Deck 7: Drug Dissolution, Ph-Partition Theory, and Drug Forms

Question 1

The deleterious effect of various coatings on drug dissolution is shown in orders below. Which one of them is the correct order?

A)Enteric coat > sugar coat > nonenteric film coat
B)Enteric coat > nonenteric film coat > sugar coat
C)Nonenteric film coat > sugar coat > enteric coat
D)Sugar coat > enteric coat > nonenteric film coat

Answer 1

Enteric coat > sugar coat > nonenteric film coat

Question 2

Which of the following will be an example of an organic suspending agent?

A)CMC
B)MC
C)Acacia
D)Carbowaxes

Answer 2

Acacia

Question 3

Which one of these is not a mechanism of the working of surfactants?

A)Promote wetting by increasing the effective surface area
B)Helps in the dissolution of drug
C)Better membrane contact of the drug
D)Decrease membrane permeability

Answer 3

Decrease membrane permeability

Question 4

PABA complex is used for the enhancement of ______________

A)Enhanced chelation
B)Enhanced dissolution
C)Enhanced membrane permeability
D)Enhanced lipophilicity

Question 5

The concentration of colorant does not affect the drug solubility.

A)True
B)False
C)none
D)all

Question 6

Suspending agent and some sugars can be used as viscosity imparters.

A)True
B)False
C)none
D)all

Question 7

According to the pH-partition hypothesis which one of the given options doesn't govern the absorption?

A)The molecular size of the drug
B)PH at the absorption site
C)Lipid solubility of unionized drugs
D)Dissociation constant

Question 8

If the pH of either side of the membrane is different, then the compartment whose pH favours greater ionization will have less amount of drug.

A)True
B)False
C)none
D)all

Question 9

Which of the following equations correct for Henderson-Hasselbach equation for weak acids?

A)PH = pKa - log (Unionized drug concentration /Ionized drug concentration)
B)PH = pKa - log (Ionized drug concentration/ Unionized drug concentration)
C)PH = pKa + log (Ionized drug concentration/ Unionized drug concentration)
D)PH = pKa + log (Unionized drug concentration /Ionized drug concentration)

Question 10

Which of the following equations correct for Henderson-Hasselbach equation for weak bases?

A)PH = pKa - log (Unionized drug concentration /Ionized drug concentration)
B)PH = pKa - log (Ionized drug concentration/ Unionized drug concentration)
C)PH = pKa + log (Ionized drug concentration/ Unionized drug concentration)
D)PH = pKa + log (Unionized drug concentration /Ionized drug concentration)

Question 11

What is the pH range of the stomach?

A)1-4
B)5-8
C)1-3
D)1-8

Question 12

What is the pH range of the intestine?

A)4-5
B)1-3
C)1-8
D)5-8

Question 13

Acids in the pKa range 2.5-7.5 are greatly affected by changes in pH making their absorption pH dependent.

A)True
B)False
C)none
D)all

Question 14

Which one of these is an example of a strong acid drug?

A)Diazepam
B)Ibuprofen
C)Cromolyn
D)Aspirin

Question 15

Which one of these is not an example of a basic drug with pKa range 5-11?

A)Cromolyn
B)Imipramine
C)Amitriptyline
D)Chloroquine

Question 16

Example of a drug which has PKa > 11 is ________

A)Cromolyn
B)Imipramine
C)Amitriptyline
D)Mecamylamine

Question 17

What should be the range of oil/water partition coefficient of any drug?

A)1-2
B)3-4
C)2-3
D)1-3

Question 18

Ibuprofen a weak acid, in the stomach will be present in which of the given form?

A)Ionized form mostly
B)Non-ionized form mostly
C)Half ionized and half no ionized
D)Will form aggregate

Question 19

Nitrazepam a weak base, will be in which form in the stomach?

A)Ionized form mostly
B)Non-ionized form mostly
C)Half ionized and half no ionized
D)Will form aggregate

Question 20

All drugs which are weak acids or acidic in nature will be in a unionized form in the plasma.

A)True
B)False
C)none
D)all

Question 21

Heroin with pKa 7.8 will be in which form in intestinal pH?

A)Ionized form mostly
B)Unionized form mostly
C)Half ionized and half no ionized
D)Will form aggregate

Question 22

Which one of these options is not one of the limitations of pH-partition theory?

A)Presence if virtual membrane pH
B)Absorption of ionized drugs
C)Influence of GI surface area
D)Dissolution rate

Question 23

A microclimate pH, different from the luminal pH exists at the membrane surface.

A)True
B)False
C)none
D)all

Question 24

According to the pH-partition theory which form of the drug gets absorbed mostly?

A)Hydrated form
B)Aggregated form
C)Ionised
D)Unionised

Question 25

What helps the ionized drug molecules to pass through the cell membrane passively?

A)Different pH
B)Polar group
C)Large lipophilic group
D)Hydration