Transcript Chapter 7

Chapter 7 & 8
Drugs and
Toxicology
“Having sniffed the dead man’s lips, I
detected a slightly sour smell, and I
came to the conclusion that he had
poison forced upon him.”
—Sherlock Holmes, in Sir Arthur Conan Doyle’s
A Study in Scarlet
Define
® Drug
® Controlled Substance
® Illicit Drug
® Prescription Drug
® Over the Counter Drug
® Poison
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Drug
® A natural or synthetic substance
designed to affect humans or
animals psychologically or
physiologically.
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Controlled substance
® Identified under the Federal
Schedules of the Controlled
Substances Act
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Illicit Drug
® An illegal substance used for
pleasure but not necessarily
defined in the Federal Controlled
Substance Act
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Prescription Drug
® A doctor must prescribe a drug for a
specific reason.
® Misuse makes it an illicit drug.
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Over the Counter (OTC)
® No restrictions on purchase
® Misuse of these can and does
occur
® Pseudoephedrine misuse leads to
curtailed access
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Poison
® Almost anything can be a poison if
used inappropriately
® Poison Control Center frequent
calls
®Children’s Tylenol
®Children’s Vitamins with iron
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Chapter 7 & 8
Drugs and
Toxicology
“All substances are poisons.
There is none which is not.
The right dose differentiates a
poison and remedy.”
—Paracelsus (1495-1541). Swiss
physician and chemist
Drugs
Students will learn:
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How to apply deductive
reasoning to a series of
analytical data.
The limitations of presumptive
(screening) tests.
The relationship between the
electromagnetic spectrum and
spectroscopic analysis.
The dangers of using
prescription drugs, controlled
substances, over-the-counter
medications, and illegal drugs.
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Drugs
Students will be able to:
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Chemically identify illicit
drug types.
Classify the types of illicit
drugs and their negative
effects.
Discuss the federal
penalties for possession
and use of controlled
substances.
Explain the need for
confirmatory tests.
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Drugs
 Describe IR, UV-VIS
spectroscopy, and GC-MS
 Present and interpret data
with graphs.
 Use the Physicians’ Desk
Reference (PDR) to
identify pills.
 Use technology and
mathematics to improve
investigations and
communications.
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Drugs and Crime
 A drug is a natural or synthetic substance
designed to affect the subject
psychologically or physiologically.
 “Controlled substances” are drugs that are
restricted by law
 Controlled Substances Act is a law that
was enacted in 1970; it lists illegal drugs,
their category and their penalty for
possession, sale or use.
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Controlled Substances Act
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Schedule I—high potential for abuse; no currently acceptable
medical use in the US; a lack of accepted safety for use under
medical supervision
Schedule II—high potential for abuse; a currently accepted
medical use with severe restrictions; abuse may lead to severe
psychological or physical dependence
Schedule III—lower potential for abuse than the drugs in I or II; a
currently accepted medical use in the US; abuse may lead to
moderate physical dependence or high psychological dependence
Schedule IV—low potential for abuse relative to drugs in III; a
currently accepted medical use in the US; abuse may lead to
limited physical or psychological dependence relative to drugs in III
Schedule V—low potential for abuse relative to drugs in IV;
currently accepted medical use in the US; abuse may lead to
limited physical or psychological dependence relative to drugs in IV
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Examples of Controlled
Substances and Their Schedule
Placement
 Schedule I—heroin (diacetylmorphine), LSD,
marijuana, ecstasy (MDMA)
 Schedule II—cocaine, morphine, amphetamines
(including methamphetamines), PCP, Ritalin
 Schedule III—intermediate acting barbiturates,
anabolic steroids, ketamine
 Schedule IV—other stimulants and depressants
including Valium, Xanan, Librium, phenobarbital,
Darvon
 Schedule V—codeine found in low doses in cough
medicines
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Identification of Drugs
 PDR—Physicians’ Desk Reference
 Field Tests—presumptive tests
 Laboratory Tests—conclusive
tests
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Physicians’ Desk
Reference
PDR—a physicians’ desk reference is
used to identify manufactured pills, tablets
and capsules. It is updated each year.
