Emulsions Lecture

Question 1

Define emulsions

Answer 1

Thermodynamically unstable

• Consist of two or more immiscible liquid phases: dispersed phase and dispersion medium
• Stabilized by emulsifying agents

Question 2

Application and advantages of emulsions

Answer 2

Oral admin

• Reduced droplet size of oil globules make the oil more digestible and more readily absorbed
• Spread easily and completely over skin
• Irritation producing drugs
• More softening to the skin; resist drying
• Easily removed

Question 3

Oral emulsions are? External are?

Answer 3

o/w

w/o

Question 4

Define multiple emulsions

Answer 4

Droplet size of dispersed phase is smaller

• Miscible with continuous phase
• Prolonged action, taste masking, improved stability
• Putting two incompatible hydrophilic substance in te inner and outer aqueous phases separated by the middle oil phase

Question 5

Two types of multiple emulsions

Answer 5

O/W/O

W/O/W

Question 6

Define micro-emulsions

Answer 6

Stable
Transparent
Both o/w and w/o
Rapid and efficient oral absorption of drugs
Enhanced permeation through skin
Targeting of cytotoxic drugs to cancer cells

Question 7

Dye test?

Answer 7

Water-soluble dye
O/w: distributes
W/O: clumps

Question 8

Electrode tests?

Answer 8

Electrode in emulsions
O/W: passes through
W/O no current passes

Question 9

Oral?
IV?
IM?
Semisolids?

Answer 9

O/W
O/W
W/O
Either

Question 10

Oil phase to be used?

Answer 10

Affects the viscosity and spreadability

- Can be active agent

Question 11

Define emulsion consistency

Answer 11

Texture and feel
w/o: greasy
- Allow dispensing from a flexible plastic container

Question 12

Define emulsifying agents

Answer 12

Based on type, safety and route of admin
Non-ionic: not irritating
Ionic: irritating

Question 13

Define Antioxidant

Answer 13

prevent oxidation of drugs and oil components

Question 14

Define preservative

Answer 14

prevent the growth of microorganisms

Question 15

Dry gum method

Answer 15

4 oil, 2 water, 1 gum
Acacia with oil then water
“primary emulsion”

Question 16

Wet gum method

Answer 16

Acacia with water

Oil slowly

Question 17

Bottle method

Answer 17

Acacia with oil then water

Question 18

Industrial manufacturing

Answer 18

Subjected to high shearing and hydraulic forces

-Discharged and recirculated

Question 19

Define creaming

Answer 19

flocs or aggregates rise to the top of the emulsion

- redistributed upon shaking

Question 20

Define upward creaming

Answer 20

Dispersed phase is less dense than the continuous o/w

- negative velocity of sedimentation

Question 21

Define downward creaming

Answer 21

Internal phase is heavier than teh external

w/o

Question 22

Define density

Answer 22

greater the difference the larger the globules

Question 23

Define viscosity

Answer 23

Less viscous the external phase, greater rate of creaming

Question 24

Define coalescene

Answer 24

merge to form larger droplets

Question 25

Define breaking

Answer 25

Separation of internal phase from extermal

• irreversible
• protective sheath breaks

Question 26

Stabilization

Answer 26

Globule size should be reduced

• Density difference should be minimal
• Viscosity should be reasonably high
• Increased electrostatic repulsion

Question 27

Storage

Answer 27

Protected from extreme cold and heat and outside stuff

Appropriate formulation and packaging