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WO1990001919A1 - Polymeric skin colorant - Google Patents

Polymeric skin colorant Download PDF

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Publication number
WO1990001919A1
WO1990001919A1 PCT/US1989/003585 US8903585W WO9001919A1 WO 1990001919 A1 WO1990001919 A1 WO 1990001919A1 US 8903585 W US8903585 W US 8903585W WO 9001919 A1 WO9001919 A1 WO 9001919A1
Authority
WO
WIPO (PCT)
Prior art keywords
hydroxyindole
periodate
colorant
alkyl
solution
Prior art date
Application number
PCT/US1989/003585
Other languages
French (fr)
Inventor
James J. Carroll
Karla Leum Stoner
Leon M. Wilkins
Steven J. Woltman
Original Assignee
The Gillette Company
Repligen Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by The Gillette Company, Repligen Corporation filed Critical The Gillette Company
Publication of WO1990001919A1 publication Critical patent/WO1990001919A1/en

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Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61KPREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K8/00Cosmetics or similar toiletry preparations
    • A61K8/18Cosmetics or similar toiletry preparations characterised by the composition
    • A61K8/30Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds
    • A61K8/49Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds containing heterocyclic compounds
    • A61K8/4906Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds containing heterocyclic compounds with one nitrogen as the only hetero atom
    • A61K8/4913Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds containing heterocyclic compounds with one nitrogen as the only hetero atom having five membered rings, e.g. pyrrolidone carboxylic acid
    • A61K8/492Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds containing heterocyclic compounds with one nitrogen as the only hetero atom having five membered rings, e.g. pyrrolidone carboxylic acid having condensed rings, e.g. indol
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61KPREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K8/00Cosmetics or similar toiletry preparations
    • A61K8/18Cosmetics or similar toiletry preparations characterised by the composition
    • A61K8/72Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61QSPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
    • A61Q1/00Make-up preparations; Body powders; Preparations for removing make-up
    • A61Q1/02Preparations containing skin colorants, e.g. pigments
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08GMACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G61/00Macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain of the macromolecule
    • C08G61/12Macromolecular compounds containing atoms other than carbon in the main chain of the macromolecule
    • C08G61/122Macromolecular compounds containing atoms other than carbon in the main chain of the macromolecule derived from five- or six-membered heterocyclic compounds, other than imides
    • C08G61/123Macromolecular compounds containing atoms other than carbon in the main chain of the macromolecule derived from five- or six-membered heterocyclic compounds, other than imides derived from five-membered heterocyclic compounds
    • C08G61/124Macromolecular compounds containing atoms other than carbon in the main chain of the macromolecule derived from five- or six-membered heterocyclic compounds, other than imides derived from five-membered heterocyclic compounds with a five-membered ring containing one nitrogen atom in the ring
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61KPREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K2800/00Properties of cosmetic compositions or active ingredients thereof or formulation aids used therein and process related aspects
    • A61K2800/40Chemical, physico-chemical or functional or structural properties of particular ingredients
    • A61K2800/42Colour properties
    • A61K2800/43Pigments; Dyes

Definitions

  • the present invention relates to skin staining compositions.
  • an artificial skin staining agent which can mimic the tanning effect of the sun on the melanin in the skin.
  • Natural tanning is a time intensive process with potentially harmful short and long term side effects.
  • the harmful side effects of tanning range from simple sunburn to various serious forms of skin cancer.
  • the process is time intensive.
  • the healthy look of a tan is a cosmetically and therefore commercially important consideration.
  • An artificial skin stain which could provide the cosmetic look of a natural tan while avoiding all the problems associated therewith would be of considerable significance.
  • the problems associated with a compound which will stain skin and provide a natural color are significant.
  • Skin is a highly sensitive substrate to stain.
  • the dye also must be nontoxic.
  • the dye must be relatively substantive but it is generally undesirable for the stain to have long term permanence. Also it is undesirable to have the stain penetrate too deeply into the epidermis.
  • the color must be a natural hue and must avoid fading into unnatural oranges or greens while on the skin.
  • SUBSTITUTESHEET like color Accordingly it is a general object of the invention to provide a compound which is suitable for staining skin to provide a natural tan coloration.
  • the present invention is .a polymeric skin colorant comprising the reaction product of a hydroxyindole and an oxidant.
  • the skin colorant according to the present invention is based upon hydroxyindoles which have been partially oxidized to color resembling that of natural melanin.
  • hydroxyindoles useful in the present invention can be shown as follows:
  • R x is H or alkyl (1-4C) ;
  • R , R 5 , R 6 , R 7 can be the same or different but one must be OH and the others selected from: H, alkyl (1-4C) ,
  • the hydroxyindole is suitably oxidized by chemical or physical oxidants.
  • this oxidation produces a skin colorant with melanin-like spectral and optical characteristics which when stabilized provides a dye suitable for application to human skin as an artificial tanning agent.
  • Another advantageous property of the present invention may be protection of skin against damage by ultraviolet light. While oxidants such as UV light and electric current can be employed, a particularly suitable oxidant in accordance with the invention is a periodate oxidant having the general formula:
  • MI0 4 wherein M is an alkali metal, preferably sodium or potassium, and most preferably potassium.
  • periodic acid and salts of rubidium, cesium, magnesium, calcium, strontium, bromine, lanthanum, manganese, iron, copper, zinc, and aluminum can be used.
