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Toxicity studies
General principles
Introduction
 Toxin is a substance that is any of these: dangerous, harmful, unsafe,
injurious, poisonous, undesired or fatal.
 Toxicology is a branch of pharmacology concerned with the study of
adverse effects of chemicals, biologicals and physical agents on living
organisms
 Relationship between dose and adverse effects
 All things are poisonous and nothing is without poison; only the dose makes a thing not poisonous.
Factors that influence toxicity
 Dosage
 Both large single exposures (acute) and continuous small exposures (chronic) are studied.
 Route of exposure
 Ingestion, injection, inhalation or skin absorption
 Other factors
 Species
 Age
 Sex
 Health
 Environment
 Individual characteristics
Methods of conducting toxicity studies
 In vivo
 Ex vivo
 In vitro
 In silico
 Before conducting any toxicological testing in animals or collecting tissue or
cell lines from animals, the study should be approved by the IAEC or the
protocol should satisfy guidelines of local governing body
Animals used for toxicity testing
Types of toxicity studies
 Single dose/ acute toxicity
 Repeat dose/ subacute or chronic toxicity
Key factors for designing toxicity studies
 Selection of species/ strain/ sex
 Age
 Number
 Interim necropsy
 Infection during study
 Caging
 Diet
 Mortality
 Autolysis
Key factors for designing toxicity studies
 Identity
 Composition/ purity
 Storage
 Exp Date
Key factors for designing toxicity studies
 Duration of testing
 Route of administration
 Diet
 Drinking water
 Oral gavage
Key factors for designing toxicity studies
 Treatment doses
 Controls
Observations and Clinical tests
 Daily observation for changes in skin, fur, eyes, mucous membranes,
secretions, excretions, autonomic activity (lacrimation, pilorection, pupil
size, unusual respiratory pattern)
 Changes in gait, response to handling, stereotypes (excessive grooming,
repetitive circling) or bizarre behavior (self-mutilating, walking backwards)
 Body weight
 Feed and water intake
Clinical testing to support observations
 Opthalmological examination
 Hematology
 Clinical chemistry
 Urinalysis
 Neurotoxicity
 Immunotoxicity
Necropsy
 Gross necropsy
 Organ weight
 Microscopy

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Toxicity studies.pptx and its guidelines

  • 2. Introduction Toxin is a substance that is any of these: dangerous, harmful, unsafe, injurious, poisonous, undesired or fatal. Toxicology is a branch of pharmacology concerned with the study of adverse effects of chemicals, biologicals and physical agents on living organisms Relationship between dose and adverse effects All things are poisonous and nothing is without poison; only the dose makes a thing not poisonous.
  • 3. Factors that influence toxicity Dosage Both large single exposures (acute) and continuous small exposures (chronic) are studied. Route of exposure Ingestion, injection, inhalation or skin absorption Other factors Species Age Sex Health Environment Individual characteristics
  • 4. Methods of conducting toxicity studies In vivo Ex vivo In vitro In silico Before conducting any toxicological testing in animals or collecting tissue or cell lines from animals, the study should be approved by the IAEC or the protocol should satisfy guidelines of local governing body
  • 5. Animals used for toxicity testing
  • 6. Types of toxicity studies Single dose/ acute toxicity Repeat dose/ subacute or chronic toxicity
  • 7. Key factors for designing toxicity studies Selection of species/ strain/ sex Age Number Interim necropsy Infection during study Caging Diet Mortality Autolysis
  • 8. Key factors for designing toxicity studies Identity Composition/ purity Storage Exp Date
  • 9. Key factors for designing toxicity studies Duration of testing Route of administration Diet Drinking water Oral gavage
  • 10. Key factors for designing toxicity studies Treatment doses Controls
  • 11. Observations and Clinical tests Daily observation for changes in skin, fur, eyes, mucous membranes, secretions, excretions, autonomic activity (lacrimation, pilorection, pupil size, unusual respiratory pattern) Changes in gait, response to handling, stereotypes (excessive grooming, repetitive circling) or bizarre behavior (self-mutilating, walking backwards) Body weight Feed and water intake
  • 12. Clinical testing to support observations Opthalmological examination Hematology Clinical chemistry Urinalysis Neurotoxicity Immunotoxicity
  • 13. Necropsy Gross necropsy Organ weight Microscopy