Suspensions

Question 1

Define suspension

Answer 1

Question 2

Based on what are the suspensions classified

Answer 2

Based on routes of administration
Based on proportion of solid particles
Based on electro-kinetic nature of solid particles
Based on size of solid particles

Question 3

What is the classification of suspension based on the routes of administration ?

Answer 3

Question 4

What is the classification of suspension based on the proportion of solid particles ?

Answer 4

Question 5

What is the classification of suspension based on the electro-kinetic nature of solid particles ?

Answer 5

Question 6

What is the classification of suspension based on the size of solid particles?

Answer 6

Question 7

List advantages of suspensions

Answer 7

Overcomes difficulty of swallowing
Faster rate of dissolution and oral absorption
Higher rate of bioavailability
Useful for low solubility drugs
Masks unpleasant taste of drugs in their soluble form
Improves chemical stability
Duration and onset of action can be controlled

Question 8

List disadvantages of suspensions

Answer 8

Question 9

What are the properties of good suspension

Answer 9

Question 10

What is considered during formulation of suspensions

Answer 10

Question 11

Why it is important to consider particle size for suspensions?

Answer 11

Question 12

Why is it important to consider particle shape for suspension?

Answer 12

Question 13

What is zeta potential ?

Answer 13

The difference in potential between the surface of tightly bound layer

Question 14

What is flocculation

Answer 14

Question 15

What is the value for zeta potential

Answer 15

+- 30mV

Question 16

What are the differences between flocculated and deflocculated suspension ?

Answer 16

Question 17

What are the excipients present in suspensions?

Answer 17

Wetting agents
Suspending agents
Thickening agents
Buffers and pH adjusting agents
Coloring agents
Preservatives

Question 18

What is wetting agent?

Answer 18

A substance that lowers the surface tension of a liquid and thus allows it to spread more easily

Question 19

What will happen if there is excessive amount of wetting agent ?

Answer 19

Will lead to foaming or undesirable taste or odor to suspension

Question 20

What does the wetting ability depend on?

Answer 20

The angle of contact between the particle and the solvent which should be less than 90

Question 21

Example of wetting agents

Answer 21

Alcohol in tragacanth mucilage
Glycerin or glycol in sodium alginate

Question 22

What are suspending agents ?

Answer 22

They form film around particle and decrease the inter-particle attraction

Question 23

What do the surfactants with negative charge do ?

Answer 23

They are absorbed on the particles, minimize flocculation in the presence of positive ions because of natural repulsion of like charges

Question 24

Example of negative charge surfactant

Answer 24

Sodium lauryl sulphate, sodium dioctyl sulphocinate

Question 25

Example of non-ionic surfactant

Answer 25

Tweens, carbowaxses

Question 26

What is thickening agent

Answer 26

They increase the viscosity of the continuous phase so that the particles remain suspended for a sufficient long time

Question 27

What are the thickening agents rarely used ?

Answer 27

Natural thickening agents - acacia, tragacanth, sodium alginate

Question 28

What are the thickening agents used commonly ?

Answer 28

Semi-synthetic structured vehicles - methyl cellulose, CMC, hydroxypropyl methyl cellulose

Question 29

What are other example of thickening agents

Answer 29

Clays such as hydrated aluminium silicate or magnesium silicate

Question 30

What are the requirements for preservatives ?

Answer 30

Question 31

What are the examples of preservatives ?

Answer 31

Benzoic acid, sodium benzoate, methyl and propyl paraben

Question 32

What are the factors affecting stability of suspensions ?

Answer 32

Particle size Increasing the viscosity Temperature

Question 33

The rate of sedimentation, agglomeration is affected by what?

Answer 33

Particle size

Question 34

What is the most efficient method of producing small particle size ?

Answer 34

Dry milling Wet milling for potentially explosive ingredients

Question 35

What will happen to the rate of sedimentation if the viscosity is increased?

Answer 35

The rate of sedimentation will be reduced

Question 36

What else is dependent on viscosity ?

Answer 36

The rate of release of a drug from suspension

Question 37

How does temperature affect stability of suspensions?

Answer 37

Temperature fluctuations can lead to caking and claying

Question 38

What are the methods for stabilizing suspension ?

Answer 38

Electrical stability Steric stability

Question 39

What is electrical stability ?

Answer 39

Question 40

What is steric stability ?

Answer 40

Question 41

What is the packaging of suspensions?

Answer 41

Wide mouth containers having adequate space above the liquid to ensure proper mixing Parenteral suspensions are packed in either glass ampules or vials

Question 42

What are the characteristics for ideal packaging of suspension

Answer 42

Question 43

What should the labeling of suspension include ?

Answer 43

Question 44

What conditions should the suspension be stored at ?

Answer 44

Question 45

What are the recent advances in suspensions ?

Answer 45

Nanosuspensions Tastebmasked pharmaceutical suspensions Sustained release suspensions

Question 46

What are nanosuspensions ?

Answer 46