Introduction To Pharmokinetics

Question 1

What is pharmacokinetics?

Answer 1

The movement of drugs within the body

Question 2

What is pharmacodynamics?

Answer 2

The effect of drugs on the body

Question 3

What is bioavailability?

Answer 3

The fraction of the drug that reaches the systemic circulation as intact drug

Question 4

What is drug disposition?

Answer 4

All processes by which the body handles drugs

Question 5

What is the ADME model?

Answer 5

A bsorption, D istribution, M etabolism, and E limination

Question 6

What are most drugs classed as?

Answer 6

Weak acids or weak bases

Question 7

What is drug-protein binding?

Answer 7

The reversible interactions of drugs with proteins.

Question 8

What is the first-pass effect?

Answer 8

The extent to which a drug is removed by the liver during its first passage into the portal vein

Question 9

What is the function of the epithelial cell layer?

Answer 9

To define the boundary of the body

Question 10

What is the largest constituent of the human body?

Answer 10

Plasma

Question 11

What are the different proteins that drugs can bind to

Answer 11

Proteins in the plasma, tissue components, RBCs.

Question 12

What is the definition of pKa?

Answer 12

The pH where ionised and unionised forms of the weak acid or base are equal

Question 13

What is absorption?

Answer 13

The extent to which intact drug is absorbed from the gut lumen into the portal vein

Question 14

What separates each compartment?

Answer 14

Various barriers e.g epithelial cells

Question 15

What are the non-covalent bonding forces involved in drug-protein binding?

Answer 15

Van der Waal’s forces, ionic bonding, hydrogen bonding.

Question 16

What are cell membranes?

Answer 16

Barriers between compartments in the body

Question 17

What are the different routes of drug administration?

Answer 17

Subcutaneous, Intramuscular, Oral, Intravenous, Intraarterial, Rectal, Vaginal, Transdermal, Sublingual, Intranasal, Intravitreal, Inhalational,

Question 18

What is the volume of distribution

Answer 18

Extent of distribution in the body

Question 19

What are the components of cell membranes?

Answer 19

Lipids, proteins, and carbohydrates

Question 20

How is cell membrane formed

Answer 20

Lipid bilayer

Question 21

How does the pKa value affect the strength of an acid or base?

Answer 21

Lower pKa value indicates a stronger acid or base, while higher pKa value indicates a weaker acid or base

Question 22

What is the function of the intestinal wall and liver?

Answer 22

To prevent entry of xenobiotics into the body

Question 23

Which proteins have binding sites selective for basic drugs?

Answer 23

Alpha 1-acid glycoproteins and Beta-globulins.

Question 24

How is the volume of distribution used?

Answer 24

To calculate the dose for therapeutic drug concentration

Question 25

What is the function of cholesterol in the cell membrane?

Answer 25

Affects membrane fluidity and stability

Question 26

What is lipophilicity?

Answer 26

The ability of a molecule to dissolve in lipids

Question 27

Where do lipid soluble drugs partition?

Answer 27

Into the lipid bilayer.

Question 28

How is lipophilicity measured?

Answer 28

By the partition coefficient (Log P)

Question 29

What determines the adequate drug concentration at the site of action?

Answer 29

Absorption and distribution

Question 30

What does a higher Log P value indicate?

Answer 30

Higher lipophilicity and permeability

Question 31

What is the volume of distribution (V)

Answer 31

The relationship between the total amount of drug in the body and the concentration of drug in the plasma.

Question 32

What is the general rule for absorption of weak acids and weak bases in the intestine?

Answer 32

Weak acids are well absorbed from the acidic environment of the intestine as a larger fraction exists as the unionised form, while weak bases are absorbed more slowly as a larger fraction exists in the ionised form

Question 33

What are the barriers to getting drugs into the systemic circulation following oral administration?

Answer 33

Cell membrane barriers

Question 34

What is the principle of minimum hydrophobicity?

Answer 34

Designing drugs with low hydrophobicity to reduce toxicity

Question 35

Give the equation for the volume of distribution

Answer 35

equation: V = Total amount of drug / Concentration of drug in plasma.

Question 36

What is distribution in pharmacology?

Answer 36

The movement of drug molecules from the circulating blood to other areas of the body

Question 37

What factors determine the ability of a drug to permeate the cell membrane barriers?

Answer 37

Lipophilicity and ionisation status

Question 38

What is the volume of distribution of a drug if it is 100 L and the blood plasma concentration is 10 mg/L?

Answer 38

1000mg

Question 39

What is the volume of distribution referred to as?

Answer 39

The ‘apparent’ volume of distribution.

Question 40

What factors does drug distribution depend on?

Answer 40

Blood flow, concentration gradient, permeability of cell membranes, drug binding to plasma proteins or tissue components

Question 41

What is the bioavailability of a drug?

Answer 41

The amount of drug that reaches the systemic circulation

Question 42

What do proteins binding drugs act as?

Answer 42

A reservoir for drug transport and a pharmacologically inactive mass-transit unit

Question 43

What is the effect of first-pass metabolism on drugs?

Answer 43

It reduces the bioavailability of drugs

Question 44

What does distribution depend on?

Answer 44

Blood flow and protein binding

Question 45

What is route of drug through oral administration and dissolution?

Answer 45

Mouth, oesophagus, liver, stomach, small intestine, colon

Question 46

Equation for bioavailability:

Answer 46

Fraction absorbed into portal vein x fraction escaping through first pass