SUNSCREEN COMPOSITIONS CONTAINING TITANIUM DIOXIDE AND
TRIAZINE DERIVATIVES
FIELD OF THE INVENTION
The present invention relates to improved UV-A sunscreen compositions comprising titanium dioxide and one or more triazine derivatives .
BACKGROUND OF THE INVENTION
The prolonged exposure to UV radiation, such a from the sun, can lead to the formation of light dermatoses and erythemas, as well as increase the risk of skin cancers, such as melanoma, and accelerate skin aging, such as loss of skin elasticity and wrinkling. Both light having wavelengths in the UV-A range (from about 320 to 400 nm) and the UV-B range (from about 280 to about 320 nm) can cause such skin damage, and, thus, sunscreen compositions should preferably comprise both UV-A and UV-B absorbers/reflectors (UV sunscreens) . Numerous UV-B absorbers are available for sunscreening purposes, however there are far fewer choices available for UV-A filtration, particularly in the longer wavelength regions of the UV-A (340-400nm) . Also hampering the efforts to provide high UV-A protection are strict regulations on the concentrations of these UV-A filters that can be included in sunscreen products. In order to provide high UV-A protectiveness, multiple UV-A actives must be included at their highest permissible levels, which contributes to undesirable cost of materials, as well as to unpleasant aesthetic properties of the preparations. Thus, the optimal
product would provide high UV-A protectiveness by use of low concentrations of only one or two UV-A sunscreen absorbers and one or two UV-B sunscreen absorbers. The present invention relates to the finding of an unexpected synergistic effect between a class of UV-A absorbing agents and the UV-B absorbing agent titanium dioxide, thus, providing the opportunity to manufacture effective sunscreen compositions with minimal number of UV sunscreen agents .
SUMMARY OF THE INVENTION
In one aspect, the invention features a composition comprising: (a) titanium dioxide and (b) one or more triazine derivative (s) . What is meant by a triazine derivative is a compound comprising one or more triazine group (s) and capable of absorbing radiation in the UV-A range (e.g., from about 290 to about 320 nm) . In one embodiment, the triazine derivative is of the formula (I)
(I)
wherein,
Ri and R2, independently, are C3-Cι8 alkyl, C2-Cι8 alkenyl, a radical of the formula -CH2 -CH(OH) -CH2-0-R8, or a radical of the formula (II)
(ID
Rg is a direct bond, Cι-C4 alkenyl, or a radical of the formula -CmιH2mj.- or -CmlH2mι-0- ;
Rio,- ii/ and Ri2, independently, are Cι-Cι8 alkyl, Ci- Cis alkoxy, or a radical of the formula (III)
(III)
Rι3 is Ci -C5 alkyl; ml is 1 to 4; m2 is 0 to 5;
Rθ is a radical of the formula (IV)
(IV)
(V)
(VI)
R3 is hydrogen, Ci-Cio alkyl, or a radical of the formula - (CH2CHR5-0)m4-R4-CH2 or -CH(OH) -CH2-0-R8;
R4 is hydrogen, a metal cation, C1-C5 alkyl, or a radical of the formula - (CH2)m3-0-R8;
R5 is hydrogen or methyl;
R8 is hydrogen or Cι-C8 alkyl;
R7 is C1-C18 alkyl;
m3 is 1 to 4; and m4 is 1 to 16.
Examples of compounds of Formula (I) , and the synthesis thereof, are describe in U.S. Patent No. 5,955,060. In one embodiment, the compound of formula
(I) is 2, 4-Bis { [4- (2-ethyl-hexyloxy) -2-hydroxy] -phenyl}- 6- (4-methoxyphenyl) -(1,3,5) -triazine.
In one embodiment, titanium dioxide is present in an amount from about 0.1% to about 20%, by weight, of the composition (e.g., about 1% to about 10%, by weight, of the composition) and the triazine derivative is present in an amount from about 0.1% to about 20%, by weight, of said composition (e.g., about 1% to about 10%, by weight, of the composition) . The invention also features a method of protecting mammalian skin or hair from UV light comprising topically applying to the skin or hair the above composition.
Other features and advantages of the present invention will be apparent from the detailed description of the invention and from the claims
DETAILED DESCRIPTION OF THE INVENTION
It is believed that one skilled in the art can, based upon the description herein, utilize the present invention to its fullest extent. The following specific embodiments are to be construed as merely illustrative,
and not limitative of the remainder of the disclosure in any way whatsoever.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Also, all publications, patent applications, patents, and other references mentioned herein are incorporated by reference. As used herein, unless otherwise indicated, all alkyl, alkenyl, and alkoxy groups may be straight or branched chain groups .
