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DRUGS

Chapter 5

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Introduction• A drug can be defined as a natural or synthetic

substance that is used to produce physiological or psychological effects in humans.

• This includes the two most widely used drugs in America; Alcohol and Marijuana.

• Drug crimes cut across all aspects of society• Because of their epidemic proportions, 75% of

evidence evaluated by crime labs is drug related.

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Narcotics

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Narcotics

• The term, “narcotics" is often used to refer to any illegal drug.

• That could include anything from prescription pills to cocaine.

• However, "narcotics" does actually refer to a specific type of drug as well.

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Narcotics• Narcotics actually refers

to drugs that are derived from opium which originates from the opium poppy plant.

• Common types of narcotics include barbituates, heroin, opium in the form of morphine and codeine, oxycodone and Vicodin.

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Opiates• Morphine is readily extracted from opium and

is used to synthesize heroin.• Addicts frequently dissolve heroin in water by

heating it in a spoon, and then inject in the skin.

• Heroin produces a “high” that is accompanied by drowsiness and a sense of well-being that generally last for three to four hours.

• Codeine is also present in opium, but it is usually prepared synthetically from morphine.

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Other Opiates• OxyContin, with the active ingredient

oxycodone, is not derived from opium or morphine, but does have the same physiological effects on the body as do opium narcotics.

• OxyContin is prescribed to a million patients for treatment of chronic pain.

• Methadone is another well-known synthetic opiate.

• Methadone, which is pharmacologically related to heroin, appears to eliminate the addict’s desire for heroin while producing minimal side effects.

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MarIjuana

•HallucinogensHallucinogens

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Hallucinogens• Another class of drugs is hallucinogens;

marijuana is the most well-known member of this class.

• Hallucinogens cause marked changes in normal thought processes, perceptions, and moods.

• Marijuana is the most controversial drug in this class because its long-term effects on health are still largely unknown.

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Marijuana

• aunt mary, boom, chronic, dope, ganja, gangster, grass, hash, herb, kif, mary jane, pot, reefer, sinsemilla, skunk, and weed

• Marijuana refers to a preparation derived from the plant Cannabis.

• The chemical substance largely responsible for the hallucinogenic properties of marijuana is known as tetrahydrocannabinol, or THC.

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Marijuana• The THC content of Cannabis varies in

different parts of the plant, generally decreasing in the following sequence: resin, flowers, leaves, with little THC in the stem, roots or seeds.

• The THC-rich resin is known as hashish.

• Marijuana does not cause physical dependency, but the risk of harm is in heavy, long-term use.

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Other Hallucinogens• Other hallucinogens include LSD, mescaline,

PCP, psilocybin, and MDMA (Ecstasy).• LSD is synthesized from lysergic acid, and can

cause hallucinations that can last for 12 hours.• Phencyclidine, or PCP, is often synthesized in

clandestine laboratories and is often smoked, ingested, sniffed.

• Phencyclidine is often mixed with other drugs, such as LSD, or amphetamine, and is sold as a powder (“angel dust”), capsule, or tablet.

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Depressants

• Depressants are a type of drug that can take several forms; however, the most common type is administered by prescription. Many people are prescribed depressant drugs which have beneficial effects but wind up dependant on them or addicted.

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Depressants• Depressants are another class of drugs.

• Depressants are substances used to depress the functions of the central nervous system.

• Depressants calm irritability and anxiety and may induce sleep.

• These include alcohol (ethanol), barbiturates, tranquilizers, and various substances that can be sniffed, such as airplane glue, model cement, or aerosol gas propellants such as Freon.

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Depressants• 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.

• Barbiturates, or “downers,” are normally taken orally and create a feeling of well-being, relax the body, and produce sleep.

• Tranquilizers, unlike barbiturates, produce a relaxing tranquility without impairment of high-thinking faculties or inducing sleep.

• Sniffing has immediate effects such as exhilaration, but impairs judgment and may cause liver, heart, and brain damage, or even death.

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Stimulants

• Stimulants are a class of drugs that elevate mood, increase feelings of well-being, and increase energy and alertness.

