D8

Question 1

What’s an emulsion?

Answer 1

It’s a liquid medicine in which one insoluble liquid is dispersed as microscopic globules in another liquid (both are immiscible

Question 2

How does an emulsion look like

Answer 2

External or continuous phase ( the liquid vehicle)
Internal or dispersed phase ( the droplets)
Molecular film of emulsifying agents at the oil/ water interface

Question 3

The types of emulsion

Answer 3

1. Oil in water o/w Milky white
2. Water in oil w/o translucent
3. The third one can be multiple emulsions w/o/w or o/w/o which is droplets within the droplets

Question 4

Stability

Answer 4

They are physically unstable and they would want to separate

Question 5

Creaming

Answer 5

When the oil collects near the surface

Question 6

Cracking

Answer 6

This is the separation phase, it’s an irreversible Reaction, which is very different from caking. The separation happen because the density of oils is less than water

Question 7

Cracking

Answer 7

This is the separation phase, it’s an irreversible Reaction, which is very different from caking. The separation happen because the density of oils is less than water

Question 8

Preventing creaming and cracking by droplet size

Answer 8

The smaller the droplets the more stable
Shelf like up to 2 years which is very short.

Question 9

Preventing creaming and cracking by temperature

Answer 9

Shouldn’t be exposed to heat or temperature fluctuations, freezing causes rapid separation, the crystals destablise the film between oil and water

Question 10

What type of emulsion is more stable

Answer 10

The oil in water is more stable than water in oil
That’s because creams are more stable than liquid emulsions

Question 11

What are emulsifiers

Answer 11

( surface active) long molecules that locate at the oil water surface interface

Question 12

What are emulsifiers 2?

Answer 12

They are amphiphiles as they have hydrophilic head and hydrophobic tail

Question 13

Position of amphiphiles

Answer 13

Between water and air, The hydrophilic head faces the water and the hydrophobic tail faces the air

Question 14

Position of emulsifiers

Answer 14

Between water and oil the hydrophobic tail faces the oil while hydrophilic head faces the water

Question 15

The types of emulsifiers including charges

Answer 15

Anionic which has a negative charge
Cationic which has a positive charge
Non-janie which has no overall charge

Question 16

Why we don’t use single charged amphiphile

Answer 16

Positive charged ones repel the internal phase droplets
Negative repel each other at the surface
Can react with drugs or excipients

Question 17

Why do we use mixed emulsifiers

Answer 17

We use charged and non-ionic
Dense inter facial film
Better for stabilising emulsions

Question 18

What are the stability issues with oil in water emulsions

Answer 18

They have a huge surface area internally which makes it very sensitive to hydrolysis and fat oxidation so usually need oil soluble antioxidant

Question 19

What are the issues with oil in water

Answer 19

The ester bonds hydrolyse
The unsaturated bonds oxidise
Forming short chain fatty acid
Then they become rancid( bad smell and change in appearance/ taste)

Question 20

Stability issues with oil in water emulsions

Answer 20

Microorganisms grow well
Preservative must be added, but can destabilise the emulsifier film making it insectivore

Question 21

Are emulsions stable

Answer 21

They are physically, chemically and mierobiologically unstable

Question 22

The oral Route, by mouth

Answer 22

More palatable
easier to administer
More eligestible due to large surface area of droplets

Question 23

Topical Route

Answer 23

Lotions
creams

Question 24

What’s a cream

Answer 24

Emulsion to be applied on the skin in which one of the 2 phases is a semi solid or a wax

Question 25

Creams

Answer 25

Can be oil in water or water in oil
Insoluble powders
Ingredients that are soluble either in oily or aqueous phase