Oecd guidelines

The given presentation is a short description about OECD GUIDELINES.

1. Name:- Umangi Thakkar Class:- MS.c.Part-2 Roll no:-062 Topic:-Introduction to OECD

2. WHAT IS TOXICOLOGY ? Toxicology is the scientific study of adverse effects that occur in living organisms due to chemicals . It involves observing and reporting symptoms, mechanisms, detection and treatments of toxic substances ,in particular relation to the poisoning of humans

3. Introduction to OECD The Organisation for Economic Co-operation and Development (OECD) is an international organisation that works to build better policies for better lives The OECD  Guidelines for the Testing of Chemicals  is a collection of about 150 of the most relevant internationally agreed testing methods used by government, industry and independent laboratories to identify and characterise potential hazards of chemicals. They are a set of tools for professionals, used primarily in regulatory safety testing and subsequent chemical and chemical product notification, chemical registration and in chemical evaluation. They can also be used for the selection and ranking of candidate chemicals during the development of new chemicals and products and in toxicology research. This group of tests covers physical-chemical properties .

4. OECD Guidelines for the testing of chemicals The OECD Guidelines are a unique tool for assessing the potential effects of chemicals on human health and the environment. Accepted internationally as standard methods for safety testing. Guidelines are used by:- Professionals in Industry Academia And government involved in the testing and Assesement of chemicals (Industrial chemicals ,pesticides ,personal care products

5. The following tests are conducted for toxicity detection Acute toxicity tests (14 Days) Sub acute toxicity tests ( doses upto 14 to 28 days) Sub Chronic toxicity tests (daily dose :-up to 90 days) Chronic toxicity tests (daily dose:- 6 months and more)

6. A Simple flow of all the guidliNEs INTIAL CONSIDERATIONS The testing laboratory should consider all available information on the test substance prior to conducting study. The Identity and chemical structure of the substance . Its physio-chemical properties. The results of any other in vivo or in vitro toxicity tests on the substance. Toxicological data on structurally related substance.

7. DESCRIPTION OF METHOD Selection of animal species :- Healthy young adult animals of commonly used laboratory strains should be employed. Females should be nullilliparous and non-pregnant. Each animal,at the commencement of its dosing ,should be between 8 and 12 weeks old and its weight should be fall in an interval within + 20% of the mean weight of any previously dosed animals. HOUSING AND FEEDING CONDITIONS The Temperature of the experimental animal room should be 22°C(+/- 3°C) Although the relative humidity should be at least 30% and preferably not exceed 70% other than during room cleaning the aim should be 50-60℅

8. Lighting should be artificial,the sequence being 12 hours light ,12 hours dark . For feeding conventional laboratory diets may be used with the unlimited supply of drinking water. Animals may be group –caged by dose ,but the number of animals per cage must not be interfere with clear observations of each animal. Preparation of animals Preparation of doses Administration of doses:- The test substance is administrated in a single dose by gavage using a stomach tube or suitable incubation canula. In the main unusual circumstances that a single dose is not possible ,the dose may be given in smaller fractions over a period not exceeding 24 hours.

9. Animals should be fasted prior to dosing . (e.g.with the rat food ,but not water should be withheld ovenight ,where with the mouse ,food but not water should be withheld for 3-4 hours) Following the period of fasting ,the animal should be weighed and the test substance administrated .after the substance has been administrated, food may be withheld for a further 3-4 hours in rats . Where dosite is administrated in fractions over a period of time,it may be necessary to provide the animals with food and water depending on length of the period. What is LD50? LD50 Represents the individual dose requrired to kill 50 percent of a population of test animals.It is an index deteimation of medicine and poisons virulence .lower the LD50 dose,the more toxic the pesticide. What is LC50? The concentration of the chemical in air that kills 50% of the test animals during the observation period us the LC50 Value .other durations of exposure (versus the traditional 4 hours) may apply depending on specific laws

