7.1 Drugs and Toxicology

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Unformatted text preview: YSCN0017 From Sherlock YSCN0017 Holmes to Modern Forensic Science Drugs and Forensic Toxicology Dr. W.T. Chan Rm. 305, CYM Chemistry Building wtchan@hku.hk A drug can be defined as a natural or synthetic substance that is used to produce physiological or psychological effects in humans or other higher order animals. Rave Party Drugs: Ecstasy (搖頭丸) Ketamine(氯胺酮/K仔) 2 Top 10 misused drugs in the world: many of them are legal substance. Tobacco Tobacco Alcohol Alcohol Prescription Drugs Prescription Methamphetamine Methamphetamine Marijuana Marijuana MDMA (Ecstasy) MDMA Crack Cocaine Crack Heroin Heroin Steroids Steroids Inhalants Inhalants http://www.streetdrugs.org/topten.htm Accessed on November 12, 2008 Physical harm and dependence of various drugs - The Lancet (March 24, 2007) [http://en.wikipedia.org/wiki/Marijuana#Effects] 3 Common Abused Drugs in Hong Kong (excluding the legal substance): Heroin (海洛英) Heroin Cannabis (大麻) Cannabis Methamphetamine (甲基安非他命/冰) Methamphetamine Methadone (美沙酮) Methadone Cocaine (可卡因) Cocaine Benzodiazepines (苯并二氮嗪類/安定) Benzodiazepines Ecstasy (狂喜/搖頭丸) Ecstasy Ketamine (氯胺酮) Ketamine Source: HK Government Laboratory 4 Drug Dependence Psychological dependence: Psychological The conditioned use of a drug caused by underlying emotional needs. Physical dependence: Physical Physiological need for a drug that has been brought for about by its regular use. Dependence is characterized by withdraw sickness when administration of the drug is withdraw when abruptly stopped. 5 Five major drug types will be discussed: Narcotic: Narcotic: Analgesic (pain-killing) substance that depresses vital body functions such as blood pressure, pulse rate, and breathing rate. The regular administration of narcotics will produce physical dependence. Examples: morphine, heroin, methadone, codeine morphine, Hallucinogen: Hallucinogen: A substance that induces changes in mood, attitude, thought, or perception. Example: marijuana, LSD, phencyclidine (PCP) marijuana, 6 Drug Types (continued) Depressant: Depressant: A substance used to depress the functions of the central nervous system. Depressants claim irritability and anxiety and may induce system. sleep. Examples: barbiturates, alcohol, methaqualone, barbiturates, chlordiazepoxide Stimulant: Stimulant: A substance taken to increase alertness or activity. Examples: amphetamines, cocaine, caffeine, nicotine amphetamines, Anabolic steroids: Anabolic Steroids that promote muscle growth. Sylvester Stallone 7 The most common source of narcotic drugs is opium, extracted from poppies. Opium (鴉片) is a gummy, milky juice exuded through Opium is gummy, a cut made in the unripe pod of the poppy (Papaver somniferum 罌粟). Ripening capsule http://en.wikipedia.org/wiki/Opium_poppy 8 Crude opium contains ~ ¼ by weight of alkaloids ~10% of total alkaloid content is ~10% morphine. Morphine (嗎啡) is readily Morphine extracted from opium. The regular use of a narcotic The drug will invariably lead to physical dependence. Codeine Codeine Morphine 9 Opiates are any of the narcotic alkaloids found in opium, as well as any derivatives of such alkaloids. Morphine Morphine Heroin is made by reacting morphine with acetic Heroin anhydride or acetyl chloride. Addicts frequently dissolve heroin in water by heating it in a Addicts spoon, and then inject in the skin. Heroin produces a “high” that is accompanied by drowsiness Heroin and a sense of well-being that generally last for three to four hours. Codeine (cough suppressant) is also present in opium, Codeine but it is usually prepared synthetically from morphine. 10 Synthesis of Heroin HO H3C O CH3 O O H N CH3 O O O H3C O O H3C O H N CH3 HO Morphine Heroin An acetylation reaction An Reflux purified morphine with either acetic anhydride (preferred) Reflux or acetic acid at 90°C for 5 hours Solution cooled & neutralized with sodium carbonate Solution Precipitated by addition of conc. HCl Precipitated conc 11 Morphine & heroin act on the central nervous system by fitting into & blocking a specific receptor site (mu site) on nerve site) cells. Heroin is more fat soluble than morphine & Heroin crosses the blood-brain barrier more easily Heroin hydrolyzes to morphine in the body Heroin 12 Heroin Packaging Heroin Block Photo Source: HK Government Laboratory 13 Street heroin is usually no more than 35% pure. Common diluents include: Caffeine (咖啡因) (茶) Caffeine Paracetamol (撲熱息痛) (苦) Paracetamol Antipyrine (安替比林) (的, 糖) Antipyrine Carbetapentane (咳必清) Carbetapentane Theophylline (茶鹼) Theophylline Chlorpheniramine (撲爾敏) (咳, 安) Chlorpheniramine Midazolam (咪達唑侖) Midazolam Estazolam (舒樂安定) Estazolam Diazepam (安定) Diazepam Methamphetamine (甲基安非他明) Methamphetamine Glucose (葡萄糖) Glucose 14 The challenge or difficulty of forensic drug identification comes in selecting analytical procedures that will ensure a specific identification of a drug. Two phases of analysis: Two Screening test : nonspecific and preliminary; the Screening goal is to reduce the possibilities to a manageable number. (Color tests and microcrystalline tests). Confirmation test : a single test that specifically Confirmation identifies a substance. (Instrumental analysis). 15 Color Tests (Spot Tests) Before Marquis Solution 2% formaldehyde in sulfuric acid ■ Turns purple in the presence of most opium derivatives ■ Becomes orange-brown with amphetamines & methamphetamines ■ After Cobalt thiocyanate solution 16 Color Tests (Spot Tests) Marquis (purple); Froehde’s reagent (purple, changing Marquis to olive green on standing); Mecke’s (yellow, turning to green on standing). Spot test is not specific for a particular drug. Negative test is a good indicator for the absence of Negative the controlled substances that respond positively to it. 17 Microcrystalline Tests Reagents: Reagents: Platinum chloride Platinum Sodium acetate Sodium Mercuric chloride Mercuric Heroin crystals Heroin (10% Na acetate) Heroin crystals in mercuric iodide www.nwacc.edu/academics/criminaljustice/documents/DrugsandToxicology1.ppt 18 Microcrystalline Tests Identify specific substances by the color and Identify morphology of the crystals formed when the substance is mixed with specific reagents. The size and shape of the crystals, under The microscopic examination, are highly characteristic of the drug. Hundreds of crystal tests are available to Hundreds characterize the most commonly abused drugs. 19 Confirmation Test Once the preliminary analysis is completed and Once the result is positive, a confirmation test is required. Forensic chemists will employ a specific test to Forensic identify a drug substance to the exclusion of all other known chemical substances. Typically infrared spectrophotometry or mass Typically spectrometry is used to specifically identify a drug substance. 20 Separation of the target compound from other compounds in the sample is often required before the specific tests. Gas chromatography (GC) Gas Liquid chromatography (HPLC) Liquid Thin layer chromatography (TLC) Thin 21 Thin layer chromatography (TLC) Drug molecules are easily Drug separated from cutting agents (diluents), e.g., quinine, procaine, etc. etc Mobile phase (solvent): Mobile acetic acid : ethanol : water = acetic 30 : 60 : 10 22 Infrared Spectrometry (FTIR) An infrared spectrum is infrared a “fingerprint” of a compound. 23 Gas Chromatography-Mass Spectrometry (GC-MS) GC separation Mass spectrum (specific identification) 24 Liquid Chromatography-Mass Spectrometry (LC-MS) Mass spectrometry is the golden standard of golden identification. 25 Some opiates are synthetic and have medical applications OxyContin OxyContin Not derived from opium or morphine, but does have the Not derived same physiological effects on the body as do opium narcotics. Prescribed to millions for treatment of chronic pain. Prescribed Active ingredient is oxycodone. Active Methadone (美沙酮) Methadone Pharmacologically related to heroin Pharmacologically Eliminate the addict’s desire for heroin while producing Eliminate minimal side effects. 26 Hallucinogens cause marked changes in normal thought processes, perceptions, and moods Marijuana is the most well-known hallucinogen. Marijuana Marijuana is the most controversial drug in this class Marijuana because its long-term effects on health are still largely unknown. 27 Marijuana refers to a preparation derived from the plant Cannabis or Hemp (大麻). The chemical substance responsible for the The hallucinogenic properties of marijuana is tetrahydrocannabinol (THC). tetrahydrocannabinol The THC content of Cannabis varies in different parts The of the plant: resin (5-10%) resin unfertilized flowering top of female plants (9-18%) unfertilized leaves (3-5%) leaves stem (< 1%), roots, or seeds stem The preparation is typically mixture of crushed leaves, The plant’s flower, stem and seed. THC content 3 – 4.5%. 