Sunscreens

Sunscreens- types,SPF..

1. S U N S C R E E N S

2. - Greeks - olive oil - Egyptians - extracts of rice, jasmine, and lupine plants - Early synthetic sunscreens emulsion containing benzyl salicylate and benzyl cinnamat - 1928 . - First major commercial product - 1936 , introduced by founder of L'Oreal , Eugène Schueller

3. - 1944 - Benjamin Green - Red Vet Pet (red veterinary petrolatum) red , sticky substance similar to petroleum jelly In 1946 , Franz Greiter first modern sunscreen - Gletscher Crème ( Glacier Cream ) - In 1974 , Greiter introduced " sun protection factor " (SPF) worldwide standard for measuring effectiveness of sunscreen

4. Photoprotective agents protect skin by preventing and minimizing damaging effects of UV rays of natural light . A lter UV-Radiation effects on skin by absorption and/or reflection

5. Spectrum of UV radiation The biologically active components of UV radiation ( 200-400 nm ) UVC (200-290 nm) UVB (290-320 nm) UVA (320-400 nm )

6. Variability of UV Factors affecting terrestrial UV radiation

7. Time of study -Diurnal variation UVR. max at noon. 20 %-30% of UVR - 11 am & 1 pm ; 75% - 9 am & 3 pm Season – Max. in summer, min. winter Altitude - A 1-km ↑ - 10 %- 25% ↑ in UVR Surface reflection - The albedo of various surfaces cause variation in local UVR Cloud cover - Scattered clouds little effect on surface UVR and complete high cloud cover ↓ es by about 50%

8. Indications 1 . Sunburn 2. Freckling, discoloration 3. Photoaging 4. Skin cancer 5. Phototoxic/ photoallergic reactions 6. Photosensitivity diseases 7 . Photoaggravated dermatoses 8. Post-inflammatory hyperpigmentation

9. Characteristics of an ideal sunscreen • A combination of physical and chemical agents • Broad spectrum • Cosmetically elegant • Substantive • Non-irritant • Hypoallergenic • Non- comedogenic • Economical

10. CLASSIFICATION OF SU NS CR EE NS

11. Mechanisms of Action

12. There are three commonly used nomenclatures for sunscreen agents in the world. Example: A vobenzone (USAN ), butylmethoxydibenzoylmethane (INCI name), Parsol 1789 ( trade names). International Nomenclature Cosmetic Ingredient (INCI) US adopted name (USAN ) Trade name

13. ORGANIC SUNSCREENS

14. Organic UV filters absorb UV radiation Once UV filter absorbs energy, it moves from a low-energy ground state to a high-energy excited state. From excited state, any of following 3 processes occur , depending on ability of filter to process absorbed energy

15. ORGANIC SUNSCREENS UVB filters UVA filters B road spectrum (UVA + UVB) filters

16. 1 . UVB filters a. PABA derivatives – Padimate O b. Cinnamates – Octinoxate c. Salicylates – Octisalate , Homosalate d. Octocrylene e. Ensulizole 2. UVA filters a. Benzophenones (UVB and UVA2 absorbers) - Oxybenzone , Sulisobenzone b. Avobenzone or Parsol 1789 (UVA1 absorber) c. Meradimate (UVA2 absorber)

17. Newer generation broad spectrum (UVA + UVB) filters Ecamsule , Silatriazole , Bemotrizinol ( Tinosorb S), Bisoctrizole ( Tinosorb M ) Ecamsule -UVA filter, patented by L’Oréal Tinosorb M - new class of UV filters combine - both UV filters (organic and inorganic) – it scatters, reflects and absorbs UV light.

18. ULTRAVIOLET B BLOCKERS

19. Para- aminobenzoic acid first chemical sunscreens limitations – alcoholic vehicle , staining of clothes, ADR Ester derivatives, padimate O or octyl dimethyl PABA assoc. with greater compatibility , lower potential for staining and ADR Padimate O - most potent UV-B absorber.

20. Cinnamates replaced PABA derivatives as most potent UV-B absorbers Octinoxate or Octyl methoxy cinnamate most frequently used sunscreen ingredient . Octinoxate is less potent than padimate O

21. Octyl salicylate Octisalate used to augment UVB protection Salicylates weak UV-B absorbers and used in combination with other UV filters good safety profile.

22. Octocrylene used in combination with other UV absorbers to achieve higher SPF formulas in combination such as avobenzone , add to overall stability of these ingredients in a specific formula

23. Phenyl benzimidazole sulfonic acid/ Ensulizole water soluble lighter and less oily, such as daily use cosmetic moisturizers . It is a selective UV-B filter, allowing almost all UV-A transmission.

24. ULTRAVIOLET-A BLOCKERS

25. Benzophenone benzophenones primarily UV-B absorbers, O xybenzone absorbs well UV-A2. Oxybenzone can be considered a broad-spectrum absorber

26. Anthranilate weak UV-B filters and absorb in UV-A2 portion of spectrum less effective than benzophenones , less widely used . Avobenzone provides superior protection through the UV-A range, including UV-A1 concerns regarding its photostability and its potential to degrade other sunscreen ingredients.

