Topic 4 - Pharmacokinetics

Question 1

Compartments (wrt. compartmental analysis)

Answer 1

Systems that are continuous and nonhomogenous are replaced with compartments that are discrete and in which concentrations, and so on, are homogenous

Question 2

Assumptions of open one-compartment model (3)

Answer 2

1. Process of distribution to each compartment is much faster than absorption into blood and elimination
2. Drug concentration everyone in compartment is equal (CSTR)
3. Elimination processes are pseudo-1st order

Question 3

What makes Vd higher than the assumed 40 L?

Answer 3

Drugs can bind to proteins in the plasma and extracellular spaces, then accumulate in these spaces.

Question 4

Absolute bioavailability

Answer 4

Comparison between the amount of drug reaching the bloodstream through extravascular administration, and iv.

Question 5

Relative bioavailability

Answer 5

Determined by comparing a drug’s AUC using iv to a “standard dosage form”

Question 6

TD50 vs. ED50

Answer 6

TD 50 = toxic dose for 50% of the population

ED 50 = effective dose for 50% of the population

Question 7

Bioequivalence

Answer 7

Comparing amounts of the same drug that are absorbed from 2 different formulations of the same dosage form. The two forms are considered equivalent if there is no significant difference between ANY of the C_max, t_max, and AUC.