The toxic effect of some industrial chemicals on rabbit ileum in vitro compared with eye irritancy in vivo.

The concentrations of acetone, acetophenone, allyl alcohol, n-butanol, carbitol, dioxane, ethanol, formaldehyde, iso-propanol, mercaptoethanol, methanol and propylene glycol required to block spontaneous contractions of rabbit isolated ileum by 50% (EC50) in vitro were determined. The EC50's correlated reasonably well with published data on rabbit eye irritation in vivo caused by these agents. Better correlation might be impossible to obtain owing to the subjective nature, and therefore relative unreliability, of in vivo eye testing. The ileum model may provide a possible alternative to some of the in vivo eye irritancy testing carried out at present.