Repeated dose toxicity comprises the adverse general toxicological effects occurring as a result of repeated daily exposure dose to a substance for a specified period up to the expected lifespan of the test species.
The studies yield information on general characteristics of the toxicity, the target organs of toxicity, the dose–response (curve) for each toxicity endpoint, responses to toxic metabolites formed in the organism, delayed responses, cumulative effects, the margin between toxic/non-toxic dose, information on reversibility/irreversibility of the effect, and NOAEL (No Observed Adverse Effect Level), NOEL (No Observed Effect Level) for toxicity.
The repeated dose study is an integral part of the data package produced to perform quantitative risk assessment (QRA) of industrial chemicals, cosmetic ingredients, biocides, pesticides, pharmaceuticals. The point of departure most commonly used for systemic toxicity safety assessment is the NOAEL which is used in the calculation of the MoS (Margin of Safety) or MoE (Margin of Exposure).
The following in vivo repeated dose toxicity tests are available as OECD Test Guidelines:
- 28-day Oral Toxicity Study in Rodents: OECD test guideline 407
- 90-Day Oral Toxicity Study in Rodents: OECD test guideline 408
- 90-Day Oral Toxicity Study in Non-Rodents: OECD test guideline 409
- Dermal Toxicity: 21/28-day Study (rat, rabbit or guinea pig): OECD test guideline 410
- Dermal Toxicity: 90-day Study (rat, rabbit or guinea pig): OECD test guideline 411
- Inhalation Toxicity: 28-Day Study in Rodents: OECD test guideline 412
- Inhalation Toxicity: 90-day Study in Rodents: OECD test guideline 413
- Chronic Toxicity Studies in Rodents: OECD test guideline 452
EURL ECVAM validated alternative test methods
There are no alternative test methods that are validated in this area.[/collapse]
Test methods under validation by EURL ECVAM
There are no alternative test methods currently under validation in this area.[/collapse]
Development/optimisation/improvement of alternative methods
EU FP6 Predictomics project: Short-term models assays for long-term toxicity (EU contract no 504761)
The aim of this European project was to develop a novel strategy for predicting chronic toxicity in the two most important target organs affected by drugs and xenobiotics, the liver and the kidney (Jennings et al., 2009). Advanced culture technology, genomic, proteomic and cytomic analysis were combined to detect the early events of cellular injury. The data generated were examined in view of the known pathophysiological changes linked to the chronic disease.
EURL ECVAM was part of the executive board and had an advisory role to ensure that methods were sufficiently well developed so that they could be considered for entering, eventually, future validation process.
EU FP6 Marie Curie Actions Research Training Network PULMO-NET: Pathogenesis of pulmonary disease (EU contract no MRTN-CT-2004-512229)
Pulmonet was created with the aim to improve methodological approaches to study lung function (such as fluid transport, secretion of surfactant, mucous or inflammatory mediators, and barrier/ transport functions) and dysfunction on a cellular and molecular level, gaining a better understanding of normal lung function, toxicity of environmental compounds, cell and tissue damage and generation of pulmonary disease.
The network consisted of experts from diverse fields, such as on lung proteins required for host defense and reduction of surface tension (surfactant proteins), lung cell isolation and culture, endotoxins and cell signalling, cytokines, inflammation and immune response, and use of cell lines (such as Calu-3) for barrier function and toxicity tests.
EURL ECVAM contributed to the network by setting up appropriate in vitro model(s) to study chemically induced damage to pulmonary barrier after exposure to substances of various kinds (Forti et al., 2010; Forti et al., 2011).
EU FP7 Predict-IV project: Profiling the toxicity of new drugs: a non animal-based approach integrating toxico-dynamics and biokinetics (EU Contract no. 202222)
The ultimate goal of Predict-IV was to develop a testing strategy integrating in vitro systems with knowledge of cell biology, mechanistic toxicology and in silico (pharmacokinetic) modelling.
EURL ECVAM lead activities on in vitro neurotoxicity testing, and contributed to OMICs profiling methods and on monitoring European efforts towards other non animal-based integrative approaches.
The relevant findings of this large scale integrating Project were published in a special issue of Toxicology in Vitro.
For more information, see Predict-IV website.
EU FP7 SEURAT-1: Towards the replacement of in vivo repeated dose systemic toxicity testing
This Research Initiative (2011-2016) was a first step to address the long term strategic target of "Safety Evaluation Ultimately Replacing Animal Testing (SEURAT)".
It was composed of six complementary research projects (SCR&Tox, HeMiBio DETECTIVE, COSMOS, NOTOX, ToxBank) and a coordination and support action (COACH) project.
The European Commission Joint Research Centre is a partner in SCR&Tox, DETECTIVE, COSMOS, and COACH.
For more information, see SEURAT-1 website.
H2020 EU-ToxRisk: An Integrated European 'Flagship' Programme Driving Mechanism-based Toxicity Testing and Risk Assessment for the 21st century
The EU-ToxRisk is designed as the follow up of the SEURAT 1 research initiative and will focus on two areas: repeated dose systemic toxicity, using the lung, kidney, liver and nervous system as examples of potential target organs; and developmental and reproductive toxicity.
For more information, see EU-Tox-Risk website.[/collapse]