Drug Dispositon

Question 1

What is the drug disposition acronym?

Answer 1

ADME

Question 2

What is absorption?

Answer 2

The way in which the drug enters the body from its site of administration

Question 3

What is distribution?

Answer 3

transport of the drug around the general circulation

Question 4

What is metabolism in relation to drug disposition?

Answer 4

process by which tissue enzymes catalyse the chemical conversion of a frequently lipid soluble drug to a more polar form that is readily excreted

Question 5

What is excretion?

Answer 5

The processes that remove the drug or its metabolites from the body

Question 6

What are the 3 physiochemical factors controlling drug absorption from GI tract?

Answer 6

Solubility, chemical stability or lipid to water partition coefficient

Question 7

What is the final factor controlling drug absorption?

Answer 7

degree of ionisation

Question 8

Can ions get across lipid bilayer?

Answer 8

no

Question 9

What does degree of ionisation of drug depend on?

Answer 9

pH and pKa

Question 10

do acidic drugs become more or less ionised in an acidic environment?

Answer 10

more

Question 11

Give 2 factors which affect GI absorption

Answer 11

blood supply to stomach and intestines, pH at point of absorption

Question 12

What is oral availability?

Answer 12

fraction of drug that reaches systemic circulation after oral ingestion

Question 13

What is systemic availability?

Answer 13

fraction that reaches systemic circulation after absorption

Question 14

What is volume of distribution?

Answer 14

the apparent volume in which a drug is dissolved

Question 15

If Vd<10 what does that mean?

Answer 15

retained in vascular

Question 16

If Vd between 10 and 30 what does that mean?

Answer 16

restricted to extracellular water

Question 17

If Vd>30 what does that mean?

Answer 17

distribution throughout total body water