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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
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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
Acids & Bases • 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?