  • the hydroxyindole is generally in aqueous solution at a concentration of about 0.5% to 2.0% by weight, although a saturated solution, i.e., approximately 2% by weight, is preferred.
  • the alkali metal is preferably potassium.
  • a basic solution is generally obtained by adding a conventional base such as an alkali hydroxide to the KI0 4 solution.
  • Sodium and potassium hydroxide are preferred, with potassium being more desirable because of the likelihood of sodium in the solution forming insoluble sodium periodate precipitates.
  • a pH above 8 is. desirable.
  • the periodate is added to a 1% by
  • the color- forming reagent solution can also contain an added amount of a color modifying agent such as 3,6- di ethylcatechol (3,6-DMC) or 3-methoxycatechol (3-MC) .
  • a color modifying agent such as 3,6- di ethylcatechol (3,6-DMC) or 3-methoxycatechol (3-MC) .
  • the preferred coloring agent. is 3,6-DMC, which adds to the red/brown tint.
  • 3,6-DMC and the hydroxyindole compete in the polymerization reaction to form the end polymer dye. Both influence the color produced, with 3,6-DMC generally observed as adding to the red portion of the spectrum.
  • the color modifying agent is employed in an aqueous solution at from about 0.01% to 0.5% by weight, and preferably about 0.25% by weight, since no significant advantage is seen above that amount.
  • the weight ratio of color modifying agent to hydroxyindole generally ranges from 1:100 to 1:2, preferably 1:3.
  • 5-hydroxyindole (0.1-10%) was found to produce progressively darker browns and, eventually, black through the addition of 3-methylcatechol (0.1-10%), 3- ethoxycatechol (0.1-10%), or 3,6-dimethylcatechol (0.1- 10%) followed by oxidation by sodium periodate (15%) .
  • the ratio of the two color forming agents, i.e., the catechols and the hydroxyindole, to the periodate is generally such that the periodate is in an approximately 1:1 molar ratio. Using less than an equi- molar amount of periodate typically results in a product which is difficult to precipitate and when acid is used for the precipitation, an unacceptable color will result. Using an excess of periodate will generally result in an insoluble product not useful as a stain.
  • the color produced by the reaction of the periodate with the color forming agents varies according to the pH of the reaction solution. The pH of such - 6 - solution is preferably determined by varying the pH of the periodate solution to produce the desired color or tone.
  • An acceptable pH range is from about 8 to 13, preferably about 8 to 10, and most preferably about 8.
  • Preparation of the oxidized skin staining polymer according to one embodiment of the present invention is achieved by reacting the hydroxyindole, and optionally a color forming agent, with the periodate.
  • the reagents which react to form the polymer can be combined in any order.
  • the aqueous hydroxyindole solution, the aqueous periodate solution, and the color modifier solution, if used, can be simultaneously mixed, combined sequentially, or added in aliquots. If added in aliquots, the order of addition and sequence can be varied according to need or desire.
  • the aliquots of the three potential solutions can be added or any one or more solutions can be added by aliquots to a mixture of the remaining solution(s) .
  • This aliquot addition can be used to alter the nature and manner of the monomer addition to the product polymer dye.
  • the 3,6-DMC and the hydroxyindole solution can be added in successive aliquots to the oxidant solution. This successive addition will tend to produce a more homogeneous polymer.
  • potassium periodate/potassium hydroxide produces a more desirable product than sodium periodate, since potassium periodate allows use of a basic reaction medium, thereby favoring formation of the more desirably colored polymers.
  • the pH can be adjusted to affect the color of the polymer formed in the reaction.
  • the acidic precipitation is generally followed by a washing step.
  • the precipitated product is washed with an aqueous liquid, preferably an acidic solution, having a pH ranging from about 1 to 4. It has been found that an acid solution of about pH 2 is particularly effective.
  • the washed product is then placed in a storage stable wet or dry form.
  • the wet stabilized form of the polymer is generally a pH adjusted alcohol solution.
  • a suitable alkaline agent includes a pH 10 glycine buffer, although other conventional acid/base additions may also be employed.
  • the buffer is generally added to a 50% aqueous ethyl alcohol solution of acidic polymer to form a storage stable form of the polymer.
  • ethanol preparations of polymers containing 3-MC are not particularly sensitive to pH and can be stored in acidic or basic conditions.
  • the dry form is conveniently prepared by moderate heating under vacuum, or lyophilization.
  • the heat treatment generally is for several hours, e.g., eight to twelve hours.
  • hydroxyindoles can be dry-oxidated to an acceptable tan color by exposure to ultraviolet light.
  • ultraviolet light For example, exposure to low intensity ultraviolet light of a wavelength less than about 290 nm for about two of three days is typically adequate. Long term atmospheric
  • SUBSTITUTESHEET - 8 - exposure can also be employed as a substitute.
  • the product of this reaction can be washed free of unreacted monomer by alkaline extraction and acid precipitation.
  • a storage stable form is produced as above.
  • An optional additive to-the basic hydroxyindole solution is silica gel, which catalyzes oxidation when physical means such as UV light or electric current are employed.
  • the skin is contacted with a formulation containing about 0.1 to about 10% of a hydroxyindole, a cosmetic carrier such as SYLOID 63 (Davison Chemical Co., Baltimore, Maryland) and a solvent such as water or ethanol.
  • a cosmetic carrier such as SYLOID 63 (Davison Chemical Co., Baltimore, Maryland)
  • a solvent such as water or ethanol.
