Human relevance of in vivo and in vitro skin irritation tests for hazard classification of pesticides.

Test methods to inform hazard characterization and labeling of pesticides to protect human health are typically conducted using laboratory animals, and for skin irritation/corrosion the rabbit Draize test is currently required by many regulatory agencies. Although the Draize test is generally regarded to provide protective classifications for human health, new approach methodologies (NAMs) have been developed that offer more human relevant models that circumvent the uncertainty associated with species differences that exist between rabbits and humans. Despite wide applicability and use of these test methods across a broad range of chemicals, they have not been widely adopted for testing pesticides and pesticidal formulations.

Defined approaches to classify agrochemical formulations into EPA hazard categories developed using EpiOcular reconstructed human corneal epithelium and bovine corneal opacity and permeability assays.

Many sectors have seen complete replacement of the rabbit eye test with reproducible and relevant and methods to assess the eye corrosion/irritation potential of chemicals. However, the rabbit eye test remains the standard test used for agrochemical formulations in some countries. Therefore, two defined approaches (DAs) for assessing conventional agrochemical formulations were developed, using the EpiOcular Eye Irritation Test (EIT) [Organisation for Economic Co-operation and Development (OECD) test guideline (TG) 492] and the Bovine Corneal Opacity and Permeability (OECD TG 437; BCOP) test with histopathology.

Human-relevant approaches to assess eye corrosion/irritation potential of agrochemical formulations.

There are multiple and eye irritation and corrosion test methods that are available as internationally harmonized test guidelines for regulatory use. Despite their demonstrated usefulness to a broad range of substances through inter-laboratory validation studies, they have not been widely adopted for testing agrochemical formulations due to a lack of concordance with parallel results from the traditional regulatory test method for this endpoint, the rabbit eye test. The inherent variability of the rabbit test, differences in the anatomy of the rabbit and human eyes, and differences in modelling exposures in rabbit eyes relative to human eyes contribute to this lack of concordance.

The kinetic direct peptide reactivity assay (kDPRA): Intra- and inter-laboratory reproducibility in a seven-laboratory ring trial.

While the skin sensitization hazard of substances can be identified using non-animal methods, the classification of potency into UN GHS sub-categories 1A and 1B remains challenging. The kinetic direct peptide reactivity assay (kDPRA) is a modification of the DPRA wherein the reaction kinetics of a test substance towards a synthetic cysteine-containing peptide are evaluated. For this purpose, several concentrations of the test substance are incubated with the synthetic peptide for several incubation times.

Pathway-based predictive approaches for non-animal assessment of acute inhalation toxicity.

New approaches are needed to assess the effects of inhaled substances on human health. These approaches will be based on mechanisms of toxicity, an understanding of dosimetry, and the use of in silico modeling and in vitro test methods. In order to accelerate wider implementation of such approaches, development of adverse outcome pathways (AOPs) can help identify and address gaps in our understanding of relevant parameters for model input and mechanisms, and optimize non-animal approaches that can be used to investigate key events of toxicity.

Dermal absorption for pesticide health risk assessment: Harmonization of study design and data reporting for North American Regulatory submissions.

Although an internationally-adopted in vitro dermal absorption test guideline is available (OECD Test Guideline 428), the replacement of the in vivo approach in North America for pesticide formulations has not occurred due to concern over the reliability and consistency of the in vitro results. A 2012 workshop convened a panel of experts in the conduct of in vitro studies used for pesticide risk assessment, together with North American regulators, to examine techniques for in vitro dermal absorption testing. Discussions led to the recommended "best practices" for the conduct of in vitro dermal absorption studies provided herein.

In vitro exposure systems and dosimetry assessment tools for inhaled tobacco products: Workshop proceedings, conclusions and paths forward for in vitro model use.

In 2009, the passing of the Family Smoking Prevention and Tobacco Control Act facilitated the establishment of the FDA Center for Tobacco Products (CTP), and gave it regulatory authority over the marketing, manufacture and distribution of tobacco products, including those termed 'modified risk'. On 4-6 April 2016, the Institute for In Vitro Sciences, Inc. (IIVS) convened a workshop conference entitled, In Vitro Exposure Systems and Dosimetry Assessment Tools for Inhaled Tobacco Products, to bring together stakeholders representing regulatory agencies, academia and industry to address the research priorities articulated by the FDA CTP.

In vitro assessment of skin irritation potential of surfactant-based formulations by using a 3-D skin reconstructed tissue model and cytokine response.

The personal care industry is focused on developing safe, more efficacious, and increasingly milder products, that are routinely undergoing preclinical and clinical testing before becoming available for consumer use on skin. In vitro systems based on skin reconstructed equivalents are now established for the preclinical assessment of product irritation potential and as alternative testing methods to the classic Draize rabbit skin irritation test. We have used the 3-D EpiDerm™ model system to evaluate tissue viability and primary cytokine interleukin-1α release as a way to evaluate the potential dermal irritation of 224 non-ionic, amphoteric and/or anionic surfactant-containing formulations, or individual raw materials.

Implementation of New Test Methods into Practical Testing.