27. Terephthalylidene dicamphor sulfonic acid or Mexoryl SX protection within the near UV-A range (320- to 340-nm) it is water soluble and less water resistant Bisethylhexyloxyphenol methoxy phenyl triazene broadband sunscreen filter lends photostability to avobenzone containing sunscreens.

28. INORGANIC SUNSCREENS

29. Zinc oxide 2 . Titanium dioxide 3. Others - iron oxide, red veterinary petrolatum, kaolin , calamine, ichthammol , talc

30. Inorganic agents function by reflecting, scattering or absorbing UV radiation . Their opaque nature and “whitening effect” - disadvantages, minimized by use of micronized or ultrafine particles.

31. SYSTEMIC PHOTOPROTECTIVE AGENTS - β- carotene, Antimalarials , Ascorbic acid, α- tocopherols (vitamins A, C, and E), retinol, S elenium , green tea polyphenols , PABA, I ndomethacin , corticosteroids

32. SUNSCREEN-RELATED INDICES

33. The efficacy of a product is related to its SPF and Substantivity

34. sunburn protection factor (SPF) Minimal erythema dose (MED) of photoprotected skin ----------------------------------------------- MED of unprotected skin Grading system for SPF: • Low: SPF 2 - 15 • Medium: SPF 15 – 30 • High: SPF 30 - 50 • Highest: SPF >50

35. Important - aware - good SPF value will not protect skin from entire UV spectrum. In 2007, FDA proposed expansion of SPF changed to “ sunburn protection factor ” to indicate - index of protection against sunburn or UVB-induced erythema, does not imply UVA or broad spectrum protection .

36. Substantivity : • Sweat-resistant: protects upto 30 mins of continuous heavy perspiration • Water-resistant: protects upto 40 mins of continuous water exposure • Waterproof: protects for upto 80 mins of continuous water exposure PABA and its esters demonstrate more resistance to sweating and/or water immersion than other chemical sunscreens

37. For measuring UVA protection of sunscreen - commonly used in vivo methods are immediate pigment darkening (IPD ), persistent pigment darkening ( PPD)and protection factor in UVA PPD - pigmentation remains stable between 2 and 24 hrs and sensitive for all UVA filters

38. UVA protection indices Japanese standard (persistent pigment darkening) UVA protection factor (UVA PF) UVA dose that induces persistent pigment darkening 2 to 24 hrs after exposure in sunscreen protected skin ------------------------------------------------------------ UVA dose that induces persistent pigment darkening 2 to 24 hrs after exposure in unprotected skin

39. Broadspectrum protective effect evaluated- spectrophotometry – assesses critical wavelength value(wavelength below which 90% of sunscreen’s UV absorbency occurs measured at 290 to 400 nm) broad-spectrum sunscreens should have critical wavelength of ˃ 370 nm and a PPD in UVA greater than 4 .

40. Immune protection factor (IPF ) Ability to prevent UV-induced immunosuppression assessed by ability - inhibit either sensitization or elicitation of delayed-type HS reactions to allergens such as dinitrochlorobenzene ( DNCB) , nickel IPF - correlates better with UVA-protectiveness of a sunscreen than with its SPF

41. Clothing indices - UV protection factor (UPF) average effective UV radiation transmitted and calculated through air ----------------------------------------------------- average effective UV radiation transmitted and calculated through fabric (how much long a person can stay in sun when fabric covers skin , erythema being the end-point ) Grading of UPF: • good protection (UPF 15 to 24) • very good protection (UPF 25 to 39) • excellent protection (UPF 40 to 50 +)

42. Group 1 : Polyester, best UV absorber Group 2 : Wool, silk and nylon Group 3 : Cotton and rayon (cellulosic fibers), poorest absorbers

43. UV absorbers Factors that affect UPF of a fabric- 1. Tightly woven thicker fibers - better UPF. 2. Washing ↑ UPF( shrinkage ),hydration ↓ . 3. Fabrics prone to stretch - lower UPF 4. Chemical treatment - bleaching agents results in attenuation of UV rays. 5. Colored fabric - greater UPF. 6. Greater distance of fabric from skin- photoprotection .

44. Sunglass standards • Luminous transmittance Amount of light transmitted through a sunglass lens (e.g. lens with 20% luminous transmittance allows 20% of light to pass through it ) • The Australian Standard (AS/NZS 1067:2003) classifies sunglasses and fashion spectacles based on the amount of UV radiation that passes through the lenses

45. SUNSCREEN-RELATED DEFINITIONS

46. Critical wavelength: wavelength below which 90% of sunscreen’s UV absorbency occurs Broad spectrum sunscreen : Critical wavelength > 370 nm AND UVA protection factor > 4 Water-resistant sunscreen : Maintains label SPF value after two sequential immersions in water for 20 min (40 min ) Very water-resistant sunscreen: Maintains label SPF value after four sequential immersions in water for 20 min