  • the polymer of the present invention can be applied to the skin in any of various cosmetic formulations well known to those skilled in the art. These include gels, alcoholic solutions, lotions, and creams.
  • the following example illustrates a procedure for preparing a polymer according to the present invention.
  • Sightly over-concentrated solutions are made and adjusted to the above concentrations by mixing with appropriate volumes of dH20 in volumetric flasks.
  • the solutions should be made up the day they are to be used.
  • the polymer is dried or lyophilized.
  • a 1% by weight aqueous solution of 5- hydroxyindole was added to a 1% by weight aqueous solution of 3,6-DMC in a ratio of 3:1 by volume in a centrifuge tube to provide 25 ml.
  • To 4 ml aliquots of this mixture were added 1 drop of 1% by weight aqueous NaOH.
  • 8 ml of 1% by weight KI0 4 /1% by weight KOH in aqueous solution was added to each aliquot. This mixture was mixed in a vortex and allowed to stand overnight.
  • To the resulting reaction product was added 3 ml of 0.25M HCl to aid in precipitation of the polymer product. The precipitated product was centrifuged for ten minutes at 3000 rpm.
  • the pellet formed in the centrifuge tube was washed twice with 10 ml of 1% by volume of acetic acid. A vortex was used in each instance to break up the pellet followed by centrifuging. The washed pellet was then transferred to an evaporation dish with the aid of ethanol. The pellet was dried to a paste-like consistency followed by heat treatment in an oven for 1 hour at 100 to 110 ⁇ C. Six samples were treated in the above manner.
  • the average yield was 1.436 ⁇ 0.05 grams product/grams precursor.
  • the increase in weight could generally be attributable to entrapped periodate or solvent.
  • EXAMPLE 3 A skin staining polymer was formed by adding 3 ml of 2% by weight 5-hydroxyindole in aqueous solution and 1 ml of 2% by weight 3,6-DMC in aqueous solution to 4 ml 5% by weight KI0 4 and 1% by weight NaOH in aqueous solution and allowing the reaction mixture to sit for two days. The reaction mixture was then mixed with 1.8 ml of 0.25M HCl to precipitate the product, followed by centrifugation and rinsing with 2 mis of a pH3 buffer.
  • EXAMPLE 4 A 2% by weight solution of 5-hydroxyindole was mixed at a ratio of 1:1 with a 1% by weight KI0 /1% by weight NaOH in aqueous solution which resulted in a dark brown precipitate with a brownish-yellow halo on #40 Whatman filter paper.
  • EXAMPLE 5 A 2% by weight solution of 5-hydroxyindole was mixed at a ratio of 1:1 with a 1% by weight KI0 /1% by weight NaOH in aqueous solution which resulted in a dark brown precipitate with a brownish-yellow halo on #40 Whatman filter paper.
  • a 3% by weight aqueous solution of 3- methoxycatechol is mixed with a 2% by weight aqueous solution of 5-hydroxyindole at a 1:1 volume ratio. This mixture was then added to an equal volume of a 5% by weight KI0 4 /1% by weight NaOH solution with a pH of 11. this mixture was allowed to stand overnight to produce a dark brown precipitate.
  • EXAMPLE 6 A preformed hydroxyindole dye product was formed by reacting a 2% solution of 5-hydroxyindole in H 2 0 with an equal volume of a 10% sodium periodate solution. After 15 minutes at room temperature the precipitate was collected and dried. A 2% suspension of this preformed dye product in ethanol was applied to human skin. After the carrier had evaporated, the skin was stained a brown color.

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Abstract

A polymeric skin colorant comprising the reaction product of a hydroxyindole and an oxidant.

Description

- 1 -
POLYMERIC SKIN COLORANT BACKGROUND OF THE INVENTION
The present invention relates to skin staining compositions. There is a considerable demand and need for an artificial skin staining agent which can mimic the tanning effect of the sun on the melanin in the skin. Natural tanning is a time intensive process with potentially harmful short and long term side effects. The harmful side effects of tanning range from simple sunburn to various serious forms of skin cancer. Furthermore, the process is time intensive. However, the healthy look of a tan is a cosmetically and therefore commercially important consideration. An artificial skin stain which could provide the cosmetic look of a natural tan while avoiding all the problems associated therewith would be of considerable significance. The problems associated with a compound which will stain skin and provide a natural color are significant. Skin is a highly sensitive substrate to stain. The dye also must be nontoxic. Furthermore, the dye must be relatively substantive but it is generally undesirable for the stain to have long term permanence. Also it is undesirable to have the stain penetrate too deeply into the epidermis. Of course, the color must be a natural hue and must avoid fading into unnatural oranges or greens while on the skin.
Despite activity in the art the search goes on for a stable skin stain which will impart a natural tan-
SUBSTITUTESHEET like color. Accordingly it is a general object of the invention to provide a compound which is suitable for staining skin to provide a natural tan coloration. SUMMARY OF THE INVENTION The present invention is .a polymeric skin colorant comprising the reaction product of a hydroxyindole and an oxidant."
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION The skin colorant according to the present invention is based upon hydroxyindoles which have been partially oxidized to color resembling that of natural melanin.
