EVALUATION OF A MODIFIED HET-CAM ASSAY AS A SCREENING-TEST FOR EYE IRRITANCY

The hen's egg test-chorioallantoic membrane (HET-CAM) assay, an altern ative to the Draize eye irritation test, was developed by Luepke and h as been improved on by means of a microscopic examination and the use of a test substance applicator (TSA). The TSA is a double teflon ring in which a perlon mesh is locked. and has several advantages over conv entional protocols, reducing subjectivity of the method and avoiding t he need for rinsing after treatment. It was confirmed by statistical a nalysis that the HET-CAM-TSA method can reproduce potential in vivo ir ritant effects on the conjunctiva. The classification based on the in vitro results was compared with four in vivo classifications [MAS (max imal average score) with thresholds of 15.0 and 25.0; the Kay and Cala ndra method; and EC criteria]. Cooper's parameters (specificity, sensi tivity and concordance with the Draize test) were calculated according to these four in vivo classifications. When the most rigorous classif ication (MAS threshold of 15.0) was taken into account, a sensitivity of 80%, a specificity of 81.3% and a concordance with the Draize test of 80.4% were obtained for this set of 46 compounds. Copyright (C) 199 6 Elsevier Science Ltd.