Pharmaceutical Toxicology Lab: Types of Poisons

Pharmaceutical Toxicology Lab

• A poison is any agent that can cause serious body injury, disease, or death when applied, introduced into, or developed within the body.

Kinds of Poisons

• Corrosive: chemically causes local destruction of tissues upon contact, and remains poisonous even when highly diluted.
• Cumulative: suddenly increases in intensity of action after gradual addition.

Classifications of Poisons

Based on Origin

• Natural: from natural sources like plants and animals.
• Synthetic: manufactured, such as dioxins, some pesticides, and nerve gases.

Based on Physiological Action

• Asphyxiants: gases that cause tissue hypoxia.
• Lacrimators: cause tears.
• Sternutators: cause sneezing.
• Asthenics or Exhaustives: cause muscle weakness.
• Narcotics: cause mental weakness or depression.
• Tetanics: cause spasmodic and continuous muscle contraction.
• Depressant or Sedative: retard or depress the physiological action of an organ.
• Anesthetic: cause pain insensitivity.
• Inflammatory: cause sensitization, provoke an immune response.
• Mutagenic: inherited by DNA damage.
• Teratogenic: cause fetal damage.

Classifications of Poisons (continued)

Based on Chemical Properties

• Inorganic: volatile, non-volatile, mineral acid, mineral alkali.
• Organic: volatile, alkaloids, animal poison, bacterial, glycoside.

Based on Validity or Strength

• Numerical value toxicity rating:
  • 6: Super toxic (5mg/kg)
  • 5: Extremely toxic (5-50 mg/kg)
  • 4: Very toxic (50-500 mg/kg)
  • 3: Moderately toxic (0.5-5g/kg)
  • 2: Slightly toxic (5-15g/kg)
  • 1: Practically toxic (Above 15g/kg)
  • Nontoxic: no toxicity rating

Material Safety Data Sheet (MSDS)

• Required by chemical manufacturers, distributors, or importers for hazardous chemicals.
• Sections:
  • 1. Identification
  • 2. Hazard Identification
  • 3. Composition/Information on Ingredients
  • 4. First-aid measures
  • 5. Fire-fighting methods
  • 6. Accidental Release Measures
  • 7. Handling and Storage
  • 8. Exposure Controls/Personal Protection
  • 9. Physical and Chemical Properties
  • 10. Stability and Reactivity
  • 11. Toxicological Information
  • 12. Ecological Information
  • 13. Disposal Considerations
  • 14. Transport Information
  • 15. Regulatory Information
  • 16. Other Information

Poisoning

• Clinical toxicity secondary to accidental exposure.
• Types of poisoning:
  • Acute: prompt and marked disturbances of function or death within a short period of time.
  • Chronic: gradual and progressive deterioration of the functioning of the tissues.
  • Cumulative: suddenly increases in its intensity of action when a certain limit is reached.

According to Legal Viewpoint

• Accidental: the poison was taken without intention to cause death.
• Suicidal: the poison was taken by the victim voluntarily for the purpose of taking their own life.
• Homicidal: the poison was given willfully and with intent to cause death to the victim.
• Undetermined: the history is hazy as to how the poison was obtained and why it was administered.

Evidences of Poisoning

• Circumstantial or Moral: deduced from various events or facts.
• Symptomatic: poisoning signs and symptoms are observed.
• Chemical: detection of suspected substance via chemical analysis of samples of body fluids collected.
• Post mortem/Autopsy: gathered from an examination of tissues and organs after death.
• Experimental: administering the suspected substance to a living animal and noting the effect or symptoms.

Toxicity Testing

• Two main principles:
  • Effects produced by a compound in laboratory animals are applicable to humans when properly qualified.
  • Exposure of experimental animals to toxic agents in high doses is a necessary and valid method of discovering possible hazards in humans.
• Types of toxicity testing:
  • Acute toxicity testing: first toxicity test performed on a new chemical.
  • Acute lethality studies: essential for characterizing the toxic effects of chemicals and their hazard to humans.
  • Skin and eye irritations
  • Sensitization
  • Subacute (repeated-dose study): repeated administration typically for 14 days.
  • Subchronic: 90 days
  • Chronic: 6 months to 2 years