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Stimulants• The drug classification of stimulants

includes amphetamines, sometimes known as “uppers” or “speed,” and cocaine, which in its free-base form is known as crack.

• Stimulants are substances taken to increase alertness or activity, followed by a decrease in fatigue and a loss of appetite.

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Stimulants• Amphetamine and methamphetamine, often

injected intravenously, cause an initial “rush,” followed by an intense feeling of pleasure.

• This is followed by a period of exhaustion and a prolonged period of depression.

• Cocaine, extracted from the leaves of Erythroxylin coca, causes increased alertness and vigor, accompanied by the suppression of hunger, fatigue, and boredom.

• Crack is cocaine mixed with baking soda and water, then heated.

• Crack is often smoked in glass pipes, and like cocaine stimulates the brain’s pleasure center.

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Club Drugs• The term club

drugs refers to synthetic drugs that are used at nightclubs, bars, and raves (all-night dance parties).

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Club Drugs• Substances that are often used as club

drugs include, but are not limited to, MDMA (Ecstasy), GHB (gamma hydroxybutyrate), Rohypnol (“Roofies”), ketamine, and methamphetamine.

• GHB and Rohypnol are central nervous system depressants that are often connected with drug-facilitated sexual assault, rape, and robbery.

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Ectasy

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Ecstasy• Methylenedioxymethamphetamine, also

known as MDMA or Ecstasy, is a synthetic mind-altering drug that exhibits many hallucinogenic and amphetamine-like effects.

• Ecstasy enhances self-awareness and decreases inhibitions, however, seizures, muscle breakdown, stroke, kidney failure, and cardiovascular system failure often accompany chronic abuse.

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Ketamine

• Ketamine is primarily used as a veterinary animal anesthetic that in humans causes euphoria and hallucinations.

• Ketamine can also cause impaired motor functions, high blood pressure, amnesia, and mild respiratory depression.

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Steroids

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Anabolic Steroids• Yet another category of drugs is the anabolic

steroids. • These are synthetic compounds that are

chemically related to the male sex hormone testosterone.

• Anabolic steroids are often abused by individuals who are interested in accelerating muscle growth.

• Side effects include unpredictable effects on mood and personality, depression, diminished sex drive, halting bone growth, and liver cancer.

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Drug Control Laws

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Drug-Control Laws• The U.S. federal law known as the

Controlled Substances Act created a legal drug-classification system to prevent and control drug abuse.

• This federal law establishes five schedules of classification for controlled dangerous substances on the basis of a drug’s – potential for abuse– potential for physical and psychological

dependence– medical value

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Schedules of Classification• Schedule I — drugs with a high abuse

risk. These drugs have NO safe, accepted medical use in the United States. Some examples are: – heroin – marijuana – LSD – PCP– crack cocaine

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Schedules of Classification• Schedule II — drugs with a high abuse

risk, but also have safe and accepted medical uses in the United States. These drugs can cause severe psychological or physical dependence. Schedule II drugs include:– morphine– cocaine – oxycodone (Percodan®)– methylphenidate (Ritalin®)– dextroamphetamine (Dexedrine®)

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Schedules of Classification• Schedule III, IV, or V — drugs with an abuse

risk less than Schedule II. These drugs also have safe and accepted medical uses in the United States. Schedule III, IV, or V drugs include those containing smaller amounts of certain narcotics including:– acetaminophen with codeine (Tylenol® No.3)

– hydrocodone with acetaminophen (Vicodin®)

– diazepam (Valium®)

– alprazolam (Xanax®)

– propoxyphene (Darvon®)

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Drug Identification

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Drug Identification• The challenge or difficulty of forensic

drug identification comes in selecting analytical procedures that will ensure a specific identification of a drug.

• This plan, or scheme of analysis, is divided into two phases.– Preliminary screening test– Confirmation test that is a single test that

specifically identifies a substance.

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Preliminary Analysis• Faced with the prospect that the unknown

substance may be any one of a thousand or more commonly encountered drugs, the analyst must employ screening tests to reduce these possibilities to a small and manageable number.

