The History of Sunscreen PHOTOPROTECTION Sun exposure: main cause of photocarcinogenesis, photoaging, and photosensi%vity UV radia=on: main e%ological agent of most types of skin cancer •  Sunscreens are among the best photoprotec%ve measures WHAT IS SUNSCREEN? A lo%on/spray/gel or other topical agent that absorbs or reflects some of the sun’s ultraviolet (UV) radia%on on skin exposed to light •  Helps to protect against sunburns Sunblock: typically an opaque sunscreen effec%ve at blocking both UVA & UVB rays •  Uses a heavy carrier oil to resist being washed off Ideal requirements for a topical sunscreen: 1. 
protec%on against UVB radia%on 2. 
protec%on against long‐wavelength UVA radia%on 3. 
reac%ve oxygen species scavenging capability 4. 
inclusion of enzymes or ac%ve reagents that ac%vate the cellular DNA repair systems 5. 
stability and safety of the filters Anna H. Chacon, MD; Katlein Franca, MD; Jennifer Ledon, BS; Keyvan Nouri, MD Department of Dermatology & Cutaneous Surgery University of Miami Miler School of Medicine, Miami, FL No conflicts of interest or financial disclosures. THE EARLY DAYS Late 19th century: photosensi%vity diseases were described 1911: Paul Unna used Hammer’s acidified quinine sulfate, turned to aesculin deriva%ves, searching for sunscreen materials 1911: Leopold Freund inves%gated a variety of exis%ng sunscreens using a photographic method to test UVR absorp%on capabili%es •  suggested wavelengths < 325 nm = main cause of erythema 1922: Eder & Freund suggested use of 2‐naphthol‐6,8‐disulfonated sodium, 2‐4% in an ointment base (An%lux) 1925: Meyer & Amster prefer 10% tannin in alcohol, which they presumed changed the colloid chemical structure of skin components 1926: Stephen Rothman observed that local injec%on of procaine prevented erythema & pigmenta%on from UVR, probably because it absorbed at about 300 nm 1928: Behagel et al inves%gated rela%onship between selec%ve UVR absorp%on and chemical cons%tu%on •  PABA & deriva%ves absorb from 260‐313 nm, with maximum at 278.5 nm 1934: Raabe examined protec%ve effect from various ointments •  Ultrazeozon (7% aesculin deriva%ve) and yellow Vaseline – most effec%ve •  lanolin, white Vaseline, nivea – moderately effec%ve SPF (SUN PROTECTION FACTOR) 1956: Concept was originally introduced by Schulze •  By first determining the minimal erythema dose (MED) for human skin, and then exposing the same person to mul%ples of the MED, a reproducible index for effec%veness could be determined 1984: Expanded proposal by Austrian scien%st, Franz Greiter •  Useful method for studying water resistance of sunscreens Quan%ta%ve measure of effec%veness of a sunscreen formula%on •  Usefulness, relevance, & methods recently severely cri%cized ‐> especially actual applied thickness SIDE EFFECTS & CONTROVERSIES • 
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Contact reac%ons Photostability Safety Vitamin D synthesis • 
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Systemic absorp%on Hormonal ac%vity Mutagenicity Risk for the environment “Materials which prevent UVR from reaching the skin protect it from erythema solare…” (Hammer 1891) MODERN DEVELOPMENT ANCIENT PROTECTION Ancient Egypt Pale skin was an ideal among women •  Recently translated papyri and tomb walls reveal the ingredients of po%ons used to ward off a tan and heal damaged skin Some ingredients rediscovered by modern scien%sts: •  Rice bran extract ‐> gamma oryzanol •  Jasmine – heals DNA at the cellular level •  Lupine extract – skin lightener Forms of physical protec=on: •  1st century BC: Celsus recommended covering the head and rubbing the skin with oil •  Tibetans