The hydroxyindoles useful in the present invention can be shown as follows:
Figure imgf000004_0001
wherein:
Rx is H or alkyl (1-4C) ;
R , R5, R6, R7 can be the same or different but one must be OH and the others selected from: H, alkyl (1-4C) ,
COOR' (R' is alkyl 1-4C or H) , .C0NH2, S03M (M is H or an alkali metal), NR'2 (R' is alkyl 1-4C or H) , halogen (Cl, Br, I, F), OR" (R" is alkyl 1-4C) ; CH2OH, CH2NH2, CONR'R" wherein R' and R" can be the same or different; R , R3 can be the same or different and are: H, OH, alkyl (1-4C) , NH2, COOR' (R' is alkyl 1-4C or H) , C0NH2, halogen (Cl, Br, I, F) , OR" (R" is alkyl 1-4C) ; CH2OH, CH2NH2, CONR'R" wherein R' and R" can be the same or different. The hydroxyindoles can be used alone or in a mixture. The preferred hydroxyindole is 5-hydroxyindole because it provides a color which most closely resembles natural melanin.
BSTITUTESHEET - 3 -
The hydroxyindole is suitably oxidized by chemical or physical oxidants. In one embodiment, this oxidation produces a skin colorant with melanin-like spectral and optical characteristics which when stabilized provides a dye suitable for application to human skin as an artificial tanning agent.
Another advantageous property of the present invention may be protection of skin against damage by ultraviolet light. While oxidants such as UV light and electric current can be employed, a particularly suitable oxidant in accordance with the invention is a periodate oxidant having the general formula:
MI04 wherein M is an alkali metal, preferably sodium or potassium, and most preferably potassium.
When a polymeric colorant is prepared by oxidizing prior to application to skin, the periodate is generally added in aqueous solution to an aqueous solution of hydroxyindole. The periodate solution generally ranges from about 0.1% by weight to the maximum solubility of the particular periodate being employed, which is about 15% by weight for sodium periodate and about 3% by weight for potassium periodate. More preferably the solution contains up to about 2.0% by weight, and most preferably about 1% by weight.
In addition to the preferred oxidants, other oxidants which can be used in the present invention include periodic acid, other water-soluble salts of periodate, and any of the isolated equilibrium species of periodate. Specifically, periodic acid and salts of rubidium, cesium, magnesium, calcium, strontium, bromine, lanthanum, manganese, iron, copper, zinc, and aluminum can be used.
Other equilibrium states of periodate are as follows:
SUBSTITUTESHEET - 4 -
In an aqueous solution (pH=0-7) periodic acid exists as an equilibrium mixture between the free acid (H5I06) and its various ions. A shift in equilibrium would be expected on changing the pH, on dilution, or on mixing with an organic solvent
H5I06 ^ H4I06- + H+ H4I06- -£ I04- + 2H20+ H4I06- ^± H3I06 2" + H+ H3I06 2~ ^± H2I06 3" + H+ 2H3I06 2" ^ H2I2O1 0 4" + 2H20(pH = 10).
Any of these'chemical species and many others could be trapped and isolated and when placed into solution would reequilibrate to the other chemical species. The hydroxyindole is generally in aqueous solution at a concentration of about 0.5% to 2.0% by weight, although a saturated solution, i.e., approximately 2% by weight, is preferred.
When 5-hydroxyindole is employed, the formation of a solution of the particular alkali periodate and the reaction of the chosen periodate with 5-hydroxyindole are both pH sensitive. For example, when the periodate employed is NaI04, the solution self acidifies to a pH of about 3 which solvates the oxidant. Such acidic conditions must be maintained, because a 5% by weight NaI0 solution will begin precipitating at a pH of about 6.
If an alkaline medium is employed, the alkali metal is preferably potassium. A basic solution is generally obtained by adding a conventional base such as an alkali hydroxide to the KI04 solution. Sodium and potassium hydroxide are preferred, with potassium being more desirable because of the likelihood of sodium in the solution forming insoluble sodium periodate precipitates. Generally, a pH above 8 is. desirable. In an exemplary embodiment employing 3% by weight of potassium periodate, the periodate is added to a 1% by
UTESHEET - 5 - weight potassium hydroxide solution.
In addition to the hydroxyindole, the color- forming reagent solution can also contain an added amount of a color modifying agent such as 3,6- di ethylcatechol (3,6-DMC) or 3-methoxycatechol (3-MC) . The preferred coloring agent. is 3,6-DMC, which adds to the red/brown tint.
While not wishing to be bound by theory, it is believed that 3,6-DMC and the hydroxyindole compete in the polymerization reaction to form the end polymer dye. Both influence the color produced, with 3,6-DMC generally observed as adding to the red portion of the spectrum.
Generally, the color modifying agent is employed in an aqueous solution at from about 0.01% to 0.5% by weight, and preferably about 0.25% by weight, since no significant advantage is seen above that amount. The weight ratio of color modifying agent to hydroxyindole generally ranges from 1:100 to 1:2, preferably 1:3.
5-hydroxyindole (0.1-10%) was found to produce progressively darker browns and, eventually, black through the addition of 3-methylcatechol (0.1-10%), 3- ethoxycatechol (0.1-10%), or 3,6-dimethylcatechol (0.1- 10%) followed by oxidation by sodium periodate (15%) .
