Module 6 - FINAL Flashcards
(104 cards)
1
Q
What are the features of an ideal cosmoceutical?
A
- Have an immediate effect
- Have a long-lasting effect
- Have a low/no-side effect profile
- Be inexpensive
- Treat a variety of skin conditions
2
Q
What are common myths promoted by common skincare companies?
A
- Drinking 2L water a day is necessary to have good skin - no evidence about specific amount of water, hydration is good for health, skin hydration is related to a healthy skin barrier preventing excessive water loss
- More expensive creams are better - no evidence for this, most important considerations is suitability, blinded studies showed preference for cheaper
- Moisturisers remove wrinkles - they increase hydration so minimise appearance of wrinkles
- Skincare products should be perfume-free, hypoallergenic and natural - perfume-free only if has perfume allergy, all products should be hypoallergenic for approval anyway, natural does not necessarily mean safe or effective, pharmaceutical grade ingredients most effective
- Topical = oral application - depends on cosmeceutical agent
- Must penetrate skin barrier to work - not necessarily
- Self-tanning agents provide sun protection - no at most equivalent. SPF 3-4
3
Q
Define acne.
A
Acne is a common skin condition characterised by open and closed skin comedones results in spots and pustules often on face, chest and back. Commonly affects teenagers.
4
Q
Define Alpha Hydroxy Acids (AHA).
A
A group of carboxylic acids that can be found naturally in the skin and can be synthetically made to add to cosmeceuticals.
AHAs include glycolic acid, lactic acid and manic acid.
Primarily used as exfoliating agents but at higher concentrations can peel the skin.
5
Q
Define antioxidants.
A
Products which prevent or inhibit the oxidation of other molecules (by free radicals) and can protect cells from the damaging effects of oxidation.
6
Q
Define botanicals.
A
Plant extracts found in skincare products. They do not require extensive testing so are cheaper for manufacturers to put into products compared to pharmacological agents.
7
Q
Define cosmeceuticals.
A
Products that are neither pure cosmetics or drugs but have elements of both.
8
Q
Define emollients.
A
Products with a lipid content that produce a layer on the skin reducing trans-epidermal water loss and thereby soothing and hydrating skin.
- Ointments - contain lipid with no water e.g. vaseline
- Water in oil emulsions - high lipid content e.g. hydrous ointment (Nivea)
- Oil in water emulsion - high water content e.g. aqueous cream
- Lotions - high water content e.g. vaseline intensive care lotion
9
Q
Define hydroquinone.
A
An inhibitor of melanin production often used in depigmentation creams to lighten skin
10
Q
Define melasma.
A
A condition causing hyperpigmentation on the face of women. It is affected by sunlight and the presence of oestrogen (endogenous and exogenous).
Occurs in pregnancy called chloasma.
11
Q
Define peptides.
A
Short chains of amino acid sequences that make up larger proteins. Three types used in cosmeceuticals: 1. Signal peptides 2. Carrier peptides 3. Neurotransmitter blocking peptides
12
Q
Define retinoids.
A
Analogues of Vitamin A (retinol), which is derived from beta-carotene. They activate the nuclear retinoid receptors to produce a variety of effects.
13
Q
Define rosacea.
A
A condition in which there is telangiectasia of blood and lymph vessels which leads to facial redness and eventually to papules, pustule and (in men) hypertrophy of sebaceous glands on the nose causing rhinophyma.
14
Q
Define sunscreens.
A
Physical or chemical means to prevent the effects of UV radiation on the skin.
Physical sunscreens such as titanium dioxide or zinc oxide reflect light and have a broad spectrum of action.
Chemical sunscreens such as para-aminobenzoic acid, benzophenones and cinnamates absorb UV light and re-emit it as heat.
15
Q
Define trans-epidermal water loss.
A
A technique to measure the barrier function of the stratum corneum and is used to assess the effects of ideas and of treatment of skin.
16
Q
How to treat photo-damage?
A
A cluster of different changes in the skin including atrophy, telangiectasia, fine and deep wrinkles, yellow and dyspigmentation.
Prevention is important in untreated patients and particularly in those who have had rejuvenation treatments (e.g. skin peels).
