Skin Physical Enhancers & Skin Hydration Flashcards

1
Q

Is it still a cosmetic if we inject something into the skin?

A

No. It is only a cosmetic if it is applied to the external surface of skin

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2
Q

What are physical enhancers

A

They are an alternative to chemical enhancers to disrupt the SC for delivery of large molecules
e.g. iontophoresis, ultrasound, electroporation, thermal ablation, microneedles

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3
Q

What is iontophoresis

A

Acts by applying a small electric current to the skin

e.g. used for those who have overactive sweat glands

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4
Q

What about ultrasounds

A

Makes use of ultrasound waves that generate small bubbles of water on the surface of the skin
safer alternative to liposuction

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5
Q

What is thermal ablation

A

Applies localised heat for a short period of time to create microscale pores across the SC

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6
Q

What are microneedles

A

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

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7
Q

How does skin hydration work?

A

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

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8
Q

What is TEWL (Transepidermal water loss)?

A

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

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9
Q

What are the 2 basic formulations of cosmetics?

A
  1. Oil-in-water (water as dominant phase)

2. water-in-oil (oil as dominant phase)

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10
Q

What are the main ingredients in cosmetics for skin hydration?

A
  1. Occlusive agents
    - forms a barrier across skin to lock water e.g. petrolatum & ceramides
  2. Humectants
    - attracts & hold water to be within skin e.g. NMFs, glycerin
  3. Emollients
    - fill the space between desquamating corneocytes with droplets
  4. Hydrophillic matrices
  5. Sunscreens
  6. Charged surfectants
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11
Q

Give some e.g. of occlusives

A

They retard TEWL but do not allow SC to repair its barrier function
e.g. petrolatum, lanolin, lecithin, cholesterol

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12
Q

Humectants

A

Absorbs water from surroundings, drags water to skin

e.g. glycerin/glycol, hyaluronic acid, urea, sodium lactate, PCA

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13
Q

Glycerine

A

Humectant
Part of the NMF present in skin
used as a preservative

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14
Q

Lactic Acid

A

Humectant

is an AHA, exfoliating agent

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15
Q

Urea

A

Humectant

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16
Q

Propylene Glycol

A

Antimicrobial agent
used as a solvent
chemical skin permeation enhancer

17
Q

Butylene glycol

A

Preservative

used in hair sprays as it retards loss of aromas and keeps away moisture so the hair stays

18
Q

Panthenol

A

aka provitamin B5
moisturising, soothing & sedative properties
particular affinity with hair

19
Q

Pyrrolidone Carboxylic Acid (PCA)

A

Naturally occurring humectant in SC, NMF

20
Q

What are hydrophillic matrices?

A

Large molecular weight substances that retard TEWL

e.g. hyaluronic acid and vitamins

21
Q

Hyaluronic Acid

A

Absorbs up to 1000x its own weight

gives mechanical support to skin

22
Q

Proteins & amino acids

A

belong to NMFs

most widely used protein types are hydrolysed proteins

23
Q

What does staying in water for too long do to the skin?

A

negatively affects SC barrier function

causes SC swelling and weakens corneocyte cohesion

24
Q

What is desquemation?

A

Exfoliation, SC normally takes 1 mth to go
to speed up the process, we use lactic acid/micro beads/microneedles to exfoliate
slows down with age

25
Q

How do emollients work?

A

Function by filling the space between the desquemated corneocytes with oil droplets
e.g. castor oil, sesame oil, diisopropyl dilinoleate