Abstract
An alternative nonanimal test to the Draize test to evaluate the eye irritancy of surfactants has been newly developed. The physicochemical lysis of liposomal membranes by various surfactants, such as sodium dodecyl sulfate (SDS), dodecyldimethylbenzylammonium chloride (BTC), tetradecyldimethylbenzylammonium chloride (Sanisol M-100), benzyldimethy1-2- (2-p-1, 1, 3, 3-tetramethylbutylphenoxy) ethoxyethylammonium chloride (Hyamine 1622), dodecanoyldiethanolamide (LDE), and polyoxyethylene (n=21) -sorbitan monostearate (Tween 80), was correlated with the results of the Draize test with the same surfactants. Egg phosphatidylcholine small unilamellar vesicles (SUVs) coated with O-palmitoylamylopectinsulfonic acid were employed as a model of the human corneal epithelium. The lysis of liposomes with the surfactants was monitored quantitatively by following the release of carboxyfluorescein (CF) from the interior water phase of the liposomes suspended in an aqueous medium containing almost the same salt composition as that in the human tear film. The order of efficiencies of these surfactants in perturbing the liposomal membrane was Sanisol M-100 > Hyamine 1622 >BTC> (Tween 80>) LDE>SDS. With the exception of Tween 80, whose critical micelle concentration (cmc) is relatively low (9.6 × 10-6M) compared with those of the other surfactants (approximately 5-7× 10-4M), a reliable correlation was found between the results of animal and nonanimal tests.