10. Limit test MAIN TEST A main study is typically performed using five males And five females (Or 5 animals of the susceptible sex if Known)per concentration level,with the least three concentration levels. The first animal is dosed a step below the best preliminary estimate of the LD50. If the animal survives, the second animal receives a higher dose. If the first animal dies or appears moribund, the second animal receives a lower dose. The time interval between exposure groups is determined by the onset,duration ,And severity of signs. T he Limit Test is a sequential test that uses a maximum of 5 animals. A test dose of 2000, or exceptionally 5000 mg/kg, may be used. .As with any limit test protocol, the probability of correctly classifying a compound will decrease as the actual LD50 more nearly resembles the limit dose. The limit test is primarily used in situations where the experimenter has information indicating that the test material is likely to be nontoxic, i.e., having toxicity below regulatory limit doses.

11. Observation s Animals are observed individually afterbdoaing at least once during the first 30 minutes,periodically during the first 24 hours ,with special attention given during first 4 hours ,and daily thereafter ,for a total od 14 days ,except where they need to be removed from the study and humanely killed for animal welfare reasons or are found dead. However, the duration of observation should not be fixed rigidly. Body weight:- 1.Individual weights of animals should be deterermined shortly before the substance is administrated and at least weekly thereafter. 2.Weight changes should be calculated and recorded .At the end of the test surviving animals are weighed and then humanely killed. PATHOLOGY All test animals (including those that die during the test or removed from the study for animal welfare reasons) Should be subjected to gross necroscopy. All gross pathological changes should be recorded for each animal Microscopic examination of organs showing evidence of gross pathology in animals surviving 24 or more hours after the INTIAL dosing may also be considered because it may yield useful information.

12. Data And Reporting Test SUBSTANCE :-1)PHYSICAL NATURE ,PURITY AND PHYSIOCHEMICAL PROPERTIES. 2)IDENTIFICATION OF DATA Test animals Species/strains Used. Microbiological status of anjmal Number,age,sex of An animals Source,housing conditions And diet.etc Test conditions:- Details of test substance formulation. Details of the administration of the test substance including dosage volume And timing of dosing. Details of food And water quality

13. Results :- Tabulation of response Data And dose level for each animal (I.e.animal showing sign of toxicity including mortality ,nature ,severity And duration of effects) Tabulation of body weight changes. Individual weights of animals at the of dosing in weekly intervals thereafter And a time of death Or sacrifice . Time course of onset of signs of toxicity And whether these were reversible for each animal. Discussion And interpretation of results Conclusions

14. Some Alternatives To the Use of Animals In Testing In vitro (test tube)test methods And models based on human cell And tissue cultures. Computarized patient –drug database And virtual drug trials. Computer models And simulations. Stem cell And genetic testing methods. Non-invasive imaging techniques such as MRIs And CT Scans. Microdosing (in which humans are given very low quantities of a drug to test the effects on the body on the cellular level,without affecting the whole body system

15. Why OECD GUIDLINES?? Cover safety testing of chemicals in its broadest sense with respect to physical-chemical properties, effects on biotic systems (Eco toxicity), environmental fate (degradation/accumulation), health effects (toxicity), and other areas such as pesticide residue chemistry and efficacy testing of biocides. • Are internationally accepted as standard methods for safety testing and provide the common basis for the mutual acceptance of test data. • Are essential for professionals working in industry, academia and government on the testing and assessment of chemical substances. • Aim to reflect the current state-of-the-art in hazard identification and characterisation testing. • Are updated in order to keep pace with progress in science, and to address animal welfare concerns.

16. References:- https://www.oecd.org/chemicalsafety/testing/oecdguidelinesforthetestingofchemicals.htm https://www.oecd-ilibrary.org/environment/oecd-guidelines-for-the-testing-of-chemicals-section-4-health-effects_20745788 https://pubmed.ncbi.nlm.nih.gov/23138894/ https://www.sciencedirect.com/science/article/pii/S0273230019300534

17. Thankyou