Chapter 7 Drugs

Chapter 7

Drugs“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

Kendall/Hunt Publishing Company 2Chapter 8

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.


Controlled Substances Act

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


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


Human ComponentsUsed for Drug Analysis

Blood

Urine

Hair

Gastric Contents

Bile

Liver tissue

Brain tissue

Kidney tissue

Spleen tissue

Vitreous Humor of the Eye


Identification of Drugs

PDR—Physicians’ Desk Reference

Field Tests—presumptive tests

Laboratory Tests—conclusive tests


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.


Drug IdentificationScreening 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

Confirmatory tests Spectrophotometry

Ultraviolet (UV) Visible Infrared (IR)

Mass spectrometry


Presumptive Color Tests

Marquis—turns purple in the presence of most opium derivatives and orange-brown with amphetamines

Dillie-Koppanyi—turns violet-blue 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


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.


Paper Chromatography

Stationary phase—paper Mobile phase—a liquid solvent

Capillary action moves the mobile phase through the stationary phase


Spectroscopy

Spectroscopy—the interaction of electromagnetic radiation with matter.

Spectrophotometer—an instrument used to measure and record the absorption spectrum of a chemical substance.


SpectrophotometryComponents

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


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


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.


Mass Spectrometry

In a mass spectrometer, an electron beam is directed at sample molecules in a vacuum chamber. The electrons break apart the sample molecules into many positive charged fragments. These are sorted and collected according to their mass-to-charge ratio by an oscillating electric or a magnetic field.


Mass Spectra

Each molecular species has its own unique mass spectrum.


IR Spectrophotometry andMass Spectrometry

Both work well in identifying pure substances.

Mixtures are difficult to identify in both techniques

Both are compared to a catalog of knowns

Chapter 8

Toxicology:Poisons and Alcohol

“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

—Jhn Trestrail from “Criminal Poisoning”


Toxicology

Definition—the study of the adverse effects of chemicals or physical agents on living organisms.

Types:Environmental—air, water, soilConsumer—foods, cosmetics, drugsMedical, clinical, forensic


Forensic Toxicology

Postmortem—medical examiner or coroner

Criminal—motor vehicle accidents (MVA) Workplace—drug testing Sports—human and animal Environment—industrial, catastrophic,

terrorism


Toxicology

Toxic substances may: Be a cause of death Contribute to death Cause impairment Explain behavior


The Severity of the Problem

“If all those buried in our cemeteries who were poisoned could raise their hands, we would probably be shocked by the numbers.”

—John Harris Trestrail, “Criminal Poisoning”


Aspects of Toxicity

Dosage The chemical or physical form of the substance The mode of entry into the body Body weight and physiological conditions of the

victim, including age and sex The time period of exposure The presence of other chemicals in the body or

in the dose


Lethal Dose

LD50—refers to the dose of a substance that kills half the test population, usually within four hours

Expressed in milligrams of substance per kilogram of body weight


Toxicity Classes

LD50 (rat,oral) Correlation to Ingestion by 150 lb Adult Human

Toxicity

<1mg/kg a taste to a drop extremely

1-50 mg/kg to a teaspoon highly

50-500 mg/kg to an ounce moderately

500-5000 mg/kg to a pint slightly

5-15 g/kg to a quart practically non-toxic

Over 15g/kg more than 1 quart relatively harmless


Federal Regulatory Agencies

Food and Drug Administration (FDA)

Environmental Protection Agency (EPA)

Consumer Product Safety CommissionDepartment of Transportation (DOT)

Occupational Safety and Health Administration (OSHA)


Symptoms of Various Typesof Poisoning

Type of Poison Symptom/Evidence Caustic Poison (lye) Characteristic burns around the lips and

mouth of the victim Carbon Monoxide Red or pink patches on the chest and

thighs, unusually bright red lividity Sulfuric acid Black vomit Hydrochloric acid Greenish-brown vomit Nitric acid Yellow vomit Phosphorous Coffee brown vomit. Onion or garlic odor Cyanide Burnt almond odor Arsenic, Mercury Pronounced diarrhea Methyl (wood) or Nausea and vomiting, unconsciousness,

Isopropyl (rubbing) alcohol possibly blindness


Critical Informationon Poisons

Form Common color Characteristic odor Solubility Taste Common sources Lethal dose Mechanism Possible methods of administration Time interval of onset of

symptoms.