Sunblock should be used daily with UVA and UVB.
At least 25 in summer and 15 rest of time to prevent photo-damage.
Topical retinoids have small effect of signs of photo-damage (need to continue Tx for a year)
17
Q
How to treat hyperpigmentation?
A
Superficial:
- caused by photo-damage or melasma
- excess melanin is contained in epidermal melanocytes so can be easily accessed by topical agents.
Deep:
- post-inflammatory changes
- excess melanin contained in macrophages deep in dermis
Most effective treatment is hydroquinone:
- works by inhibiting the conversion of tyrosine to melanin
- In UK it is prescription only and limited to 4% concentration
- May be formulated with steroid/retinoid/sun screen to enhance effectiveness
- Botanical agents such as kojic acid not as effective
18
Q
How to treat facial redness?
A
May be a sign of photo-damage or rosacea
Typical notice facial flushing with heat, exercise, spicy foods and stress
Sensitive skin and intolerant of many products
Advised to use cheaper products with less ingredients as likely to have less irritant effects
Soothing botanicals - aloe vera, allantoin, bisabolol
Botanicals for facial redness - green tea, gingko
Most effective topical agent is metronidazole (Rozex cream) or topical azelaic acid (Finacea cream)
Avoid potent steroid creams
19
Q
How to treat wrinkles?
A
Mostly due to sun damage (only 10% due to intrinsic ageing)
Deep wrinkles not amenable to topical therapy
Most important product is retinol - tretinoin has greater efficacy
Effectiveness needs to be balanced with irritant potential
20
Q
What are simple rules to giving good skincare advice?
A
- Keep up to date with adverse reactions - Cosmetic ingredient Review has list of unsafe ingredients and can be accessed on www.cir-safety.org
- Manage expectation
- Evaluate critically product claims
- Tailor the treatment to the patient - knowledge of skin type and any sensitivities
- Always stay objective - don’t be influenced by marketing or cheap deals, offer advise on best evidence available
21
Q
What are retinoids?
A
- Class of compounds with basic core of Vitamin A and its oxidised metabolites
- Naturally occurring but can be made synthetically (retinoids)
- Retinoids can be delivered both enterally or topically
- Retinoids are lipophilic, easily penetrate epidermis
- OTT as cosmeceuticals and via prescription
22
Q
What are the benefits of retinoids?
A
- Renewing epidermal cells
- Acting as UV filters
- Preventing oxidative stress
- Controlling cutaneous bacterial flora
- Improving skin ageing and photo-ageing
23
Q
What skin conditions can be treated with retinoids?
A
- Acne
- Psoriasis
- Photo-damaged skin (fine lines, wrinkles, hyperpigmentation)
- Rosacea
24
Q
What are the side effects of retinoids?
A
- Local irritation (topical) - dryness, scaling, flaking, dermatitis
- Teratogenic (oral) - must NOT be prescribed to pregnant women or women who are thinking of getting pregnant
25
What is the molecular biology of retinoids?
- Derivative of beta-carotene and its metabolites
- Retinaldehyde, retinol, retinyl esters, retinoid acid
- Important role in: angiogenesis, dermatological haemostats, development (ocular development)
- Retinoic acid oxidised version of Retinol
- Retinoic acid binds to and antagonise RAR/RXR, which in turn influences RARE location and gene expression.
- Retinols are located in both the digestive system and skin
- Free retinol is esterifed via LRAT or ARAT to retinyl palmitate which is then stored
- Retinyl palmitate further oxidised to active form
- Free retinol oxidised to retinoic acid (in cytoplasm) is rate limiting step in generation of active retinoid metabolites
- Then activates gene expression by RAR/RXR mechanism
26
How is retinol derived?
Hydrolysis of beta-carotene into 2 molecules
27
What are the indications for retinol Tx?
- Acne
| - Photo-damaged skin
28
What is the concentration of retinol Tx?
<0.08%
29
What is the mechanism of action of retinol?
Conversion to retinoic acid
30
What is retinaldehyde?
Oxidised form of retinol and is intermediary step between retinol to retinoic acid conversion
31
What are the indications for retinaldehyde Tx?
