Forensic Toxicology Cengage Learning. All Rights Reserved

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Diana Hopkins
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2 2 History (Obj 9.1) Early 1700 s first use of chemistry to detect poisons Early 19th century toxicology became a new scientific discipline France in 1840 Charles Lafarge trial involved testing for arsenic

3 Mathieu Orfila Father of Toxicology (1787 1853) argued that arsenic in the soil around graves could be drawn in to the body and

3 3 Mathieu Orfila Father of Toxicology ( ) argued that arsenic in the soil around graves could be drawn in to the body and be mistaken for poisoning. Often called to act as a medical expert in widely publicized criminal cases Helped solve the Lafarge case

4 2012 Cengage Learning. All Rights Reserved 4 Forensic Toxicology Toxicology is the study of harmful effects of chemicals or drugs on living systems. Toxicologists detect and identify drugs and poisons in body fluids, tissues, and organs AND determine their influence on humans

5 2012 Cengage Learning. All Rights Reserved 5 Forensic Toxicology - Duties Assist with Autopsy an examination of a dead body to find out the COD. Many involve analysis of body fluids and tissues for the detection of drugs or poisons. Determine whether alcohol or drugs were contributing factors in criminal cases.

6 2012 Cengage Learning. All Rights Reserved 6 Forensic Toxicology Forensic toxicology is that branch of toxicology that deals with the medico-legal aspects of toxicology. Forensic toxicologist role is limited to matters that pertain to violations of criminal law.

7 2012 Cengage Learning. All Rights Reserved 7 Forensic Toxicology Forensic toxicologists answer the question, "Did prescription or illegal drugs and/or alcohol lead or contribute to the person's death or intoxication?" Answering this question often requires law enforcement officers, forensic pathologists, forensic toxicologists, other forensic scientists, and crime scene investigators to work together.

8 2012 Cengage Learning. All Rights Reserved 8 Challenges A. Extremely hard to ID drugs and poisons without supportive info ie) symptoms, personal effects, nearby empty drug containers, etc. B. Drug analysts often deal with nanogram to microgram concentrations because the drug has been distributed and dissapated throughout the body.

9 2012 Cengage Learning. All Rights Reserved 9 Challenges C. The human body is an active chemistry lab. Substances are constantly being metabolized. Chemists must know how the body alters the chemical structure of a drug ie) Heroin is almost immediately metabolized into morphine in the blood stream.

10 2012 Cengage Learning. All Rights Reserved 10 Challenges D. Dosage matters Toxicologist must determine toxicity Paracelsus (Swiss/German scientist) Poison is in everything, and no thing is without poison. The dosage makes it either a poison or a remedy. Tolerance in response to prolonged, heavy intake of alcohol or other drugs, the body s need for progressively larger amounts of a chemical to cause the same levels of intoxication

11 2012 Cengage Learning. All Rights Reserved 11 Chemical Evidence Professionals present work together to decide what samples and the quantity of samples taken for testing. Upsurge in drug use and abuse means overwhelming majority of fatal and nonfatal toxic agents are drugs, rather than poisons. Alcohol, marijuana, and cocaine account for 90% or more of drugs encountered in a typical lab.

13 2012 Cengage Learning. All Rights Reserved 13 Basic Chemistry Principles Period Table Columns Groups or Families; form similar reactions (group # = # of valence electrons). Some have specific names ex) Halogens, Noble Gases Rows Periods (The shell number that is valence)

16 2012 Cengage Learning. All Rights Reserved 16 Ionic Compounds Bonds between oppositely charged ions (cation+, anion-); usually between metals(+) and nonmentals(-); high melting points and rigid structures. Named by listing the cation first and anion last.

17 2012 Cengage Learning. All Rights Reserved 17 Chemical Equations Shorthand method to communicate information about a reaction. Coefficients show numbers of compounds. Subscripts show numbers of atoms.

18 18 Pharmacokinetics the study of the bodily absorption, distribution, metabolism, and excretion of drugs How the body processes chemicals, and for our purposes, drugs.

