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sunscreen.pptx
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- 2. • Beneficial effects: •Sunlight promotes vitamin D synthesis through the activation of 7- dehydrocholesterol contained in skin fat. • Increases the formation of hemoglobin and also decrease blood pressure. • Activate various hormones , vitamins, enzymes • Moderate exposure -- better physiological feelings , fitness, peace of mind. • Sun rays cause thickening of skin by producing melanin which increases body's natural protective mechanism against sun burns. • Reduces the symptoms of modern ailment SAD (Seasonal Affective Disorder) 2
- 3. Adverse effects: (excessivesun exposure) • Sun burn with symptoms of mild irritation to serious inflammation, from a slight erythema to blistering on skin. • Release of histamine by the sun affected cells dilation of blood vessels and erythema • Skin cancers • Destroys vitamin-D present in skin fat and produces some toxic steroids • Dermatological disorders • Wrinkled appearance of skin • Premature skin ageing • Pain, redness and permanent damage of underlying skin 3
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- 6. UV Light • UVC •Most damaging • Little makes it through atmosphere • UVB • Still damaging • Most common cause of skin cancer • UVA • Least damaging • Causes many of sun’s aging effects
- 7. Sun Light • Wavelengthranges from 1000nm to 100nm • 1000-750nm is IR, detectable as heat • 750-400nm is visible light, enabling to see objects • 400-100nm is UV region responsible for adverse biological reactions like sunburn, skin ageing/tanning, photo-dermatoses, immuno- suppression and skin cancer 7
- 8. UV Radiation • Far-UV (100-200nm) • UV-C (200-280nm) • UV-B (280-320nm) • UV-A (320-400nm) • The far UV and UV-C are germicidal because of its ability to kill single cell organisms and are prevented from reaching the earth’s surface by the ozone layer • UV-C radiation at very low exposure levels is both cytotoxic and produce severe sunburn 8
- 9. • UV-B (burning– simply referred so) is the primary initiator of sunburn, contributing approx. 85% of summer sunburn reaction. • Initiation of photodermatoses, skin cancers, • premature skin ageing and for generation of photoprotective pigment “melanin” responsible for tanned appearance of skin • The erythemal reactions develop after 8 hrs of exposure and may persist for 24 hrs and longer • responsible for synthesis of Vitamin D in the skin 9
- 10. • UV-A (ageing),its long term effects include wrinkling and ageing of the skin due to deeper penetration into the dermis • It generates both immediate and delayed skin pigmentation called tanning response (contributes 15% of summer sunburn reaction) • Direct exposure may lead to polymorphic light eruption (PLE), solar urticaria, chronic actinic dermatitis (CAD) • Immediate pigmentation develops after a few hours of exposure and reddening may not take place for up to 72 hrs of exposure 10
- 11. Skin types • I)always burns easily; never tans • II) burns easily; tans minimally • III) burns moderately; tans gradually • IV) burns minimally; tans easily • V) rarely burns; tans profusely • VI) never burns; deeply pigmented • The consumer should be aware of his/her skin type and benefits of products which screen against both UV-A and UV-B 11
- 12. Sun protection factorSPF • It is the level of protection from sunburn afforded by a sunscreen product • It is tested both in-vivo (human volunteers) and in- vitro (measuring physical absorbance of sunscreen agent) • SPF testing is measuring the sunscreen effectiveness by 12
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- 14. • Sun burnpreparations classified into 3 groups • 1. sunscreen preparations: • Either scatter the incident light effectively or they should absorb the erythemal portion of suns radiant energy. Ideal sunscreen agent • Absorb light preferentially over the range of 280- 320nm • Be stable to heat, light, and perspiration • Non toxic and non irritant • Not be rapidly absorbed • Be neutral • Be readily soluble in suitable vehicles 14
- 15. Product ingredients 1) sunscreenagents - organic -inorganic 2) Waterproofing agents 3) Emollients and diluents 4) Other ingredients 5) Artificial tanning agents 6) After- sun preparations 15
- 16. Sunscreen agents • Organicsunscreens:- 1) PABA & its derivatives- UV-B screening agents, allowable limits is up to 8% (octyldimethyl PABA) 2) Cinnamates- Cinnamic acid esters used up to levels of 10% (octylmethoxy cinnamate) 3) Salicylates- often used at levels up to 5% , protective effect is poor and used as synergist with other sunscreens and aids their solubility 4) Anthranilates- methyl anthranilate upto 5% in USA 16
- 17. 5)Camphor derivatives- 3-(4-methylbenzylidene) camphorincreases the photostability of product and used up to 6% 6) Benzophenones- used up to 10% concentration in combination with UV-B screens for broad spectrum protection 7) Dibenzoylmethanes- UV-A absorbing materials , in USA used up to 1-3% and in Europe up to 5% 8) Octocrylene- new sunfilter used up to 10% and chemically it is cyano-diphenyl acrylic acid- ethylhexyl ester. 17
- 18. • Inorganic sunscreens:- •Natural minerals and pigments – talc, kaolin, mica and metal oxides • ZnO has good light-barrier properties against UV-A, UV-B and visible spectrum – broad UV protection • Titanium dioxide has similar protective properties that of ZnO and can be used in a combination • Both tend to give a white colour to the skin when used in its standard pigmentary form • The efficiency of titanium dioxide depends on its particle size. Decreasing particle size decreases whitening and makes UV protection less broad 18
