Analysis of Toxic Agents

8/12/2019 Analysis of Toxic Agents

1/18


2/18

Two-Step Procedure 1. Screening test

A rapid, simple, qualitative procedure

Intended to detect specific substances or classes of toxicants

Has good analytic sensitivity but lacks specificity

2. Confirmatory test

Used to confirm a positive result from screening test

Analytic Methods Immunoassays (screening), thin-layer chromatography, gas

chromatography


3/18

Alcohol General toxic effects disorientation, confusion, euphoria;

progressing to unconsciousness, paralysis, & even death

Specific toxic effects Ethanol

Associated with abusive alcoholic consumption

Results in diminution of judgment & motor performance

Chronic consumption leads to alcoholic hepatitis, cirrhosis.


4/18

Alcohol Specific toxic effects

Methanol(a common solvent) Can cause severe acidosis, leading to death; blindness

Isopropanol(rubbing alcohol) Can cause severe acute-phase ethanol-like symptoms

Ethylene glycol(component of hydraulic fluid & antifreeze) Ethanol-like effects, severe metabolic acidosis, renal tubular

damage


5/18

Carbon Monoxide Produced by incomplete combustion of carbon-containing

substances

Primary environmental sources gasoline engines, improperlyvented furnaces, & wood or plastic fires

A colorless, odorless, tasteless gas rapidly absorbed into bloodfrom inspired air

Considered highly toxic due to its affinity for & binding tohemoglobin

Decreases amount of oxygen to tissue, producing hypoxia

Tests differential spectrophotometry & gas chromatography


6/18

Caustic Agents Found in many household products & occupational settings

Aspiration leads to pulmonary edema, shock, death. Ingestion leads to lesions in esophagus & GI tract, leading to

perforations, hematemesis, abdominal pain, shock.

Cyanide Found in industrial processes, insecticides, rodenticides; produced

by burning of some plastics; common suicide agent

Expresses toxicity by binding to heme iron

Causes headaches, dizziness, respiratory depression, leading toseizure, coma, & death


7/18

Pesticides Substances intentionally added to environment to kill or harm an

undesirable life form (insecticides & herbicides)

Contamination of food is major route of exposure.

Inhalation, transdermal absorption, & ingestion are common

occupational/accidental routes of exposure. Wide range of toxic effects chronic & acute disease states, death Types organophosphates, carbamates, & halogenated

hydrocarbons


8/18

Salicylates Aspirin (acetylsalicylic acid) is a common analgesic, antipyretic, &

anti-inflammatory drug.

Function decreases thromboxane & prostaglandin formationthrough inhibition of cyclooxygenase

Toxic effects (when ingested at high doses) Metabolic acidosis, possibly leading to death

Hyperventilation, respiratory alkalosis, acidbase disturbance

Inhibition of Krebs cycle, resulting in excess conversion ofpyruvate to lactate

Excess ketone body formation


9/18

Acetaminophen A commonly used analgesic drug

Overdose is associated with severe hepatotoxicity.

In overdose, accumulation of reactive intermediates, including freeradicals, in cell results in toxic effect, necrosis of liver

Onset of hepatocyte damage is long: 35 days after ingestion.

Initial symptoms of toxicity are vague, nonspecific, & notpredictive of hepatic necrosis.

Quantitation immunoassay (most common); high-performanceliquid chromatography (reference)


10/18

Acetaminophen A commonly used analgesic drug

Overdose is associated with severe hepatotoxicity.

In overdose, accumulation of reactive intermediates, including freeradicals, in cell results in toxic effect, necrosis of liver

Onset of hepatocyte damage is long: 35 days after ingestion.

Initial symptoms of toxicity are vague, nonspecific, & notpredictive of hepatic necrosis.

Quantitation immunoassay (most common); high-performanceliquid chromatography (reference)


11/18

Prediction of acetaminophen-induced hepaticdamage based on serum concentration


12/18

Reasons for Testing for Drugs of Abuse To identify drug in overdose to ensure appropriate treatment

To identify drug abuse in non-overdose cases to provide arationale for treatment

Drug Testing Screening of a single urine specimen for many substances Identification of chronic abuse involves several positive tests in

conjunction with clinical evaluation.

Analytic methods immunoassays (screening & confirmation);thin-layer chromatography (screening); liquid & gas

chromatography (confirmation)


13/18

Amphetamines Therapeutic drugs used for narcolepsy & attention deficit disorder

Stimulants with a high abuse potential

Produce initial sense of increased mental & physical capacity &perception of well-being

Initial effects followed by restlessness, irritability, & possiblepsychosis

Overdose hypertension, cardiac arrhythmias, convulsions, death Testing urine analysis, immunoassay screening, confirmation by

liquid or gas chromatography


14/18

Anabolic Steroids Group of compounds related chemically to male sex hormone

testosterone

Increase muscle mass & can improve athletic performance

Toxic effects

Toxic hepatitis; accelerated atherosclerosis, abnormalaggregation of platelets, stroke & myocardial infarction

Enlargement of heart, leading to ischemia, cardiac arrhythmias,& possible sudden death

Males testicular atrophy, sterility, impotence; femalesdevelopment of masculine traits, breast reduction, sterility


15/18

Cannabinoids Group of psychoactive compounds found in marijuana

Of these, tetrahydrocannabinol (THC) is most potent & abundant.

Marijuana can be smoked or ingested.

Produce sense of well being & euphoria

Associated with impairment of short-term memory & intellectualfunction

Overdose not associated with specific physiologic toxic outcomes

Immunoassay for THC-9-carboxylic acid is screening test.

Gas chromatography with mass spectrometry is confirmation test.


16/18

Cocaine An effective local anesthetic with few adverse effects at

therapeutic concentrations

At higher concentrations, it is a potent CNS stimulator that elicitsa sense of excitement & euphoria; high abuse potential.

An alkaloid salt that can be administered directly (insufflation orIV injection) or inhaled as vapor when smoked (crack)

Toxic effects hypertension, arrhythmia, seizure, myocardialinfarction

Testing detection of benzoylecgonine in urine by immunoassay(screening); gas chromatography with mass spectometry(confirmation)


17/18

Opiates A class of substances capable of analgesia, sedation, &

anesthesia; high abuse potential

Derived from opium poppy; heroin is a chemically modified form

Toxic effects respiratory acidosis, myoglobinuria, cardiacdamage, death by cardiopulmonary failure

Phencyclidine Illicit drug with stimulant, depressant, anesthetic, & hallucinogenic

properties; high abuse potential

Adverse effects agitation, hostility, paranoia Toxic effects stupor, coma


18/18

Sedative-Hypnotics Tranquilizers; CNS depressants

Wide range of therapeutic roles & are commonly used

Barbiturates & benzodiazepines are most common types abused.

Toxic effects lethargy, slurred speech, coma, respiratorydepression, hypotension

Documents

Analysis of Toxic Agents