The present invention relates to compositions containing titanium dioxide and one or more triazine derivatives. In one embodiment, the composition further comprises a dibenzoylmethane derivative UV-A absorbing agent . What is meant by a dibenzoylmethane UV-A absorbing agent is a compound comprising a dibenzoylmethane group and capable of absorbing radiation in the UV-A range
(e.g., from about 320 to 400 nm) . Examples of dibenzoylmethane derivative UV-A absorbing agent include those of the formula (VII) :
(VII)
wherein R
19 and R
20, independently, are Cι-C
8 alkyl or Cι-C
8 alkoxy, m9 is 0 to 3 , and mlO is 1 to 3. Examples and the synthesis of such compositions are disclosed in U.S. Patent No. 4,489,057 and include, but are not limited to, 4- (1, 1-dimethylethyl) -4' -methoxydibenzoylmethane
(avobenzone and sold as Parsol® 1789, Roche Vitamins and Fine Chemicals, Nutley, New Jersey, USA), 2- 2- methyldibenzoylmethane, 4- methyl-dibenzoylmethane, 4- isopropyldibenzoylmethane, 4-tert-butyldibenzoylmethane, 4-tert-butyl-4' -methoxydibenzoylmethane , 2,4- dimethylbenzoylmethane, 2,5- dimethylbenzoylmethane, 4,4' -diisopropylbenzoylmethane, 2-methyl-5-isopropyl-4' - methoxydibenzoylmethane, 2-methyl-5-tert-butyl-4 ' - methoxydibenzoylmethane, 2 , 4-dimethyl-4 ' - methoxydibenzoylmethane, and 2, 6-dimethyl-4-tert-butyl- 4 ' -methoxydibenzoylmethane . In one embodiment, the dibenzoylmethane derivative can range from about 0.1% to about 20%, by weight, of the total composition (e.g., from about 1% to about 10%, by weight) . In one embodiment, the composition further comprises one or more additional UV-A and/or UV-B absorbing/reflecting agent (s). Examples of such absorbing/reflecting agents include, but are not limited to : methoxycinnamate derivatives such as octyl methoxycinnamate and isoa yl methoxycinnamate; camphor derivatives such as 4-methyl benzylidene camphor, camphor benzalkonium methosulfate, and terephthalylidene dicamphor sulfonic acid; salicylate derivatives such as
octyl salicylate, trolamine salicylate, and homosalate; sulfonic acid derivatives such as phenylbenzimidazole sulfonic acid; benzone derivatives such as dioxybenzone, sulisobenzone, and oxybenzone; benzoic acid derivatives such as aminobenzoic acid and octyldimethyl para-amino benzoic acid; octocrylene; dioctyl butamido triazone; zinc oxide; iron oxides; octyl triazone; butyl methoxydibenzoyl methane; drometrizole trisiloxane; and menthyl anthranilate. Other UV absorbers/reflectors useful herein can be found in Sagarin, Cosmetics Science and Technology, Chapter VIII, pages 189 et seq. and the ICI Handbook page 1672. A list of such compounds is also disclosed in U.S. Patent Number 4,919,934. The individual UV absorbing/reflecting agent concentration can range from about 0.1% to about 30%, by weight, of the composition (e.g., from about 1% to about 20%, by weight) . The total concentration of all such agents should be based on the desired sunscreen protection factor ("SPF") level (e.g., an SPF level of from about 10 to about 60) .
In one embodiment, the composition further comprises one or more triazole derivative (s) . What is meant by a triazole derivative is a compound comprising one or more triazole groups. Examples of triazoles are compounds of the formulae (VIII) or (IX) :
(VIII)
(IX)
wherein Rι is Ci-Ciβ alkyl or hydrogen; Rι
5 and R
2, independently, are Ci-Ciβ alkyl optionally substituted with a phenyl group, and R
2i is Cχ-C
8 alkyl. Compounds of Formulae (VIII) and (IX) are describe in U.S. Patent No. 5,869,030, and include, but not limited to, methylene bis-benzotriazolyl tetramethylbutylphenol (Tinosorb M®, Ciba Specialty Chemicals Corporation, Greensboro, North Carolina, USA) . In one embodiment, the triazole derivative can range from about 0.1% to about 20%, by
weight, of the total composition (e.g., from about 1% to about 10%, by weight) .
In one embodiment, the composition further comprises a diester or polyester of a naphthalene dicarboxylic acid. Examples of diesters and polyesters of a naphthalene dicarboxylic acid are compounds of formulae (X) or (XI) :
(X)
(XI )
wherein Riβ and R23, independently, are selected from the group consisting of a Cχ-C2 alkyl, a diol having the structure HO-Rι8-OH, and a polyglycol having the structure HO-Rι7- (-0-Rι8-)m5-OH; Rχ7 and Ris, independently, are Ci-Cβ alkenyl; and m5 and m6, independently, are each in the range of 1 to about 100. Examples, including the synthesis, of such diesters or polyesters of naphthalene dicarboxylic acid are described in U.S. Patent No.
