OECD TG 402 is the “Acute Dermal Toxic ity ” standard, which is included in Section 4 (Health Effects) of the OECD Test Guidelines for the Testing of Chemicals. It was first adopted in 1987 and updated in 2017. The test is an in vivo toxicity test designed to evaluate the acute toxic effects of a substance following a single application to the skin.
The primary objective of the test is to determine the systemic toxic effects that occur following absorption of the test substance through the skin, as well as the LD50 value and the GHS/CLP classification. In addition, local effects (erythema, edema, etc.) may be observed at the application site; however, the assessment of local irritation and corrosivity is covered by separate standards (TG 404, TG 430, TG 431).
The basic principle of the test is as follows:
- The test substance is typically applied as a single dose to a shaved, healthy area of skin on rats or rabbits.
- The application site is typically kept covered with a closed or semi-closed dressing for 24 hours; after that, any excess substance is removed.
- The application site is selected based on the physical and chemical properties of the substance and the expected exposure.
- The animals are kept under clinical observation for at least 14 days; during this time, signs of toxicity, reversibility, changes in body weight, and mortality are recorded.
- At the end of the study, a necropsy is performed and the macroscopic findings are documented.
- Doses are determined based on preliminary tests (range-finding) or existing toxicity data; typically, several dose groups and a control group are used.
The main parameters reported in the study are:
- The doses administered (mg/kg body weight) and the administration conditions (duration, type of coverage, area)
- Clinical observations and their onset
- Changes in Body Weight
- Mortality and Survival Times
- Local findings at the application site (erythema, edema, necrosis, etc.)
- Necropsy findings
- LD50 value and confidence interval
- GHS/CLP Category for Acute Dermal Toxicity and Rationale for the Classification
- Animal species used, sex, age, method of administration, and conditions of use
- Data on Measurement Uncertainty and Repeatability
Why is it performed?
OECD TG 402 is being conducted for the following scientific and regulatory purposes:
- Determination of Acute Dermal Toxicity: Identification of systemic toxic effects and target organs resulting from a single dermal exposure
- Determination of the LD50 Value: Quantitative Assessment of the Potential for Acute Dermal Toxicity
- GHS/CLP Classification: Determining the substance's acute dermal toxicity category and identifying labeling requirements
- Support for Regulatory Submissions: Use in Safety Assessments of Chemicals, Pesticides, Biocidal Products, Drugs, and Non-Cosmetic Products
- Contribution to Risk Assessment: Provision of Baseline Data for Risk Assessment in Exposure Scenarios Involving Dermal Exposure
- Selection of the route of exposure: Provision of data on alternative routes of exposure when oral or inhalation testing is not appropriate
Labeling and Transport: Data on acute dermal toxicity are used in the classification of chemicals for labeling and transport purposes. Weight-of-evidence approach: Contribution to the comprehensive assessment of the substance in conjunction with other toxicological, physicochemical, and exposure data.
OECD TG 402 aims to determine a definitive LD50 value; however, from an animal welfare perspective, dose selection, preliminary tests, and criteria for early termination are of crucial importance.
The results should be interpreted in the context of the substance's chemical structure, other acute toxicity data, data on local irritation/corrosion, and the exposure assessment.
As part of our nano-testing services, we conduct acute dermal toxicity studies in accordance with OECD TG 402 within our accredited laboratory infrastructure and under our quality management system, applying scientific rigor. Our scope of services includes the following:
Study Design and Protocol Development
- Preparation of a test report in accordance with OECD TG 402
- Scientific justification of the dosages and conditions of use based on the physicochemical properties of the test substance and the available toxicity data
- Selection of a suitable carrier (vehicle) and evaluation of solubility and stability
- Determination of species, sex, age, scope of application, and type of skin covering
- Compliance with Ethical Review and Animal Welfare Requirements
- If necessary, design of a preliminary test (range-finding)
For information on study design, dose determination, suitability of the carrier, application conditions, sample acceptance criteria, the timeline, and reporting procedures for your acute dermal toxicity studies in accordance with OECD TG 402, please feel free to contact Nano-Test.