47. SUNSCREEN APPLICATION The ideal sunscreen should have a high SPF rating, be well tolerated, cosmetically pleasant, non-toxic, equally effective against UVA and UVB, photostable , water-resistant and inexpensive

48. RECOMMENDATIONS FOR SUNSCREEN APPLICATION T o all sun exposed areas (2 mg/cm2) allowed to dry completely before exposure reapplied every 2 hours, and after swimming, vigorous activity, excessive perspiration, or toweling

49. 3 mL 6 mL

50. I ndividuals do not apply enough to achieve adequate protection only 20-50% of required amount used by most To cover the average 1.73 m2 adult, approx 35ml required Using adequate amount (2 mg/cm2) provides greater sun protection than using an inadequate amount of a sunscreen with a higher SPF rating .

51. DEBATABLE ISSUES

52. Sunscreen use in infants not known to be hazardous, not recommended for infants ˂ 6 months recommended that aminobenzoic acid should be avoided in children ˂ 6 months

53. Contact dermatitis M ost common cause oxybenzone Sunscreens - contain aminobenzoic acid and its esters (PABA ), cinnamates and oxybenzone cause photosensitivity reactions.

54. A new nitrosamine - NPABAO was found in certain sunscreens containing padimate -O. Nitrosamines themselves carcinogenic but uncertain whether this is present in sufficient quantities in sunscreens to be of concern

55. Nanosized particles range in size from 1-100 nm . Microfine forms ZnO and TiO2 particle size of 20-50 nm. inorganic sunscreens more cosmetically acceptable (less whitening ) In recent years, nanoparticles can induce free radical formation in presence of UV radiation However studies show particles remain on surface of skin or s.corneum , hence safe for human use .

56. Vitamin D production UVB responsible for ˃ 90% of vitamin D production in skin concerns of use of sunscreens, those with high SPF, may lead to decrease in vitamin D production . However , normal usage donot result vitamin D insufficiency.

57. Hormonal effects O xybenzone , avobenzone , octinoxate , padimate O - estrogenic/anti-androgenic properties in animal studies - endocrine effects remain controversial, warranting further human studies.

58. PHOTOPROTECTION FOR HAIR 1⁰ photoaging effect of sunlight on hair → oxymelanin production → lightening of hair + disulphide bond disruption → physical weakening of hair shaft . shampoos , conditioners and hairstyling products- photoprotection . The degree of protection – minimal thicker application result better photoprotection -difficult - massive surface area A better approach - use of clothing, such as a cap, hat, scarf or umbrella.

59. NEW SUNSCREEN TECHNOLOGIES

60. SunSpheres Styrene/ acrylate copolymers do not absorb UV irradiation but enhance effectiveness of the active sunscreen ingredients. The SunSphere polymer beads are filled with water, which migrates out of the particle, leaving behind tiny airfilled spheres

61. Microencapsulation Active sunscreen ingredients entrapped within a silica shell → allergic or irritant reactions to active ingredient minimized, and incompatible sunscreen ingredients can be safely combined , without loss of efficacy.

62. SPER by Wockhardt • Zinc Oxide 2 %w/w • Oxybenzone 6 %w/w • Octocrylene 3 %w/w • Octinoxate 7.5 %w/w • Avobenzone 2 % w/w • 100 mL Lotion @ Rs 250/- • SPF 26

63. SUNBAN forte by H&H Pharma • Octyl Methoxycinnamate 8.5% w/w • Oxybenzene 3.0% w/w • Titanium Dioxide • Micronised silica coated 6.0% w/w • Methylparaben 0.2% w/w • Propylparaben 0.02% w/w • 60 g Cream @ Rs 485 /- • SPF 50+

64. CETAPHIL UVA+UVB by Galderma Octinoxate 7.5% Octocrylene 7% Oxybenzone 6% Titanium oxide 5.7% • SPF 50 • 4 49 Rs/-

65. Sunstop 19 Cream by Ajanta Pharma Zinc oxide 7.5 % Oxothiazolidine SPF 19 60 g Cream @ 260/-

66. FUTURE TRENDS IN PHOTOPROTECTION A ntioxidants - caffeic acid, poly podium leukotomes , zinc, polyphenolic compounds, isoflavone , N- acetylcysteine and butyrated hydroxytoluene ( synthetic antioxidant) Calcitriol and citrus , free radical scavengers . Plant oligosaccharides and genistein - prevention of UV induced immunosuppression

67. GUIDELINES FOR PHOTOPROTECTION • Avoid direct sun exposure - 10 AM and 4 PM • Seek shade to shelter from DSE • Wear protective clothing, hats, and sunglasses • Apply sunscreen - exposed skin - outdoors • Use sunscreen with SPF ≥ 30 labeled as Broad spectrum • Use adequate sunscreen to cover exposed skin • Apply sunscreen 15 minutes before • Use a water resistant sunscreen if going to swim or perspire heavily • Re-apply sunscreen every 2 hours or after swimming or excessive sweating • Spray sunscreens - applied liberally to achieve rated SPF