Skin lightening compositions

Details Skin lightening compositions Skin lightening compositions

1999-05-04

2002-12-24

Page, Thurman K. (Department: 1615)

Drug, bio-affecting and body treating compositions

Bleach for live hair or skin

C424S401000

Reexamination Certificate

active

06497860

ABSTRACT:

TECHNICAL FIELD
The present invention relates to the field of skin lightening. Specifically, the present invention relates to novel compositions comprising a specific reducing agent for skin lightening.
BACKGROUND
The formation of melanin depends upon the availability of three substances: (1) a suitable substrate such as tyrosine and dopa, (2) molecular oxygen and (3) enzyme tyrosinase (a copper protein complex). If any of these substances are absent or reduced, the formation of melanin is impaired.
The reducing agent retards melanin formation by the following three mechanism: (1) It sequesters some of the copper in the enzyme system and the enzymatic formation of melanin is reduced by sequestering copper since the co-enzyme of tyrosinase is a copper protein complex. (2) The necessary substrates for melanin formation(tyrosine and dopa) are formed from both bacteriological and enzymatic breakdown of protein. A decrease in the available bacteria would depress proteolytic destruction and thereby aid in decreasing melanogensis since the reducing agent such as sodium sulfite is a bactericide. (3) The strong reducing agent such as sodium sulfite itself gets oxidized in preference to the melanin substrates..
Romanian patent application No. 100161 is assigned to Institute of Chemical-Pharmaceutical Research, Bucharest and discloses that a reducing agent such as sodium metabisulfite is used to eliminate the unpleasant odor.
U.S. Pat. No. 4,13,6166 is assigned to Helena Rubinstein, U.S. Pat. No. 4,792,443 is assigned to Warner-Lambert, U.S. Pat. No. 5,514,437 is assigned to The Proctor & Gamble Company and Japanese Patent Laid-open No.6-263624 is assigned to Mochida Pharmaceutical Co. and they disclose that sulfite salts, hydrogen sulfite salts and metabisulfite salts are used as a stabilizer or an antioxidant.
Japanese Patent Laid-open No.54-129134 is assigned to Shiseido and discloses that a combination of (i) sulfite or hydrogensulfite and organic solvent, (ii) ferrous salt and (iii) hydrogen peroxide shows an effect of bleaching a melanin of hair.
Japanese Patent Laid-open No. 3-101609 is assigned to Sansyo Pharmaceutical, No.3-279313 is assigned to Shiseido, No. 4-352708 is assigned toKose, No. 63-174910 is assigned to Shiseido and No. 7-25742 is assigned to Kao, and they disclose that sulfites, hydrogensulfites and pyrosulfites have an effect of preventing the product from coloring.
Japanese Patent Laid-open No. 5-139928 is assigned to Hisamitsu Pharmaceutical Co. and discloses that sodium hydrogen sulfite and sodium metabisulfite are used as an antioxidant.
Japanese Patent Laid-open No. 5-179300 is assigned to Kitano Kagaku and discloses that sodium hydrogen sulfite is used to bleach leather.
Japanese Patent Laid-open Nos. 7-215888, 8-12548, 8-12549, 8-12550, 8-12552, 8-12554, 8-12556, 8-12557, 8-12558 and 8-12565 are assigned to Shiseido and Japanese Patent Laid-open No. 59-157009 is assigned to Yakurigaku Cyuo kenkyusho and they disclose that very low level of sodium hydrogensulfite or sodium sulfite is included in a skin lightening or melanin controlling composition comprising a specific skin lightening or melanin controlling active ingredient.
It has been discovered that the water-soluble reducing agent selected from the group consisting of sodium sulfite, potassium sulfite, ammonium sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, ammonium hydrogen sulfite, sodium metabisulfite, potassium metabisulfite, formic acid and oxalic acid, and mixtures thereof lightens mammalian skin.
SUMMARY
The present invention relates to skin lightening cosmetic compositions comprising:
a) a safe and effective amount of at least one water-soluble reducing agent selected from the group consisting of sodium sulfite, potassium sulfite, ammonium sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, ammonium hydrogen sulfite, sodium metabisulfite, potassium metabisulfite, formic acid, oxalic acid, and mixtures thereof
