M. Corvaro

An in vitro approach for comparative interspecies metabolism of agrochemicals

ABSTRACT The metabolism and elimination of a xenobiotic has a direct bearing on its potential to cause toxicity in an organism. The confidence with which data from safety studies can be extrapolated to humans depends, among other factors, upon knowing whether humans are systemically exposed to the same chemical entities (i.e. a parent compound and its metabolites) as the laboratory animals used to study toxicity. Ideally, to understand a metabolite in terms of safety, both the chemical structure and the systemic exposure would need to be determined. However, as systemic exposure data (i.e. blood concentration/time data of test material or metabolites) in humans will not be available for agrochemicals, an in vitro approach must be taken. This paper outlines an in vitro experimental approach for evaluating interspecies metabolic comparisons between humans and animal species used in safety studies. The aim is to ensure, where possible, that all potential human metabolites are also present in the species used in the safety studies. If a metabolite is only observed in human in vitro samples and is not present in a metabolic pathway defined in the toxicological species already, the toxicological relevance of this metabolite must be evaluated. HIGHLIGHTSGuidance outlining in vitro comparative metabolism approaches for agrochemicals.The design allows metabolic comparison between humans and species in safety studies.This experimental approach allows identification of human unique metabolites.Human unique metabolites may need to be addressed in the regulatory risk assessment.

A retrospective analysis of in vivo eye irritation, skin irritation and skin sensitisation studies with agrochemical formulations: Setting the scene for development of alternative strategies

&NA; Analysis of the prevalence of health effects in large scale databases is key in defining testing strategies within the context of Integrated Approaches on Testing and Assessment (IATA), and is relevant to drive policy changes in existing regulatory toxicology frameworks towards non‐animal approaches. A retrospective analysis of existing results from in vivo skin irritation, eye irritation, and skin sensitisation studies on a database of 223 agrochemical formulations is herein published. For skin or eye effects, high prevalence of mild to non‐irritant formulations (i.e. per GHS, CLP or EPA classification) would generally suggest a bottom‐up approach. Severity of erythema or corneal opacity, for skinor eye effects respectively, were the key drivers for classification, consistent with existing literature. The reciprocal predictivity of skin versus eye irritation and the good negative predictivity of the GHS additivity calculation approach (>85%) provided valuable non‐testing evidence for irritation endpoints. For dermal sensitisation, concordance on data from three different methods confirmed the high false negative rate for the Buehler method in this product class. These results have been reviewed together with existing literature on the use of in vitro alternatives for agrochemical formulations, to propose improvements to current regulatory strategies and to identify further research needs. HighlightsRetrospective analysis of local toxicity data from 223 agrochemical formulations.Low prevalence of skin and eye irritants, suggesting bottom‐up approaches.GHS additivity showed good negative predictivity for skin and eye irritation.The reciprocal negative predictivity of skin versus eye irritation confirmed.

One science-driven approach for the regulatory implementation of alternative methods: A multi-sector perspective

ABSTRACT EU regulations call for the use of alternative methods to animal testing. During the last decade, an increasing number of alternative approaches have been formally adopted. In parallel, new 3Rs‐relevant technologies and mechanistic approaches have increasingly contributed to hazard identification and risk assessment evolution. In this changing landscape, an EPAA meeting reviewed the challenges that different industry sectors face in the implementation of alternative methods following a science‐driven approach. Although clear progress was acknowledged in animal testing reduction and refinement thanks to an integration of scientifically robust approaches, the following challenges were identified: i) further characterization of toxicity pathways; ii) development of assays covering current scientific gaps, iii) better characterization of links between in vitro readouts and outcome in the target species; iv) better definition of alternative method applicability domains, and v) appropriate implementation of the available approaches. For areas having regulatory adopted alternative methods (e.g., vaccine batch testing), harmonised acceptance across geographical regions was considered critical for broader application. Overall, the main constraints to the application of non‐animal alternatives are the still existing gaps in scientific knowledge and technological limitations. The science‐driven identification of most appropriate methods is key for furthering a multi‐sectorial decrease in animal testing.