5,993,789, and include, but not limited to, diethylhexyl naphthalate (HallBrite® TQ, C.P. Hall Company, Bedford Park, Illinois, USA). See Bonda, et al., Allured' s Cosmetic & Toiletries Magazine, 115(6) :37-45 (2000) disclosing the uses of such compounds in sunscreen compositions. In one embodiment, the diester or polyester of a naphthalene dicarboxylic acid can range from about 0.1% to about 30%, by weight, of the total composition (e.g., from about 1% to about 10%, by weight) .
In one embodiment, the composition further comprises an alkyl benzoate derivative. Examples of alkyl benzoate derivatives are compounds of the formulae (XII) or (XIII) :
(XII)
wherein m7 is 5, 7, or 9 and n is 4, 6, or 8;
wherein m8 is 5 or 7 and p is 4 or 6.
The compounds of formulae (XII) and (XIII) may be formed by typical esterification and transesterification reactions, e.g., as describe in U.S. Patent No. 5,783,173. Examples of such long branched chain alkyl benzoates are listed in U.S. Patent No. 5,783,173 and include, but not limited to, butyloctyl salicylate (HallBrite® BHB, C.P. Hall Company, Bedford Park, Illinois, USA) . In one embodiment, the alkyl benzoate derivative can range from about 0.1% to about 30%, by weight, of the total composition (e.g., from about 1% to about 10%, by weight) .
In one embodiment, the compositions of the present invention further comprise one or more other cosmetically active agent (s) . What is meant by a "cosmetically active agent" is a compound that has a cosmetic or therapeutic effect on the skin, e.g., agents to treat wrinkles, acne, or to lighten the skin. In one embodiment, the agent is selected from, but not limited to, the group consisting of: hydroxy acids; benzoyl peroxide; sulfur resorcinol; D-panthenol; hydroquinone; anti-inflammatory agents; skin lightening agents; antimicrobial and antifungal agents such a miconazole,
ketoconazole, and elubial; vitamins such as ascorbic acid; tocopherols and tocotrienols such as tocopheryl acetate; retinoids such retinol, retinal, retinyl palmitate, retinyl acetate, and retinoic acid; hormones such as estrogens and dihydroxyandrostene dione; 2- dimethylaminoethanol ; lipoic acid; amino acids such a proline and tyrosine; lactobionic acid; self-tanning agents such as dihydroxy acetone; dimethyl aminoethanol; acetyl-coenzyme A; niacin; riboflavin; thiamin; ribose; electron transporters such as NADH and FADH2 ; botanical extracts such as ginkgo biloba, aloe vera, and soy; and derivatives thereof. The cosmetically active agent will typically be present in the composition of the invention in an amount of from about 0.001% to about 20% by weight of the composition, e.g., about 0.01% to about 10% such as about 0.1% to about 5% by weight of the composition.
Examples of hydroxy acids include, but are not limited, to (i) alpha-hydroxy acids such as glycolic acid, lactic acid, malic acid, citric acid, and tartaric acid, (ii) beta-hydroxy acids such as salicylic acid, and/or (iii) polyhydroxy acids. See, e.g., European Patent Application No. 273,202.
Examples of derivatives of ascorbic acid include, but are not limited to, ascorbyl palmitate, magnesium ascorbyl phosphate, sodium ascorbyl phosphate, zinc ascorbyl phosphate, ascorbyl glucoside, sodium ascorbate, and ascorbyl polypeptide. An example of a
derivative of hydroquinone includes, but is not limited to, arbutin.
The compositions of the present invention may also comprise one or more of the following: antioxidants (e.g., ascorbic acid, tocopherols, polyphenols, tocotrienols, BHA, and BHT) , chelating agents (e.g., EDTA) , and preservatives (e.g., parabens) . Examples of suitable antioxidants, preservatives, and chelating agents are listed in pp. 1612-13, 1626, and 1654-55 of the ICI Handbook. In addition, the topical compositions useful herein can contain conventional cosmetic adjuvants, such as dyes, opacifiers (e.g., titanium dioxide), pigments, and fragrances.
The compositions of the present invention can be used by topically administering it to a mammal, e.g., by the direct laying on or spreading of the composition on the skin or hair of a human. The cosmetic compositions useful in the subject invention, thus, involve formulations suitable for topical application to mammalian skin, the formulation comprising (i) titanium dioxide, (ii) triazine derivative (s) , (iii) optionally, other compounds/agents such as other UV-A and UV-B reflectors/absorbers listed herein, and (iv) a cosmetically-acceptable topical carrier. The term "cosmetically-acceptable topical carrier" refers to a carrier for topical use that is capable of having titanium dioxide, the triazine derivative (s) , and any
other agents dispersed or dissolved therein, and possessing acceptable safety properties.