New toxicology test methods, especially those using in vitro methods, are continually being developed. Some are used by industry for screening purposes; others are eventually validated for regulatory use. However, for a new test method to be firmly adopted by industry it must be readily available, generally through an in-house industry laboratory, an academic laboratory, or a contract research organization.

Local tolerance testing under REACH: Accepted non-animal methods are not on equal footing with animal tests.

In general, no single non-animal method can cover the complexity of any given animal test. Therefore, fixed sets of in vitro (and in chemico) methods have been combined into testing strategies for skin and eye irritation and skin sensitisation testing, with pre-defined prediction models for substance classification. Many of these methods have been adopted as OECD test guidelines.

Assessment of in vitro COPD models for tobacco regulatory science: Workshop proceedings, conclusions and paths forward for in vitro model use.

The Family Smoking Prevention and Tobacco Control Act of 2009 established the Food and Drug Administration Center for Tobacco Products (FDA-CTP), and gave it regulatory authority over the marketing, manufacture and distribution of tobacco products, including those termed 'modified risk'. On 8-10 December 2014, IIVS organised a workshop conference, entitled Assessment of In Vitro COPD Models for Tobacco Regulatory Science, to bring together stakeholders representing regulatory agencies, academia, industry and animal protection, to address the research priorities articulated by the FDA-CTP. Specific topics were covered to assess the status of current in vitro technologies as they are applied to understanding the adverse pulmonary events resulting from tobacco product exposure, and in particular, the progression of chronic obstructive pulmonary disease (COPD).

Using the cytosensor microphysiometer to assess ocular toxicity.

Measuring in vitro cytotoxicity is one method currently used to estimate damage to the eye after chemical exposure. The Cytosensor Microphysiometer method evaluates cytotoxicity by measuring the test material-induced reduction in the metabolic rate of L929 cells. Changes in metabolic rate are measured indirectly as a function of changes in the extracellular acidification rate of the cells.

Assessment of the predictive capacity of the 3T3 Neutral Red Uptake cytotoxicity test method to identify substances not classified for acute oral toxicity (LD50>2000 mg/kg): results of an ECVAM validation study.

Assessing chemicals for acute oral toxicity is a standard information requirement of regulatory testing. However, animal testing is now prohibited in the cosmetics sector in Europe, and strongly discouraged for industrial chemicals. Building on the results of a previous international validation study, a follow up study was organised to assess if the 3T3 Neutral Red Uptake cytotoxicity assay could identify substances not requiring classification as acute oral toxicants under the EU regulations.

Prediction of ocular irritancy of 26 chemicals and 26 cosmetic products with isolated rabbit eye (IRE) test.

Objective: This study aims to establish and evaluate the methodology of isolated rabbit eye (IRE) test.

Methods: IRE test was performed according to modifications of the in vitro toxicology (INVITTOX) Protocol No.85: Rabbit enucleated eye test by European Centre for the Validation of Alternative Methods (ECVAM), and then 26 chemicals and 26 cosmetic products were tested in both in vitro IRE and in vivo Draize tests.

Vaginal irritation models: the current status of available alternative and in vitro tests.

Mucosal surfaces, such as the vaginal epithelium, are natural barriers to infection that are constantly exposed to bacteria and viruses, and are therefore potential sites of entry for numerous pathogens. The vaginal epithelium can be damaged mechanically, e.g.

The bovine corneal opacity and permeability test in routine ocular irritation testing and its improvement within the limits of OECD test guideline 437.

Data on eye irritation are generally needed for the hazard identification of chemicals. As the Bovine Corneal Opacity and Permeability (BCOP) test has been accepted by many regulatory agencies for the identification of corrosive and severe ocular irritants since September 2009 (OECD Test Guideline 437, TG 437), we evaluated this alternative method for routine testing at BASF. We demonstrated our technical proficiency by testing the reference standards recommended in TG 437, and 21 additional materials with published BCOP and in vivo data.

A database of IC50 values and principal component analysis of results from six basal cytotoxicity assays, for use in the modelling of the in vivo and in vitro data of the EU ACuteTox project.

The main aim of the ACuteTox project (part of the EU 6th Framework programme) is to demonstrate that animal tests for acute systemic toxicity can be replaced by alternative in vitro assays. In this project, data for 97 reference chemicals were collected in the AcuBase database, designed to handle deposited in vitro and in vivo (human and animal) data. To demonstrate the applicability of in vitro basal cytotoxicity tests and in vitro-in vivo modelling, it was deemed necessary to obtain data that were generated via defined standard operating procedures.

The ECVAM international validation study on in vitro tests for acute skin irritation: report on the validity of the EPISKIN and EpiDerm assays and on the Skin Integrity Function Test.

ECVAM sponsored a formal validation study on three in vitro tests for skin irritation, of which two employ reconstituted human epidermis models (EPISKIN, EpiDerm), and one, the skin integrity function test (SIFT), employs ex vivo mouse skin. The goal of the study was to assess whether the in vitro tests would correctly predict in vivo classifications according to the EU classification scheme, "R38" and "no label" (i.e.