Transdermal

Question 1

What are the functions of the skin?

Answer 1

• protection
• apart of immune, nervous and endocrine system
• maintains tempt, electroyltes, fluid balance
• metabolism of lipids, proteins ect

Question 2

advantages of transdermal delivery

Answer 2

1. convenient
2. avoid GI tract
3. Avoid first pass
4. continious drug administration
5. can remove quickly

Question 3

Disadvantages for transdermal

Answer 3

1. for slow release only
2. depends on drug pK
3. skin irritation
4. may develop tolerance

Question 4

difference between intercellular and transcellular delivery

Answer 4

intercellular = drug moves between the cells, easier to achieve, stays in aqueous stage

transcellular = drug moves as cross flies through cells, must have aqueous and lipid layer, harder to achieve

Question 5

What influences skin penetration

Answer 5

• age
• condition, injury/disease
• anatomical site
• blood flow
• skin metabolism
• species

Question 6

where dose the most absorption occur

Answer 6

• scrotum
• forehead
• jaw

Question 7

How to predict drug suitability?
MW
MP
potency
partition 
half life
solubility 
vol dis

Answer 7

<500 
<100
potency
1-3
1-9 hr 
oily
<65L

Question 8

Reservoir systems
how it is made
characteristics

Answer 8

1. Blacking film, drug reservoir, release membrane, adhesive, release liner
2. slow and constant

Question 9

Matrix system
how it is made
characteristics

Answer 9

1. backing film, matrix later, release liner

2. initial rapid release, then is slows down, thinner type

Question 10

Azone

Answer 10

• used to increase skin penetration
• binds to ONE ceramide molecule through H bonding
• leaves gaps in pores allowing drug to pass through

Question 11

N-9015-Ceramide

Answer 11

actually makes the H bonding between ceramide in skin stronger, thus decrease drug penetration

Question 12

chemical enhancers

1. to increase diffusion coefficient
2. increase drug solubility

Answer 12

1. azone, terepenes (eucalyptus oil), ethanol

2. propylene glycol, ethanol

Question 13

physical enhancers

1. liposomes (carriers)
2. ionphorersis
3. sonophoresis
4. magnetophoresis

Answer 13

1. flexible, may squish themselves to fit between cells
2. eletrical current with different charge to drug molecules, thus causes eletrorepulsion and eletroosmotic effect - pushing drugs into skin eg fentanyl patch
3. ultrasound wave that shakes up structure of stratnun cornea, easier for drug to move into skin
4. magenetic energy

Question 14

How to Microneedles work?

Answer 14

Solid
Coated with drug
dissolable
hollow