Raman Govindarajan, MD, PhD. Regional Director Medical and Scientific Affairs Johnson and Johnson Asia Pacific Toxicology Fundamentals

A Day in Toxicology The Fundamentals of Toxicology Preclinical Safety Assessment of Cosmetics & Toiletries How? Case Studies

Toxicology: Fundamentals What is Toxicology? The traditional definition of toxicology: " the science of toxin ”.

Toxicology: Fundamentals What is Toxicology? A more descriptive definition of toxicology: "the study of the adverse effects of chemicals or physical agents on living organisms".

Toxicology: Fundamentals Which one of the following is a toxin? 1. Alcohol 2. Aspirin 3. Water 4. Table salt

Toxicology: Fundamentals Toxicity depends on the DOSE

Toxicology: Fundamentals “All substances are poisons; there is none which is not a poison. The right dose differentiates a poison and a remedy.” -- Paracelsus

Toxicology: Fundamentals Toxicity depends on the dose –High oxygen level cause “oxygen intoxication”

Toxicology: Fundamentals Toxicity depends on the dose –High oxygen level cause “oxygen intoxication” –Too much water (several gallons) can cause osmotic imbalance and brain damage

Toxicology: Fundamentals Toxicity depends on the dose –High oxygen level cause “oxygen intoxication” –Too much water (several gallons) can cause osmotic imbalance and brain damage –1 beer vs. a six pack of beer

Toxicology: Fundamentals Toxicity depends on the dose –High oxygen level cause “oxygen intoxication” –Too much water (several gallons) can cause osmotic imbalance and brain damage –1 beer vs. a six pack of beer –1 sleeping pill vs. a bottle of sleeping pills

Toxicology: Fundamentals Toxicity depends on the dose –High oxygen level cause “oxygen intoxication” –Too much water (several gallons) can cause osmotic imbalance and brain damage –1 beer vs. a six pack of beer –1 sleeping pill vs. a bottle of sleeping pills –1 aspirin vs. a bottle of aspirins

Toxicology: Fundamentals What is LD 50 ? 1. Fifty Lead molecules 2. A famous singer in 1950’s 3. A Latin dance introduced in 1950’s 4. A means to measure toxicity

Toxicology: Fundamentals How is Toxicity measured by?

Toxicology: Fundamentals Toxicity is measured by LD 50 : Lethal Dose that kills 50% of the population

Toxicology: Fundamentals Toxicity is measured by: LD 50 : Lethal Dose that kills 50% of the population Dosage measured in weight of toxin per body weight

Toxicology: Fundamentals Dose-response curves are used to derive dose estimates of chemical substances. A common dose estimate for acute toxicity is the LD 50 (Lethal Dose 50%).

Toxicology: Fundamentals Examples of LD 50 : Chemical LD 50 (ppm) Nicotine1 DDT100 Table Salt3000 Trichloroethylene5000

Toxicology: Fundamentals What is ED 10 ? 1. The 10th version of ET movie 2. Brief for the 10th Edward in the family 3. The 10th Executive Director in a company 4. Indication of the effectiveness of a substance

Toxicology: Fundamentals Effective Doses (EDs) are used to indicate the effectiveness of a substance. Normally, effective dose refers to a beneficial effect (relief of pain). It might also stand for a harmful effect (paralysis). Thus the specific endpoint must be indicated.

Toxicology: Fundamentals Effective Dose

Toxicology: Fundamentals What does EC stands for? –1. Title for a TV show starring a talking horse –2. Effective concentration –3. Exposure concentration –4. New musical show in Broadway

Toxicology: Fundamentals EC 10 This is the commonly used abbreviation for the exposure concentration of a toxicant causing a defined effect on 10% of a test population

Toxicology: Fundamentals Absorption is the process whereby a substance moves from outside the body into the body.

Toxicology: Fundamentals

Definition

Toxicology: Fundamentals What is Toxicokinetics? Toxicokinetics is the study of "how a substance gets into the body and what happens to it in the body". Essentially, it is the study of “the kinetics of all toxic substances”.

Toxicology: Fundamentals Toxicity/Preclinical Safety Review Single Dose Study Multiple Dose Study: Subacute, Subchronic, Chronic Mutagenicity/Carcinogenicity Study

Toxicology: Fundamentals Acute toxicity results from a single exposure to a poisonous substance. Route of administration: Oral, IV, IP, Dermal, Subcutaneous

Toxicology: Fundamentals Acute toxicity results from a single exposure to a poisonous substance –Usually has an immediate life-threatening effect

Toxicology: Fundamentals Acute toxicity results from a single exposure to a poisonous substance –Usually has an immediate life-threatening effect –Usually easily diagnosed

Toxicology: Fundamentals Acute toxicity results from a single exposure to a poisonous substance –Usually has an immediate life-threatening effect –Usually easily diagnosed –Most of the time there are antidotes that can reduce the toxicity of the chemical

Toxicology: Fundamentals Multiple Dose Tests: Subacute: days to 2 wks Subchronic: wks Chronic: months in rodents years in non-rodents Study design depending on the objective of the study

Toxicology: Fundamentals Chronic toxicity results from prolonged exposure to a poisonous substance over a long period of time

Toxicology: Fundamentals Chronic toxicity results from prolonged exposure to a poisonous substance over a long period of time –No immediate effect but could be life- threatening in the long term

Toxicology: Fundamentals Chronic toxicity results from prolonged exposure to a poisonous substance over a long period of time –No immediate effect but could be life- threatening in the long term –Usually hard to diagnose and treat

Toxicology: Fundamentals Chronic toxicity results from prolonged exposure to a poisonous substance over a long period of time –No immediate effect but could be life- threatening in the long term –Usually hard to diagnose and treat –Hard to distinguish effects from other influences

Toxicology: Fundamentals What is mutagenic? 1. Something to do with music 2. Something to do with DNA 3. Something to do with mutes

Toxicology: Fundamentals Mutagenesis The process whereby a substance damages DNA and produces alterations in or loss of genes or chromosomes.

