Skin Physical Enhancers & Skin Hydration Flashcards
Is it still a cosmetic if we inject something into the skin?
No. It is only a cosmetic if it is applied to the external surface of skin
What are physical enhancers
They are an alternative to chemical enhancers to disrupt the SC for delivery of large molecules
e.g. iontophoresis, ultrasound, electroporation, thermal ablation, microneedles
What is iontophoresis
Acts by applying a small electric current to the skin
e.g. used for those who have overactive sweat glands
What about ultrasounds
Makes use of ultrasound waves that generate small bubbles of water on the surface of the skin
safer alternative to liposuction
What is thermal ablation
Applies localised heat for a short period of time to create microscale pores across the SC
What are microneedles
Some are permanent while some are dissolvable
length rather than density of microneedle is more impt bc if its too long it may hit the nerve
How does skin hydration work?
Stratum corneum: water content is 15-20%
Viable epidermis: water content is 70%
water gradient allows lipids to provide an optimal way to replenish water within skin
What is TEWL (Transepidermal water loss)?
indirect measure of how good the SC is as a barrier
higher the reading, higher the loss of water
readings would be diff in diff ctys (due to temp & humidity diff) therefore need a baseline when comparing
What are the 2 basic formulations of cosmetics?
- Oil-in-water (water as dominant phase)
2. water-in-oil (oil as dominant phase)
What are the main ingredients in cosmetics for skin hydration?
- Occlusive agents
- forms a barrier across skin to lock water e.g. petrolatum & ceramides - Humectants
- attracts & hold water to be within skin e.g. NMFs, glycerin - Emollients
- fill the space between desquamating corneocytes with droplets - Hydrophillic matrices
- Sunscreens
- Charged surfectants
Give some e.g. of occlusives
They retard TEWL but do not allow SC to repair its barrier function
e.g. petrolatum, lanolin, lecithin, cholesterol
Humectants
Absorbs water from surroundings, drags water to skin
e.g. glycerin/glycol, hyaluronic acid, urea, sodium lactate, PCA
Glycerine
Humectant
Part of the NMF present in skin
used as a preservative
Lactic Acid
Humectant
is an AHA, exfoliating agent
Urea
Humectant