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Flashcards in Semi-solid preparations Deck (22)
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1
Q

What are semi solid preparations used for?

A
Inflammation 
Pain
Itching
Protection
Lubrication
Emollient
2
Q

What are the 4 types of semi solids?

A

Ointments
Creams
Pastes
Gels

3
Q

Can semi-solids be used for systemic action?

A

Yes - e.g. Percutol ointment

4
Q

Ointments are highly occlusive therefore good for oily skin. True or false?

A

False - good for dry skin

5
Q

Do ointments have hydrous or anhydrous vehicles?

A

Anhydrous

6
Q

Creams are more occlusive than ointments therefore good for macerated skin. True or false?

A

False- less occlusive

7
Q

Pastes form a thick _______ layer on skin.

A

impermeable

8
Q

What are polymers e.g. carbomer for in gels?

A

To produce a matrix to allow the drug to diffuse through the gel to the site of action

9
Q

Liquid paraffin, soft paraffin and paraffin wax are examples of _________ used in semi-solids

A

mineral oil vehicles

10
Q

What are surfactants used for in semi-solid preparations?

A

To help oil and water form a stable uniform mix

Increase the penetration of the drug

11
Q

Sorbitan laurate is an example of a _______ surfactant

A

non-ionic

12
Q

Humectants such as ______ reduce loss of water from creams and gels

A

glycerol

13
Q

Products high in water are usually most stable. True or false?

A

False - products low in water e.g. ointments and pastes

14
Q

What affects the stability of semi-solids?

A

Heat
Light
Micro-organism growth

15
Q

What are the advantages of ointments and pastes?

A

More stable than creams and gels
Occlusive and protective
Good for dry skin
Less need for preservative

16
Q

What are the disadvantages of ointments and pastes?

A

Greasy and sticky
Slow absorption into skin
Not to be used on macerated skin
High oil content could lead to them being flammable

17
Q

What are the advantages of creams and gels?

A

Non greasy
Rapid absorption into skin
Have cooling effect on evaporation
Can be used on macerated skin

18
Q

What are disadvantages of creams and gels?

A

Susceptible to microbial contamination
Require preservatives which can cause sensitisation
Less stable
Short duration of action due to rapid absorption

19
Q

Drugs in aerosols require _______

A

propellants

20
Q

Why must you shake an aerosol?

A

To disperse the propellant and drug

21
Q

What is the definition of trituration?

A

incorporating liquids or powders into a semi-solid using a ceramic tile

22
Q

What does levigation mean?

A

Applying pressure to incorporate a powder into a semi-solid.

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