SOT Society of Toxicology annual meeting
L'Oréal, Research & Innovation, USA
In vitro Ocular Testing
Consumer ocular exposures sometimes occur with shampoo products. Shampoos for children and adults should be safe for use without resulting in significant ocular irritation. Dilute solutions of shampoos can be clinically evaluated in adults via direct ocular instillation or by indirect ocular instillation mimicking in use conditions. In either case, the investigator would like some assurance of ocular safety of the shampoo solution prior to human exposure studies. In Vitro ocular models have been used by the personal care industry for many years as an alternative to the Draize ocular irritation test for chemicals and finished products. We compared the in vitro ocular irritation scores (HETCAM and/or BCOP) and the scores for redness and stinging from clinical ocular instillation for 11 children and 6 adult shampoos. The shampoos had different surfactant systems and surfactant concentrations. The differences in clinical scores between formulations with similar surfactant systems may be related to differences in the fragrances, preservative systems and/or other components of the formulation. Our results indicate a correlation trend between in vitro scores and the degree of redness or stinging in clinical ocular instillation studies of adult shampoos. The trend is towards higher irritation scores with higher surfactant concentrations and/or stronger surfactant systems. For children’s shampoos, in vitro and clinical scores were in the lower range across all surfactant systems as all of the formulations contained low surfactant concentrations or milder surfactant systems. Shampoos with in vitro scores in the lower range can generally move directly to clinical studies. For shampoos with in vitro scores in the moderate range, rising dose studies are done to the maximal test concentration of 10%. It can be concluded that low in vitro scores are indicative of mild to moderate irritation potential and useful in screening and evaluating potential irritants before conducting clinical ocular safety studies.