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Toxicology and Drugs
 Toxicology:
Basic Definitions
The study of toxins and drugs in the body.
 Toxin:
Any material exerting a life threatening effect upon a living organism.
 Toxic materials exist in many forms (gaseous, liquid, solid, animal, mineral,
and vegetable), and may be ingested, inhaled, or absorbed through the
skin.
 Toxins work in minute quantities or low levels, requiring sensitive
analytical instruments for detection.
 Toxic substances may
-Contribute to death
-Be cause of death
-Cause impairment
-Explain behavior
 Poisons are a subgroup of toxins.
 Poisons generally enter the body in a single massive dose, or accumulate to
a massive dose over time.
Types of Toxicology
 Environmental: Air, Water, Soil
 Consumer: Food, Cosmetics
 Medical, Clinical, Forensic
Forensic Toxicology
 Detects and Identifies
-Presence of drugs & poisons
-Body Fluids
-Examines tissues & organs
 Work in crime labs & medical examiners’ office
Forensic Toxicology
 May also work in hospital labs to identify drug overdoses or monitor the
intake of drugs
 Major job is measurement of alcohol in the body (motor vehicle accidents)
Aspects of Toxicology
 Dosage
-The chemical or physical form of the substance
-The mode of entry into the body
 Toxin/Poison
-Influenced by body weight & the physiological including age & sex
-The mode of entry into the body
 Toxin/Poison
-The time period of exposure
-The presence of other chemicals in the body
 LD50
- Refers to the dose of a substance that kills half the test population,
usually within four hours
- Expressed in milligrams of substance per kilogram of body weight
Toxicity Classes
To x ic it y Cl a s s es
LD50 (rat,oral)
Correlation to
Toxicity
Ingestion by 150 lb
Adult Human
<1mg/kg
a taste to a drop
extremely
1-50 mg/kg
to a teaspoon
highly
50-500 mg/kg
to an ounce
moderately
500-5000 mg/kg
to a pint
slightly
5-15 g/kg
to a quart
practically non-toxic
Over 15g/kg
more than 1 quart
relatively harmless
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Federal Regulatory Agencies
Food & Drug Administration (FDA)
Environmental Protection Agency (EPA)
Consumer Product Safety Commission
Department of Transportation (DOT)
Occupational Safety & Health Administration (OSHA)
Poisons
Ty pes o f Po is o ns & Sy mpt o ms
Poison Type
Evidence/Symptoms
Sulfuric
Acid
Black Vomit
Carbon
Monoxide
Red or pink patches on the
chest and thighs, unusually
bright red lividity
Caustic Poison
(Lye)
Characteristic burns around
the lips and mouth of the
victim
Cyanide
Burnt Almond Odor
Ty pes o f Po is o ns & Sy mpt o ms
Poison Type
Evidence/Symptoms
Hydrochloric
Acid
Greenish-brown vomit
Phosphorus
Coffee brown vomit
Garlic or onion odor
Methyl (Wood) or Isopropyl
(Rubbing) Alcohol
Nausea and vomiting
Unconsciousness, possibly
blindness
Nitric Acid
Yellow Vomit
Ty pes o f Po is o ns & Sy mpt o ms
Poison Type
Evidence/Symptoms
Arsenic or Mercury
Pronounced diarrhea
Arsenic accumulates
in hair & nails
Critical Information on Poisons
Form
Common Color
Characteristic Odor
Solubility
Taste
Common Sources
Lethal Dose
 Mechanism
 Possible Methods of Administration
 Time Interval of Onset of Symptoms
 Symptoms resulting from an acute exposure
 Symptoms resulting from chronic exposure
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 Disease states mimicked by poisoning
 Notes relating to victim
 Specimens from victim
 Analytical detection methods
 Known toxic levels
 Notes pertinent to analysis of poison
 List of cases in which poison was used
Proving a Poison case
 Prove a crime was committed
 Motive & Intent
 Access to poison & victim
 Death was caused by poison
 Death was a homicide
Forensic autopsy
 Look for
-Irritated tissues
-Characteristic odors
-Mees lines: single transverse white bands on nails
 Order Toxicological Screens:
–Postmortem concentrations should be done at the scene for comparison
–No realistic calculation of dose can be made from a single measurement
 Specimens Taken for Analysis
-Liver, Kidney, Brain tissue
-Blood & Urine
-Hair & Nails
-Bile & Gastric Contents
-Vitreous Humor of Eye
Toxicology of ethyl Alcohol
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Most abused drug
40% of traffic death are alcohol related
Affects the central nervous system
Acts as a depressant
 Appears in the blood within minutes
 Full absorption occurs in 30-90 minutes
 Rate of Absorption Depends on
-Alcohol content
-Time taken to consume the drink
-Amount consumed
