Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
2002-01-16
2004-09-07
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S059000, C424S060000, C424S400000
Reexamination Certificate
active
06787147
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to novel compositions that protect humans and objects from damaging exposure to solar radiation. The invention also relates to active compounds which occur naturally in plants, algae and cyanobacteria as well as to the chemical derivatives of these compounds that protect against solar radiation.
BACKGROUND OF THE INVENTION
The various layers of the earth's atmosphere absorb most of the solar radiation reaching earth with the more energetic ultraviolet radiation (UV) filtered out by the ozone layer. Of the solar radiation reaching the earth's surface that is of biological interest, only about 2% of the radiation is UV-B with its characteristic wavelength range of 280 to 315 nm. The remainder consists mainly of UV-A with the characteristic wavelength range of 315 to 400 nm, visible light of 400 to 700 nm and infrared radiation (>740 nm). Anthropogenic depletion of the stratospheric ozone layer (Madronich et al., 1995, Ambio 24: 143) has resulted in elevated levels of UV radiation reaching the earth and these levels are expected to increase In the future. The higher levels of radiation have been linked to a significant rise in the incidence of skin lesions and skin cancer in humans (Jagger, 1985, Solar-UV Actions on Living Cells, Praeger Pub., N.Y.). Skin cancer now occurs more frequently than all other cancers combined. In 1998, there will be approximately one million new cases of skin cancer in North America alone. According to the American Cancer Society, diagnosed cases of skin cancer have increased at a rate of about 4% per year in the U.S. since 1973 (Science News 1997, 151: 383). Thus, increased incidence of skin cancer has become a serious health concern.
Skin damage is caused by both UV-A and UV-B radiation. Although damage caused by UV-B radiation has been extensively studied (Motoyoshi et al., 1998, Cosmetics and Toiletries 113: 51), only a few published papers describe the effects of UV-radiation on human hair or quantify photodamage (Hoting et al., 1995, J. Soc. Cosm. Chem. 46: 85). Erythma is the most apparent result of the sunburn reaction but sunburn can also disturb DNA and RNA structure and metabolism. The most serious results of chronic sun exposure are photoaging and photocarcinogenesis.
The natural human skin pigment, melanin, has evolved to provide a certain level of protection against the damaging effects of solar radiation (Kollias et al., 1991, J. Photochem. Photobiol. B: Biol. 9:135). The epidermis has the ability to interfere with the transmission of UV-radiation. Only about 20% of the incident radiation between 300 and 350 nm reaches the dermis. This penetration rises gradually to about 80% at or near 550 nm. Evidently, the cells of the stratum comeum are a remarkably effective block against UV-B radiation. Keratinocytes are, however, exposed to UV-A radiation even though the more energetic UV-B wavelengths are excluded. Moreover, UV-A radiation has been shown to induce mutations and to be potentially lethal (Jagger, 1985, Solar-UV Actions on Living Cells, Praeger Pub., N.Y.).
Strategies to protect skin against solar radiation have most often involved the application of compositions that either block the radiation or absorb the harmful UV component (Gasparro et al., 1998, Photochem. Photobiol. 68:243). Although sunscreens on the market today protect people from sunburn to varying degrees, they do not prevent skin cancer. The use of sunscreens has increased significantly in the last five to ten years but cases of melanoma have also continued to rise (ASP News, 1998, 27:7). Typical sunscreen preparations block UV-B but UV-A passes through very easily. It has been reported that although UV-B causes sunburn, UV-A plays a major role in inducing skin cancer (ASP News, 1998, 27:7). We believe that there is a clear need to devise strategies to supplement the body's natural protective mechanisms against both UV-A and UV-B radiation. A suitable composition must have high activity against UV-A as well as UV-B, be safe for application to human skin and provide good cosmetic application and appearance.
Cosmetic chemists have incorporated sunscreen activities into formulations in order to achieve the desired protection. Formulating products with an improved UV screening capacity is a challenge for cosmetic chemists due to concerns over the use of high levels of organic actives (Dromgoole et al., 1990, Sunscreens: development, evaluation and regulatory aspects. Marcel Dekker, N.Y., pp 313-317). Sunscreen compounds are most effective when they remain on the surface of the epidermis but unfortunately, they are often absorbed to deeper layers of the skin, thereby limiting their efficacy and causing irritation. Cosmetic chemists use organic compounds in their sunscreen formulations. For example, combinations of nylon, butyl methoxydibenzoylmetan and octylmethoxycinnamate have been used as UV-screens in many solar lotions. (Cosmetics and Toiletries, 1998, 113: 83; Gasparro et al., 1998, Photochem. Photobiol. 68:243) (see Table 1).
TABLE 1
Example of a Sunscreen Lotion/Cream Formulation (Cosmetics &
Toiletries, 1998, 113:84)
% Composition
A.
Carbomer
0.15
B.
Water
70.70
C.
Propylene glycol
2.0
methylparaben
0.20
D.
Sodium cocoyl lactylate
0.50
Octoaryl alcohol
1.60
Octyl methoxycinnamate
7.00
Benzophenone-3
2.00
Octyl salicylate
3.50
C12-15 alkyl benzoate
5.00
Isopropyl palmitate
2.00
Propylparaben
1.10
E.
DMDM hydantoin
0.20
This formulation provides some protection against UV-B but provides minimal protection against UV-A.
Based on recent reports showing the harmful effect of UV-A exposure on skin tissue, it is imperative that the cosmetic industry develops as soon as possible protective lotions by broadening the light absorption range of skin lotions (Gasparro et al., 1998, Photochem. Photobiol. 68:243).
Photoautotrophic plants and microorganisms such as green algae and cyanobacteria have evolved to protect the sensitive photosynthetic process against the damaging effects of UV-radiation. Photosynthetic organisms as well as heterotrophic organisms such as fungi and bacteria produce naturally occurring compounds that protect them from the damaging effects of solar radiation. To date, these organisms have not been exploited as sources for sunscreen compounds that can be applied to human skin. This is probably due in part, to the scientific background of the industrial scientists involved in the cosmetic industry. These scientists are typically synthetic organic chemists with limited knowledge and expertise in photosynthesis research and the biology and biochemistry of terrestrial plants, green algae and cyanobacteria. It would be helpful if the naturally occurring sunscreens from these organisms could be adapted to protect humans from solar radiation.
SUMMARY OF THE INVENTION
We identified several naturally occurring compounds which: (1) act as natural sunscreening agents; (2) protect not only against visible light and UV-B radiation but also protect against UV-A radiation; (3) can be produced in large quantities; (4) are easily isolated; (5) are easily incorporated in sunscreen lotions which will offer protection to humans against both harmful forms of ultraviolet radiation (UV-A and UV-B); (6) and as a consequence, should reduce the development of skin cancers, sunburn, photoaging and photodamage to hair and eyes upon exposure to sunlight.
The invention includes several main components: First, we showed that cyanobacteria principally use a combination of three different types of compounds to protect themselves from the harmful affects of solar radiation: (i) carotenoids (ii) scytonemin and (iii) mycosporine amino acids. These compounds may be used to formulate sunscreen compositions that provide significant protection from solar radiation. The compositions are non-toxic, resistant to absorption by the skin, non-irritating to the skin and capable of application to the skin in compositions that create a uniform, continuous film. In addition, the compounds are chemically stable and resistant to chemical and ph
Huner Norman
Ivanov Alexander
Krol Mariana
Sarhan Fathey
Dodson Shelley A.
McKee Voorhees & Sease, P.L.C.
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