The ratio of the two color forming agents, i.e., the catechols and the hydroxyindole, to the periodate is generally such that the periodate is in an approximately 1:1 molar ratio. Using less than an equi- molar amount of periodate typically results in a product which is difficult to precipitate and when acid is used for the precipitation, an unacceptable color will result. Using an excess of periodate will generally result in an insoluble product not useful as a stain. The color produced by the reaction of the periodate with the color forming agents varies according to the pH of the reaction solution. The pH of such - 6 - solution is preferably determined by varying the pH of the periodate solution to produce the desired color or tone. An acceptable pH range is from about 8 to 13, preferably about 8 to 10, and most preferably about 8. Preparation of the oxidized skin staining polymer according to one embodiment of the present invention is achieved by reacting the hydroxyindole, and optionally a color forming agent, with the periodate. The reagents which react to form the polymer can be combined in any order. The aqueous hydroxyindole solution, the aqueous periodate solution, and the color modifier solution, if used, can be simultaneously mixed, combined sequentially, or added in aliquots. If added in aliquots, the order of addition and sequence can be varied according to need or desire. The aliquots of the three potential solutions can be added or any one or more solutions can be added by aliquots to a mixture of the remaining solution(s) . This aliquot addition can be used to alter the nature and manner of the monomer addition to the product polymer dye.
For example, when 3,6-DMC is employed, there is evidence that its reaction kinetics and therefore addition to the polymer is more rapid than that of the hydroxyindoles. In order to prevent a heterogeneous polymer with distinct polymers or polymer segments, the 3,6-DMC and the hydroxyindole solution can be added in successive aliquots to the oxidant solution. This successive addition will tend to produce a more homogeneous polymer. Generally it has been found that potassium periodate/potassium hydroxide produces a more desirable product than sodium periodate, since potassium periodate allows use of a basic reaction medium, thereby favoring formation of the more desirably colored polymers. Except for consideration of the periodate used, the pH can be adjusted to affect the color of the polymer formed in the reaction.
SUBSTITUTESHEET The reaction product is generally isolated in the form of a precipitate from the reaction solution. If the reaction product is in solution in whole or in part, formation of a precipitate can be encouraged by allowing the reaction media to stand for a period of time ranging from a few hours to a few days or more. In addition, precipitation is generally encouraged by either addition of an electrolyte, such as (NH4) S04, or by acidification of the reaction media, for example by HC1 or an ascorbic acid solution.
The acidic precipitation is generally followed by a washing step. The precipitated product is washed with an aqueous liquid, preferably an acidic solution, having a pH ranging from about 1 to 4. It has been found that an acid solution of about pH 2 is particularly effective.
The washed product is then placed in a storage stable wet or dry form. The wet stabilized form of the polymer is generally a pH adjusted alcohol solution. A suitable alkaline agent includes a pH 10 glycine buffer, although other conventional acid/base additions may also be employed. The buffer is generally added to a 50% aqueous ethyl alcohol solution of acidic polymer to form a storage stable form of the polymer. However, it should be noted that ethanol preparations of polymers containing 3-MC are not particularly sensitive to pH and can be stored in acidic or basic conditions.
The dry form is conveniently prepared by moderate heating under vacuum, or lyophilization. The heat treatment generally is for several hours, e.g., eight to twelve hours.
It has additionally been found that hydroxyindoles can be dry-oxidated to an acceptable tan color by exposure to ultraviolet light. For example, exposure to low intensity ultraviolet light of a wavelength less than about 290 nm for about two of three days is typically adequate. Long term atmospheric
SUBSTITUTESHEET - 8 - exposure can also be employed as a substitute. The product of this reaction can be washed free of unreacted monomer by alkaline extraction and acid precipitation. A storage stable form is produced as above. An optional additive to-the basic hydroxyindole solution is silica gel, which catalyzes oxidation when physical means such as UV light or electric current are employed.
Encapsulation can be performed by adding silica solutions .such as Ludox AM (a silica sol, E.I. du Pont, Wilmington, Delaware) to the hydroxyindole followed by CaCl , or other gelation agents, to gel the silica. The gel, with incorporated hydroxyindole, is dried (e.g., 100-110'C.) and stirred to form pellets. The pelleted form of hydroxyindole can then be oxidized by the method outlined above.
Protein can also be added directly to a solution of hydroxyindole prior to polymerization. However, it has been generally found that bovine albumin has an effect on the polymer color only in basic reaction media.
In another procedure the skin is contacted with a formulation containing about 0.1 to about 10% of a hydroxyindole, a cosmetic carrier such as SYLOID 63 (Davison Chemical Co., Baltimore, Maryland) and a solvent such as water or ethanol. Upon subsequent exposure to UV radiation of skin which has been contacted with the topical dye material, the skin is stained a pleasing tan shade, especially if a 5- or 6- hydroxyindole is utilized.
The polymer of the present invention can be applied to the skin in any of various cosmetic formulations well known to those skilled in the art. These include gels, alcoholic solutions, lotions, and creams.
In order to further illustrate the present invention and the advantages thereof, the following - 9 - specific examples are given, it being understood that these examples are intended only to be illustrative without serving as a limitation on the scope of the present invention. EXAMPLE 1
The following example illustrates a procedure for preparing a polymer according to the present invention.
A. Synthesis of polymer. 1. The following precursor solutions are used: a. 1.65% KIO4/0.5% KOH/dH20 b. 0.9% 5HI/0.1% 3-MC/dH20.
Sightly over-concentrated solutions are made and adjusted to the above concentrations by mixing with appropriate volumes of dH20 in volumetric flasks. The solutions should be made up the day they are to be used.