-Food present in stomach
-Physiology of the consumer
 Alcohol Levels
-Elimination of alcohol throughout the body
-Detoxification occurs in the liver (90%)
-Excretion occurs unchanged in breath, urine, & perspiration (5%)
 Blood Alcohol Content (BAC)
-Expressed as weight per volume of blood
-Influenced by:
Body weight, Alcohol content, number of beverages, time between
consumption
-Rate of elimination from the bloodstream is approximately 0.15% per hour
Alcohol and the Law
 In 1972 legal limit made 0.08% (w/v)
 In 1973 “implied consent” adopted by all states (drivers on a public
highway will submit for a test for alcohol intoxication)
 Preliminary Field Tests
-Used to determine the degree of a suspect’s physical impairment & if
other tests are justified
 Psychophysical Tests
-Three types
1. Horizontal Gaze Nystagmus
-Follow a pen or flashlight, tracking left to right with one’s eye
-Wavering at 45 degrees indicates 0.10% BAC
2. Divided Attention Tests
-Comprehension of two instructions
-Examples
-Nine Step Walk & Turn (WAT)
-One Leg Stand (OLS)
 Breathalyzer
-Collects and measures alcohol content in alveolar breath (deep
lung breath)
-Need 1.5 L of breath
-Chemical ones phased out in 1970s
-Today computerized using infrared light absorption
Drugs
 Drug:
-Natural or synthetic
-Affect psychology or physiology
-Most produced legitimately for Rx
-If obtained by illegal means = “illicit drug” or “drugs of abuse”
-If taken in excess causing illness or death = poison
Drug types
 Most drugs fit into one or more of the following categories
-Stimulants
-Narcotics
-Depressants
-Hallucinogens
 Stimulants
-Speed up the CNS (amphetamines)
 Narcotics
-Induce a state of sluggishness
-Most derived from the poppy plant
(codeine, heroin. morphine, oxycontin)
 Depressants
Drug types
-Slow down the CNS (alcohol, inhalants)
 Hallucinogens
-Cause marked alterations in thought process, perceptions, & mood
(LSD, PCP, marijuana)
Controlled substance act
 Controlled Substance Act (1970)
-Drugs restricted by law
-Lists illegal drugs, their category
and their penalty for possession, sale or use.
-Five schedules based on potential for abuse & dependence & medical
use
 Schedule I
-High potential for abuse
-No accepted medical use
-Lack of accepted safety for use under medical supervision
-heroin, LSD, ecstasy (MDMA), marijuana
Controlled substance act
 Schedule II
-High potential for abuse
-Currently accepted medical use with severe restrictions
-Abuse may lead to severe psychological or physical dependence
-cocaine, morphine, amphetamines, Ritalin, PCP, opium
 Schedule III
-Lower potential for abuse than I or II
-Currently accepted medical use
-Abuse may lead to moderate psychological or physical dependence
-intermediate acting barbiturates, steroids, ketamine
 Schedule VI
-Lower potential for abuse relative to drugs in III
-Currently accepted medical use
-Abuse may lead to limited psychological or physical dependence relative
to drugs in III
-other stimulants & depressants, valium, Darvon, librium, phenobarbital
 Schedule V
-Lower potential for abuse relative to drugs in VI
-Currently accepted medical use
-Abuse may lead to limited psychological or physical dependence relative
to drugs in IV
-codeine found in cough medicine
Drug Identification
 PDR (Physician's Desk Reference)
-Identifies manufactured pills, tablets, & capsules
-Gives a picture of the drug, whether OTC, prescription, or controlled
substance
-Updated yearly
 Presumptive or Screening Tests
-Scott Test
Turns blue in the presence of cocaine
-Marquis Test
Turns purple in the presence of heroin, morphine, & most opium
derivatives
Turns orange-brown in the presence of amphetamines
 Presumptive or Screening Tests
-Van Urk
Turns blue purple in the presence of LSD
-Dillie-Koppanyl
Turns violet-blue in the presence of barbiturates
Drug Identification
 Presumptive or Screening Tests
-Duquenois-Levine
Turns a purple in the presence of marijuana
 Microcrystalline Test
-A reagent is added that produces a crystalline precipitate which is unique
for a certain drug
-More specific than color tests
 Confirmatory Test
-Spectrophotometry
Ultraviolet (UV)
Visible
Infrared (IR)
Mass Spectrometry
 Chromatography
Drug Identification
-Separates components of a mixture
-Consists of 2 phases mobile & stationary
-Mobile: liquid solvent
-Stationary: Depends on type of
chromatography. Can be paper, glass,
silica
 Chromatography
Drug Identification
-Types
Thin Layer (TLC)
Gas (GC)
Liquid (LC)
High Pressure Liquid (HPLC)
Paper
Column