• This objective is often accomplished by subjecting the material to a series of color tests that will produce characteristic colors for the more commonly encountered illicit drugs.

• Microcrystalline tests can also be used to identify specific drug substances by studying the size and shape of crystals formed when the drug is mixed with specific reagents.

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Conformational Determination• Once this preliminary analysis is completed, a

conformational determination is pursued.

• Forensic chemists will employ a specific test to identify a drug substance to the exclusion of all other known chemical substances.

• Typically infrared spectrophotometry or gas chromatography-mass spectrometry is used to specifically identify a drug substance.

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Qualitative vs. Quantitative• Another consideration in selecting an

analytical technique is the need for either a qualitative or a quantitative determination.

• The former relates just to the identity of the material, whereas the latter requires the determination of the percent composition of the components of a mixture.

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Analytical MethodsGC

TLC

MS

SP

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Chromatography• Chromatography is a means of separating and

tentatively identifying the components of a mixture.

• The theory of chromatography is based on the observation that chemical substances have a tendency to partially escape into the surrounding environment when dissolved in a liquid or when absorbed on a solid surface.

• Those materials that have a preference for the moving phase will slowly pull ahead and separate from those substances that prefer to remain in the stationary phase.

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Thin Layer Chromatography• TLC uses a solid stationary phase usually coated

onto a glass plate and a mobile liquid phase to separate the components of the mixture.

• The liquid will slowly rise up the plate by capillary action causing the sample to become distributed between the stationary phase and the moving liquid phase.

• Because most compounds are colorless, the materials must be visualized by placing the plates under ultraviolet light or spraying the plate with a chemical reagent.

• The distance a spot travels up a thin-layer plate can be assigned a numerical value.

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Gas Chromatography• In GC, the moving phase is actually a gas called

the carrier gas, which flows through a column. • The stationary phase is a thin film of liquid

contained within the column. • After a mixture has traversed the length of the

column, it will emerge separated into its components.

• The written record of this separation is called a chromatogram.

• The time required for a component to emerge from a GC column is known as retention time.

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TLC data output GC data output

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Spectrophotometry• Just as a substance can absorb visible light to

produce color, many of the invisible radiations of the electromagnetic spectrum are likewise absorbed.

• Spectrophotometry, an important analytical tool, measures the quantity of radiation that a particular material absorbs as a function of wavelength and frequency.

• The quantity of light absorbed at any frequency is directly proportional to the concentration of the absorbing species. This is known as Beer’s Law.

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The Spectrophotometer• The spectrophotometer is the instrument used

to measure and record the absorption spectrum of a chemical substance.

• The components of a spectrophotometer are:– A radiation source– A monochromator or frequency selector– A sample holder– A detector to convert electromagnetic radiation into

an electrical signal– A recorder to produce a record of the signal

• Absorption spectra can be done in the visible, ultraviolet (UV) or infrared (IR) regions.

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Spectrophotometry

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UV and IR Spectrophotometry• Currently, most forensic laboratories use UV and

IR spectrophotometers to characterize chemical compounds.

• The simplicity of the UV spectrum facilitates its use as a tool for determining a material’s probable identity, although it may not provide a definitive result.

• The IR spectrum provides a far more complex pattern.

• Different materials always have distinctively different infrared spectra; each IR spectrum is therefore equivalent to a “fingerprint” of that substance.

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Mass Spectrometry• In the mass spectrometer, a beam of high-energy

electrons collide with a material, producing positively charged ions.

• These positive ions almost instantaneously decompose into numerous fragments, which are separated according to their masses.

• The unique feature of mass spectrometry is that under carefully controlled conditions, no two substances produce the same fragmentation pattern.

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GC and Mass Spectrometer • A direct connection between the GC

column and the mass spectrometer allows each component to flow into the mass spectrometer as it emerges from the GC.

• The separation of a mixture’s components is first accomplished by the GC.

• Then, fragmentation of each component by high-energy electrons in the mass spectrometer, will produce a distinct pattern, somewhat like a “fingerprint”, of the substance being examined.