THE APPLICATION OF REFERENCE STANDARDS IN THE PREVALIDATION AND VALIDATION OF IN VITRO TESTS FOR EYE IRRITATION.

The present project arose out of the proposals of a working group on reference standards established by ECVAM in 1997. The primary objective of this pilot study was to determine whether the current approach of using in vitro data to make safety assessment decisions, employed in-house by many companies, could be accepted in a regulatory context as scientifically valid and applicable. Reference standards are used in many areas of science to provide a scale against which an unknown is judged. It is considered likely that the value of existing in vitro methods can be significantly improved by the use of reference standards appropriate both to the limitations of the assay and to the unknown substances under test. The methods selected for investigation in this study are: isolated chicken eye (ICE); bovine cornea opacity and permeability (BCOP); HET-CAM/NRU; EpiOcular™ and red blood cell (RBC). The study is divided into two main phases. The first phase establishes results for five known chemicals in each assay. The chemicals will be selected by a small team of people as being the best reference standards for that assay and will form the basis of a prediction model that will be used in phase 2. The second phase will test a further set of five chemicals, together with the reference standards. The test set will be provided as coded “blind” samples. Each laboratory will be required to predict the eye irritation of the five test chemicals using the prediction model developed in phase 1. The study is expected to be completed in June 2000. Further information on study design and early stages of the study will be incorporated into the poster.

ECVAM, EpiOcular, Eye irritation, Ocular irritancy testing, Ocular irritation, Ocular irritation testing, Pre-validation, Prevalidation, Validation