T2 - 2-COM Model

Question 1

What is a compartment?

Answer 1

An imaginary unit in which different tissues with similar rates of drug are grouped together

Question 2

How is a compartment a homogenous unit?

Answer 2

1. Drug concentration is uniform throughout at all times
2. Drug concentration in a compartment is continuously changing with time
3. Pharmacokinetic models

Question 3

What are pharmacokinetic models?

Answer 3

Differential equations used to describe the rate of change in drug concentration

Question 4

What comprises a compartment?

Answer 4

1. Amount of drug distributed in a volume to give drug concentration in the compartment
2. A drug in blood stream -> distributes to the tissues in the body
3. A drug in blood stream -> distributes to the tissues in the body

Question 5

Why are pharmacokinetic models mathematically constructed?

Answer 5

1. Describe the rate of movement/transfer of drug between compartments
2. Explain the relationship of drug concentration with time after drug dose
3. Predict the time-course of drugs in the body to allow us to maintain drug concentration in the therapeutic range to monitor
4. Summarize data

Question 6

How are clinically observed plasma concentration-time profiles described?

Answer 6

One, two, or three compartment pharmacokinetic models

Question 7

Describe the schematics of an one compartment model?

Answer 7

Question 8

Describe the schematics of a two compartment model?

Answer 8

Question 9

Describe the schematics of a three compartment model?

Answer 9

Question 10

What is the process of a drug moving from central to peripheral compartment?

Answer 10

Distribution = Distribution Cl

Question 11

What is the process of a drug moving from peripheral to central compartment?

Answer 11

Redistribution = Clearance

Question 12

What are the most clinically used compartments?

Answer 12

one or two due to its simplicity

Question 13

What are the assumptions of the 2 com model?

Answer 13

1. At 𝑡=0, no drug is present in the peripheral compartment.
2. Each compartment is individually well-stirred.
3. Distribution and elimination are first-order.
4. Change in the rate of drug concentration over time is represented by: (𝑑𝐶/𝑑𝑡) = - k * C

Question 14

Describe the differences between 1 and 2 com models?

Answer 14

Question 15

How can we determine the rate of a 2 Com model?

Answer 15

1. 𝐑𝐚𝐭𝐞 𝐨𝐟 𝐜𝐡𝐚𝐧𝐠𝐞 𝐨𝐟 𝐭𝐡𝐞 𝐚𝐦𝐨𝐮𝐧𝐭 𝐨𝐟 𝐝𝐫𝐮𝐠 𝐢𝐧 𝐭𝐡𝐞 𝐟𝐢𝐫𝐬𝐭 𝐜𝐨𝐦𝐩𝐚𝐫𝐭𝐦𝐞𝐧𝐭 =𝐑𝐚𝐭𝐞 𝐨𝐟 𝐢𝐧𝐩𝐮𝐭𝐬 𝐢𝐧𝐭𝐨 𝐭𝐡𝐞 𝐟𝐢𝐫𝐬𝐭 𝐜𝐨𝐦𝐩𝐚𝐫𝐭𝐦𝐞𝐧𝐭 − 𝐑𝐚𝐭𝐞 𝐨𝐟 𝐨𝐮𝐭𝐩𝐮𝐭𝐬 from the first compartment
2. 𝐚𝐭𝐞 𝐨𝐟 𝐜𝐡𝐚𝐧𝐠𝐞 𝐨𝐟 𝐭𝐡𝐞 𝐚𝐦𝐨𝐮𝐧𝐭 𝐨𝐟 𝐝𝐫𝐮𝐠 𝐢𝐧 𝐭𝐡𝐞 𝐬𝐞𝐜𝐨𝐧𝐝 𝐜𝐨𝐦𝐩𝐚𝐫𝐭𝐦𝐞𝐧𝐭 =𝐑𝐚𝐭𝐞 𝐨𝐟 𝐢𝐧𝐩𝐮𝐭𝐬 𝐢𝐧𝐭𝐨 𝐭𝐡𝐞 𝐬𝐞𝐜𝐨𝐧𝐝 𝐜𝐨𝐦𝐩𝐚𝐫𝐭𝐦𝐞𝐧𝐭 − 𝐑𝐚𝐭𝐞 𝐨𝐟 𝐨𝐮𝐭𝐩𝐮𝐭𝐬 from the second compartment

Question 16

What is the equation to determine the concentration of a 2 com system?

Answer 16

Question 17

What is the difference between Ae^-at and Be^-bt?

Answer 17

A: distribution
B: elimination

Question 18

What are the micro-rate constants?

Answer 18

k10, k12, and k21

Question 19

What are the macro rate constants?

Answer 19

A, B, a, and b

Question 20

What are micro-rate constants for?

Answer 20

1. Relate the amount of drug being transferred from one compartment to another.
2. Required to calculate the apparent volumes of distribution (V1 & V2): central and peripheral

Question 21

What is distribution half-life?

Answer 21

Question 22

What is the elimination half-life?

Answer 22

Question 23

What does distribution half-life used for?

Answer 23

To determine how long a drug takes to distribute from central to peripheral compartment

Question 24

How do you find AUC using macro and micro rate constants?

Answer 24

Question 25

How do you calculate total clearance?

Answer 25

Question 26

How do you calculate distributional clearance?

Answer 26

Question 27

What is distributional clearance?

Answer 27

Clearance of the drug between the involved compartmens

Question 28

How do you calculate C0?

Answer 28