Exam 3 absorption

Question 1

which route of administration avoids the need to cross the biological membrane in order to reach the systemic circulation

Answer 1

intravaneous

Question 2

which route of administration avoids the need to cross the biological membrane in order to reach the CNS

Answer 2

intraspinal

Question 3

the 6 factors that determine movement across membrane

Answer 3

characteristics of the membrane, mechanism of passage across mem, dwell time of drug-membrane interface, physicochemical characteristic of drug, ph of environment and surface area of absorptive surface

Question 4

T/F the most oral drug absorption occurs in the small intestine

Answer 4

True

Question 5

the inner walls of the small intestine are covered by numerous folds called

Answer 5

plicae circulares-folds of Kerckring

Question 6

the small intestine folds contain tiny projections called

Answer 6

villi x30 and microvilli x600

Question 7

the small intestine folds increase

Answer 7

the surface area by 3 times

Question 8

the transit time to the small intestine influences the

Answer 8

peak concentration

Question 9

what impact would a drug that speeds up stomach emptying have on the peak concentration for acetaminophen

Answer 9

increase peak concentration

Question 10

increased stomach emptying does what to the half life

Answer 10

decreases

Question 11

increased rate of elimination does what to the half life

Answer 11

decreases

Question 12

decreased half life does what to the peak concentration

Answer 12

increases

Question 13

what are the mechanisms by which drugs cross the biological membranes

Answer 13

paracellular, transcellular, carrier protein, endocytosis

Question 14

what does paracellular mean

Answer 14

travels between cells, small molecules

Question 15

what does transcellular mean

Answer 15

travels through the cell

Question 16

that does carrier protein mean

Answer 16

requires a transpotein to move them through cell

Question 17

what does endocytosis mean

Answer 17

a vesicle is created to carry though cell

Question 18

what is the driving force for movement of drug via paracellular and transcellular

Answer 18

concentration gradient- high to low

Question 19

facilitated diffusion and active transport are both examples of

Answer 19

carrier-mediated transport

Question 20

how much of drugs are predominantly by passive transcellular diffusion

Answer 20

95%

Question 21

transcellular permeability can be increased by

Answer 21

removing charged (ionized) groups, increasing lipophilicity and reducing size

Question 22

passive diffusion across membrane is dependent on

Answer 22

pKa and pH

Question 23

Base: pKa < pH

Answer 23

base passes through

Question 24

Base: pKa > pH

Answer 24

conjugated base passes

Question 25

Acid: pKa > pH

Answer 25

conjugated acid passes

Question 26

Acid: pKa < pH

Answer 26

acid passes

Question 27

paracellular diffusion allows what to pass

Answer 27

small and polar molecules

Question 28

what may open the junction in paracellular diffusion

Answer 28

toxins

Question 29

for a drug which undergoes passive diffusion, the rate of transport across the membrane should increase as the concentration

Answer 29

increases

Question 30

Carrier-mediated mechanism of facilitated diffusion uses

Answer 30

the concentration gradient

Question 31

T/F carrier-mediated transport required energy

Answer 31

FALSE, concentration gradient does not need energy

Question 32

carrier-mediated mechanism of active transport uses

Answer 32

energy to go against concentration gradient

Question 33

what exists on both the apical and basolateral membrane of intestinal and other cells

Answer 33

transport proteins

Question 34

if a drug is a substrate for pgp in the enterocyte, how would co-administration with another drug that inhibited pgp change the amount of drug that entered the systemic circulation

Answer 34

increases

Question 35

consequences of the efflux transporter P-glycoprotein

Answer 35

limited drug absorption, enhanced drug elimination, limited distribution

Question 36

endocytosis is typically for

Answer 36

large molecules

Question 37

T/F there are different mechanisms of endocytosis depending on size

Answer 37

TRUE