Toxicology: Fundamentals Mutagenicity Tests –Ames Test –Mammalian Chromosomal Aberration –Micronucleus Test (in vivo)

Toxicology: Fundamentals What is carcinogenic ? 1. A place that makes cars 2. Something to do with gambling 3. Something that can cause tumors 4. A place that repairs cars

Toxicology: Fundamentals Carcinogen A carcinogen is any substance which causes cancer

Toxicology: Fundamentals Carcinogenicity Studies Traditional 2-year Bioassay –different routes of administration, use rats and mice –two year duration, expensive, labor-intensive –interspecies extrapolation problem, especially mice

Toxicology: Fundamentals Carcinogenicity Studies Traditional Testing –different routes of administration, use rats and mice –two year duration, expensive, labor-intensive –interspecies extrapolation problem, especially mice Transgenic Animal Testing –P53, Neonatal, TgAc, XPA, XPA/P53 and RasH2 models –shorter testing period, less expensive, less labor-intensive –have genes relevant to humans –predictability? -- not enough data

Toxicology: Fundamentals What is a reproductive toxin?

Toxicology: Basic Reproductive toxicity is defined as adverse effects on the male and female reproductive systems that result from exposure to chemical substances.

Toxicology: Fundamentals Which of the following causes reproductive toxicity? 1. Alcohol 2. Vitamin A 3. Tobacco smoke (primary) 4. Aspirin

Toxicology: Fundamentals Special Toxicity Studies Eye Irritation Skin Irritation Contact Sensitization Comedogenicity Genital/Mucus Membrane Irritation

Toxicology: Fundamentals Irritation: Any substance causing inflammation following immediate, prolonged, or repeated contact with skin or mucous membrane.

Toxicology: Fundamentals The most common cause of Occupational Skin Disease is irritation of the skin from contact with substances at work.

Toxicology: Fundamentals Strong irritants (e.g. acids, alkaline or solvents) cause skin inflammation after a short period of skin contact. Dermatitis from cement

Toxicology: Fundamentals Weak irritants (such as water, detergents, coolants) cause inflammation after repeated exposures over a longer time.

Toxicology: Fundamentals Dermal Irritation Tests –Primary Irritation Test Single Dose –Cumulative Irritation Test Multiple Dose

Toxicology: Fundamentals In intracutaneous irritation tests using albino rabbits, the raised blebs caused by injecting extracts of test materials are either resolved without causing any visible changes or produce inflammation marked by redness and swelling in the 24 to 72 hours following injection.

Toxicology: Fundamentals Sensitization or hypersensitivity reactions usually occur as a result of repeated or prolonged contact with a substance that interacts with the body's immune system.

Toxicology: Fundamentals Which of the following is considered to be a sensitizer? 1. Latex Gloves 2. DNCB (1-chloro-2, 4-dinitrobenzene) 3. Kathon ® CG 4. All of the above

Toxicology: Fundamentals After wearing natural latex gloves daily for several weeks or months, a person may develop a rash

Toxicology: Fundamentals Biomaterials and devices that cause sensitization reactions do so by means of their extractable chemical caused cell-mediated immunity.

Toxicology: Fundamentals Commonly Used Sensitization Tests Guinea Pig Maximization Test (Magnuson-Kligman Test) Modified Buhler’s Test Local Lymph Node Assay

Toxicology: Fundamentals Positive response to DNCB in a guinea pig, seen in the maximization test

Toxicology: Fundamentals What does following compounds have in common? 1. Polycyclic aromatic hyrocarbons 2. Quinolones 3. Tetracyclines 4. PABA

Toxicology: Fundamentals Ingredients absorb in the solar spectrum ( nm) Photomutagenicity Phototoxicity Photosensitization Photocarcinogenicity

Toxicology: Fundamentals Studies to support Product Claims Ocular Irritation (Draize or TEP) Genital/Mucus Membrane Irritation Comedogenicity HET CAM – eye irritation test

Toxicology: Fundamentals What is comedone?

Comedone: A follicle that has been plugged with a combination of hardened oil (sebaceous material) and dead skin cells.

Toxicology: Fundamentals Which of the following can causes a comedogenic reaction? 1. Cocoa Butter 2. Lanolin 3. Amydimethyl PABA 4. All of the above

Toxicology: Fundamentals 1. Cocoa Butter - a skin softener and lubricator. It is considered comedogenic and may cause allergic reactions. 2. Lanolin - a sheep’s wool derivative, it is highly comedogenic. 3.Amyldimethyl PABA - causes skin irritation. 4.All of the above

Toxicology: Fundamentals Skin Absorption Data Toxicokinetic and Pharmacokinetic Data Other important information:

Toxicology: Fundamentals Photosensitization : Hypersensitivity to light. An abnormally heightened response, especially of the skin, to sunlight or ultraviolet radiation, caused by certain disorders or chemicals and characterized by a toxic or allergic reaction

Toxicology: Fundamentals Safety Testing Knowledge of Toxicity is primarily obtained in 3 ways: –by studies using cells (in vitro) –by experimental studies using animals –by the study and observation of people during normal use of a substance

Toxicology: Fundamentals Four basic steps in the risk assessment process:

Toxicology: Fundamentals

Toxicology quiz What is “toxicologist”? 1. A person who always kills my project 2. A person who is intoxicated 3. A person who can not make it to medical school 4. Our partner in R&D

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