1. The Role of the Toxicologists
10.6 Notes
The Role of the Toxicologists

2. Objectives
Appreciate the significance of finding a drug in human tissues and organs to assessing impairment

3. Challenges
Presented with body fluids and/or organs and asked to examine for drugs or poisons
Sometimes they possess clues to type of toxic substance
Victim’s Symptoms
Postmortem pathological examination
Examination of victim’s physical effects
Presence of containers
Household cleaners
Without those clues, rely on general screening procedures

4. Challenges continue…
Dealing with drugs that have been dissipated and distributed throughout the body
Not at concentrated level found in pills and powders
Forced to work with nano or microgram amounts
Factor in metabolic activity of body
Must be prepared to assess toxicity levels

5. Capabilities of toxicologist
Dependent on input from
Attending physician
Medical Examiner
If victim is dead, M.E. decides what to send to toxicologist
If living = blood and urine send to toxicologist
Police Investigator

6. Collection & Preservation
Upsurge in drug use and abuse means overwhelming majority of fatal and nonfatal toxic agents are drugs
90% accounted for by alcohol, marijuana, and cocaine

7. (acetylsalicylic acid)
Acids & Bases
Acid Drugs
Basic Drugs
Barbiturates
Methadone
Aspirin
(acetylsalicylic acid)
Amphetamines
Cocaine
Acid = donates hydrogen ion (H+)
0-7 on pH scale
Base = accepts H+
7-14 on pH scale
Neutral = water = 7 on pH scale

8. Extraction of Acids & Bases
Add acidic or basic substances to water to change pH value
Control pH value of water solution into which blood, urine or tissues are dissolved

9. Extraction of Acids & Bases
Toxicologist can control the type of drug that is recovered
Drugs extracted from altered water by adding organic solvents
Acid drugs easily extracted from acidified water solution

10. 10.6 Questions
Describe the two challenges toxicologists face in detecting drugs and determining their toxicity.
What three drugs account for 90% or more of the drugs encountered in a typical toxicology laboratory?
What bodily fluids should be collected from any suspected drug user?
What are acids and bases? How are they used to extract and categorize drugs?
What is the first task of a forensic toxicologist when establishing an analytical scheme to detect and identify drugs?