All Flashcards
What are the general steps of an LD50 test?
Animal testing, dose/concentration exposure, observation, calculation.
What is LD50?
Lethal Dose 50: The dose that kills 50% of a test population.
What is LC50?
Lethal Concentration 50: The concentration that kills 50% of a test population.
Define LDlo.
Lowest dose that has caused death in a test population.
Define LD100.
Dose that kills 100% of the test population.
Define ED50.
Dose that causes a specific effect in 50% of the population.
Define NOAEL.
No-Observed-Adverse-Effect Level: Highest dose with no adverse effects.
Define NOEL.
No-Observed-Effect Level: Highest dose with no observable effects.
Define POD.
Probable-Effect-Dose: Dose at which an effect is likely to occur.
Define TD50.
Therapeutic Dose: Dose that causes a therapeutic effect in 50% of the population.
Define EC50.
Effective Concentration: Concentration that causes a specific effect in 50% of the population.
What does a low LD50 value indicate?
A lower LD50 value means a substance is more toxic.
What is the purpose of studying LD50s?
To compare toxicity, assess risk, guide regulation, and identify hazards.
Why is it important to consider the route of exposure when interpreting LD50 values?
Toxicity can vary significantly depending on whether a substance is ingested, inhaled, or absorbed through the skin.
What are the limitations of using LD50 values alone to assess risk?
LD50 values only measure acute toxicity and don't predict long-term effects or the effects of chemical mixtures.
Why is animal data not directly applied to humans?
Significant differences exist in how different species respond to chemicals.
What is the primary use of LD50/LC50 values?
To determine acute toxicity.
Why is the history of LD50 important?
J.W. Trevan's work provided a standardized way to measure and compare chemical toxicity.
What is the significance of NOAEL?
It represents the highest dose of a substance that does not cause any observable adverse effects.
What is the use of the ED50 value?
It represents the dose at which 50% of the population shows a specific effect, whether good or bad.
What is the relationship between LD50 and toxicity?
The lower the LD50, the more toxic the substance.