used a combina%on of tars and herbs as sunscreen •  Guyana Indians: a variety of plant extracts used to decorate the skin also served as sunscreen THE MODERN DEVELOPMENT OF SUNSCREENS 1936: Eugene Schueller prepared a sunscreen with benzyl salicylate as UVR absorber in an oily vehicle 1939: Bachem & Fantus made spectroscopic studies of individual compounds and followed them with limited human studies – wool fat, yellow/white petrolatum, diachylon ointment, %tanium dioxide, aesculin & methyl salicylate 1940: Henschke studied transmission through a 0.01‐mm thick layer of a very large number of sunscreen materials 1942: Rothman & Rubin described 10‐15% PABA in an ointment base, the most popular sunscreen in the US for many years 1942: Army Air Force approached the AMA reques%ng advice about the most effec%ve protec%ve substance for the prophylaxis of sunburn 1946: Luckiesh et al were asked to inves%gate protec%ve effects of 12 combina%on materials •  Dark red veterinary petrolatum; recommenda%ons – 10% phenylsalicylate addi%on 1950: Giese et al reported on the sunscreen absorp%on spectra of 90 compounds 1957: Ippen extensively reviewed light‐induced injury by cosme%cs & sunscreen materials 1962: Introduc%on of two important advances in sunscreen materials and tes%ng •  Knox et al. – benzophenone which strongly absorbed UVA •  Wiskemann & Heissen introduced a water‐cooled xenon high‐pressure arc for skin tes%ng 1963: Schulze first calculated the rela%ve effec%veness for erythema of solar radia%on •  Increasing evidence that UVA, especially 315‐340 nm, can cause chronic skin damage in healthy people 2001: Not yet feasible to produce a UVA protec%ve factor similar to SPF THE FUTURE OF SUNSCREEN List of chemicals useful for sunscreen formula%on is now extensive •  The FDA, COLIPA, and the European community have published approved chemicals and inorganic filters Goal: development of a pill Astaxanthin – found in red ocean plants and animals, i.e. salmon •  An%oxidant, reduces pain & swelling associated with sunburn •  Effec%ve protec%on against free radicals 1. Urbach F. The historical aspects of sunscreens. Journal of 8. Rothman S, Henningsen AB. The sunburn‐protec%ng photochemistry and photobiology. B, Biology. Nov 15 effect of para‐aminobenzoic acid. J Invest Dermatol. Dec 2001;64(2‐3):99‐104. 1947;9(6):307‐313. 2. Gonzalez S, Fernandez‐Lorente M, Gilaberte‐Calzada Y. 9. Christensen E, Giese AC. Changes in absorp%on spectra of
The latest on skin photoprotec%on. Clin Dermatol. Nov‐Dec nucleic acids and their deriva%ves following exposure to 2008;26(6):614‐626. ozone and ultraviolet radia%ons. Archives of biochemistry 3. Lautenschlager S, Wulf HC, Pirelkow MR. and biophysics. Jul 1954;51(1):208‐216. Photoprotec%on. Lancet. Aug 11 2007;370(9586):528‐537. 10. Knox JM, Griffin AC, Hakim RE. Protec%on from 4. Wolf R, Wolf D, Morgan% P, Ruocco V. Sunscreens. Clin ultraviolet carcinogenesis. J Invest Dermatol. Jan Dermatol. Jul‐Aug 2001;19(4):452‐459. 1960;34:51‐58. 5. Sturgen G. Historical observa%ons. Dermatology. Clin 11. Cole C. Sunscreen protec%on in the ultraviolet A region: Dermatol. Mar‐Apr 1996;14(2):135‐142. how to measure the effec%veness. Photodermatology, 6. Couteau C, Coiffard L. [History of sun protec%on]. Revue photoimmunology & photomedicine. Feb 2001;17(1):2‐10. d'histoire de la pharmacie. Jul 2010;58(366):151‐162. 12. Stenberg C, Larko O. Sunscreen applica%on and its 7. Luckiesh M, Taylor AH, et al. Protec%ve skin coa%ngs for importance for the sun protec%on factor. Arch Dermatol. the preven%on of sunburn. Journal of the American Medical Nov 1985;121(11):1400‐1402. AssociaQon. Jan 5 1946;130:1‐6.