Topical and Transdermal

Question 1

Why apply drugs on skin?

Answer 1

• Skin surface treatment - suncream
• Target dermal layers - antiseptic (ringworm infection)
• Systemic deliver - choose area of skin higher systemic blood level

Question 2

Skin structure

Answer 2

• Stratum corneum
• Epidermis
• Dermis - nerve endings
• Subcutaneous fat

Question 3

Drug to skin

Answer 3

• Diffuse through the stratum corneum
• Enter viable epidermis or dermis
• Systemic circulation

Question 4

Entry point of drug to skin

Answer 4

• Sweat gland and sweat ducts/ Sebaceous gland
• Mainly direct diffusion from stratum corneum barrier to water leaving

Question 5

Stratum corneum structure

Answer 5

• Cells are polar and the motor is lipid rich (non-polar)
• Can diffuse directly or around in the continuous motor phase

Question 6

Topical drugs

Answer 6

• Need to have an intermediate partition coefficient
• Needs to be in its unionised form (Low log)
• Low molecular weight required <500 dalton s

Question 7

Formulation factors

Answer 7

• Leads to hydration
• Creams and ointments

Question 8

Most to least penatration

Answer 8

• Genitals
• Head and neck
• Trunk
• Arms and Legs

Question 9

Eczema

Answer 9

• Dry rash skin
• Damage to stratum corneum reduces ability to loose water
• First line treament to dry scaly skin
• Only oily ingreedients