Suspensions

Question 1

What is a pharmaceutical suspension?

Answer 1

Coarse dispersion

Question 2

What does a suspension contain?

Answer 2

finely divided insoluble particulate material suspended in a

liquid or semisolid medium (continuous phase or vehicle)

Question 3

What is the criteria for a suspension? (3)
PMS

Answer 3

Particles are uniformly distributed
Minimal solubility in the continuous phase
Size is from 1-100um

Question 4

What are the advantages of suspensions?

Answer 4

Deliver poor water soluble drugs
Chemical stability
Palatability
Sustained release

Question 5

What are the disadvantages of a suspension?

Answer 5

Settling over time leading to lack of uniformity of the dose
Manufacturing difficulties

Question 6

What are the components of a suspension?

Answer 6

Hydrophilic solids
Hydrophobic solids
External phase (Dispersion medium and vehicle)

Question 7

What are the external phases that can make up 100% of the medium?

Answer 7

Water
Simple Syrup
Cherry syrup

Question 8

What are the non-polar liquids of the external phase of suspensions?

Answer 8

Oils
Fatty esters
Hydrocarbons

Question 9

What are some other ingredients added to suspensions? (2)

They do something

Answer 9

Flocculating agents

Viscosity modifiers

Question 10

Do electrolytes decrease or increase Zeta potential?

Answer 10

Decrease

Question 11

Do ionic surfactants decrease or increase Zeta potential?

Answer 11

decrease

Question 12

Why are polysaccharides used only for extemporaneous compounding?

Answer 12

Susceptibility to microbial growth

Question 13

What are the 3 polysaccharides we should know?

Answer 13

Acacia gum
Tragacanth
Alginates

Question 14

What do semi-synthetic cellulose derivatives do?

Answer 14

Increase the range of viscosity

Question 15

What are the water soluble cellulose derivatives we should know? (Viscosity modifiers)

Answer 15

Methylcellulose
Microcrystalline cellulose

Question 16

What are the hydrated silicates we should know?

Answer 16

Bentonite

Just increases viscosity

Question 17

WHat are acrylic acid polymers?

Answer 17

HMW cross linked polymers of acrylic acid form gels in neutralized aqueous dispersions

Question 18

What is the acrylic acid polymers we should know?

Answer 18

Carbopol, enhance viscosity and trap particles

Question 19

What is colloidal silicon dioxide?

Aerosil

Answer 19

Fluffy white powder used as either a suspending or thickening agent or a tablet/capsule diluent

Helps with thickening of formulation in tablet capsule diluent

Question 20

What are the properties of a ideal suspending agent/viscosity modifier?

Answer 20

Dissolved/dispersed without special techniques

Uniformly incorporated

Loosely packed system

no effect on Bioavailability

no Incompatibilities

Stability

Question 21

What are the suspension types? (5)

Answer 21

Oral suspensions
Topical suspensions
Parenteral suspensions
Sterile topical suspensions
Cosmetics

Question 22

What are deflocculated suspensions?

Answer 22

Dispersed particles are small discrete units and have slower gravitational settling

Very difficult to redisperse because the small particles settle and no liquid is between them

Question 23

What are flocculated suspensions?

Answer 23

Particles settle as flocs and the rate of sedimentation is rapid, but liquid is trapped hence it becomes easy to redisperse

Question 24

Is the supernatant clouding or clear in flocculated suspensions

Answer 24

Clear

Question 25

Is the supernatant clouding or clear in deflocculated suspensions

Answer 25

cloudy

Question 26

What are the physical properties of a well-formulated pharmaceutical suspension?

Answer 26

Resuspendable Suspended long enough to remove a dose Sufficiently small Suitable viscosity

Question 27

What are the properties of a high zeta potential?

Answer 27

Have greater repulsive forces > Attractive forces The system is dispersed or deflocculated hence it will cake

Question 28

What are the properties of a low zeta potential?

Answer 28

Have greater attractive forces > repulsive forces System will be flocculated (Hence prevents caking)

Question 29

What is the reason and solution for caking

Answer 29

High zeta potential (Deflocculated) solute is flocculate

Question 30

What is the reason and solution for Crystal Growth

Answer 30

Partial solubility, temp fluctuation Select the insoluble form of the drug, keep it at constant temp, and narrow size distribution

Question 31

What is the reason and solution for Poor redispersibility

Answer 31

Caking, High viscosity, deflocculated suspension Flocculate, keep viscosity optimal

Question 32

What is the reason and solution for cap lock

Answer 32

Sugar in the formula Use a mix of sugar and artificial sweetener

Question 33

What is the reason and solution for settling

Answer 33

Low viscosity, large particles Increase viscosity, reduce particle size

Question 34

What is the reason and solution for Flavour changes

Answer 34

Incompatibility Select another flavour

Question 35

What is the reason and solution for colour changing

Answer 35

Incompatibility, too much air incorporated Solve incompatibility, avoid air bubbles

Question 36

What are most pharmaceutical substances?

Answer 36

Hydrophobic solids

Question 37

What are hydrophobic solids?

Answer 37

Not wetted by water but wetted by oils

Question 38

What are hydrophilic solids

Answer 38

Readily wetted by water

Question 39

What are the only polar liquid solvents you can go up to 100%

Answer 39

Water, Simple syrup, cherry syrup

Question 40

What are the external phase non-polar liquids that we can use up to 100%

Answer 40

Oils Fatty esters Hydrocarbons

Question 41

What are the external phase structured vehicles we should know? ATCMC

Answer 41

Acacian Tragacanth Carbopol methyl cellulose derivatives Colloidal silicon dioxide

Question 42

What is thixotropic

Answer 42

Gets solid when standing, but liquid when moving

Question 43

What is Zeta potential>

Answer 43

It is the particle charge

Question 44

Does larger zeta potential on particles lead to flocculation or deflocculation?

Answer 44

deflocculation (More dispersed)

Question 45

Decreases in zeta potential

Answer 45

decrease deflocculation (Hence making particles more clumpy and more flocculated)

Question 46

What are deflocculated suspensions usually used/made

Answer 46

Usually pharmacy compound for short term

Question 47

What does sodium lauryl sulfate <1% do?

Answer 47

Neutralized static electricity *compounding tip*

Question 48

In a suspension the particles have a ___ solubility in the continuos phase.

Answer 48

minimal

Question 49

Why are suspension not used for parenteral administration?

Answer 49

Due to the settling and sometimes thixotropic effects of the suspension

Question 50

What are some sweeteners one could use for a suspension?

Answer 50

Sugar, lactose, dextrose

Question 51

How can we decrease Zeta potential

Answer 51

Adding electrolytes, ionic surfactants

Question 52

Does polymeric flocculating agents effect Zeta potential?

Answer 52

No, instead if increases viscosity

Question 53

Which type (Flocculated or Defloculated) is not recommended for storing over a long period of time?

Answer 53

Defloculated due to caking

Question 54

What does Magnesium stearate <1% do?

Answer 54

Enhances flowability

Question 55

What does Sodium Lauryl sulphate do <1%?

Answer 55

Neutralized static electricity