Exam 1: Disposition of Drugs

Question 1

Study of the movement of drugs in the body across biological membranes from the time of absorption until elimination?

Answer 1

Pharmacokinetics

Question 2

What are the 4 stages of drug disposition?

Answer 2

1. Absorption
2. Distribution
3. Biotransformation
4. Excretion

Question 3

Factors affecting disposition of the drug:

Answer 3

1. biological cell memb
2. conc. gradient
3. Pump mech.
4. site of admin.
5. Total body water
6. plasma prtoein binding
7. disease

Question 4

List 4 properties of the biological cell memb.

Answer 4

1. phospholipid bilayer
2. memb. proteins and carbohydrates
3. cell junctions
4. aqueous pores

Question 5

List 4 mechanisms of transport across cell membranes:

Answer 5

1. Passive diffusion
2. Facilitated diffusion
3. Active transport
4. Pinocytosis

Question 6

Type of transport that does not require energy

Answer 6

Passive diffusion

Question 7

What are the 3 mechanisms of passive diffusion

Answer 7

1. transmembrane
2. paracellular
3. simple diffusion

Question 8

Movement by passive diffusion through aqueous protein channels in the cell memb.

Answer 8

Transmembrane

Question 9

Movement via filtration through intracellular aqueous pores

Answer 9

Paracellular

Question 10

Movement through lipid memb.

Answer 10

Simple diffusion

Question 11

The majority of drugs move through the body via _____

Answer 11

Simple diffusion

Question 12

T/F Energy is not required for facilitated diffusion

Answer 12

T

Question 13

T/F Active transport needs both a carrier and ATP

Answer 13

T

Question 14

T/F Active transport moves drugs from high conc. to low

Answer 14

F. low to high

Question 15

Na+/K+ ATPase transport pump is an example of primary or secondary active transport?

Answer 15

Primary

Question 16

Na dependent glucose transporters are examples of primary or secondary active transport

Answer 16

Secondary

Question 17

Specific type of endocytosis where cell engulfs the drug molecules dissolved in water “cell drinking”

Answer 17

Pinocytosis

Question 18

T/F Facilitated diffusion moves down the conc. gradient?

Answer 18

T

Question 19

T/F Facilitated diffusion requires a carrier and energy

Answer 19

F no energy

Question 20

T/F Facilitated diffusion is saturable

Answer 20

T

Question 21

T/F in facilitated diffusion the substance can be transported in or out of cell

Answer 21

T

Question 22

T/F passive diffusion moves down the concentration gradient

Answer 22

T

Question 23

T/F Passive diffusion requires energy

Answer 23

F

Question 24

T/F Facilitated diffusion is the most common form of transport

Answer 24

F. Passive diffusion

Question 25

T/F Active transport moves uphil from llow to high conc.

Answer 25

T

Question 26

T/F Active transport uses symporters and anitporters

Answer 26

T

Question 27

T/F active transport is not saturable

Answer 27

F

Question 28

T/F Pinocytosis can be toxic

Answer 28

t

Question 29

T/F Pinocytosis does not work if drug is dissolved in water

Answer 29

F. must be

Question 30

What are the 3 factors that affect simple diffusion

Answer 30

1. Conc. gradient
2. Lipid solubility
3. Degree of drug ionization

Question 31

T/F. The higher the lipid solubility of the drug the faster crossing the cell memb

Answer 31

T

Question 32

T/F. membranes are more permeable to ionized forms of drugs

Answer 32

F. non ionized

Question 33

T/F Drugs cros biological membranes in non ionized forms

Answer 33

T

Question 34

T/F rate of diffusion depends on degree ofionization

Answer 34

T

Question 35

What 3 things does degree of ionization depend on?

Answer 35

1. pH of the drug
2. pKa of the drug
3. pH of environment in vivo

Question 36

T/F weakly basic drugs are more ionized in alkaline solutions

Answer 36

F. acidic solutions

Question 37

Equal to the pH of the mediam at which the dissolved drug is 50% ionized and 50% not

Answer 37

pKa

Question 38

Henderson Hasselbach equation can be used to determine the ____

Answer 38

degree of ionization