Sunscreen, Classifications, Sun Protection Factor(SPF), Regulatory aspects

Sunscreens
Sun Protection
Mechanism of Photoreaction
Sunscreen Classifications
Sunscreen Agents
UV filters
Sun protection factor (SPF)
Regulatory aspects

1. Sunscreens Presented By Simran M . Pharmacy 2 nd sem GGSCOP, YNR

2. Introduction Sunscreen (also known as sunblock or suntan lotion is a lotion, spray, gel or other topical product that absorbs or reflects the sun’s ultraviolet (UV) radiation and protects the skin. Using lotions, creams, or gel that contain sunscreens can help protect the skin from premature aging and damage that may lead to skin cancer.

3. Ideal sun-screen characteristics Absorb light preferentially over the range of 280-320nm.
Resistance to water Be stable to heat, light and perspiration.
Preferably odorless, if mild odor: accepted by user
Be non-toxic, non-irritant, non-sensitizing Capable of retaining sun screening property for several hours
Non-stain
Not be rapidly absorbed.
Be neutral
Be rapidly soluble in suitable vehicles.

4. Sun Protection Protection from sunlight is often equated with use of sunscreens, but this approach is too narrow, and protection should consist of : avoiding overexposure to sunlight, using sunscreens, and wearing protective clothing.
Solar ultraviolet (UV) radiation influences the skin, causing aging, sunburns, precancerous and cancerous lesions, and immunosuppression. Sun protection is essential to skin can prevent about 90% of non melanoma skin cancers and 80% of melanomas are associated with exposure to UV radiation from the skin.

5. UV radiation comprises of 3 categories depending on wavelengths are: UVA: low energy ranges between 320 to 400 nm
most responsible radiation for immediate tanning or darkening of the skin due to excess production of melanin in the epidermis UVB: high energy ranges between 280 to 320 nm
known as burning rays as they are 1000 times more capable of causing sunburn than UV-A UVC: Very high energy ranges between 200 to 280 nm filtered by stratospheric ozone layers so less effective and hazardous

6. Very High Energy Radiation (UVC) is currently blocked by the ozone layer.
High Energy Radiation (UVB) does the more immediate damage. But Lower Energy Radiation (UVA) can penetrate deeper into the skin, leading to long term damage.

7. Mechanism of photoreaction Photo-oxidative mechanism depending on light-driven reactive oxygen species (ROS) generation is now accepted to cause skin photoaging and photo carcinogenesis.

8. Why use sun-screen? Too much unprotected sun exposure leads to: Premature skin aging Sun-burn Skin cancer

9. Sunscreen classifications Physical - opaque formulations containing: titanium dioxide - UV filter- it helps protect skin by blocking absorption of the sun’s UV light talc, kaolin - lubricant zinc oxide - work by scattering the sun’s rays, which prevents damaging UV radiation from getting to the skin. Ferric chloride - increase the absorption and protection against visible light and UVA radiation. Ichthyol , red petrolatum- treatment of skin blemishes, redness or itching associated with various skin disorders. Mechanism : scatters or reflects uv radiation due to large particle size.

10. Sunscreen classifications Chemical - Formulations containing one or more: PABA, PABA ester- can absorb ultraviolet (UV) rays benzophenone - absorbs and scatters the sun’s harmful ultraviolet (UV) rays. Cinnamate - flavouring or fragrance, also good UVB absorbers salicylate- weakly absorbing UVB filters. digalloyl trioleate - anti-oxidizing Anthranilates- sunscreen agent and as an ultraviolet light absorber. Mechanism : absorbs UV radiation

11. Sunscreen agents PABA (Para-amino benzoic acid) Very effective in the UV range (200-320 m).
Most effective in conc of 5% in 70% ethanol
Maximum benefit when applied 60 minutes prior to exposure to ensure penetration and binding to stratum corneum.
Contact dermatitis can develop
May stain clothing

12. Sunscreen agents PABA Esters (Padimate A, Padimate O. Glyceryl PABA) Also very effective in UVB range (280-320)
Most effective in conc. 25-8% in 65% alcohol May penetrate less effectively than PABA
Similar application and adverse effect
Less staining Anthranilates Minimally effective, absorbs UVA spectrum 250-322 nm Usually combined with UVB agent to broaden spectrum.

