have been used for irrita ncy screening. Three IRAG data submissions on the silicon microphysiom eter test showed strong in vivo/in vitro correlations for surfactants and surfactant-based personal care and household cleaning products in a range of mild to moderate ocular irritancy. This and published infor mation support the reproducibility of the method and its use as an ocu lar irritancy screening test for aqueous-soluble liquid, surfactant-ba sed formulations. (C) 1997 Elsevier Science Ltd.