Drugs

Question 1

What is the difference between topical and transdermal drug administration?

Answer 1

Topical; aims for local effect

Transdermal; aims for systemic effects

Question 2

What affects the vehicle used for drug delivery?

Answer 2

The condition of the skin - dry or oozing etc

Question 3

What affects the rate of absorption of a drug across the skin surface?

Answer 3

Ficks law: thickness and surface area (and the diffusion gradient)

Question 4

What type of drug in what kind of vehicle has the best delivery across the skin?

Answer 4

Lipophilic drug in hydrophilic base (as is more soluble in the skin so diffuses/partitions into the skin)

Question 5

What is an excipient?

Answer 5

A pharmacologically inert substance that increases the solubility of the drug in its vehicle

Question 6

What is the purpose of excess (supersaturated drug)?

Answer 6

This becomes dissolved once the already dissolved drug has diffused across the skin barrier increasing the duration of effectiveness

Question 7

What is the partition coefficient and what is the main factor which affects this?

Answer 7

The extent to which the drug diffuses across the stratum corneum into the skin, this is massively affected by the hydration of the skin

Question 8

How to glucocorticoids work?

Answer 8

They turn on/off genes to modify the rate of synthesis of different proteins