- Acne
- Photo-damaged skin
- Rosacea
(Rarely used in OTC products)
32
What is the mechanism of action of retinaldehyde?
Conversion to retinoic acid
| much better side effect profile to retinol in terms of less skin irritation
33
What are retinyl esters?
- These are the primary form of retinol
- Stored in cell lipids
- Acyl chains in retinyl esters plays a key role in activity and irritation profiles
34
Give examples of retinyl ester.
Retinyl proprionate
- active in human skin
- elicits retinoid like effects
- much less irritative profile
- stabile ester, prolonged half life when delivered topically
Retinyl palmitate
- predominant form of retinol storage
- weak activity profile
- not commonly used
35
What are the indications for tretinoin Tx?
- Acne
- Photo-damaged skin
Bench-mark agent for topical Tx
Side effects of irritation
36
What is Adapalene?
Synthetic retinoid analogue
| Mimics tretinoin nit has fewer side effects
37
What are the indications for Adapalene Tx?
- Acne (0.1%)
Only licensed for above but likely to have restorative effects on photo-damaged skin
38
What is Tazarotene?
Synthetic analogue of retinoid
39
What are the indications for Tazarotene Tx?
- Plaque psoriasis
- Acne
- Photo-damaged skin
SE: dryness and peeling can be v. significant
40
What are the B vitamins?
```
B1 - Thiamine
B2 - Riboflavin
B3 - Niacinamide
B5 - Pantothenic acid and Pro-Vitamin B5
B6 - Pyroxidine
B7 - Biotin
B9 - Folic acid
B12 - Cobalamin
```
41
What are the skin conditions treated by vitamin B?
1. Acne
2. Wounds
3. Dryness
4. Blotchinesss
5. Hyperpigmentation
6. Texture
7. Yellowness/sallowness
42
What is niacinamide?
- Precursor for co-factor nicotinamide adenine dinucleotide (NAD)
- This co-factor can be further reduced to NADP and NADPH which are antioxidants
- Water soluble, stable, low-molecular weight vitamin, readily penetrates the stratum corneum
43
What are the uses of vitamin B3?
1. Prevents photo-immunosuppression and photo-carcinogenesis
2. Acne
3. Bullous pemphigoid
4. Improve barrier function
5. Photo-ageing (texture, hyperpigmentation, wrinkles)
6. Reduced sebum production
44
What is the mechanism of action of vitamin B3?
- Reduced trans-epidermal water loss = less prone to environmental damage (reduces redness and blotchiness)
- Reduced melanocyte production of melanin by inhibiting melanosome transfer from melanocytes to keratinocytes
- Antigylcation properties through NADPH action - glycation is spontaneous oxidative reaction between sugar and protein, produces cross-linked proteins. which are yellow/brown in colour
- Reduce sebum production = reduces pore size, improve skin texture
- Wrinkle improvement - increase in dermal collagen production and decrease in excess GAG formation
45
What is pentothenic acid/pro-vitamin B5?
- Precursor for co-enzyme A complex
- This has critical role in cellular metabolism: fatty acid synthesis (improves skin lipid synthesis and barrier function) and gluconeogenesis
- Promotes fibroblast proliferation and epidermal re-epithelialisation
46
What are the uses of vitamin B5?
1. Radiation dermatitis
2. Bruises
3. Wounds and scars
4. Improves barrier function + hydration of stratum corneum
5. Anti-inflammatory + anti-pruritic
6. Atopic + contact dermatitis
7. Psoriasis
47
What is the mechanism of action of vitamin B5?
- Hydration properties - hygroscopic properties which are increased if used in combination glycerol, often used in combination with retinoids to combat their irritative side effects
- Panthenol is a precursor to pentothenic acid which is a co-factor in barrier lipid biosynthesis = improvement in skin barrier function
48
What is vitamin E?
- 8 naturally occurring molecules (4 tocopherols, 4 tocotrienols)
- a-tocopherol is most abundant in humans
- lipophilic antioxidant present in cell membranes, blood plasma, many body tissues
- good antioxidant and photo-protective properties
- preventative
49
What are the skin conditions treated by vitamin E?
