chapter 12. drugs and drug analysis and forensic toxicology nature of drugs and drug abuse major...

Chapter 12

Drugs and Drug Analysis and Forensic Toxicology

• Nature of Drugs and Drug Abuse

• Major Classes of Abused Drugs

• Controlled Substance Laws

• Analysis of Controlled Substances in the Forensic Laboratory

• Forensic Toxicology – Antemortem and Postmortem

• Alcohol and Drugs and Driving

I. Nature of Drugs and Drug Abuse

1. Working Definition of a Drug:

• A drug is any substance that produces physiological or psychological change within a short period of time after ingestion and from a easily ingested dose

2. Nature of Drug Dependence:

• Drug dependence is when an individual becomes strongly attached to a drug

• Dependency is subdivided into two categories: physiological and psychological


2a. Physiological Dependence:

• With physiological dependence, there is a need by the body to have the drug present

• A person experiences sickness if they stop taking the drug

2b. Psychological Dependence:

• A person develops an uncontrollable “craving” (mental or emotional need) for a drug

• The craving is a desperate need to continue


Drugs and Society - Controlled Substances:

• Access to drugs is regulated by the Federal Controlled Substances Act and by State Acts in all 50 States

• The Drug Enforcement Administration of the US DOJ administers the Controlled Substances Act

• Society through its laws tries to control the abuse of drugs

• Forensic science laboratories are involved with cases where drugs have been abused

II. Major Classes of Abused Drugs

Drugs of abuse can be divided into six basic categories– Narcotic Drugs – taken to dull pain (analgesic)

– Stimulants – taken to increase mental and physical energy

– Hallucinogens – taken to change one’s mental state

– Depressants, Hypnotics, & Tranquilizers – taken to dull one’s senses, to reduce anxiety, or induce sleep

– Club Drugs – taken to enhance one’s enjoyment of a party or other social activities

– Performance Enhancing Drugs – taken to build muscles, endurance, or enhance athletic performance


1. Opiates or Narcotic Drugs:

• Narcotic drugs are painkillers (analgesics)

• Morphine is a narcotic and the primary active drug in opium, the dried sap of the opium poppy plant

• Opium can be smoked directly or chemically processed to isolate pure morphine

• All natural and drug compounds derived from opium are known as opiates


• Opiates are psychologically addictive drugs, with withdrawal causing severe physiological symptoms

• Codeine is the second most plentiful chemical component of opium, used as a strong painkiller and cough suppressant

• Heroin, a derivative of morphine is at least as addictive as morphine

• Synthetic painkillers include Darvon & Demerol


2. Stimulants:

• Stimulants are taken to make one feel more energetic, strong, or awake

• Amphetamine, methamphetamine, and cocaine are examples of abused stimulants

• Methamphetamine is the drug most commonly produced in clandestine labs


• Cocaine is a very powerful stimulant and is enormously psychologically addicting

• Cocaine hydrochloride is usually inhaled through the nose

• Cocaine in its free base form, “crack”, is vaporized by heat in a pipe and inhaled into the lungs


3. Hallucinogens:

• Are taken to cause a significantly altered mental state, often including hallucinations

• Marijuana is one of the oldest

• The physiologically active ingredients are known as cannabinoids, found in the resinous leaf coating of Cannabis sativa

• The most active cannabinoid is THC


• Hashish is another form of marijuana, traditionally a more potent form, made from the flowering tops of the plant

• Hash oil is made by taking the plant material and cooking it with a solvent to remove the plant resin

• The solvent is then evaporated leaving a thick oily material which is almost pure resin

• The concentrated hash oil can be mixed with tobacco or other vegetable material


• LSD is an extremely potent hallucinogen

• The normal dose is only 30-50 micrograms

• Causes visual hallucinations, brilliant colors, and the perception that one is wise

• PCP or “angel dust” is another popular hallucinogen

• PCP is fairly simple to make, with the vast majority made in clandestine labs


• Naturally occurring hallucinogens include peyote, the bud of a particular cactus

• The main active ingredient in peyote is “mescaline”

• Magic mushrooms are mushrooms of the genus Psilocybe, which contains two active components, psilocin and psilocybin


4. Depressants, Hypnotics, & Tranquilizers:• Alcohol, a depressant, is the most abused drug in the Western world

• Barbiturates are highly physiologically active depressants, resulting in a physical & mental state similar to alcohol-induced intoxication

• Valium, a benzodiazepine, is a tranquilizer drug designed to relieve anxiety

• Rohypnol or “roofies” is a benzodiazepine and a major drug of abuse at raves and the club scene


5. Club Drugs:

• MDMA, the “love drug” or “Ecstasy” is either prepared by clandestine labs, or obtained legally from other countries

• GHB, gamma hydroxybutyrate, is synthesized in clandestine labs or diverted from legal production

• GHB and related compound GBL, are used for their hypnotic or depressant effects


• Ketamine, is an anesthetic and animal tranquilizer that can cause anterograde amnesia, the loss of memory while under its influence

• Rohypnol, GHB, and ketamine have been implicated in cases of drug-facilitated sexual assaults, thus also known as “date-rape” drugs


6. Athletic Performance Enhancers:• Athletes trying to gain a competitive edge may abuse stimulants

and painkillers

• The first drug controlled because of their abuse by athletes were anabolic steroids

• Anabolic steroids promote cell growth resulting in growth of muscle tissue and sometimes bone size and strength

