Medicilon’s acute toxicology test is based on the knowledge of the test substance, following the principle of “specific analysis of specific problems”, and selecting a reasonable test method according to the structural characteristics, physicochemical properties, indication characteristics and test purpose of the compound , Design an appropriate test plan, and combine other pharmacological and toxicological research information to conduct a comprehensive evaluation of the test results.
Single dose toxicity test (rodent and non-rodent)
Repeated dose toxicity test (rodent and non-rodent)
Safety pharmacological tests: central nervous system research, cardiovascular system (canine and monkey telemetry and non-telemetry technology), respiratory system
Reproductive toxicity test [Fertility and early embryo development toxicity test (reproduction stage I), embryo-fetal development toxicity test (reproduction stage II)]
Local toxicity test (hemolysis, allergy, irritation test)
Animal acute toxicity test (Acute toxicity test, Single dose toxicity test), to study the toxicity reaction of animals within a certain period of time after the animal is given the test substance multiple times within one or 24 hours.
Drugs intended for use in humans usually require acute toxicity testing in animals. The acute toxicity test is in the early stage of drug toxicology research, and it is of great significance to clarify the toxic effects of drugs and understand their toxic target organs. The information obtained from the acute toxicity test has important reference value for the design of the long-term toxicity test dose and the selection of the initial dose of certain drug phase I clinical trials, and can provide some information related to acute poisoning of human drug overdose.
The acute toxicity test of a drug belongs to a safety evaluation study, which complies with the basic principles of general animal tests, namely random, controlled and repeated.
Acute toxicity test research
- Test substance
The test substance for the acute toxicity test should be a sample with a stable preparation process and conforming to the quality standards for clinical trials, and indicate the name, source, batch number, content (or specifications), storage conditions and preparation methods of the test substance, and Attached to the self-inspection report of the research unit. The auxiliary materials and solvents used should be marked with batch number, specifications and manufacturer, and meet the test requirements.
- Experimental animals
① Species: Animals of different species have their own characteristics, and the response to the same drug will be different. The results obtained from rodent and non-rodent acute toxicity tests will differ in both quality and quantity. From the perspective of sufficient exposure to the toxicity of the test substance, sufficient safety information should be obtained from rodents and non-rodent animals. Therefore, the acute toxicity test should use at least two mammals. Generally, one rodent plus one non-rodent should be selected for acute toxicity test. If non-rodent animals are not used for acute toxicity tests, their rationality should be stated.
②Gender: Usually two kinds of animals are used for the test, half male and female. If single-sex animals are used for testing, their rationality should be stated.
③, age: usually use healthy adult animals for testing. If the test substance is intended for children or may be used for children, it is recommended to use young animals for testing if necessary.
④ Number of animals: The number of animals used should be determined according to the species of animal and research purpose. The number of animals should meet the needs of the test method and the analysis and evaluation of the results. Under the premise of obtaining as much information as possible, use as few animals as possible.
⑤ Weight: The initial weight of the animal should not exceed or fall below 20% of the average weight. According to the purpose of the test and the characteristics of the test substance, the sex and age of the experimental animal can be determined. Animals should meet the level requirements of the relevant national regulations, the source, strain, and genetic background are clear, and they must have a laboratory animal quality certificate.
- Route of administration
Depending on the route of administration, the absorption rate, absorption rate and exposure of the test substance will be different. Therefore, different routes of administration are required for acute toxicity tests. In addition, by comparing the results of different routes of administration, some preliminary bioavailability information can be obtained. Generally, the route of administration should include at least a clinically intended route and a route that allows the original drug to enter the circulation more completely (such as intravenous injection). If the clinical intended route is intravenous administration, only this one route is sufficient.
Animals should be fasted for a period of time (usually overnight) without water before oral administration. Stomach contents will affect the administration volume of the test substance, and the length of fasting in rodents will affect the activity of drug metabolizing enzymes and the intestinal absorption of the test substance, thus affecting the exposure of toxicity.
- Dosage level
The focus of the acute toxicity test is to observe the toxic reactions that occur in animals. Appropriate methods can be selected for acute toxicity studies. Non-rodent animals should be given a dose that exhibits significant toxicity. The dose does not need to reach a lethal level.
In general, the dosage should be from no toxic dose to a serious toxic (life-threatening) dose, with a blank and/or vehicle (excipient) control group.
Common test methods for acute toxicity test
- Approximate lethal dose method: This method is mainly used for non-rodent animal experiments.
- Maximum dose method: This method can be used for some low-toxic test substances. Under the premise of a reasonable maximum administration concentration and administration volume, a single administration at the maximum allowable dose or multiple administrations within 24 hours (the dose generally does not exceed 5g/kg body weight), observe the animal’s reaction. Generally, 10-20 animals are used for 14 days of continuous observation.
- Fixed-dose procedure: Instead of taking death as the end point of observation, evaluate the obvious toxic signs as the end point.
- Up and down method (ladder method, sequential method, Up and down method): The characteristic is to save experimental animals, at the same time, not only can observe the toxicity performance, but also can estimate the LD50 and its credible limit, suitable for causing rapid animal death drug.
- Cumulative dose design method: This method can be used for acute toxicity tests in non-rodent animals.
- Half-lethal method
Summary: The results of the acute toxicity test can be used as a reference for the dose selection of subsequent toxicological studies, and can also prompt some indicators that need to be observed in subsequent toxicity studies. In addition, according to the animal’s response to different routes of administration, the bioavailability of the test substance is preliminarily judged to provide a reference for the development of the dosage form.