1. Epidermolysis bullosa
2. Cutaneous ulcers
3. Wound healing
4. Atopic dermatitis
5. Yellow nail syndrome
6. Collagen Synthesis
50
What are the photo-protective effects of a-tocopherol?
- UVR and PUVA induced damage
- PUVA-induced erythema
- skin wrinkling
- skin tumour formation
- lipid peroxidation
51
What is the mechanism of action of vitamin E?
- Cannot be synthesised by humans within cells
- Dietary intake: vegetable oil, cereals, nuts, fresh vegetables
- Also absorbed topically
Antioxidant:
- arrest of chain propagation by scavenging lipid peroxyl radicals, one molecule of tocopherol can absorb 2 radicals
- enhanced by co-antioxidants e.g. ascorbate or glutathione, which regenerates vitamin E
- co-enzyme Q recycles a-tocopherol (if not present then antioxidant properties of vitamin E diminished)
- vitamin C also co-antioxidant
Photo-protection from UVR:
- reduced acute skin reactions (erythema, oedema, lipid peroxidation)
- reduced chronic skin reactions (skin wrinkling, skin formation tumour)
52
How is vitamin E prescribed?
Topical:
- concentration 0.1%
- given with vitamin C to increase efficacy
Oral:
- little evidence
- increase skin concentration
- delay in antioxidant protection up to 2 weeks
53
What are the side effects of vitamin E?
- Contact dermatitis
- Urticaria
- Involvement of cytochrome p450 system (supra-nutritional doses of drug with drugs that use this system e.g oestrogen)
- Inhibits plt aggregation (supra-nutritional doses of drug with anticoagulants)
54
What is vitamin C?
- naturally occurring antioxidant
- cannot be synthesised by humans
- first active for L-ascorbic acid (oxidised upon air exposure)
- magnesium ascorbic phosphate (MAP) or ascorbyl-6-palmitate - more stable
- MAP is lipophilic, readily moves across stratum corneum
- L-ascorbic acid is hydrophilic, can be delivered across stratum corneum aslong as ionic charge is removed
- exposure to UVB reduces vitamin C levels
55
What are dietary sources of vitamin C?
1. Citrus fruits
| 2. Leafy green vegetables
56
What is ascorbyl-6-palmitate?
- An antioxidant
- Fat soluble analogue of L-ascorbic acid
- When hydrolysed becomes L-ascorbic acid and palmitic acid
- Easily transported into cells
- Free radical scavenger
- Non-irritating and neutral pH
- Reduces UVB induced erythema + anti-inflammatory effects + tumour inhibition
57
What is MAP?
- Magnesium ascorbyl phosphate
- lipophillic, stable, neutral pH, readily crosses stratum corneum
- free-radical scavenger
- stimulates collagen production
58
What skin conditions are treated by vitamin C?
1. Photo-damage
2. Hyperpigmentation
3. Rosacea
4. Acne
59
What are the anti-aging mechanisms of vitamin C?
1. Reduces oxidative stress
- ROS causes direct DNA damage, damage collagen and cell membranes
- Generated in skin when exposed to UV light
- L-ascorbic acid donates electrons to neutralise free radicals
2. Essential for collagen synthesis
- Ascorbate is a co-factor lysyl and prolyl hydroxylase responsible for stabilising and cross-linking collagen
- Directly stimulates collagen synthesis
- Biosynthesis of fibroblasts may be inhibited by ascorbate therefore reducing elastic accumulation
3. Photoprotection
- reduce UVB induced erythema, oedema and sunburn cells
4. Anti-inflammatory
- reduced activation of NG-kB, which responsible for production of many pro-inflammatory cytokines
60
How is vitamin C prescribed?
Topical:
- enhances collagen production in skin
- applied before UV exposure
- given with microdermabrasion and co2 lasers
Oral:
- enteral absorption in gut was limited by active transport mechanism in gut
61
What are common myths about botanicals?
1. Botanicals are natural - most are modified and chemically synthesised to obtain bioactive form
2. Do not produce allergic reactions
62
What are the classifications of botanicals?
