RESUMEN
Skin irritation is a key human health endpoint assessed by in vitro and in vivo methods. The OECD TG 404 guideline (in vivo) is based on erythema and oedema translated semi-quantitatively into Draize scores, providing hazard statements for substance classification following EUCLP/UNGHS criteria. Draize scores require quantitation from subjective in vivo observations, to obtain a scoring index, the Primary Irritation Index (PII). However, it is not recognised under REACH due to translating difficulties, notably the cut-off limit for classification and non-inclusion of corrosive effects. The aim of this study was to determine if classification can be driven by just one of the observed effects, erythema only, to create a Simplified Irritation Index (SIISKIN). This simplifies the scoring calculation and reduces subjectivity. A quantitative approach with cut-off limits is thus proposed for classification. Substances can be classified as non-irritant, potentially irritant, irritant, or corrosive. The Simplifed Irritation Index (SIISKIN) is based on validated studies, representing multiple chemical groups. A significant correlation between SIISKIN and the harmonised classification was observed, and a proportionate relationship between the SIISKIN and the corresponding PII. The index proved to be useful in the development of an in silico model.
Asunto(s)
Cáusticos/toxicidad , Simulación por Computador , Irritantes/toxicidad , Pruebas de Irritación de la Piel/métodos , Alternativas a las Pruebas en Animales , Corrosión , Humanos , Piel , Enfermedades de la PielRESUMEN
Eye irritation is a key human health endpoint assessed by in vitro and in vivo methods. One of the commonly used scoring methods to quantify the eye irritation potential of chemicals is the Modified Maximum Average Score (MMAS). It is dependent on the eye irritation effects (e.g. corneal opacity) originally proposed by Draize and then partially adopted by the OECD TG 405. These scores are not always fully reported in regulatory dossiers and lead to several drawbacks, 1) the difficulty to translate MMAS into a classification within the existing EU CLP/UN GHS criteria, 2) the absence of corrosion (serious eye damage), and 3) the dependency on input parameters which are usually not required under the OECD TGs (e.g. eye surface area). This study determined if classification can be driven by a maximum of two observed effects thereby simplifying the scoring calculation. The Simplified Irritation Index (SIIEYE), based only on corneal opacity and conjunctival redness, was developed using validated studies representing multiple chemical groups. A correlation was observed between the MMAS and the SIIEYE allowing harmonisation of the classification for the existing data. This index proved to be useful in the development of in silico model.
Asunto(s)
Cáusticos/toxicidad , Ojo/efectos de los fármacos , Pruebas de Toxicidad/métodos , Alternativas a las Pruebas en Animales , Animales , Opacidad de la Córnea , Corrosión , Humanos , IrritantesRESUMEN
The use of lower cut-off values/concentration limits for the calculation of mixture classification in UN GHS/EU CLP versus the previous regulatory scheme (EU Dangerous Preparations Directive, DPD), has resulted in an increased number of classifications in the highest eye hazard category. Herein, a semi-quantitative categorisation of severity of eye effects, following accidental human exposures to detergents, was compared to the classification category of the products. Three schemes were evaluated: EU DPD; EU CLP (based on all available data and information, including weight of evidence); and EU CLP (based entirely on the calculation method). As reported by four EU Poison Centres, the vast majority of exposures had caused minor or no symptoms. Classification was a poor predictor of effects in man subjected to accidental exposure. Note however that this is also because effects are not only driven by the intrinsic hazard (as reflected in the classification), but also by the exposure conditions and mitigation (i.e. rinsing). EU CLP classification using all available data and information was more predictive of medically relevant symptoms than the EU CLP calculation method. The latter led to a poorer differentiation between irritating products versus products potentially causing serious eye damage.
Asunto(s)
Detergentes/toxicidad , Lesiones Oculares/clasificación , Irritantes/toxicidad , Animales , Lesiones Oculares/etiología , Humanos , Centros de Control de Intoxicaciones , Índices de Gravedad del TraumaRESUMEN
A thorough understanding of which of the effects assessed in the in vivo Draize eye test are responsible for driving UN GHS/EU CLP classification is critical for an adequate selection of chemicals to be used in the development and/or evaluation of alternative methods/strategies and for properly assessing their predictive capacity and limitations. For this reason, Cosmetics Europe has compiled a database of Draize data (Draize eye test Reference Database, DRD) from external lists that were created to support past validation activities. This database contains 681 independent in vivo studies on 634 individual chemicals representing a wide range of chemical classes. A description of all the ocular effects observed in vivo, i.e. degree of severity and persistence of corneal opacity (CO), iritis, and/or conjunctiva effects, was added for each individual study in the database, and the studies were categorised according to their UN GHS/EU CLP classification and the main effect driving the classification. An evaluation of the various in vivo drivers of classification compiled in the database was performed to establish which of these are most important from a regulatory point of view. These analyses established that the most important drivers for Cat 1 Classification are (1) CO mean ≥ 3 (days 1-3) (severity) and (2) CO persistence on day 21 in the absence of severity, and those for Cat 2 classification are (3) CO mean ≥ 1 and (4) conjunctival redness mean ≥ 2. Moreover, it is shown that all classifiable effects (including persistence and CO = 4) should be present in ≥60 % of the animals to drive a classification. As a consequence, our analyses suggest the need for a critical revision of the UN GHS/EU CLP decision criteria for the Cat 1 classification of chemicals. Finally, a number of key criteria are identified that should be taken into consideration when selecting reference chemicals for the development, evaluation and/or validation of alternative methods and/or strategies for serious eye damage/eye irritation testing. Most important, the DRD is an invaluable tool for any future activity involving the selection of reference chemicals.
Asunto(s)
Cosméticos/efectos adversos , Cosméticos/clasificación , Evaluación Preclínica de Medicamentos/métodos , Ojo/efectos de los fármacos , Pruebas de Toxicidad/métodos , Animales , Cosméticos/toxicidad , Bases de Datos Factuales , Europa (Continente) , Humanos , Irritantes/clasificación , Irritantes/toxicidad , Conejos , Reproducibilidad de los ResultadosRESUMEN
The EpiSkin™ skin corrosion test method was formally validated and adopted within the context of OECD TG 431 for identifying corrosive and non-corrosive chemicals. The EU Classification, Labelling and Packaging Regulation (EU CLP) system requires the sub-categorisation of corrosive chemicals into the three UN GHS optional subcategories 1A, 1B and 1C. The present study was undertaken to investigate the usefulness of the validated EpiSkin™ test method to identify skin corrosive UN GHS Categories 1A, 1B and 1C using the original and validated prediction model and adapted controls for direct MTT reduction. In total, 85 chemicals selected by the OECD expert group on skin corrosion were tested in three independent runs. The results obtained were highly reproducible both within (>80%) and between (>78%) laboratories when compared with historical data. Moreover the results obtained showed that the EpiSkin™ test method is highly sensitive (99%) and specific (80%) in discriminating corrosive from non-corrosive chemicals and allows reliable and relevant identification of the different skin corrosive UN GHS subcategories, with high accuracies being obtained for both UN GHS Categories 1A (83%) and 1B/1C (76%) chemicals. The overall accuracy of the test method to subcategorise corrosive chemicals into three or two UN GHS subcategories ranged from 75% to 79%. Considering those results, the revised OECD Test Guideline 431 permit the use of EpiSkin™ for subcategorising corrosive chemicals into at least two classes (Category 1A and Category 1B/1C).