2. In Pyrex No. 9825 20 x 125 mm screwcap tubes, place 4 L of precursor mixture
(lb.). Add 4 mL of periodate (la.) to the tube, immediately cap and vortex 5 sec. at low speed.
3. Allow the mixture to stand at room temperature for 16 hours to allow 5-HI/3-
MC to fully react with the KI04 and KOH.
4. Dilute the mixture to 20 mL with dH20. Cap the tube and invert 2X to mix. Add 600 micro!iter 1 N HC1, cap the tube and invert 2X to mix.
5. Centrifuge at 1600 x g for 5 minutes. Decant the supernatant liquid to 4 mL using a Pasteur pipette connected to an aspirator flask. B. Washing of the polymer.
6. Add 160 microliters of glacial acetic acid (to keep the polymer precipitated) , dilute
.SUBSTITUTE SHEE - 10 - to 20 milliliters with dH20, and vortex a minimum of 10 seconds, making certain that the pellet is completely broken up.
7. Centrifuge and decant as in step 5. 8. Repeat steps 6 and 7 one time.
9. Add 160 microliters of IN HC1. Dilute to 20 mL with dH20. Vortex as in step 6.
10. Centrifuge and decant as in step 5, but carefully draw off all supernatant liquid from the pellet.
11. Direct solvation of polymer. a. Add 3 mL of 95% punctilious EtOH. Vortex for a minimum of 20 seconds. b. Adjust pH from 2.5 to 3.0 with IN NaOH. c. Centrifuge at 1600 x g for 5 minutes. Withdraw the supernatant liquid from above the pellet of undissolved material. d. The supernatant liquid is the final product of this procedure.
C. Drying of polymer.
12. The polymer is dried or lyophilized.
D. Yield determination.
13. Wet pellets from step 10 were transferred into tared 20 mL borosilicate glass scintillation vials, using 2 mL of 95% punctilious EtOH, followed by 5 1-mL lots for transfer. Add each lot of EtOH, vortex 5-10 seconds and transfer liquid with a 9 3/4" Pasteur pipette.
Remove EtOH and H20 from samples by first drying to the consistency of a thick paste on a hot plate at low setting. Complete drying by maintaining vials in an evacuated, heated vacuum desiccator.
Weigh samples when the polymer appears dry, then after successive 1 hour periods
EET - 11 - in desiccator until no additional weight loss occurs. The drying time thus determined may be used directly for subsequent runs. EXAMPLE 2 "
A 1% by weight aqueous solution of 5- hydroxyindole was added to a 1% by weight aqueous solution of 3,6-DMC in a ratio of 3:1 by volume in a centrifuge tube to provide 25 ml. To 4 ml aliquots of this mixture were added 1 drop of 1% by weight aqueous NaOH. Then 8 ml of 1% by weight KI04/1% by weight KOH in aqueous solution was added to each aliquot. This mixture was mixed in a vortex and allowed to stand overnight. To the resulting reaction product was added 3 ml of 0.25M HCl to aid in precipitation of the polymer product. The precipitated product was centrifuged for ten minutes at 3000 rpm. The pellet formed in the centrifuge tube was washed twice with 10 ml of 1% by volume of acetic acid. A vortex was used in each instance to break up the pellet followed by centrifuging. The washed pellet was then transferred to an evaporation dish with the aid of ethanol. The pellet was dried to a paste-like consistency followed by heat treatment in an oven for 1 hour at 100 to 110βC. Six samples were treated in the above manner.
The average yield was 1.436 ± 0.05 grams product/grams precursor. The increase in weight could generally be attributable to entrapped periodate or solvent.
EXAMPLE 3 A skin staining polymer was formed by adding 3 ml of 2% by weight 5-hydroxyindole in aqueous solution and 1 ml of 2% by weight 3,6-DMC in aqueous solution to 4 ml 5% by weight KI04 and 1% by weight NaOH in aqueous solution and allowing the reaction mixture to sit for two days. The reaction mixture was then mixed with 1.8 ml of 0.25M HCl to precipitate the product, followed by centrifugation and rinsing with 2 mis of a pH3 buffer.
SUBSTITUTESHEET The washed product was solvated with 5 ml of 50% (vol/vol) aqueous ethanol and 0.5 ml of a pH 10 glycine buffer (1.4M) .
EXAMPLE 4 A 2% by weight solution of 5-hydroxyindole was mixed at a ratio of 1:1 with a 1% by weight KI0 /1% by weight NaOH in aqueous solution which resulted in a dark brown precipitate with a brownish-yellow halo on #40 Whatman filter paper. EXAMPLE 5
A 3% by weight aqueous solution of 3- methoxycatechol is mixed with a 2% by weight aqueous solution of 5-hydroxyindole at a 1:1 volume ratio. This mixture was then added to an equal volume of a 5% by weight KI04/1% by weight NaOH solution with a pH of 11. this mixture was allowed to stand overnight to produce a dark brown precipitate.
EXAMPLE 6 A preformed hydroxyindole dye product was formed by reacting a 2% solution of 5-hydroxyindole in H20 with an equal volume of a 10% sodium periodate solution. After 15 minutes at room temperature the precipitate was collected and dried. A 2% suspension of this preformed dye product in ethanol was applied to human skin. After the carrier had evaporated, the skin was stained a brown color.
Other embodiments of the invention will be apparent to those skilled in the art from a consideration of this specification or practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only with the true scope and spirit of the invention being indicated by the following claims.