Botanical anti-oxidants:
- Curcumin - polyphenol antioxidant from turmeric root
- Soy - source of antioxidant flavinoids genistein and daidzein
- Silymarin - extract of milk thistle, prevents lipid oxidation
Botanical anti-inflammatories:
- Gingko biloba - contains terpenoids, flavonoids, flavinol glycosides
- Green tea - topical and oral use, nutritional supplement, contains flavonoids
Botanical soothing agents:
- Witch hazel - oily skin and acne
- Allantoin - root of Comfrey last, induce cell proliferaiton
- Papaya - proteolytic enzyme to heal wounds
Botanical anti-infectious/alopecia agents:
- Echinacea - contains immune stimulating polysaccharides and glycoproteins, flavonoids, alkalises, alkaloids
- St Johns Wort - anti-staphylococcal and anti-inflammatory
- Tea tree - treat mucocutaneous conditions e.g. acne, onychomyosis
- Lavender - contains linalool and linoyl acetate and tannins, treat acne, psoriasis and alopecia areata
63
What are the pathologies resulting in acquired hyperpigmentation?
- Inflammation secondary to trauma, acne, treatments with peels/lasers
- Hormonal imbalances e.g. melasma in pregnancy
- Sun damage e.g. solar lentigines, photo-ageing
- Response to photo-sensitising agents, cosmetic agents or drugs
- Medical conditions e.g. haemochromatosis, Addisons disease
64
What is the mechanism of action of mainstay drugs used to treat of hyperpigmentation?
- Tyrosinase inhibitor - rate limiting agent in melanin production
- Inhibit tyrosinase transcription
- Inhibit tyrosinase and peroxidase during melanin production
- Cause tyrosinase degradation
- Inhibit transfer of melanosomes
- Accelerate turnover of pigmented keratinocytes
65
What is Hydroquinone?
- Naturally occurring compound found in plants, coffee, tea, beer and wine
- Most commonly used agent for hyperpigmentation - melasma and PIH
- Tyrosinase inhibitor, prevents conversion of tyrosine to melanin
- Inhibits DNA and RNA synthesis
- Degradation of melanosomes
- 2-4% concentration
- Can be used in combination with e.g. vitamin C, glycolic acid, retinol
- Side effects: localised skin irritation (requires topical steroids in severe cases), exogenous ochronosis (bluish-grey hyperpigmentation associated with papular cutaneous lesions)
- Banned OTC, mostly used in combined Tx
66
What is Glycolic acid?
- AHA naturally derived from sugarcane
- Accelerates keratinocyte turnover by shortening cell-cycle, causes desquamation of pigmented cells
- Application at higher concentration have more severe epidermolytic effect
- Start Tx at lower concentration initially to minimise the risk of irritation, desquamation and resultant post-inflammatory hyperpigmentation
- Skin lightening effect greater in combination therapy using GA and H - increased penetration of H after removal of epidermal layer
67
What is Kojic acid?
- Produced by several fungal species inc Aspergillus, by product of rice fermentation
- Inhibitor of tyrosinase action
- Used systemically to treat skin pigmentation
- Used in combination with glycolic acid, hydroxy acid and vitamin C
- Side effects: local skin irritation, contact dermatitis
68
What is Azelaic acid?
- Dicarboxylic acid originating from Malassezia yeast
- Tyrosine inhibitor
- Targets degree of pigmentation as well as size of pigmented lesions (effective in rosacea, burn scars)
- 15-20% concentration, well tolerated even in prolonged use
- Side effects: erythema, itching, scaly skin (resolve in first month of use)
69
How does Vitamin A reduce hyperpigmentation?
- Tyrosine inhibition
- Interference with pigment transfer
- Dispersion of pigment within keratinocytes
- Increase keratinocyte turnover
- Tretinoin and retinol both used in combination therapy
70
How does Vitamin C reduce hyperpigmentation?
- Interfere with production of pigment through its reduction of L-dopaquinone (precursor of melanin)
- MAP has effect on cutaneous pigmentation
71
How does niacinamide reduce hyperpigmentation?
- Inhibits melanosome transfer between melanocytes and keratinocytes found in epidermis
72
What is Aloesin?