19 2012 Cengage Learning. All Rights Reserved 19 Pharmacokinetics Ingestion How the chemical gets into the body. Can be done with or without the person s knowledge. Can depend on water solubility ie) cocaine vs. crack-cocaine

20 2012 Cengage Learning. All Rights Reserved 20 Pharmacokinetics Absorption How the chemical gets into the blood stream. Most drugs and poisons must get into the blood stream and activate specific receptors to take effect. Determined by the physical and chemical properties of the chemical ie) solubility, acid/base

21 2012 Cengage Learning. All Rights Reserved 21 Pharmacokinetics Distribution how drug is circulated to surrounding tissues Highly dependent on solubility (water soluble vs. fat soluble) Usually fat soluble will have higher volume of distribution and last longer in the body. Some examples THC, cocaine

22 2012 Cengage Learning. All Rights Reserved 22 Pharmacokinetics Metabolism chemicals that enter the body are eventually broken down by chemicals in the body and transformed to other chemicals that are easier to eliminate. The body tries to make the chemicals more soluble in water, which makes elimination easier. MANY variables contribute to speed of metabolism

23 2012 Cengage Learning. All Rights Reserved 23 Pharmacokinetics Metabolic tolerance the body produces larger amounts of enzymes needed to remove the drug Functional tolerance a person displays fewer visible symptoms of intoxication without affecting blood concentration

24 2012 Cengage Learning. All Rights Reserved 24 Pharmacokinetics Elimination process of getting the drug out of the body Zero Order eliminated at the same speed until gone; allows you to work backwards and perform retrograde calculations First Order variable elimination rate; elimination occurs faster at different times. (Dropping a baseball vs. dropping a leaf)

26 2012 Cengage Learning. All Rights Reserved 26 Drugs Drugs are a natural or synthetic substance used to produce physiological or psychological effects in humans or animals Nicotine, caffeine, alcohol, marijuana, cocaine are all drugs. Illicit Drugs - drugs which are under international control (and which may or may not have licit medical purposes) but which are produced, trafficked and/or consumed illicitly.

Drugs Forensic Science II: Physiology of Alcohol and

Data from 2012 among 12 th grade students.

30 2012 Cengage Learning. All Rights Reserved 30 Classes of Illicit Drugs Narcotic (Opiate) from Greek word narkotikos, meaning numbness or deadening Pharmacology definition substances that relieve pain and produce sleep; NOT just drugs that are socially unacceptable Examples Morphine, Heroin, Methadone, Codeine, Oxycontin

31 2012 Cengage Learning. All Rights Reserved 31 Classes of Illicit Drugs Hallucinogens cause marked alterations in normal thought processes, perceptions and moods. Most popular is marijuana/cannabis Effect mostly depends upon the potency of the preparation Examples THC, LSD, PCP, Ecstasy

32 2012 Cengage Learning. All Rights Reserved 32 Classes of Illicit Drugs Depressants slow down, or depress the Central Nervous System (CNS) Main example is Alcohol most widely used drug in the US Examples are Barbiturates, Benzodiazepines, Rohypnol

33 2012 Cengage Learning. All Rights Reserved 33 Alcohol (Obj 9.2, 9.3) In everyday speech, alcohol usually refers to the ethanol used in alcoholic beverages. In chemistry, alcohols are a group of substances with a hydroxyl (OH) group.

34 2012 Cengage Learning. All Rights Reserved 34 Alcohol All alcohols are toxic in sufficient quantities As little as 30 ml of methanol can kill Ethanol, ethyl alcohol, is a colorless liquid obtained from fermented grains or fruits Initial reaction to alcohol is euphoria

35 2012 Cengage Learning. All Rights Reserved 35 Alcohol Pharmacokinetics 1.) Ingestion Drinking 2.) Absorption - Alcohol diffuses through the stomach (20%) and small intestines (80%) and gets into the blood stream. 3.) Distribution moved from blood into the water containing parts of the body Ex) Brain (not fat, hair, bone); Post mortem look in water rich organs. 4.) Metabolism by Oxidation in the liver C 2 H 5 OH CH 3 OH CH 3 COOH CO 2 + H 2 0 Ethanol Acetalhyde Acetic Acid

37 2012 Cengage Learning. All Rights Reserved 37 Stages of Intoxication Alcohol affects different people differently Concentration Behavior 0.01 to 0.05 Normal behavior 0.03 to 0.12 Euphoria begins 0.09 to 0.25 Vision blurs, loss of balance, sleepiness 0.18 to 0.30 Speech slurs, dizzy, disoriented, emotional

38 2012 Cengage Learning. All Rights Reserved 38 Stages of Intoxication (cont.) Alcohol affects different people differently Concentration Behavior 0.25 to 0.40 Standing and walking is difficult 0.35 to 0.50 Impaired respiratory and circulatory systems Over 0.45 Potentially fatal

39 2012 Cengage Learning. All Rights Reserved 39 Classes of Illicit Drugs Stimulants Range of drugs that stimulate, or speed up, the CNS. Amphetamines & chemical derivative Methamphetiamine Cocaine Most often sniffed or snorted and absorbed through mucous membranes