Symptoms resulting from an acute exposure

Symptoms resulting from chronic exposure

Disease states mimicked by poisoning

Notes relating to the victim Specimens from victim Analytical detection methods Known toxic levels Notes pertinent to analysis of

poison List of cases in which poison was

used


To Prove a Case

Prove a crime was committed Motive Intent Access to poison Access to victim Death was caused by poison Death was homicidal


Forensic Autopsy

Look for: Irritated tissues

Characteristic odors

Mees lines—single transverse white bands on nails.

Order toxicological screens Postmortem concentrations should be done at the

scene for comparison

No realistic calculation of dose can be made from a single measurement


Human Specimens for Analysis

Blood

Urine

Vitreous Humor of Eyes

Bile

Gastric contents

Liver tissue

Brain tissue

Kidney tissue

Hair/nails


Alcohol—Ethyl Alcohol (C2H5OH)

Most abused drug in America About 40% of all traffic deaths are alcohol-related Toxic—affecting the central nervous system, especially

the brain Colorless liquid, generally diluted in water Acts as a depressant Alcohol appears in blood within minutes of consumption;

30-90 minutes for full absorption Detoxification—about 90% in the liver About 5% is excreted unchanged in breath, perspiration

and urine


Rate of Absorption

Depends on:amount of alcohol consumed

the alcohol content of the beverage

time taken to consume it

quantity and type of food present in the stomach

physiology of the consumer


BACBlood Alcohol Content

Expressed as percent weight per volume of blood

Legal limits in all states is 0.08% Parameters influencing BAC:

Body weight Alcoholic content Number of beverages consumed Time between consumption


BAC

Burn off rate of 0.015% per hour but can vary:

MaleBAC male = 0.071 x (oz) x (% alcohol)

body weight Female

BAC female = 0.085 x (oz) x (% alcohol) body weight


Henry’s Law The concentration of alcohol in breath is proportional to

that in the blood. This ratio of alcohol in the blood to the alcohol in the

lungs is approximately 2100 to 1. In other words 1 ml of blood will contain nearly the same amount of alcohol as 2100 ml of breath.


Field Tests Preliminary tests—used to determine the degree of

suspect’s physical impairment and whether or not another test is justified.

Psychophysical tests—3 Basic Tests Horizontal gaze nystagmus (HGN): follow a pen or small

flashlight, tracking left to right with one’s eyes. In general, wavering at 45 degrees indicates 0.10 BAC.

Nine Step walk and turn (WAT): comprehend and execute two or more simple instructions at one time.

One-leg stand (OLS): maintain balance, comprehend and execute two or more simple instructions at one time.


The Breathalyzer More practical in the field Collects and measures alcohol content of alveolar breath

Breath sample mixes with 3 ml of 0.025 % K2Cr2O7 in sulfuric

acid and water2K2Cr2O7 + 3C 2H5OH + 8H 2SO4 2Cr2(SO4)3 + 2K2SO4 + 3CH3COOH + 11 H2O

Potassium dichromate is yellow, as concentration decreases its light absorption diminishes so the breathalyzer indirectly measures alcohol concentration by measuring light absorption of potassium dichromate before and after the reaction with alcohol


Generalizations During absorption, the concentration of alcohol in arterial

blood will be higher than in venous blood. Breath tests reflect alcohol concentration in the pulmonary

artery. The breathalyzer also can react with acetone (as found

with diabetics), acetaldehyde, methanol, isopropyl alcohol, and paraldehyde, but these are toxic and their presence means the person is in serious medical condition.

Breathalyzers now use an infrared light absorption device with a digital read-out. Prints out a card for a permanent record.

Chapter 7 Drugs

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