- Aloe species derived
- Tyrosinase inhibition
- Prevent UV-induced hyperpigmentation in combination therapy with arbutus
73
What is Soy?
- Active protein in fresh soy milk - Soybean Trypsin Inhibitor and Bowman-Birk Inhibitor
- STI causes interferences with melanosome transfer via its action on PAR-2 which acts as a modulate in inflammatory processes
74
What is liquorice extract?
- Active ingredient is Glabridin - tyrosinase ihibitor
- More effective than hydroquinone
- Positive results in combination with HA and Vit E
75
What is Arbutin?
- Active constituents of bearberries
- Tyrosine activity inhibitors
- Used in mono- or combination skin lightening therapy
76
What are some other agents for skin whitening?
- Melatonin - hormone secreted by pineal gland, regulates circadian rhythm, inhibit production of melanocytes
- Paper mulberry extract - tree-root extract, inhibits tyrosinase
77
What is an exfoliant?
An agent which results in the removal of the upper layers of the epidermis
- enhance appearance and quality of skin
- reduce signs of ageing e.g. thinning os skin, fine lines, dyspigmentation
Can be chemical, mechanical and thermal
78
What are exampled of chemical exfoliants?
Alpha, beta, poly and aromatic hydroxy acids
79
What are indication for use of hydroxy acids?
Chemical exfoliation and peels
Rosacea
Cutaneous Xerosis
80
What are AHAs?
- Organic carboxylic acids that occur both naturally and synthetically
- Examples - glycolic acid, lactic acid, tartaric acid, citric acid
- Indications - dry skin, acne, photo damage, scarring, keratoses
- Recommended formulation - up to 10%, min pH 3.5
- Side effects - localised skin irritation, photosensitivity, erythema, desquamation, hyperpigmentation, scarring, reactivation of herpes
- More profound effects at higher concentrations
MOA:
- Thins epidermal stratum corneum through reduction of corneocyte cohesion at lowest level of stratum corneum, adjacent to stratum granulosum
- Act as chelating agents, resulting in reduced surrounding calcium ion concentrations. This leads to disruption of desmosomal attachments of stratum corneum, rendering corneocytes vulnerable to shedding
- Increase corneocyte apoptosis + induce release of local cytokines by keratinocytes --> increased production of collagen and mucopolysaccharides --> thickening of papillary dermis and prominence of dermal papillae
Skin lightening:
- Increased keratinocyte turnover + enhancing penetration of agents (hydroquinone, retinoids)
- Glycolic and lactic acid have ph-dependent effect on Tyrosinase
81
What is salicylic acid?
- Aromatic hydroxyacid (B hydroxyacid)
- Skin and hair conditioning
- Keratolysis of stratum corneum
- Lipid soluble - beneficial for oily skin
- Indications: acne vulgaris, keratosis, seborrheic dermatitis
- Risk of salicylism - due to systemic absorption of high concentration applied over wide areas
82
What are poly-hydroxy acids?
Such as gluconolactone
Skin smoothening, plumping, moisturising, even of skin-tone
Action > AHA
More suitable for pts with dry and sensitive skin
Minimises irritative symptoms
83
What are chemical sunscreens?
- Contains range of active ingredients inc. para-aminobenzoic acid (absorbs UV radiation in form of photons that undergo transformation and are remitted as heat)
- Multiple active ingredients can be used in combination in a single agent, provided that each contributes min SPF 2
84
What are physical sunscreens?
- Zinc oxide, titanium dioxide, iron oxide
- Physical barrier - scatter and reflect UV radiation
- Semi-conductors - absorb UV rays and re-emit them as heat
85
What is the MOA of sunscreens?
- Target effect of UVB (290-320nm) and UVA (320-400nm)
- Ideal sunscreen protects against entire spectrum of UV radiation
- Broad spectrum - protects against UVA and UVB and has SPF > 15
UVB:
- UVB absorption causes mutation of p53 tumour suppressor gene, leads to formation of mutagenic and carcinogenic pyrimidine dimers
- UVB overexposure causes sunburn
- Repeated occurrence of acute sunburn - BCC, melanoma
- Chronic UVB exposure - SCC, actinic keratosis
UVA:
- Reduces number and activity of Langerhans' and antigen-presenting cells
- Formation of free radials --> DNA mutations and carcinogenesis
- Direct dyspigmentation/tanning
- UVA wavelengths are longer, penetrates deeper into dermis, can penetrate through glass
86
What is the formula for SPF?
