Drug Transport and Absorption

Question 1

What does the ionization of a weak electrolyte depend on?

Answer 1

pKa of the drug

pH of the solvent

Question 2

Do drug concentrations stay the same on either side of a membrane that has differing pH’s?

Answer 2

No, they are unequal it has a higher drug concentration on the side with a pH closer to its own. (side of greater ionization)

Question 3

How ionized do weak acidic drugs become in the stomach and plasma?

Answer 3

Largely non-ionized in stomach

40-50% non-ionized in plasma

Question 4

How ionized do weak basic drugs become in the stomach and plasma?

Answer 4

Mainly ionized in stomach

Non-ionized in plasma

Question 5

How do you trap weak acidic drugs in urine?

Answer 5

Administering sodium bicarbonate to force alkaline diuresis

Question 6

How do you trap weak basic drugs in urine?

Answer 6

Administering ammonium chloride to cause acidification of urine

Question 7

What sort of drugs are collected in breast milk?

Answer 7

Weak bases

Question 8

Why do weak acids remain less concentrated in breast milk?

Answer 8

Plasma is more alkaline than breast milk and thus draws it out

Question 9

How does lower pKa affect acidic drugs?

Answer 9

Creates a greater degree of ionization

Question 10

How does higher pKa affect basic drugs?

Answer 10

Creates a greater degree of ionization

Question 11

What happens if pH = pKa?

Answer 11

Drug is 50% ionized

Question 12

What does AMDE stand for?

Answer 12

Absorption
Distribution
Metabolism
Excretion

Question 13

What is absorption?

Answer 13

Movement of drug from the site of administration to systemic circulation

Question 14

What are the routes of administration that have no first pass effect?

Answer 14

Parenteral and Topical/transdermal/inhaled

Question 15

What is intravenous administration advantageous for?

Answer 15

Narrow therapeutic index
Poor absorption
Rapid metabolism
Poor blood circulation

Question 16

What are the disadvantages of intravenous drug administration?

Answer 16

Drug overdose
Introduce bacteria
Disrupt hemodynamics

Question 17

What should you not introduce intravenously?

Answer 17

Insoluble drugs or oils

Question 18

What is subcutaneous administration used for?

Answer 18

Non-irritating drugs

Question 19

What are the advantages of intramuscular administration?

Answer 19

Rate of absorption is good
More irritating drugs
Larger volumes

Question 20

How does using insoluble or oily drugs affect the absorption of intramuscular administration?

Answer 20

Slower absoprtion

Question 21

How does absorption in the mouth compare to that of the gastrointestinal tract?

Answer 21

4X faster from mouth

Question 22

What kind of drugs are the ideal candidates for sublingual administration?

Answer 22

Non-ionized
Highly lipid soluble
Rapid dissolution

Question 23

What are the advantages of the oral route of administration?

Answer 23

Common
Safest
Convenient
Economical

Question 24

What are the advantages of rectal administration?

Answer 24

Administer labile drugs
Compliance with unconscious patients or patients with swallowing issues
Partial avoidance of the first pass effect

Question 25

What are the disadvantages of rectal administration?

Answer 25

Irregular and incomplete absorption

Drugs can irritate rectal mucosa

Question 26

What are the least permeable body areas of the skin?

Answer 26

Palms
Soles
Nail

Question 27

What are the moderately permeable areas of the skin?

Answer 27

Back
Legs
Arm
Thigh

Question 28

What are the most permeable areas of the skin?

Answer 28

Mucous membranes

Question 29

What are the advantages of pulmonary delivery?

Answer 29

Rapid absorption
Local or systemic delivery
Rapid pharmacological response
Bypass first pass

Question 30

What are the disadvantages of pulmonary delivery?

Answer 30

Efficient aerodynamic filter
Mucociliary transporter
Low pulmonary deposition