Pharmacology

Question 1

What does a successful drug need?

Answer 1

Efficacy
ADME
Safety

Question 2

Three phases of drug action?

Answer 2

Pharmaceutical
Pharmacokinetic
Pharmacodynamic

Question 3

What does drug dissolution in the body depend on?

Answer 3

pH of the medium and pH of the site of dissolution

Question 4

Where do acidic drugs dissolved best?

Answer 4

Alkaline areas

Question 5

What does alkaline drugs dissolve best?

Answer 5

Acidic areas

Question 6

What physiochemical properties affect dissolution of a drug?

Answer 6

Ionisation
Lipophilicity

Question 7

Ways drugs can be absorbed across the GI tract?

Answer 7

Paracellular transport
Transcellular transport
Carrier-mediated transport
P-gp mediated efflux

Question 8

Which drug absorption processes are passive?

Answer 8

Paracellular
Transcellular

Question 9

What is transcellular drug absorption?

Answer 9

Directly through a cell

Question 10

Speed of transcellular drug absorption?

Answer 10

Fast

Question 11

Where can transcellular drug absorption occur?

Answer 11

All the way along the GI tract

Question 12

What properties does a drug need to undertake paracellular absorption?

Answer 12

Lipid soluble
Unionised

Question 13

What is paracellular drug absorption?

Answer 13

Via aqueous pores between cells

Question 14

Speed of paracellular transport?

Answer 14

Slower

Question 15

What can paracellular absorption take place?

Answer 15

Only the small intestine

Question 16

What is carrier-mediated drug absorption?

Answer 16

Drug uses a membrane carrier system

Question 17

What properties of a drug are needed to undertake carrier-mediated absorption?

Answer 17

Some polar molecules
Particularly if they resemble endogenous compounds

Question 18

Example of a drug that uses carrier-mediated transport and why?

Answer 18

Methotrexate as it is structurally similar to folic acid so it can be transported by the folate membrane transport system

Question 19

Physiochemical properties that affect drug absorption?

Answer 19

Ionisation
Lipophilicity
Size and shape

Question 20

Important plasma proteins in drug distribution?

Answer 20

albumin
acid-glycoprotein
beta-globulin.

Question 21

What can affect the distribution of a drug?

Answer 21

Plasma protein binding
BBB
Adipose tissues
Desired site of action

Question 22

Drugs bound to plasma proteins are active or inactive?

Answer 22

Inactive

Question 23

What kind of drugs mainly bind to albumin?

Answer 23

Acidic

Question 24

What kind of drugs mainly bind to acid-glycoprotein?

Answer 24

Basic

Question 25

Are acidic or basic drugs more likely to be plasma protein bound?

Answer 25

Acidic

Question 26

Physiochemical properties that affect drug distribution?

Answer 26

Ionisation Lipophilicity Shape and size

Question 27

Physiochemical properties of drugs that affect metabolism?

Answer 27

Lipophilicity

Question 28

Where are lipophilic compounds usually excreted?

Answer 28

Bile

Question 29

What kinds of drugs are expected to be excreted in the urine?

Answer 29

Soluble in water at urine pH Suitable size to pass glomerulus membrane

Question 30

Physicochemical properties of drugs that affect excretion?

Answer 30

Ionisation Lipophilicity Shape and size

Question 31

Physicochemical properties that affect a drug binding to the site of action?

Answer 31

Ionisation Lipophilicity Shape and size

Question 32

Why does ionization influence drug binding?

Answer 32

Electrostatic bonds Ionic bonds Hydrogen bonds

Question 33

Why does lipophilicity influence drug binding?

Answer 33

Hydrophobic interactions

Question 34

Why does shape and size influence drug binding?

Answer 34

VdW interactions Repulsive interaction

Question 35

Why does changing the chemical structure of a drug affect its behaviour?

Answer 35

Change of physicochemical properties

Question 36

What parameter is used to measure hydrophobicity?

Answer 36

LogP (partition coefficient)

Question 37

Lipophilic drugs have a ….. logP?

Answer 37

High

Question 38

Hydrophilic drugs have a ….. logP?

Answer 38

Low

Question 39

Why does increasing the logP too much reduce biological activity?

Answer 39

Drug may become so hydrophobic it is poorly soluble in the aqueous phase It may become trapped in fat depots and not reach site of action More susceptible to metabolism and elimination

Question 40

What represents the optimum partition coefficient for biological activity?

Answer 40

LogP°

Question 41

Approximate LogP of drugs targeting the CNS?

Answer 41

2

Question 42

Example of drugs where hydrophobicity only has a slight contribution to their activity?

Answer 42

Anti-malarials

Question 43

Why does the hydrophobicity of antimalarials not have much of an effect on its biological activity?

Answer 43

It’s target is in the blood

Question 44

What is Ka?

Answer 44

The dissociation constant

Question 45

What does the dissociation constant measure?

Answer 45

The extent of ionisation at at certain pH

Question 46

What is the molecular volume?

Answer 46

Measures the steric extent Determines transport characteristics

Question 47

What is MR?

Answer 47

Molecular refractivity

Question 48

What does molecular refractivity measure?

Answer 48

Volume occupied by an atom or group of atoms