the role of the toxicologists. appreciate the significance of finding a drug in human tissues and...
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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