Exam 2 Noncompartmental Analysis

Question 1

What is important to know about noncompartmental analysis?

Answer 1

only look at the data → don’t need to make assumptions to estimate AUC (CL = dose/AUCiv instead CL = k*V with compartmental analysis)

Question 2

What does MRT (mean residence time) of a drug mean?

Answer 2

MRT of drug X would mean the average time one drug molecule spends in the body from dosing to elimination (MRT = AUMC/AUC)

Question 3

What is t*C called?

Answer 3

the first moment of the concentration

Question 4

What does AUMC stand for?

Answer 4

area under the moment curve

Question 5

After IV administration, what can be estimated?

Answer 5

AUC and AUMC can be estimated regardless of peak shapes → MRT and CL can be estimated

Question 6

What are parameters from noncompartmental analysis?

Answer 6

AUC, AUMC, CL, and MRT

Question 7

Can we simplify this to a one compartment model PK?

Answer 7

major phase concept

Question 8

What would be the average drug concentration at steady state?

Answer 8

superposition principle

Question 9

What is AUC under the major phase concept?

Answer 9

AUC for one compartment model is given by C0/kel and AUC for two compartment model is given by A/alpha + B/beta

Question 10

If A is 10 and alpha is 1 and A/alpha is 10, what is the contribution of the alpha phase?

Answer 10

90%

Question 11

If B is 0.1 and beta is 0.1 so B/beta is 1, what is the contribution of beta phase?

Answer 11

10%

Question 12

If A is 1 and alpha is 5 so A/alpha is 0.2, what is the contribution of alpha phase?

Answer 12

2%

Question 13

If B is 0.5 and beta is 0.05 so B/beta is 20, what is the contribution of beta phase?

Answer 13

98%

Question 14

After multiple doses, AUC is what?

Answer 14

irrespective of peak shapes

Question 15

With the AUC superimposition principle, what can we assume?

Answer 15

Css,ave = AUCss / tau

Question 16

What is another equation for MRT?

Answer 16

MRT = 1 / kel

Question 17

What is the relationship between MRT and kel?

Answer 17

if drug is eliminated fast (high kel) → MRT value is small (MRT and kel values go in opposite directions!)

Question 18

When using both MRT equations, what should the values be?

Answer 18

they should be within 10% since AUMC and AUC will have some error

Question 19

After IV administration, Drug A and Drug B show MRT values of 1 and 5 hr, respectively. Which drug is eliminated faster?

Answer 19

Drug A

Question 20

What is Vdss?

Answer 20

1. steady state volume of distribution of a drug
2. the volume of distribution observed after the drug has distributed into the tissues
3. given by the equation MRT*CL

Question 21

What is noncompartmental analysis?

Answer 21

1. pharmacokinetic analysis performed without assuming compartmentalized distribution of drugs in body
2. provides descriptive knowledge about drugs (MRT, CL, and Vdss)

Question 22

What are noncompartmental PK parameters?

Answer 22

MRT, AUMC, AUC, CL, and Vdss

Question 23

After 1 gram of drug X is administered intravenously, the following concentration time profile is obtained. What parameters can be estimated?

Answer 23

AUC, AUMC, MRT, CL, and Vdss → just looking at data, no assumptions!

Question 24

How is non-compartmental analysis useful and limited?

Answer 24

1. minimal number of assumptions (minimizes bias)
2. will work for many types of data (descriptive)
3. can compare across data sets/drugs
4. limited in information about secondary processes
5. no assumptions about distribution into body or segmented processes in the body (holistic)
6. poor relating to specific organ function
7. sometimes, favored approach due to lack of assumptions
8. just looking at total clearance and total drug exposure

Question 25

How is compartmental analysis useful and limited?

Answer 25

1. fits data for a specific case
2. better accounts for biological processes
3. provides better insight into “fate of drug”
4. driven by data and by assumptions
5. capability to predict concentrations for certain time point → only with the equation are we able to predict certain concentrations at certain time points