FORENSIC TOXICOLOGYPart I – Drugs of Abuse

Drug vs. Poison

A drug is a natural or synthetic substance designed to affect humans (or other animals) psychologically and/or physically.

A drug taken in excess, showing its toxic effects, causing illness or death is considered a poison.

Dramamine Overdose:Drowsiness, Seizures, Convulsions, Difficulty Breathing, DEATH

Controlled and Illicit Substances

Controlled Substances are drugs or chemicals whose manufacture, possession and use are regulated by the government. Illegal Drugs (Drug Enforcement Agency) Prescription Drugs (Federal Drug Administration) Over the Counter Drugs (OTC)

Illicit Substances (aka drugs of abuse) are drugs taken strictly for pleasure whether produced legally or illegally. Designer Drugs – drugs produced solely for abuse and evasion of

specific drug laws.

Drugs Crimes and Use Statistics

Direct drug crimes consist of the possession, manufacturing, and distribution of illicit substances.

Indirect drug crimes are those that are committed to support a person’s drug addiction or are crimes that are committed while someone is under the influence of drugs.

2012 Statistics for Illicit Drug Use in the US12-17 yr. 9.5%

18-25 yr. 21.3%

>25 yr. 7%

Drug Classification According to Pharmacology (4 Types)

Pharmacology - The science of drugs, including their composition, uses, and effects

1. Hallucinogens (psychedellic drugs) Changes normal thought processes, perceptions and moods

Desired Effects Include: Hallucinations (visual or auditory) Super strength in some cases

Undesirable Side Effects Amnesia Depression Anxiety Psychosis

Drug Classification (continued)

2. Stimulants (Uppers) Act on the central nervous system to increase energy

and/or alertness while suppressing appetite and fatigue.

Desired Effects Include: Mental alertness Increased energy

Undesirable Side Effects Restlessness Anxiety Sudden Death

Drug Classification (continued)

3. Narcotics (analgesics) Act on pain centers in the central nervous system

Synthetic narcotics are known as opiates

Desired Effects Include: Pain relief Anxiety relief

Undesirable Side Effects Death Serum hepatitis

Drug Classification (continued)

4. Depressants (Downers) sometimes referred to as sedatives and tranquilizers, are

substances that can slow brain activity.

Desired Effects Include: Anxiety relief Relaxation

Undesirable Side Effects Depression Chronic Fatigue Anxiety

DEA Schedules of Controlled Substances

Schedule I Controlled Substances Substances in this schedule have no currently

accepted medical use in the United States, a lack of accepted safety for use under medical supervision, and a high potential for abuse.

Some examples of substances listed in Schedule I are: heroin, LSD, marijuana, methaqualone, and ecstasy.

DEA Schedules of Controlled Substances

Schedule II Controlled Substances Substances in this schedule have a high potential for

abuse which may lead to severe psychological or physical dependence.

Examples of Schedule II narcotics include: methadone, oxycodone, Percocet, morphine, and opium.

Example of Schedule II stimulants include: methamphetamine

Schedule III Controlled Substances Substances in this schedule have a potential for

abuse less than substances in Schedules I or II and abuse may lead to moderate or low physical dependence or high psychological dependence.

Examples of Schedule III narcotics include: Vicodin and Codeine

Examples of Schedule III non-narcotics include: ketamine, and anabolic steroids.

DEA Schedules of Controlled Substances

Schedule IV Controlled Substances Substances in this schedule have a low potential for

abuse relative to substances in Schedule III. Examples: Valium, Xanax, Halcion.

Schedule V Controlled Substances Substances in this schedule have a low potential for

abuse relative to substances listed in Schedule IV and consist primarily of preparations containing limited quantities of certain narcotics.

Example: some OTC cough medicines

DEA Schedules of Controlled Substances

Basic Laboratory Science

Standard/reference samples allow the laboratory to establish the known properties of a material so that the identity of crime scene evidence can be determined.

Positive test – A test result that indicates the substance being tested for is present in the sample. False positive test – A test result that indicates that the substance

being tested for is present when it is not.

Negative test – A test result that indicates that the substance being tested for in a sample is absent or in too small a quantity to be detected.

Basic Laboratory Science

Qualitative test – A test that determines that a substance is present.

Quantitative test – A test that determines how much of a substance is present

Doe, Jane ID# 1114 DOB 1/1/82Normal range

Serum HCG 1520 mg/dL O mg/dL

Screening tests vs. Confirmatory Tests

Screening test- a test that is nonspecific and preliminary in nature.

May test for a class of substances Example: Class: Opiates Drugs: heroin, morphine,

codeine Often can be performed in the field – field test

Confirmatory test- a single test that specifically identifies a substance

Principles of Drug Analysis Criminal penalties depend on the actual substance present in a

sample and the amount of substance present.

Drug analysis process

Step 1: Chemist performs screening tests Visual/microscopic Microcrystalline Spot test – In the field Thin-layer chromatography (TLC) – in the lab

Step 2: Chemist performs a quantitative analysis to confirm the sample’s identity and determine its mass Infrared spectroscopy (IR) Gas Chromatography and mass spectroscopy (GC/Mass Spec)

The Spot Test

Samples are mixed with chemicals to determine if drugs are present

A positive test results in a color change. Standards are always tested along with samples

Thin-layer Chromatography (TLC)

A Separation technique that takes advantage of the solubility and physical properties of the controlled substance to separate and distinguish compounds in a mixture

Has solid stationary phase (silica gel plate) and liquid moving phase (solvent).

If the sample to be analyzed is solid, it must first be dissolved in a suitable solvent.

Identifying Drugs by TLC

Procedure: A small amount of drug sample is applied to a TLC plate. Standards are always tested with samples. The plate is placed in a solvent. After a period of time, the plate is removed and visualized.

Plates can either be placed under ultraviolet light revealing those materials that fluoresce as bright spots on dark background.

Or, the plate can be sprayed with a chemical reagent that reacts with the separated substances and causes them to form colored spots.

Identifying Drugs by TLC

Analysis of a TLC plate Rf is a calculated ratio of the distance moved by a drug relative to

the distance moved by the solvent used in developing the plate.