40 2012 Cengage Learning. All Rights Reserved 40 Controlled Substances Put into one of five schedules, or categories Schedule I - drugs with no currently accepted medical use and a high potential for abuse. the most dangerous drugs of all the drug schedules with potentially severe psychological or physical dependence. Exapmles - heroin, LSD, marijuana, ecstasy

41 2012 Cengage Learning. All Rights Reserved 41 Controlled Substances Schedule II drugs with a high potential for abuse, less abuse potential than Schedule I drugs, with use potentially leading to severe psychological or physical dependence. These drugs are also considered dangerous. Examples - cocaine, codeine, morphine, oxycodone

42 2012 Cengage Learning. All Rights Reserved 42 Controlled Substances Schedule III drugs with a moderate to low potential for physical and psychological dependence. Examples - Vicodin, Tylenol with codeine, ketamine, anabolic steroids, testosterone Schedule IV - drugs with a low potential for abuse and low risk of dependence. Examples - Xanax, Soma, Darvon, Darvocet, Valium, Ativan, Talwin, Ambien

43 2012 Cengage Learning. All Rights Reserved 43 Toxicological Tests - Categories Screening (Presumptive) Tests reduce the number of possibilities to a small and manageable number. Confirmation Tests a single test that identifies a substance. May be a combination of tests that narrow the scope of truth. Evidence must rule out that other drugs could have caused the same result.

44 2012 Cengage Learning. All Rights Reserved 44 Toxicological Tests - Categories Qualitative determination simply the name or identification of the drug present. Quantitative determination percentage combination of the molecular compounds present - Gives concentration

45 2012 Cengage Learning. All Rights Reserved 45 Toxicological Tests Color Tests 1. Color Tests mix samples with chemicals to observe a resulting color change. Examples A. Marquis turns purple in presence of heroin and morphine B. Dillie-Koppaynai Turns violet-blue in presence of barbituates C. Duquenois series of tests used to determine presence of marijauana.

46 2012 Cengage Learning. All Rights Reserved 46 Toxicological Tests 2. Microcrystalline Tests drop of a chemical reagent is added to a small quantity of the drug on a microscopic slide. Drug + chemical produces a crystal structure Examiner must develop experience in interpreting results.

48 2012 Cengage Learning. All Rights Reserved 48 Toxicological Tests 3. Chromatography separating and identifying the components of a mixture. A. Thin layer Chromatography uses solid stationary phase and moving liquid phase to separate a mixture Results are rapid and sensitive Equipment needed has minimal cost Numerous samples can be analyzed simultaneously

49 2012 Cengage Learning. All Rights Reserved 49 Toxicological Tests 3. Chromatography separating and identifying the components of a mixture. B. Gas Chromatography separates mixtures based on their distribution between a stationary liquid phase and a moving gas phase.

51 2012 Cengage Learning. All Rights Reserved 51 Toxicological Tests 4. Spectrophotometry identifies a substance by exposing it to a specific type of electromagnetic radiation. Chemical substances absorb and reflect electromagnetic radiation ex) how vision works. One type Infrared Different materials always have distinctly different IR spectra. Creates a unique graph

53 2012 Cengage Learning. All Rights Reserved 53 Toxicological Tests 5. Mass Spectometry usually used in addition to Gas Chromatography. As the components of the mixture are separated by GC, they flow into the MS. High energy electrons bombard the components breaking them into fragments and giving them a + charge. (they are now ions) The ions pass through an electric or magnetic field and are separated based on their masses.

55 2012 Cengage Learning. All Rights Reserved 55 Toxicological Tests 6. Immunoassay An analytic method that identifies a target molecule by its specific interaction with another molecule. Based on antigen-antibody response ex) Kastle-Meyer blood test. Usually an antibody is created from some other animal that will react with a drug.

56 2012 Cengage Learning. All Rights Reserved 56 Detecting Drugs in Hair Most drugs remain in blood stream about 24 hours; in urine about 72 hours. Hair is nourished by blood flowing through capillaries in the root. Drugs diffuse through capillary walls and become permanently entrapped. As the hair grows, the drug location in the shaft becomes a historical marker. This is only viable approach to measure long term abuse of a drug.

58 2012 Cengage Learning. All Rights Reserved 58 Poisons (Obj 9.3, 9.4) Eaten (ingested) 90% - at home, involving children household cleaners Inhaled carbon monoxide sarin, a nerve gas Injected heroin Absorbed Poison sumac, mustard gas, ricin, anthrax

SECTION 1 LEARNING OBJECTIVES:

CHAPTER 5 DRUGS SECTION 1 LEARNING OBJECTIVES: 1. Define psychological and physical dependence. 2. Name and classify the commonly abused drugs. 3. Describe the tendency to develop psychological and physical