This can sometimes be a quick and easy
identifier of the legally made drugs that
may be found at a scene. The reference
book gives a picture of the drug, whether it
is a prescription, over the counter, or a
controlled substance; as well as more
detailed information about the drug.
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Product Inserts: use the guide to help you interpret
your example.
Answer these questions on notebook paper.
® 1. Scan your product insert
® A. List the generic name and indications
® B. List contraindications (and describe what that
means)
® C. List warnings and adverse reactions
® D. Describe dosage
® 2. Describe “black box warnings” and give 7
examples…check the handout for these.
® Does your product have a black box warning?
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Drug Identification
Screening or
presumptive tests
 Spot or color tests
 Microcrystalline test—
a reagent is added
that produces a
crystalline precipitate
which is unique for a
certain drug.
 Chromatography
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Confirmatory tests
 Spectrophotometry
 Ultraviolet (UV)
 Visible
 Infrared (IR)
 Mass spectrometry
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Presumptive Color Tests
 Marquis—turns purple in the
presence of most opium
derivatives and orange-brown
with amphetamines
 Dillie-Koppanyi—turns violetblue in the presence of
barbiturates
 Duquenois-Levine—turns a
purple color in the presence of
marijuana
 Van Urk—turns a blue-purple in
the presence of LSD
 Scott test—color test for
cocaine, blue
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Chromatography
 A technique for separating mixtures
into their components
 Includes two phases—a mobile one
that flows past a stationary one.
 The mixture interacts with the
stationary phase and separates.
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Types of Chromatography
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Paper
Thin Layer (TLC)
Gas (GC)
Pyrolysis Gas (PGC)
Liquid (LC)
High Pressure Liquid (HPLC)
Column
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Paper Chromatography
 Stationary phase—
paper
 Mobile phase—a liquid
solvent
Capillary action moves
the mobile phase
through the stationary
phase
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Thin Layer
Chromatography
 Stationary phase—
a thin layer of coating
(usually alumina or
silica) on a sheet of
plastic or glass
 Mobile phase—
a liquid solvent
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Retention Factor (Rf)
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This is a number that represents
how far a compound travels in a
particular solvent
It is determined by measuring
the distance the compound
traveled and dividing it by the
distance the solvent traveled.
If the Rf value for an unknown
compound is close to or the
same as that for the known
compound, the two compounds
are likely similar or identical (a
match).
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Gas Chromatography
Phases
 Stationary—a solid or a
viscous liquid that lines a
tube or column
 Mobile—an inert gas like
nitrogen or helium
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Analysis
 Shows a peak that is
proportional to the
quantity of the
substance present
 Uses retention time
instead of Rf for the
qualitative analysis
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Uses of Gas
Chromatography
 Not considered a confirmation of a
controlled substance
 Used as a separation tool for mass
spectroscopy (MS) and infrared
spectroscopy (IR)
 Used to quantitatively measure the
concentration of a sample. (In a courtroom,
there is no real requirement to know the concentration
of a substance. It does not affect guilt or innocence).
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Mass Spectrometry
Gas chromatography has one major drawback,
it does not give a specific identification. Mass
spectrometry cannot separate mixtures. By
combining the two (GCMS), constituents of
mixtures can be specifically identified.
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Mass Spectrometer
® A machine used to weigh molecules
® A molecular scale
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How is MS used?
® A mass spectrometer helps
scientists
®ID molecules
®Determine how many molecules are
present
®Determine what atoms are in a
molecule
®Determine how the atoms are
arranged
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Pocket change sorted
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Sorting and Counting
MIXTURE OF MOLECULE AND
FRAGMENTS
POCKET CHANGE
® Penny, nickel, dime,
quarter, half dollar,
dollar
® Sort change by value
or size
® Stack them up to sort
them visually
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® Mixture of different
molecule fragments
® Sort fragments by
mass
® Show amount of each
fragment on bar
graph
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Molecular fragments sorted
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HOW?
Using ions
® An ion is an electrically charged
atom or molecule
® Molecules must be charged to be
measured by a mass spec
® A mass spec “weighs” molecules by
electrically attracting and repelling
ions with carefully controlled
charges and force fields.
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Let’s get charged up!
