Transcript chapter_12-ppt

Chapter 12
Drugs and Drug Analysis and
Forensic Toxicology
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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
I. Nature of Drugs and Drug Abuse
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
I. Nature of Drugs and Drug Abuse
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
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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
II. Major Classes of Abused Drugs
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
II. Major Classes of Abused Drugs
• 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
II. Major Classes of Abused Drugs
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
II. Major Classes of Abused Drugs
• 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
II. Major Classes of Abused Drugs
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
II. Major Classes of Abused Drugs
• 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
II. Major Classes of Abused Drugs
• 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
II. Major Classes of Abused Drugs
• 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
II. Major Classes of Abused Drugs
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
II. Major Classes of Abused Drugs
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
II. Major Classes of Abused Drugs
• 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
II. Major Classes of Abused 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
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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
IV. Analysis of Controlled Substances in the
Forensic Laboratory
• 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:
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The Scott test for cocaine
The Duquenois-Levine test for marijuana
The Marquis test for opiates
The Van Erk test for many hallucinogenic drugs
IV. Analysis of Controlled Substances in the
Forensic Laboratory
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
IV. Analysis of Controlled Substances in the
Forensic Laboratory
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
IV. Analysis of Controlled Substances in the
Forensic Laboratory
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)
IV. Analysis of Controlled Substances in the
Forensic Laboratory
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
IV. Analysis of Controlled Substances in the
Forensic Laboratory
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
IV. Analysis of Controlled Substances in the
Forensic Laboratory
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 Toxicology
Antemortem 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
V. Forensic Toxicology
Antemortem and Postmortem
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
V. Forensic Toxicology
Antemortem and Postmortem
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
V. Forensic Toxicology
Antemortem and Postmortem
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)
VI. Alcohol and Drugs and Driving
• 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
VI. Alcohol and Drugs and Driving
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