13. Sunscreen agents Benzophenones (oxybenzone, dioxybenzone ,) Slightly less effective than PABA.
Absorbs from 250-400 nm spectrum (e. UVA & UVB).
Combined with PABA or PABA ester improves penetration and is superior to either agent used alone (200-400 mm wavelength coverage).
-Beneficial in preventing photosensitivity reactions.
- Contact dermatitis is rare. Cinnamates and Salicylates Minimally effective, absorb UVB spectrum.
Generally used in combination with one of the above.

14. Principle of effectiveness of sun-screens A protective layer can be provided to the skin that prevents the UV-rays to reach the skin either by absorbing or by reflecting them. Zinc oxide and titanium dioxide both have such tendency. Preparations reflecting UV-rays are very effective and used widely. To incorporate substances in preparations to filter the sun-rays by absorbing medium range UV-rays (280 nm-320nm)but allowing rays of higher wavelengths to pass.
All modern sun-tan preparations are based on this principle and contain such substances.

15. UV filters (Three types) Organic chemical: Compounds that absorb ultraviolet light eg. Oxybenzone Inorganic particulates: that reflect, scatter, and absorb UV light eg. Titanium dioxide, zinc oxide Organic particulates. : That mostly absorb light like organic chemical compounds, but contain multiple chromophores -may reflect and scatter a fraction of light like inorganic particulates. Eg. Tinosorb M

16. Sun protection factor (SPF) The term “sun protection factor” was adopted by the FDA to describe the effectiveness of Sunscreen. SPF is a measure of how much solar energy (UV radiation) is required to produce sunburn on protected skin The presence of sunscreen relative to the amount of solar energy required to produce sunburn an unprotected skin.
As the SPF value increases, sunburn protection increases SPFdefined as the UV energy required in producing a minimal erythemal dose (MED) on protected skin, divided by the UV energy required to produce a MED on unprotected skin

17. SPF Broad-spectrum sunscreen gel can protect your skin from: Sunburn
Suntan
Photo-aging
Dull complexion Skin inflammation and Skin Cancer (more severe cases) Sunscreens have a number written as Sun Protection Factor, i.e. SPF 15, 20, 30 or 50 on the pack.

18. Types of skin and SPF

19. Regulatory aspects Sunscreens are evaluated generally one of following method and labeling conditions as per countries guidelines. US-FDA Method The FDA proposal measures in-vitro UV transmittance through a sunscreen film using the critical wavelength method. Sunscreen products offering primarily UVB protection would have a critical wavelength less than 320nm, whereas those providing both UVB and UVA protection would have critical wavelengths between 320 and 400nm. FDA requires that sunscreen products have a critical wavelength of at least 370nm (the mean value must be equal to or greater than 370nm) to be labeled as providing “broad spectrum” UVA and UVB protection.

20. UK method of boot star rating The UK method, called as Boots star rating system, also measures the UV transmittance through a sunscreen film. The substrate for measurement is abraded PMMA plates. The ratio between the mean UVA and UVB absorbance measured before and after irradiation of the sunscreen products is calculated. Australia Australian standard (AS) method uses spectrophotometer for measurements of the solar radiation transmitted by a sunscreen product to yield a percentage of UVA radiation absorbed by the product. According to this test, a product is designated as a long wave protector only if it transmits less than 10% of the incoming UV radiation between 320 and 360 nm. India Indian being Asian population comes under Type–IV skin pattern which burns minimally and tans easily. Freckles are rare but still use of sunscreen is necessary to avoid tan. Indian regulations date from the Indian Drug and Cosmetic Act (1940) as amended from time to time considers sunscreens as cosmetics. Bureau of Indian Standards (BIS), a participating member of the ISO, sets the relevant cosmetic product standards. Key points are stability data is (similar to Australia) must and there is no maximum SPF rating for sunscreens.

21. Japan : Japan Cosmetic Industry Association (JCIA) provides self regulated standards. JCIA is a signatory to the COLIPA International SPF test method and JCIA has adopted ISO standards as they are published. For SPF, ISO 24444 is accepted. In Japan, for UVA, in-vivo testing is required and labelling is according to ratings of Protection Grade of UVA (PA) i.e PA +, PA++ and PA +++. Additionally, PA++++ was also added from 1 st January 2013. China Sunscreens are regulated under the Hygienic Standard for Cosmetics 2007. Currently sunscreens can only be labeled up to SPF 30+. The product must be labeled in Chinese language and have a Chinese name. Water resistance norms should be followed if labelled.

22. Thank you!!!