Exam Review: Key Concepts in Toxicology and Pharmacology

Exam Review: Key Concepts in Toxicology and Pharmacology

I. Fundamental Chemical Concepts

• Functional Groups:
  • Definition and identification are crucial.
  • Understanding characteristics of compounds for absorption: whether a compound is polar or nonpolar, smaller or larger, more acidic or basic, and how these interact with the compartment (e.g., stomach, blood) pH (acidic or basic).

II. Dose-Response Relationships

• Key Dose-Response Terms:
  • $LD_{50}$ (Lethal Dose 50): The dose that is lethal to $50\%$ of the population.
  • $NOEL$ (No Observed Effect Level).
  • $MOS$ (Margin of Safety).
  • $TIM$ (Therapeutic Index Margin).
  • $LNT$ (Linear No-Threshold model).
  • Effective Dose 50 ($ED_{50}$): The dose that causes an effective response in $50\%$ of the population.
• Efficacy vs. Potency: Be aware of what makes a drug efficacious versus another based on their dose-response curves.
• Therapeutic Index (TI):
  • The formula for the therapeutic index is $TI = TD<em>{50} / ED</em>{50}$, where $TD<em>{50}$ (toxic dose $50\%$) is often replaced by $LD</em>{50}$ in preclinical studies.
  • Understanding this concept is important.

III. Pharmacokinetics and Toxicokinetics (ADME)

A. Absorption

• Routes of Absorption: Major routes should be known.
• Factors Governing Absorption: Compound characteristics (polarity, size, acidity/basicity) and compartment characteristics (e.g., stomach, blood pH) play a significant role.

B. Distribution

• Volume of Distribution ($V_D$): Understand its concept.

C. Metabolism (Biotransformation)

• Phase I vs. Phase II Metabolism:
  • Contrast and compare these two phases of biotransformation.
  • Phase I: Involves adjustments to the original