SUBSTITUTESHEET

Claims

- 13 -
C L A I M S 1. A process for dyeing skin which comprises
(1) contacting the skin with a dye composition comprising
Figure imgf000015_0001
wherein
R-L is H or alkyl (1-4C) ;
R4, R5, R6, R7 can be the same or different but one must be OH and the others selected from: H, alkyl (1- 4C) , COOR' (R' is alkyl 1-4C or H) , C0NH2, S03M (M is H or an alkali metal), NR' (R' is alkyl 1-4C or H) , halogen (Cl, Br, I, F) , OR" (R" is alkyl 1-4C) ; CH2OH, CH2NH2, CONR'R" wherein R' and R" can be the same or different;
R2, R3 can be the same or different and are: H, OH, alkyl (1-4C) , NH2, COOR' (R' is alkyl 1-4C or H) , CONH2, halogen (Cl, Br, I, F) , OR" (R" is alkyl 1-4C) ; CH2OH, CH2NH2, CONR'R" wherein R' and R" can be the same or different; alone, or in a mixture;
(2) exposing the skin to UV light; and permitting the treatment to continue for about 15 minutes; and
(3) rinsing the dye away from the skin with water.
2. A process for dyeing skin which comprises
(1) preforming a hydroxyindole dye by treating a 2% solution of a hydroxyindole of the formula
Figure imgf000015_0002
SUBSTITUTESHEET - 14 - wherein
Rx is H or alkyl (1-4C) ;
R4, R5, R6, R7 can be the same or different but one must be OH and the others selected from: H, alkyl (1- 4C) , COOR' (R' is alkyl 1-4C or H) , CONH2, S03M (M is H or an alkali metal), NR'2 (R' is alkyl 1-4C or H) , halogen (Cl, Br, I, F), OR" (R" is alkyl 1-4C) ;' CH2OH, CH2NH2, CONR'R" wherein R' and R" can be the same or different;
R2, R3 can be the same or different and are: H, OH, alkyl (1-4C) , NH2, COOR' (R' is alkyl 1-4C or H) , CONH2, halogen (Cl, Br, I, F) , OR" (R" is alkyl 1-4C) ; CH2OH, CH2NH , CONR'R" wherein R' and R" can be the same or different; alone, or in a mixture; with an equal volume of a 10% solution of an oxidant selected from sodium periodate, potassium permanganate, sodium hypochorite, potassium ferricyanide, potassium dichromate, ammonium persulfate, silver oxide, Fentons reagent, ferric chloride, lead (IV) oxide, or cesium (IV) sulfate; and collecting the precipitate formed after reacting for 15 minutes at room temperature;
(2) contacting the skin with a 2% preparation of the preformed dye in a volatile carrier;
(3) allowing the carrier to evaporate; and
(4) rinsing the dye carrier away from the skin with water.
3. A process according to claim 2, wherein said hydroxyindole is 4-hydroxyindole, 5-hydroxyindole, 6- hydroxyindole, 7-hydroxyindole, indole-5-hydroxy-3-acetic acid, indole-5-hydroxy-3-hydroxyethyl, indole-5-hydroxy-2- carboxylic acid or indole-5-hydroxy-2-hydroxymethyl; alone, or in a mixture, and the oxidant is sodium periodate.
4. A process according to claim 2, wherein the volatile carrier is ethanol.
5. A polymeric skin colorant comprising the reaction product resulting from the exposure of 5-hydroxyindole to ultraviolet light.
BSTITUTESHEET - 15 -
6. A polymeric skin colorant comprising the reaction product resulting from the exposure of 5-hydroxyindole to electric current.
7. A preformed polymeric colorant produced by a process comprising:
(i) admixing in a container an aqueous solution of 5-hydroxyindole with an aqueous solution of alkali metal periodate,
(ii) reacting the resulting solution to produce an oxidized polymer,
(iii) washing the polymer, and (iv) stabilizing the polymer.
8. The colorant of claim 7, wherein the admixture further comprises a color modifier.
9. The colorant of claim 8, wherein the color modifier comprises 3-methoxycatechol or 3,6- dimethylcatechol.
10. The colorant of claim 9, wherein the color modifier is an aqueous solution of from about 0.01 to 0.5 weight percent, the alkali metal periodate is in solution at between about 0.1 weight percent and the periodate saturation point, and the 5-hydroxyindole is in solution at from about 0.5 to 2.0 weight percent.
11. The colorant of claim 10, wherein the weight ratio of color modifier to 5-hydroxyindole is from about 1:100 to 1:2.
12. The colorant of claim 7, wherein the molar ratio of 5-hydroxyindole to periodate is approximately 1:1.
13. The colorant of claim 11, wherein the molar ratio of 5-hydroxyindole and the color modifier to periodate is approximately 1:1.
14. The colorant of claim 12, wherein the periodate is a potassium periodate solution having a pH from 8 to 13.
15. The colorant of claim 13, wherein the periodate is a potassium periodate solution having a pH from 8 to 13.
16. The colorant of claim 14, wherein the aqueous
UBSTITUTESHEET washing step solution has a pH of from 1 to 4.
17. The colorant of claim 14, wherein the stabilization step comprises solubilizing the polymer in alcohol.
18. The colorant of claim 14, wherein the stabiliz¬ ation step comprises drying the polymer.
19. The colorant of claim 14, wherein the 5- hydroxyindole is encapsulated in a silica pellet.
20. The colorant of claim 14, wherein the admixture (i) further comprises bovine albumin.
21. The colorant of claim 14, further comprising admixing the stabilized polymer with a dermatologically acceptable cosmetic carrier.
