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
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