- 19. Water proofing agents •PABA type sun filters are more resistant to wash off than other organic sunscreens as they can penetrate deeper into the skin layers • Silicone oils are extremely resistant to water penetration and form a water repellent film on skin surface • Polymeric film formers like alkylated polyvinylpyrrolidones along with emollient esters are also gaining importance. 19
- 20. Emollients and diluents •A uniform and continuous film is desirable to ensure complete protection • Heavy, greasy or too tacky materials and too thin and insubstantive materials should be avoided • Branched chain esters provide even protective film, improve skin feel and acceptability of product but may disrupt the water repellent film due to their branching • UV-A screening is enhanced by decrease in polarity of solvent • Iso-arachidyl neopentanoate (branched chain ester)have remarkable SPF enhancing properties 20
- 21. Other ingredients • Rheologymodifiers – increase ease of product application and efficiency of sunscreen agents • Humectants – to counteract loss of moisture, sorbitol, glycerol, propylene glycol • Anti-oxidants- free radical scavenging and prevents anti ageing, vitamins E and C • Vitamin E also has anti- inflammatory properties and also prolong shelf life, used in a concentration of 0.05 – 0.2% of free vitamin is recommended 21
- 22. General manufacturing • Preparationsmay be Aq or oily solutions, creams or emulsions, lotions and gel type • Solutions: aq or oily can be prepared simply by mixing and dissolving the sunscreen and other ingredients in the vehicle i.e water or oil. Perfume should be added last • Creams : These are emulsion type and are prepared by taking ingredients of oil phase and aq phase separately and heating to liquefy or dissolve all ingredients and then mixing them together with continuous stirring till the cream is produced . Perfume added after cooling • Lotions can be solutions or emulsion type • Gels are highly viscous aq preparations – thickening agents dispersed in water separately, other ingredients are mixed together and dissolved in water. Then the dispersion of thickening agent is mixed with others with stirring to prepare gel. 22
- 23. 2. Palliative preparations •Used for relief of irritation and other problems resulting from sunburn • These are antiseptic preparations • Eg: calamine lotion containing antiseptics Zn pheno sulphonate or phenol etc 23
- 24. 3. Simulative preparations •Artificial sun tan preparations • They enhance colour and prevent skin damage by absorption of erythemal radiation • Normally obtained by staining the skin 24
- 25. Artificial tanning agents •Use products containing dihydroxy acetone which reacts with certain free amino acids in proteins near skin surface to form products which condense and polymerize to form dark coloured melanoids • Tablets containing β-carotene or psoralens - produce a systemic stimulation of a pigmentary reaction • Melanin precursors - accelerate tanning process- mixture of tyrosine and riboflavin , where riboflavin aid in oxidation of tyrosine and tyrosine intensify the formation of melanin 25
- 26. • Now bothsunscreens and dihydroxyacetone are combinly formulated so that the consumer can be protected from the sun and develop an artificial tan 26
- 27. After-sun preparations • Menthol-cooling effect • Aloe vera, allantoin, calamine- soothing and healing effect • Xylocaine- mild anaesthetic and reduce pain • Vit E- reduces erythemal effect and promotes enenzyme activity in healing process • Vit A- soothing, wound healing, improve elasticity and moisturizing • Antimicrobial agents- reduce risk of infection and shouldn’t be applied on broken or severely blistered skin 27
- 28. Formulations • Gels • Sticks •Oils • emulsions 28
- 29. • Gels- extremelyattractive, elegant formulation • Drawback- potential irritancy where alcohol is part of the formula, relatively low SPF and water resistant properties • Sticks- direct application to a small area such as nose, lips etc, often formulated as opaque sunscreens with good water repellency due to the presence of oils and waxes • Drawback- often expensive to prepare, firmness should be maintained in hot weather conditions 29
- 30. • Oils- lowSPF products and used for a deep coloured tan, convenient to use, have good level of water resistance • Drawbacks- limited sunscreen solubility, low SPF, form a very thin transparent film on the skin, oils have become less popular • Emulsions-most popular fomulation type, • highly convenient and cosmetically acceptable. • They may be thick creams to light milks and may be O/W , W/O or more complex in nature 30
- 31. • Have highestSPF of all formulation types because they deposit a uniform non- transparent film on the skin. • Also penetrate the skin’s horny layer to some degree thus increasing efficacy and durability 31
- 32. Evaluation • Spectrophotometric evaluation •UV radiation absorption ability • Molar extinction coefficient or absorbancy determined and compared with other std substance • Erythemal dosage – erythemally effective radiation • Solar energy transmitted through the film of suntan preparation and the effectiveness factor at that wavelength 32
- 33. • Sunscreen index–relative screening activity of sunscreen compounds. Measurement of extinction coefficient at 308 nm wavelength that is the peak wavelength for effective sun burn • In – vivo skin testing – on rabbit backside or abdomen – exposed to radiation along with un protected 33
- 34. Reference “Poucher’s Perfumes, Cosmetics& Soaps”, 10th edition 34
Editor's Notes
- #7 UVC - Most Damaging, Little makes it through atmosphere UVB -More damaging, Most common cause of skin cancer UVA- Least powerful, Present all year long, penetrates windows