b) a cosmetically acceptable carrier for the water-soluble reducing agent wherein said compositions are substantially free of hydroquinone or its derivatives.
The skin lightening compositions of the present invention preferably comprise said water-soluble reducing agent and lecithin.
The skin lightening compositions of the present invention more preferably comprise (a) said water-soluble reducing agent, (b) a cosmetically acceptable liquid oil, (c) a polyhydric alcohol, (d) a solid fatty alcohol, (e) surfactant, (f) water and (g) lecithin, wherein at least a portion of the above components (a), (b), (c), (d), (e), (f) and (g) forms a liquid crystal.
Such compositions satisfy the need for skin lightening effect of mammalian skin
DETAILED DESCRIPTION
As used herein, “topical application” means directly laying on or spreading on outer skin.
As used herein, “skin lightening” means decreasing melanin in skin, including one or more of overall lightening of basal skin tone, lightening of hyperpigmented lesions including age spots, melasma, chloasma, freckles, post inflammatory hyperpigmentation or sun-induced pigmented blemishes.
As used herein, “solid” means solid form at the temperature of 25° C., and “liquid” means liquid form at the temperature of 25° C.
As used herein, all percentages are by weight unless otherwise specified.
A. Water-soluble Reducing Agent
The composition of the present invention comprises a water-soluble reducing agent. The reducing agent is selected from the group consisting of sodium sulfite, potassium sulfite, ammonium sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, ammonium hydrogen sulfite, sodium metabisulfite, potassium metabisulfite, formic acid, oxalic acid, and mixtures thereof. If the composition comprises more than about 5% by weight of the composition, of the reducing agent, it will cause safety issue, and if it comprises less than 0.1% by weight of the composition, of the reducing agent, enough skin lightening effect is not expected.
The skin lightening composition of the present invention comprises preferably from about 0.1% to about 5%, more preferably from about 0.15% to about 5%, still more preferably from about 0.2% to about 5%, most preferably from about 0.25% to about 5% by weight of the composition, of the reducing agent.
In the reducing agent, sodium sulfite, sodium hydrogen sulfite, sodium metabisulfite and the mixtures thereof are preferred.
The skin lightening composition of the present invention is substantially free of hydroquinone or its derivatives, and preferably hydroquinone and its derivatives are absent from the present invention as they are thought to disturb the lightening activity of the water-soluble reducing agent. Such hydroquinone derivatives include 4-[(tetrahydro-2H-pyran-2-yl)oxy]phenol and 4-[(tetrahydro-2H-thiopyran-2-yl)oxy]phenol and ones which are described in WO 9523780 which is hereby incorporated by reference.
B. Lecithin
The skin lightening composition of the present invention preferably comprises said water-soluble reducing agent and lecithin. Lecithin is a natural product derived from soybean or egg yolk, and used for enhancing the skin lightening effect of the reducing agent. If the composition comprises more than 10% by weight of the composition, of lecithin, it will cause tackiness problem, and if it comprises less than 0.01% by weight of the composition, of lecithin, enough enhancing effect of the skin lightning effect of the reducing agent is not expected.
The lecithin level in the skin lightening composition of the present invention is preferably from about 0.01% to about 10%, more preferably from about 0.5% to about 3% by weight of the composition.
C. Cosmetically Acceptable Carrier
The phrase “cosmetically acceptable carrier”, as used herein, means one or more compatible solid or liquid fillers, diluents, extenders and the like, which are cosmetically acceptable as defined herein. The term “compatible”, as used herein, means that the components of the compositions of this invention are capable of being comingled with the primary actives of the present i

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