Emulsion

Question 1

What is an emulsion?

Answer 1

Dispersion of two immiscible or partially miscible liquids where one is uniformly distributed as fine droplets within the other; both must be relatively stable + homogeneous

Question 2

When are multiple phase emulsions used?

Answer 2

Often as modified/slow release dosage forms

Question 3

What is generally needed as a third phase in multiple phase emulsions?

Answer 3

An emulsifying agent; required to stabilize emulsions

Question 4

How are emulsions administered?

Answer 4

Oral
Topical
Parenteral

Question 5

Oil in water emulsions mask what?

Answer 5

Foul tasting oils

Question 6

How would you make the oil more digestible and readily absorbed?

Answer 6

Globule size reduction

Question 7

What does a globule size reduction do to the oils?

Answer 7

Makes them more digestible and readily absorbed

Question 8

What kind of emulsion is more easily removed by water?

Answer 8

Oil in water

Question 9

What kind of emulsion can be applied more evenly?

Answer 9

Water in oil

Question 10

(T/F) Advantages of Emulsion

Poorly water soluble drugs may be easily incorporated

Answer 10

True

Question 11

(T/F) Advantages of Emulsion

Does not do much to mask unpleasant taste/odor of oils

Answer 11

False; it does mask

Question 12

(T/F) Advantages of Emulsion

Enhanced abosorption

Answer 12

True

Question 13

What is the surface tension theory?

Answer 13

Assumes a shape to minimize their surface area

Question 14

According to the surface tension theory, when two or more drops of the same liquid come into contact, what is thermodynamically favorable?

Answer 14

To coalesce, form one large drop to reduce surface area

Question 15

According to the surface tension theory, what do surfacants, emulsifiers, or wetting agents do?

Answer 15

Encourage liquids to disperse into smaller drops

Lowers interfacial tension of two immiscible liquids + reduce repellent force while lowering liquids attraction for its own molecules

Question 16

According to the surface tension theory, by _______ interfacial tension, surfactants, emulsifiers help convert large globules into smaller ones that have a _____ tendency to reunite/coalesce

Answer 16

lowering

lower

Question 17

What is the oriented wedge theory?

Answer 17

Surfactant/emulsifying agents form monolayers around droplets of the internal phase of the emulsion to prevent coalescence

Question 18

What is the plastic or interfacial film theory?

Answer 18

Emulsifier forms an interface between the oil and water

Question 19

According to the oriented wedge theory, a wedge encompasses the globules preventing _____

Answer 19

coalescence

Question 20

According to the plastic or interfacial film theory, what prevents the contact and coalescing of the dispersed phase?

Answer 20

film

Question 21

According to the plastic or interfacial theory, what must the film be able to do to each drop?

Answer 21

Coat the entire surface

Question 22

According to the plastic or interfacial theory, water-soluble agents encourage what kind of emulsions?

Answer 22

Oil in water

Vice versa for the other way around

Question 23

In reality, what is the caveat behind all three theories?

Answer 23

None individually explain the mechanism by which emulsifiers form and stabilize emulsions

Question 24

It is very likely that these theories simultaneously play a part (T/F)

Answer 24

True

Question 25

When picking an emulsifier, what should it be?

Answer 25

1. Stable 2. Non-toxic 3. Little to no odor, taste or color 4. Proper HLB balance

Question 26

Carbohydrates form what emulsions?

Answer 26

Oil in water

Question 27

What are examples of carbohydrate emulsifying agents?

Answer 27

Acacia

Question 28

Proteins form what emulsions?

Answer 28

Oil in water

Question 29

What are examples of protein emulsifying agents?

Answer 29

Gelatin

Question 30

High molecular weight alcohol form what emulsions?

Answer 30

Oil in water

Question 31

Cholesterol forms what kind of emulsion?

Answer 31

Water in oil

Question 32

Surfactants + wetting agents may be: * Non-ionic * Ionic * Anionic * Cationic * Zwitterionic

Answer 32

All except ionic

Question 33

Surfactants + wetting agents form what emulsions

Answer 33

Both kinds

Question 34

Emulsions are considered physically unstable if:

Answer 34

1. Globules tend to form upon standing 2. Large globules rise/sink to form a concentrated layer 3. Ostwald ripening

Question 35

Large globules rise/sink to form a concentrated layer is known as....

Answer 35

creaming

Question 36

Is creaming reversible?

Answer 36

Yes

Question 37

How can you reduce creaming?

Answer 37

1. Form smaller particles 2. Increase viscosity 3. Decrease density difference

Question 38

What is Ostwald ripening?

Answer 38

Diffusion of material from smaller to larger droplets in the continuous phase

Question 39

When is Ostwald ripening most often observed in?

Answer 39

water in oil

Question 40

Which temperature should you protect emulsions from?

Answer 40

Extreme cold + heat

Question 41

What does freezing/heating do to emulsions?

Answer 41

Separation and coalescence of the internal phase

Question 42

When is temperature a issue in emulsions?

Answer 42

Shipping/storage, time of year, different countries

Question 43

How can small-scale emulsions prepared by?

Answer 43

1. Mortar/pestle 2. Blender 3. Simple prescription bottle

Question 44

What are the two small-scale emulsion methods?

Answer 44

1. Dry gum method | 2. Wet gum method

Question 45

Dry gum method is referred to as the ________ method

Answer 45

4:2:1 4 x oil, 2 x water, and 1 x emulsifying agent

Question 46

What is the usual emulsifying agent for the dry gum method?

Answer 46

Acacia gum

Question 47

How is the wet gum method different from the dry gum counterpart?

Answer 47

Order is different After the viscous paste is made, it is followed by a slow addition of the oil

Question 48

Higher HLB numbers means the more _______ the surfactant/emulsifying agent

Answer 48

hydrophilic

Question 49

HLB values are ______ additive

Answer 49

algebraically

Question 50

What is trituration?

Answer 50

Process of grinding to a fine powder in the dry state

Question 51

What is Levigation?

Answer 51

Process of grinding an insoluble substance to a fine powder while wet

Question 52

What is the levigating agent?

Answer 52

Liquid that is used to grind the insoluble material

Question 53

While levigation is happening, powder being ground must not be ____ in the liquid

Answer 53

soluble

Question 54

HLB values of 3-6 are greatyl _______ and produce ______ emulsions

Answer 54

Lipophilic water in oil

Question 55

HLB values of 8-18 are greatly _______ and produce ______ emulsions

Answer 55

hydrophilic oil in water