, 2007, Doucet et al., 2006 and Van Goethem et al., 2006), that is structurally very similar to the corneal mucosa of the human eye. Substances are tested using two different exposure times: (i) short term, whereby the HCE is exposed to a chemical CHIR-99021 mw or substance for 10 min, (ii) long term, whereby the HCE is exposed for 60 min followed by 16 h incubation. If the treated HCE has viability greater than 50% post treatment then it is classified as non-irritating. Both EpiOcular™ EIT and SkinEthic™ HCE models

have undergone prospective validation by EURL-ECVAM and Cosmetics Europe to distinguish irritants (GHS Classification 1/Category 2) from non-irritants (GHS No Category) (Pfannenbecker et al., 2012 and Zuang et al., 2013). Over 100 chemicals were tested and both methods showed high reproducibility (>90%) (Zuang et al., 2013). The EpiOcular™ EIT met all the predictive capacity acceptance criteria for the testing of liquids protocol, but not Romidepsin research buy all of these criteria were met by the solids protocol nor by

any of the SkinEthic™ HCE protocols (Zuang et al., 2013). The EpiOcular™ EIT solids protocol was further optimized for solids and further validation was conducted. At present the SkinEthic™ HCE model is still undergoing further optimisation for its solids protocol (Zuang et al., 2013). The final sensitivity of EpiOcular™ EIT was determined to be 96%, with specificity of 63% and accuracy of 80%, thus was considered valid for distinguishing non-irritants from irritants (OECD, 2014a). However, EpiOcular™ EIT is not intended to differentiate between GHS Category 1 (serious eye damage) and GHS Category 2 (eye irritation). A draft test guidance for EpiOcular™ EIT and performance standards has been delivered to the OECD (2014a), and the final test guidelines are expected to be adopted in 2015. Recently Katoh et al., 2012 and Katoh et al., 2013 and Jung et al. (2011) developed the LabCyte CORNEA-MODEL (Japanese Tissue Engineering Co., Ltd., Japan) and MCTT-HCE

model (MCTT, Seol, Korea), respectively. Unlike the commercially available EpiOcular™ EIT and SkinEthic™ HEC models, both utilize normal human corneal epithelial cells isolated from the human limbus of Non-specific serine/threonine protein kinase remaining corneal rim following transplantation that are cultured above and supported by cell feeder layers. They have been shown to express similar morphology and biomarker expression to the intact human corneal epithelium. Pre-validation studies have been performed for the LabCyte CORNEA-MODEL, to determine optimum treatment time, volume, post-incubation time and rinsing protocols (Jung et al., 2011). Although both MCTT-HCE and LabCyte CORNEA-MODEL have reported promising results with a high degree of accuracy, neither has yet to enter a formal validation assessment.