Semi-solid preparations

Question 1

What are semi solid preparations used for?

Answer 1

Inflammation 
Pain
Itching
Protection
Lubrication
Emollient

Question 2

What are the 4 types of semi solids?

Answer 2

Ointments
Creams
Pastes
Gels

Question 3

Can semi-solids be used for systemic action?

Answer 3

Yes - e.g. Percutol ointment

Question 4

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

Answer 4

False - good for dry skin

Question 5

Do ointments have hydrous or anhydrous vehicles?

Answer 5

Anhydrous

Question 6

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

Answer 6

False- less occlusive

Question 7

Pastes form a thick _______ layer on skin.

Answer 7

impermeable

Question 8

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

Answer 8

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

Question 9

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

Answer 9

mineral oil vehicles

Question 10

What are surfactants used for in semi-solid preparations?

Answer 10

To help oil and water form a stable uniform mix

Increase the penetration of the drug

Question 11

Sorbitan laurate is an example of a _______ surfactant

Answer 11

non-ionic

Question 12

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

Answer 12

glycerol

Question 13

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

Answer 13

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

Question 14

What affects the stability of semi-solids?

Answer 14

Heat
Light
Micro-organism growth

Question 15

What are the advantages of ointments and pastes?

Answer 15

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

Question 16

What are the disadvantages of ointments and pastes?

Answer 16

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

Question 17

What are the advantages of creams and gels?

Answer 17

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

Question 18

What are disadvantages of creams and gels?

Answer 18

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

Question 19

Drugs in aerosols require _______

Answer 19

propellants

Question 20

Why must you shake an aerosol?

Answer 20

To disperse the propellant and drug

Question 21

What is the definition of trituration?

Answer 21

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

Question 22

What does levigation mean?

Answer 22

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