Topical Products

Question 1

How are dermatological formulations applied?

Answer 1

applied directly to an external body surface by rubbing/spreading (inunction), spraying or instilling

Question 2

Give an overview of the skin.

Answer 2

It provides a sturdy, flexible, self-repairing barrier to the exterior, protecting internal body organs and fluids from external influences, harmful molecules and micro-organisms.
Skin permeability restricts excess water loss, and exercises temperature control over the body.
The skin forms an extensive sensory surface, transmitting sensations such as heat, cold, touch, pressure and pain to the central nervous system.

Question 3

What are the 3 main histological layers of skin?

Answer 3

Epidermis, dermis, subcutis.

- below this = muscles

Question 4

What controls hair on skin?

Answer 4

erector pili

-activated in cold.

Question 5

Where is stratum corneum?

Answer 5

Outermost layer of skin. Thinner around eyes, thicker at feet.

• not metabolically active.
• is the rate limiting barrier consisting of alternating amorphous lipophilic and hydrophilic layers.

Question 6

What is the effect of the nociceptors being further down the layers of skin?

Answer 6

Won’t be activated easily by gentle pressure on skin. Signals only sent if severe pain experienced.

Question 7

The epidermis is made of 5 distinct layers, what are they called?
-epidermis made of stratified epithelium.

Answer 7

Deepest layer to outermost:
Stratum germinativum 
Stratum spinosum 
Stratum granulosum 
Stratum lucidum 
Stratum corneum

Question 8

What is sebum?

Answer 8

A lipid plasticiser secreted by hair follicles associated with sebaceous glands.
- has antimicrobial properties, keeps skin supple, reduces water loss from skin surface.

Question 9

What does a barrier cream/ointment do?

Answer 9

Enhances natural barrier - retain moisture.

Question 10

What will an emollient do?

Answer 10

Will reduce the amount of water that escapes from the skin – will improve the amount of moisture that is in the stratum corneum.

Question 11

What will a moisturizer do?

Answer 11

Reduce water loss from skin will also actively delivering moisture to skin. Keeps skin hydrated.

Question 12

What will an occluding agent do?

Answer 12

Heavier version of an emollient - will stop loss of moisture completely.

Question 13

What is the use of a permeation enhancer?

Answer 13

Disrupts the structure of the stratum corneum lipids to enhance transdermal drug permeation.

Question 14

What is topical therapy used for?

Answer 14

• increasing the barrier (sunscreens, barrier creams, etc.)
• reducing the barrier efficiently (transdermal drug delivery).
• treating a barrier damaged by skin disease or infection (steroids, antibiotics, etc.).
• restoring the physical characteristics of a barrier adversely affected by the environment (emollients, moisturisers, occluding agents, etc.).

Question 15

What is the process of thinning the barrier called? And when might this be used?

Answer 15

Sloughing.

• used when barrier is distorted due to corn, calluses.
• removal using keratolytics - break apart keratinous fabric of stratum corneum.
• these agents must not be dispensed to diabetics - keratolytics e.g. salicylic acid can cause skin erosion - can lose limb if diabetic.

Question 16

What is the effect of prolonged systemic steroid use?

Answer 16

Adrenal suppression. Suddenly withdrawing steroid an cause systemic collapse.