SPF = minimum erythema dose sunscreen protected skin / minimum erythema dose sunscreen unprotected skin
87
What are the limitations of using SPF?
- Application thickness on which the products SPF is determined is often not the application thickness used by public
- Measurement of MED is a reflection of UVB rather than UVA (does not cause erythema)
- Efficacy is also affected by swimming, perspiration, activity (water-resistant offer superior protection)
88
What are the side-effects of sun screens?
- Irritation
- Allergy
- Aggravate pre-existing cutaneous pathologies
- Phototoxic (absorption of UV radiation causing excessive sunburn and cell damage in epidermis)
- Photoallergenic reactions
89
What are the three main classes of cosmeceutical peptides?
Signal peptides
Carrier peptides
Neurotransmitter inhibitory peptides
90
What are amino acids?
Organic compounds containing carbon, hydrogen, nitrogen and oxygen in a carboxyl and amino group
Non-essential amino acids can be synthesised by the body
Essential amino acids cannot be synthesised by the body
91
What are examples of non-essential AA?
```
Tyrosine
Serine
Selenocysteine
Cysteine
Aspartate
Asparagine
Arginine
Alanine
Glutamate
Glutamine
Glycine
Proline
```
92
What are examples of essential AA?
```
Penylalanine
Threonine
Tryophan
Histadine
Methinone
Lysine
Leucine
Isoleucine
Valine
```
93
What are peptides?
Small compounds consisting of 2 or more AA linked in a chain by a peptide bond (the carboxyl group links with an amino group of another AA)
Polypeptides are linear chains of linked AA
The number of AA in a chain is explained suffix e.g. pentapeptides - 5 AA
Peptides considered protein sub-fragments of their parent proteins that are liberated during cellular processes. Can therefore be made synthetically.
94
What are signal peptides?
Stimulate, inhibit or mimic certain cellular processes
- Majority of peptides are signal peptides
- Wound healing by stimulation skin fibroblasts
- Act as GFs via activation of protein kinase C (cell growth and migration)
- Hexapeptide VGVAG stimulates fibroblasts production through binding to plasmalemmal receptor on fibroblast, down-regulates elastin expression
- Peptide TTAAAAA inhibits pro-collagen C-proteinase thereby decreasing collagen breakdown
- Pentapeptide LTLTS found on type 1 pro-collagen and stimulates feedback regulation of new collagen synthesis and production of EC matrix
- Improves fine lines and wrinkles, improved skin firmsness through neocollagenesis
95
What are carrier peptides?
Aid the delivery of ionised elements such as copper into the skin
- Stabilise and aid delivery of metals through the epidermis into dermis
- Tripeptide GHK-Cu facilitates uptake of copper by dermal cells, also has signal peptide properties (through stimulation of collagen synthesis by fibroblasts through increased MMP-2 and MMP-2 mRNA)
- Copper is important in wound healing as it is a cofactor to superoxide dismutase and important antioxidant
- Copper important for function of lysyl oxidase (important in collagen and elastic production)
- Photodamaged skin - smooths out wrinkles and firms skin
96
What are neurotransmitter inhibitory peptides?
Reduce muscle contraction through inhibition of neurotransmitter release at NMJ
- Argireline is a synthetic hexapeptide has similar NT inhibitor effects to botox
- Interferes with formation and stabilisation of protein complex which is required to drive Ca dependent exocytosis
- Topical application: reaches facial muscles, decreases dynamic facial lines, decreased muscle movement
97
What are matrikines?
Messenger peptides that are biologically active fragments of EC matrix
Generated through partial proteolysis of ECM macromolecules
Regulate cell activities through interactions with receptors and play important role in EC matrix renewal, wound healing and cell proliferation
E.g. Haloxyl - compound containing 2 matrikines
98
What are proteins?