22. A process for producing a preformed polymeric colorant comprising
(i) admixing in a container an aqueous solution of 5-hydroxyindole with an aqueous solution of alkali metal periodate,
(ii) reacting the resulting solution to produce an oxidized polymer,
(iii) washing the polymer with an aqueous liquid, and
(iv) stabilizing the polymer.
23. The process of claim 22, wherein the admixture further comprises a color modifier.
24. The process of claim 23, wherein the color modifier comprises 3-methoxycatechol or 3,6- dimethylcatechol.
25. The process of claim 24, wherein the color modifier is in aqueous solution at a concentration of from about 0.01 to 0.5 weight percent.
26. The process of claim 25, wherein the color modifier to 5-hydroxyindole weight ratio is from about 1:100 to 1:2.
27. The process of claim 22, wherein the alkali metal periodate solution has a concentration of about 0.5 to 3.0
SUBSTITUTE SHEET weight percent.
28. The process of claim 22, further comprising a precipitation aid in the aqueous solution employed in the washing step (iii) .
29. The process of claim 28, wherein the precipitation aid comprises an acid, and the washing step (iii) is followed by at least one additional aqueous washing.
30. The process of claim 22, wherein the molar ratio of 5-hydroxyindole to the alkali metal periodate is approximately 1:1.
31. The process of claim 24, wherein the molar ratio of 5-hydroxyindole and color modifier to periodate is approximately 1:1.
32. The process of claim 22, wherein the alkali metal periodate is sodium or potassium periodate.
33. The process of claim 22, wherein the stabilization step comprises drying the polymer.
34. The process of claim 22, wherein the stabilization step comprises dissolving the polymer in an alcohol solution.
PCT/US1989/003585 1988-08-19 1989-08-18 Polymeric skin colorant WO1990001919A1 (en)

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FR2679771A1 (en) * 1991-08-01 1993-02-05 Oreal Use of an insoluble pigment obtained by oxidative polymerisation of indole derivatives for the temporary dyeing of keratinous fibres
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FR2695033A1 (en) * 1992-08-25 1994-03-04 Oreal Prepn. of water-soluble melanic polymer by oxidn. of indole or indoline cpd. - in presence of water-soluble polymer, used in compsn. for colouring hair or skin or make=up compsn. giving natural brown colour.
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US5290891A (en) * 1991-04-16 1994-03-01 Solvay (Societe Anonyme) Process for the preparation of polyindoles, electroconductive compositions and devices containing them and applications of the polyindoles
BE1004725A3 (en) * 1991-04-16 1993-01-19 Solvay PROCESS FOR THE PREPARATION OF polyindoles, COMPOSITIONS AND DEVICES CONTAINING ELECTRICALLY AND USES OF polyindoles.
EP0509588A1 (en) * 1991-04-16 1992-10-21 SOLVAY (Société Anonyme) Process for preparing polyindols, compositions, electroconductive device containing the same and use of polyindols
FR2679771A1 (en) * 1991-08-01 1993-02-05 Oreal Use of an insoluble pigment obtained by oxidative polymerisation of indole derivatives for the temporary dyeing of keratinous fibres
WO1993002655A1 (en) * 1991-08-01 1993-02-18 L'oreal Process for the temporary dyeing of keratin fibres involving an insoluble pigment obtained by the oxidative polymerisation of indole derivatives
US5645609A (en) * 1991-08-01 1997-07-08 L'oreal Compositions which contain and processes which use an insoluble pigment obtained by the oxidative polymerization of indole derivatives for the temporary dyeing of keratinous fibers
FR2681329A1 (en) * 1991-09-18 1993-03-19 Oreal FINE DISPERSION OF MELANIC PIGMENTS, ITS PREPARATION AND USE IN COSMETICS
US5451254A (en) * 1991-09-18 1995-09-19 L'oreal Fine dispersion of melanin pigments, its preparation and its use in cosmetics
WO1993005754A1 (en) * 1991-09-18 1993-04-01 L'oreal Fine dispersion of melanic pigments, its preparation and utilisation in cosmetics
FR2686344A1 (en) * 1992-01-16 1993-07-23 Oreal INDOLINIC PRODUCTS, THEIR PREPARATION PROCESSES AND THEIR USE IN COSMETICS.
WO1993013744A1 (en) * 1992-01-16 1993-07-22 L'oreal Indoline products, methods for preparing same, and use thereof in cosmetics
US5583234A (en) * 1992-01-16 1996-12-10 L'oreal Indoline-based products, processes for preparing them and their use in cosmetics
FR2695033A1 (en) * 1992-08-25 1994-03-04 Oreal Prepn. of water-soluble melanic polymer by oxidn. of indole or indoline cpd. - in presence of water-soluble polymer, used in compsn. for colouring hair or skin or make=up compsn. giving natural brown colour.
FR2704554A1 (en) * 1993-04-27 1994-11-04 Oreal Process for the preparation of a melanin pigment of small particle size and its use in cosmetics
WO1994025531A1 (en) * 1993-04-27 1994-11-10 L'oreal Process for the preparation of a melanin pigment with a small grain size and its use cosmetics
US5776241A (en) * 1993-04-27 1998-07-07 L'oreal Process for the preparation of a melanic pigment of small particle size and its use in cosmetics

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