28 Cannabis Resin 大麻樹脂(大麻精) 大麻樹脂 29 THC binds to cannabinoid receptors in the brain Activation of these receptors located within the central Activation brain reward circuits causes the anxiolytic (anti-anxiety) and pleasurable effects of the drug. Involved in the amplification of signal within the Involved brain’s neurons. Marijuana does not cause physical dependency, but the Marijuana risk of harm is in heavy, long-term use. Heavy users can develop a strong psychological dependence on the drug. 30 Other hallucinogens include LSD, mescaline, PCP, psilocybin, and MDMA (Ecstasy) LSD is synthesized from lysergic acid (a substance LSD produced by Clavica purpurea, a fungus which grows on Clavica rye plants) and can cause hallucinations that can last for 12 hours. Phencyclidine, or PCP, is often synthesized in Phencyclidine, clandestine laboratories and is often smoked, ingested, or sniffed. Phencyclidine is often mixed with other drugs, such as Phencyclidine LSD, or amphetamine, and is sold as a powder (“angle dust”), capsule, or tablet. 31 Depressants are substances used to depress the functions of the central nervous system Depressants calm irritability and anxiety and may Depressants induce sleep. Depressants include alcohol (ethanol), barbiturates, Depressants alcohol tranquilizers, and various substances that can be sniffed, such as airplane glue, model cement, or aerosol gas propellants such as Freon. 32 Stimulants are a group of synthetic drugs that stimulate the central nervous system Substances that provide a feeling of well-being Substances and increased alertness, followed by a decrease in fatigue and a loss of appetite. Stimulants include amphetamines (sometimes Stimulants known as “uppers” or “speed”) and cocaine, which in its free-base form is known as crack. 33 The structures of amphetamine and methamphetamine is similar to that of dopamine. Amphetamine and methamphetamine, often injected Amphetamine intravenously, cause an initial “rush,” followed by an intense feeling of pleasure. This is followed by a period of exhaustion and a prolonged This period of depression. 34 Amphetamines interfere with the reuptake of dopamine and norepinephrine Displaces these neurotransmitters from their Displaces presynaptic nerve terminals Causes an increased amount of these Causes compounds to be released Results in massive stimulation of the nervous Results system 35 Methamphetamine crystal (Ice) 甲基安非他明 (冰) 甲基安非他明 Yaba tablets 36 Apparatus for Smoking “Ice” 37 Cocaine (可卡因) is a naturally occurring alkaloid found in the coca plant Erythroxylon Erythroxylon coca, that grows in high elevations in the Andes. Cocaine is a powerful stimulant to the central nervous system. Cocaine powerful Cocaine causes increased alertness and vigor, accompanied by Cocaine the suppression of hunger, fatigue, and boredom. Cocaine (Cocaine HCl 鹽酸可卡因) is commonly sniffed or Cocaine “snorted” and is absorbed into the body through the mucous membranes of the nose. 38 Crack Cocaine (霹靂) Crack is prepared by mixing cocaine with baking soda and water, Crack heating in a pot (in an microwave oven), cooling to precipitate free-base cocaine, and drying the precipitate to form a cake which is broken into tiny chunks and sold as crack rocks. Crack is often smoked in glass pipes, and, like cocaine, stimulates Crack the brain’s pleasure center. The desire to return to a euphoric feeling is so intense that crack The users quickly develop a habit for the drug that is almost impossible to overcome. No evidence of physical dependency No accompanying cocaine’s repeated use. 39 Club Drugs refer to synthetic drugs that are used at nightclubs, bars, and raves (all-night dance parties). Club drugs include, but are not limited to, Club MDMA (Ecstasy), GHB (gamma hydroxybutyrate), Rohypnol (“Roofies”), ketamine, and methamphetamine. GHB and Rohypnol are central nervous system GHB depressants that are often connected with drugfacilitated sexual assault, rape, and robbery. 40 Club Drugs Methylenedioxymethamphetamine, also known as MDMA or Methylenedioxymethamphetamine, MDMA Ecstasy, is a synthetic mind-altering drug that exhibits many hallucinogenic and amphetamine-like effects. Ecstasy enhances self-awareness and decreases inhibitions; Ecstasy however, seizures, muscle breakdown, stroke, kidney failure, and cardiovascular system failure often accompany chronic abuse. Ketamine is primarily used as a veterinary animal anesthetic that Ketamine in humans causes euphoria and hallucinations. Ketamine can also cause impaired motor functions, high blood Ketamine pressure, amnesia, and mild respiratory depression. 