The Role of the ToxicologistsThe Role of the Toxicologists

Appreciate the significance

of finding a drug in human tissues and organs to assessing impairment

Objectives

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

Challenges

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

Challenges continue…

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

Capabilities of toxicologist

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

Collection & Preservation

Acid = donates hydrogen ion (H+) 0-7 on pH scale

Base = accepts H+ 7-14 on pH scale

Neutral = water = 7 on pH scale

Acids & BasesAcid Drugs Basic Drugs

Barbiturates Methadone

Aspirin (acetylsalicylic acid)

Amphetamines

Cocaine

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

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

Extraction of Acids & Bases

1. Describe the two challenges toxicologists face in detecting drugs and determining their toxicity.

2. What three drugs account for 90% or more of the drugs encountered in a typical toxicology laboratory?

3. What bodily fluids should be collected from any suspected drug user?

4. What are acids and bases? How are they used to extract and categorize drugs?

5. What is the first task of a forensic toxicologist when establishing an analytical scheme to detect and identify drugs?

10.6 Questions