III. Controlled Substance Laws

• A controlled substance is a drug named in either federal or state statutes that is illegal to possess except when prescribed by a physician

• The federal government has created 5 controlled substance schedules, based on their potential for abuse and medical value– No medical use (heroin, LSD, marijuana)

– Some medical use (Cocaine, morphine)

– Anabolic steroids are placed in this schedule

– Has most of the tranquilizers & many diet drugs

– Exempt preparations: e.g. cough syrup with codeine

IV. Analysis of Controlled Substances in the Forensic Laboratory

Screening tests:• Drug test kits are packets used by police officers in the field to

screen for drugs

• The tests are simple to perform and based on color changes

• A small amount of drug is added to the pouch, a sealed ampoule(s) is then broken to release a chemical reagent, mixed, and the color change noted


• The screening tests are important for establishing probable cause when making a drug possession arrest

• However, the screening tests are not a substitute for laboratory analysis

• Commonly used screening tests are:– The Scott test for cocaine

– The Duquenois-Levine test for marijuana

– The Marquis test for opiates

– The Van Erk test for many hallucinogenic drugs


Isolation and Separation:• Steps may include an initial microscopic examination to

determine the number of materials that may be present

• A purification step to separate the controlled substance from other materials, such as diluents (materials added to a drug to give bulk/volume)

• A liquid-liquid extraction or various types of chromatography are commonly used separation techniques


Microcrystal Tests:• A confirmatory test that can be used directly with street drug

samples is the microcrystal test

• The test is performed by taking a small amount of drug, placing it on a microscope slide and adding a drop of reagent

• The shape (morphology) of the crystal formed is characteristic for that particular drug and reagent

• The tests are rapid and specific


Chromatography (Separations):• Chromatography is a process that separates a mixture of different

compounds

• Separation is achieved by the differences in the partitioning of compounds between two phases: a moving phase and a stationary phase

• Chromatography provides tentative identification, based on retention time (GC) or distance traveled (TLC)


Spectroscopy/Spectrometry:• Spectroscopy refers to the interaction of electro-magnetic

radiation with a chemical to give a pattern (spectrum) characteristic of that material’s interaction with the radiation

• Mass spectroscopy (MS) or infrared spectroscopy (IR) are excellent ways to identify drugs


Spectroscopy/Spectrometry:• Spectroscopic methods work best with samples that are relatively

pure, thus often combined with gas chromatography (GC-MS; GC-IR)

• The combination of liquid chromatography and mass spectrometry (LC-MS) provides a retention time along with a spectrum for unambiguous identification


Qualitative versus Quantitative Analysis:

• Qualitative analysis means determining whether something is there or not there

• With most drug laws, a qualitative identification is all that is necessary (“aggregate weight based law”)

• Quantitative analysis indicates how much of that sample is made up of a controlled substance (percentage of the total for each controlled substance present in a sample)

V. Forensic ToxicologyAntemortem and Postmortem

• Forensic toxicologists receive blood, urine or body tissue for analysis

• Toxicologists must be able to analyze small amounts of drug and isolate them from a complex biological matrix

• In contrast to the work typically done by drug chemists, a toxicologists needs quantitative information in order to determine if the amount is consistent with a therapeutic dose or an abuse dosage

• Toxicologists must aid others in understanding the effects of the substance on the human body

• Samples from living individuals (antemortem) and deceased (postmortem) are received for analysis


Antemortem Sample Analysis:

• A number of laws and rules have to do with the workplace use of drugs

• Urine specimens from random drug testing are sent to the forensic lab for toxicology analysis

• Forensic Toxicology labs also test for the presence of certain drugs in victims of sexual assault, who may have been drugged as an adjunct to the assault


Postmortem Sample Analysis:• Medical examiners are responsible for determining the cause and

manner of sudden, suspicious, or unattended death

• Postmortem toxicology is done to assist the medical examiner with this determination

• Toxicologist’s work is complicated by the limited amount of drug in the body and by the natural process of metabolism

• The toxicologist looks for both the drug itself and the metabolites


Classes of Poisons:• The presence of poisons in the body may be critical to

law enforcement or public health investigations

• Three basic groups of poisons: – Inorganic (arsenic, cadmium, cyanide)

– Organic (strychnine, curare, digitalis)

– Biological (venoms, botulism, tetradotoxin)

VI. Alcohol and Drugs and Driving

Driving While Impaired by Alcohol:• Alcohol is one of the easiest substances for toxicologists to find in

the body fluids, due to the high dose and its chemical volatility

• There is a good correlation between the amount of alcohol in the blood and the level of impairment

• Laws define the level of alcohol above which a person would be considered impaired for the purpose of operating a motor vehicle

• Most states have defined the limit to be 0.08% w/v (80 mg ethanol/100 ml of blood)


• In the field, alcohol levels are determined by capturing a known volume of a person’s breath using the Breathalyzer or Intoxilyzer instruments

• Alcohol levels in the breath can be correlated to levels in the blood

• In the lab, blood samples are subjected to alcohol determinations using the GC


Other Drugs and Driving:• All states have laws against driving while impaired by drugs

besides alcohol

• Charges are supported primarily by behavioral observations, but laboratory analysis showing a significant level of a drug is almost always required for successful prosecution

• Prohibited levels for each drug have not been developed and placed into state laws as with alcohol

chapter 12. drugs and drug analysis and forensic toxicology nature of drugs and drug abuse major...

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