41 Forensic toxicology involves detecting and identifying drugs and poisons in body fluids, tissues, and organs Toxicologists not only work in crime laboratories and Toxicologists medical examiners’ offices, but may also reach into hospital laboratories and health facilities to identify a drug overdose or monitor the intake of drugs. A major branch of forensic toxicology deals with the major measurement of alcohol in the body for matters that alcohol pertain to violations of criminal law. 42 Alcohol (ethyl alcohol) enters the body’s bloodstream and quickly travels to the brain, where it acts to suppress the brain’s control of thought processes and muscle coordination. The analysis of alcohol exemplifies the primary The objective of forensic toxicology — the detection and isolation of drugs in the body for the purpose of determining their influence on human behavior. 43 Impairment from alcohol poisoning was originally defined by blood alcohol levels Most people show measurable mental impairment at Most mental 0.05% blood alcohol concentration (BAC). Motor functions deteriorate progressively with Motor increased blood alcohol concentrations. For the average person, unconsciousness results by For 0.4% BAC. Above 0.5% (BAC), basic body functions such as the Above breathing or the beating action of the heart can be depressed to the point that death can occur. 44 Alcohol Levels Alcohol appears in the blood within minutes after it has been Alcohol taken by mouth and slowly increases in concentration while it is being absorbed from the stomach and the small intestine into the bloodstream. When all the alcohol has been absorbed, a maximum alcohol When level is reached in the blood. Then the alcohol concentration slowly decreases by oxidation Then and excretion. Oxidation takes place almost entirely in the liver, while alcohol is excreted unchanged in the breath, urine, and perspiration. Factors such as time taken to consume the drink, the alcohol Factors content, the amount consumed, and food present in the stomach determine the rate at which alcohol is absorbed. 45 The extent to which an individual may be under the influence of alcohol is usually determined by either measuring the quantity of alcohol present in the blood system or by measuring the alcohol content in the breath The amount of alcohol exhaled in the breath is in direct The proportion to the blood concentration. The ratio of alcohol in the blood to alcohol in alveoli The ratio air is approximately 2100 to 1. 2100 46 Alcohol contents in breath are proportional to BAC because humans have a closed circulatory system. The circulatory system consisting of the heart, arteries, veins, and capillaries The Alcohol is absorbed from the stomach and small intestines into the blood Alcohol stream. Blood, carrying alcohol, moves to the heart and is pumped to the lungs. Blood, In the lungs, carbon dioxide and alcohol leave the blood and oxygen enters In the blood in the air sacs (alveoli). Then carbon dioxide and alcohol are exhaled during breathing. Then 47 A variety of technologies have been used to test a breath sample for alcohol Wet Chemistry Wet 8H+ + Cr2O72- + 3C2H5OH -----------> 2Cr3+ + 3C2H4O + 7H2O Spectrophotometry Spectrophotometry Gas Chromatography (Intoximeter) Gas Infrared Spectroscopy Infrared Semi-Conductor Sensors (Tin Oxide Sensors) Semi Electrochemical Analysis (Fuel Cell) Electrochemical 48 Breath Testers Intoxilyzer: breath testers that operate on the principle of Intoxilyzer infrared light absorption. infrared The breath testers capture a set volume of breath. The The captured breath is exposed to infrared light. The The blood alcohol concentration in breath can be determined The from the absorbed light intensity. 49 Arsenic killed Phar Lap Legendary Australian racehorse collapsed at his Legendary stables in San Francisco in 1932. His trainer found 1932 him in severe pain and with a high temperature. A few hours later, he died from internal bleeding. In 2006, scientists have used synchrotron (particle In 2006 accelerator) radiation to test a strand of the horse's hair, taken from his preserved hide. The hair was bombarded with a beam of intense X-ray to examine chemical residue. Phar Lap was ingested a large amount of arsenic Phar about 35 hours before he died. 50 ...
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