Lectures 11-13 - Topical Drug Delivery

Question 1

What systems are creams?

Answer 1

2 phase systems
require emulsifiers to stabilise the mixture of oil and water phase

Question 2

The properties of w/o creams

Answer 2

Blend easily with SC lipids, improving bioavailability of lipid soluble drugs and moisturising skin via slight occlusive effect
hydrophobic, semi solid
2 phase system
comprising a water and continuous lipid phase

Question 3

The properties of o/w creams

Answer 3

More cosmetically pleasing (less sticky and greasy) contact of outer aqueous phase with skin increases water evaporation -> cooling affect after application
hydrophobic, semi solid
2 phase system
comprising water and continuous lipid phase

Question 4

How do we maximise the flux?

Answer 4

we need to maximise the concentration that we achieve in the vehicle

Question 5

if too much PG is added what happens?

Answer 5

Drug happy to stay in the vehicle has no tendency to leave

Question 6

Benefits of using co-solvents

Answer 6

helps solubilise lipophilic compounds in water
if you increase PG you decrease the partition coefficient

Question 7

What does percutaneous absorption depend on?

Answer 7

Physicochemical properties of the drug
interactions of drug with vehicle or delivery systems and with the skin
condition of the skin

Question 8

Name the 3 pathways through the SC

Answer 8

Follicular
intracelular
transcellular