Question

6 multiple choice 1 point
calculating the therapeutic dose of a drug involves a determination of the ______ of the drug.
○ ld₅₀
○ ed₅₀
○ td₅₀
○ id₅₀

7 multiple choice 1 point
the goals of ______ clinical trials are to determine the efficacy and tolerability of an investigational drug, often in comparison to a standard of care medication for the condition of interest.
○ phase i
○ phase ii
○ phase iii
○ phase iv

8 multiple choice 1 point
when determining the bioavailability of a drug administered by a given route, if a ____ fraction of drug reaches the ____ then the bioavailability, expressed as a percentage, will be low

• small; systemic circulation
• large; systemic circulation
• small; portal circulation
• large; portal circulation

Explanation:

Question 6

To determine the therapeutic dose of a drug, we look at \( TD_{50} \) (Therapeutic Dose 50), which is the dose that produces a therapeutic effect in 50% of the test population. \( LD_{50} \) is lethal dose, \( ED_{50} \) is effective dose (not specific to therapeutic context here), and \( ID_{50} \) is infectious dose, so they don't fit.

Phase III clinical trials are designed to assess the efficacy and tolerability of an investigational drug, often comparing it to standard - of - care. Phase I is about safety and dosage, Phase II is about preliminary efficacy, and Phase IV is post - marketing surveillance.

Bioavailability is the fraction of drug that reaches the systemic circulation. If a small fraction of the drug reaches the systemic circulation, the bioavailability (expressed as a percentage) will be low. Portal circulation is part of the liver's circulation and not the main target for measuring bioavailability related to general systemic effects.

Answer:

C. \( TD_{50} \)

Question 7