Exam 1: Liquid Dosage Forms

Question 1

What are the three advantages of solutions?

Answer 1

1. No issues with content uniformity
2. Easy to manufacture
3. Good bioavailability

Question 2

What is the Handersen-Hasselbalch equation?

Answer 2

pH = pKa + log[A-]/[HA]

Question 3

What is buffering capacity?

Answer 3

The ability of a buffer to resist change in pH due to added OH- or H+. The greater the buffering capacity, the better the buffer.

Question 4

What are three things you can do if the solution’s pH cannot be adjusted to match physiologic pH?

Answer 4

1. Minimize buffering capacity
2. Minimize volume
3. Administer slowly to minimize pain

Question 5

What are the steps to designing a buffer with a specific pH and buffering capacity?

Answer 5

1. Choose option with pKa closest to pH
2. Solve Henderson-Hasselbalch for ratio of base to acid
3. Solve Van Slyke for C to get HA + A-

Question 6

What are the two mechanisms of action of antimicrobial preservatives?

Answer 6

1. Adsorption due to lipid solubility

2. Adsorption due to electrostatic attraction

Question 7

What are the four classes of antimicrobial preservatives?

Answer 7

1. Alcohols
2. Acids (unionized)
3. Esters (parabens)
4. Quaternary ammonium compounds

Question 8

What are the properties of an ideal preservative?

Answer 8

1. Effective in low concentrations against a wide variety of organisms.
2. Soluble in formulation
3. Non-toxic
4. Stable

Question 9

What are the six components of a solution?

Answer 9

1. Active Ingredient
2. Solvent and Cosolvent
3. Buffer
4. Preservative
5. Antioxidant/chelating agent
6. flavor and sweetner

Question 10

Sodium bisulfite

Answer 10

Antioxidant acting by preferential oxidation

Question 11

EDTA

Answer 11

Chelating agent

Question 12

Sorbitol solution

Answer 12

sweetener

Question 13

glycerin

Answer 13

cosolvent

Question 14

methyl paraben

Answer 14

preservative acting by lipid adsorption

Question 15

Benzalkonium chloride

Answer 15

preservative acting by electrostatic adsorption

Question 16

Ascorbic acid

Answer 16

Antioxidant, buffering agent

Question 17

Benzoic acid

Answer 17

Preservative

Question 18

Chlorpromazine

Answer 18

Active ingredient

Question 19

Citric acid

Answer 19

chelating agent, buffering agent, antioxidant

Question 20

Propylene glycol

Answer 20

Cosolvent

Question 21

Sodium bisulfite

Answer 21

antioxidant

Question 22

sodium dihydrogen citrate

Answer 22

chealting agent, buffering agent

Question 23

sucrose

Answer 23

sweetener

Question 24

water

Answer 24

solvent

Question 25

What are the two regions of a surfactant?

Answer 25

1. Hydrophobic

2. Hydrophilic

Question 26

What does a low HLB indicate?

Answer 26

Greater lipid solubility

Question 27

What is the HLB equation?

Answer 27

HLB = aX + (1-a)Y

Question 28

What is the role of emulsifiers?

Answer 28

help create a more uniform solution and stabilize the emulsion

Question 29

When does micelle formation occur?

Answer 29

When the concentration of surfactant increases above a critical concentration, the surfactant molecules self-associate into micelles

Question 30

What do hydrophilic colloids do?

Answer 30

Create a multimolecular film at interface and increase the viscosity of water. DO NOT LOWER INTERFACIAL TENSION