Toxicity of commercial products on cells in suspension culture: a possible screen for the Draize eye irritation test.

Incubation of LS cells in suspension for 4 hr in the presence of water-soluble commercial products with known Draize rabbit-eye irritation potential has shown that viability, as indicated by fluorescent dyes, is a credible screen for irritation. For product formulations containing immiscible and/or insoluble substances, there are difficulties that have been reduced by extraction of the soluble components of the formulations into the culture medium. A more sensitive and automated, though more expensive, technique based on the estimation of intracellular ATP levels has been developed and the ATP50 values (concentration that reduces intracellular ATP by 50%) for several substances indicate that this may be another suitable endpoint in cytotoxicity screening for animal irritation studies.