The Role of the Toxicologists 10.6 Notes The Role of the Toxicologists

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

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

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

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

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

(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

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

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

10.6 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?