® First, the mass spec ionizes (or
charges) the molecules
® It also breaks apart the big
molecule into pieces…like tearing
apart a jigsaw puzzle
® This is called ionization
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Sort it out!
® It sorts all of these charged
particles out by size
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® Like a pinball machine…a certain
amount of force sends the ball
where you want it
® A different size ball requires
different force
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What do the patterns tell us?
MOLECULAR
FINGERPRINTS
Scientists recognize the pieces
and assemble them to identify
the compound.
Each compound produces a
unique spectrum.
MS Fragments...pieces of a
puzzle
Mass Spectra
Each molecular species has its own
unique mass spectrum.
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Spectroscopy
 Spectroscopy—the interaction of
electromagnetic radiation with matter.
 Spectrophotometer—an instrument used to
measure and record the absorption spectrum of
a chemical substance.
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Spectrophotometry
Components
 A radiation source
 A frequency selector
 A sample holder
 A detector to convert electromagnetic
radiation into an electrical signal
 A recorder to produce a record of the signal
Types
 Ultraviolet
 Visible
 Infrared
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Infrared Spectometry
 Material absorbs energy in the near-IR region of the
electromagnetic spectrum.
 Compares the IR light beam before and after passing
through a transparent sample.
 Result—an absorption or transmittance spectrum
 Gives a unique view of the substance; like a fingerprint
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IR Spectrophotometry and
Mass Spectrometry
 Both work well in identifying pure
substances.
 Mixtures are difficult to identify in
both techniques
 Both are compared to a catalog of
knowns
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Human Components
Used for Drug Analysis
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 Blood
 Liver tissue
 Urine
 Brain tissue
 Hair
 Kidney tissue
 Gastric Contents
 Spleen tissue
 Bile
 Vitreous Humor of
the Eye
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Challenges of Tox
® Drugs must be isolated from body
components, such as urine, blood,
brain vitreous humor, stomach
contents, liver, bile, brain
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Challenges of Tox
® Drugs in the body are changed
chemically as the body metabolizes
the drug. Scientists must
understand the process and look for
the metabolites.
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Challenges of Tox
® If the patient is alive, testing must
be fast to provide medical care.
® The quantity of drug present is
often important. Remember, the
difference between medicine and
poison is often the dose.
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Challenges of Tox
® The time involved is important.
® For example, in DUI cases, the
body is breaking down alcohol at a
predictable rate…people “sober up”
® If the blood sample is taken hours
after an accident, scientists will try
to calculate what the level was at
the time of the accident.
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ID MJ
Easy, right?
® It’s a plant
® It’s easy to ID,
but difficult for a
chemist to
defend in court
because
chemists are
not botanists!
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The DUCK TEST
® Does it look like MJ?
® Does it smell like MJ?
® Pretty good chance it is MJ.
®The Duck Test
won’t fly in court!
We need science to prove it!
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QUICK TESTS
® Look for
cystolithic hairs
® Do a chemical
test for
cystolithic hairs
® Add HCl
® HCl reacts with
CaCO3 in hairs to
form bubbles
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GOOD
® First another presumptive test:
®Quick, easy, and sensitive
®NOT specific
®Add Duquenois-Levine chemical
®MJ will turn purplish in color
®The problem is, so will other things
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BETTER
® Chromatography, a confirmatory
test, but still only screening
®Components of MJ are separated
using chromatography
®We see them using D-L, but this test
offers more info due to separation
® Dip strip of paper in D-L solution
® Allow colored components to
separate
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BEST: prove it with MS
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People of Historical
Significance
Arthur Jeffrey Dempster was born in Canada, but studied
and received his PhD from the University of Chicago. He
began teaching physics there in 1916. In 1918, Dempster
developed the first modern mass spectrometer. His version
was over 100 times more accurate than previous ones
developed, and established the basic theory and design of
mass spectrometers that is still used to this day.
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People of Historical
Significance
Francis William Aston was a British physicist
who won the 1922 Nobel Prize in Chemistry
for his work in the invention of the mass
spectrograph. He used a method of
electromagnetic focusing to separate
substances. This enabled him to identify no
fewer than 212 of the 287 naturally occurring
elemental isotopes.
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