Repeated dose 90-days oral toxicity study in rodents. OECD 408: 2018.
Test with the Certificate of Good Laboratory Practices (GLPs)
The 90-day repeated dose subchronic oral toxicity test provides information on possible health hazards that may arise from repeated exposure over a prolonged period that covers maturation and post-weaning growth to adulthood of the test animals. This test provides information on the main toxic effects, the target organs, and the possibility of accumulation of the test substance, and can provide an estimate of the level of exposure without observable effect (NOAEL) that can be used to select the dose of studies of chronic toxicity and to establish safety criteria for human exposure.
Rats are the preferred animal for this test, although other rodents may be used. The study should be started as soon as possible after the weaning of the animals, before they reach 9 weeks of age. The test compound is administered by gavage, incorporated into the diet or dissolved in drinking water daily for 90 days. At least 3 dose levels and one control should be used. Each group must consist of at least 20 animals (ten males and ten females). The highest dose level should produce toxicity but not the death or suffering of the animals. An additional satellite group of 10 animals, 5 per sex, can be included to observe the reversibility or persistence of the toxic effects observed. The guideline also contemplates the possibility of carrying out a limit test with a dose level of 1.000 mg/Kg of body weight per day.
Animals should be evaluated daily to assess mortality and morbidity. A detailed clinical analysis should be done weekly. At the end of the study, an ophthalmological examination, the evaluation of reactivity to stimuli and motor activity, a hematological analysis, clinical biochemistry, and complete necropsy, and the complete histopathology of the high treatment groups as well as the control animals should be performed. In addition, this guide emphasizes the importance of endocrine analysis, which is performed in combination with sensitivity to neurological, immunological and reproductive effects.