A group of large organic molecules containing one or more long chains of AA
Fundamental component of all living cells and form important substances in body e.g. hormones, antibodies, enzymes
3D structure
99
What are the main side effects seen with peptides?
Allergic contact dermatitis (erythema, itching, papular rash)
100
Which cosmeceuticals are suitable for use in those with facial rhytides?
Botanical antioxidants:
- Flavinoid antioxidants - soy, silymarin
- Polyphenol antioxidants - curcumin, green tea
- Carotenoid antioxidants - lutein, lycopene
Vitamin antioxidants:
- A C E
Cellular regulators:
- Fibroblast growth factors e.g. epidermal GF, PDGF
- Signal peptides e.g. pentapeptide Pal-KTTKS
- Neurotransmitter peptides e.g. hexapeptide argireline
Aim to Tx wrinkles at rest
Moisturising agents in which cosmeceuticals are found act to improve appearance of wrinkles by restoring hydration
Have realistic expectations
Unlikely to have long-lasting effect unless combined with invasive techniques
101
Which cosmeceuticals are suitable for use in those with erythema?
Vasodilation and leucocyte recruitment occurring as a result of inflammatory cascade activation
Mucilage agents:
- Rich in mucopolysaccharides (protective film over surface to enhance barrier function)
- Aloe vera, prickly pear
Polyphenols:
- Green tea, Gingko Biloba
Botanical anti-inflammatory (natural):
- Aloe Vera, bisabolol, allantoin
Humectants:
- Retain moisture, hence improving skin hydration
- Panthenol (Vitamin B5)
102
Which cosmeceuticals are suitable for use in those with pigmentation disorders?
Acquired pigmentation: secondary to inflammation and trauma, hormonal imbalances, photo-damage, systemic medical conditions
Hydroquinone:
- Best used in combination with vitamin C, retinol, glycolic acid
- SE - skin irritation, exogenous ochronosis
Glycolic acid:
- Start at lower concentrations
- SE: irritation, desquamation, post-inflammatory hyperpigmentation (mostly at high concentrations)
```
Ascorbic acid (vitamin C):
- Weak lightening agent
```
Aloesin:
- Found in combination with Arbutin
- Targets UV induced hyperpigmentation
Kojic acid:
- Combination therapy
- Local skin irritation
Glabradin:
- Safe and widely used
Niacinamide:
- Weak with minimal irritation
Retinoids:
- Weak, best used in combination
Arbutin:
- Used in combination
Azalaic acid:
- Good potency
- Targets active melanocytes
- Improves degree as well as area of pigment
103
Which cosmeceuticals are suitable for use in those with dry skin?
Dry skin = poor stratum corneum composition e.g. disruption of lipid, protein and/or water constituents
Dryness, itching, rough texture, flakiness, fissuring, erythema, dullness
Occlusives:
- reduce TE water loss
- Petroleum, lanolin, liquid paraffin
Humectants:
- Help enhance movement of water from dermis to epidermis
- Glycerin, hyaluronic acid, panthenol
Stratum corneum modifiers:
- Modify structure of stratum corneum e.g. reduced corneocyte adhesion or increasing keratinocyte binding sites for water
- Ceramides, tea, lactic acid
Emollients:
- Act as gap fillers between corneocytes
- Cetyl stearate, dicaprylyl maleate
104
Which cosmeceuticals are suitable for use in those with oily skin?
Challenge - over treatment can lead to dry skin (agents disrupt intercellular lipids in SC, cannot differentiate between sebum and SC)
Salicylic acid:
- Oil soluble astringent removes sebum from both skin surface and openings of hair follicles
- Face wash
Witch hazel:
- Naturally occurring astringent removes excess sebum
- Post-cleansing tone, targeting T-zone
Niacinamide:
- Reduces surface sebum levels
- Moisturiser
Retinol:
- Drying effect, combat excessive oiliness
- Moisturising phase
Polymer absorbing beads:
- Delivered in cream medium
- Bind and absorb excess sebum found on skin surface
Papaya:
- Proteolytic enzyme eliminates excess oil and desquamating sebum
Soy:
- May have role in reducing oil production