The topical compositions useful in the present invention may be used for a variety of cosmetic uses, including, but not limited to, protection the skin or hair from UV radiation. The compositions, thus, may be made into a wide variety of product types. These include, but are not limited to lotions, creams, gels, sticks, sprays, ointments, mousses, and cosmetics/make- up. These products may comprise several types of carrier systems including, but not limited to single phase solutions (e.g., oil based solutions), emulsions, and gels .
The compositions of the present invention may be prepared using methodology that is well known by an artisan of ordinary skill . The following is a description of the manufacturing of cosmetic compositions of the present invention. Other compositions of the invention can be prepared in an analogous manner by a person of ordinary skill in the art.
Example 1: SUNSCREEN FORMULATIONS CONTAINING TITANIUM DIOXIDE AND A TRIAZINE DERIVATIVE
Three sunscreen compositions were manufactured containing the ingredients, at listed weight percentages, as indicated below in Table I. Formulation 1 (FORM. 1) contained 3% (W/W) 2 , 4-Bis{ [4- (2-ethyl- hexyloxy) -2-hydroxy] -phenyl} -6- (4-methoxyρhenyl) -
(1, 3, 5) -triazine ("TS") (Tinosorb S®, Ciba Specialty Chemicals Corporation), Formulation 3 (FORM. 3) contained 3%(W/W) titanium dioxide, and Formulation 2 (FORM. 2) contained both 3%(W/W) TS and 3%(W/W) titanium dioxide. These three examples were manufactured as follows :
Table 1
![Figure imgf000017_0001](https://patentimages.storage.googleapis.com/91/07/2f/1db65b6f845f2e/imgf000017_0001.png)
The PEG 100 stearate/glyceryl stearate (Arlacel 165V, Uniqema, Everberg, Belgium) , potassium cetyl phosphate, cetearyl alcohol, glycerin monomyristate, PVP hexadecane copolymer, C12-15 alkyl benzoate, isononyl isononoate, octyl methoxycinnamte, TS, 4-methyl benzylidene camphor, and the titanium dioxide were added, mixed, and heated to approximately 85°C in a first beaker. The tocopheryl acetate was then added to the first beaker. In a second beaker, the xanthan gum was dispersed in the glycerin. The mixture of the second beaker was then added to a third beaker containing the water, EDTA disodium, phenoxyethanol, methyl paraben, propyl paraben, and butylene glycol . The resulting mixture of the second beaker was then heated to 80°C. The heated mixture of the first beaker was then added to the third beaker under mixing conditions for approximately 20 min. The resulting emulsion was then allowed to mix and cool first to 68°C, at which time the cyclomethicone was added, and then allowed to mix and cool to 65°C, at which time the water/ ammonium polyacrylate/ isohexadecane/ PEG-40 castor oil (Simulgel A, Seppic, Paris, France) was added.
Example 2: TESTING OF SUNSCREEN FORMULATIONS CONTAINING TITANIUM DIOXIDE AND A TRIAZINE DERIVATIVE
The above formulations were tested for both their sunscreen protection factor ("SPF") and their UV-A protection factor determined using Persistent
Pigmentation Darkening ("PPD") method and the results are reported in Table II.
The SPFs of the above formulations were determined in vivo on human volunteers using a standard sunscreen testing protocol (the "Colipa Method"). Briefly, the minimum dose of solar-simulated ultraviolet radiation (UVR) required to induce a minimally perceptible erythema on human skin was determined for untreated skin and for the skin treated with one or the formulations (erythema readings were taken 24 hours after irradiation) . The ratio of the dose of UV radiation needed to induce minimally perceptible erythema for formulation protected skin (MEDp) , divided by the dose required for a minimally perceptible erythema for unprotected skin (MEDu) resulted in the SPF value of the formulation.
The irradiation apparatus used for SPF determinations was a Multiport Solar Simulator Model 601 (Solar Light Co., Philadelphia, Pennsylvania, USA) which consists of a 150W Xenon lamp filtered with a UG11 1mm thick filter and a WG320 1mm filter (Schott Co., Philadelphia, Pennsylvania, USA) to allow exposure to UV between 295 and 400 nanometers.
The determination of the protectiveness of the sunscreen in the UV-A portion of the spectrum was determined using the PPD test protocol. The procedure of this test was similar to the SPF test except that the PPD test uses only the longer portion of the UV spectrum
(from 320 to 400nm) by using UG11 1mm thick and WG335 3mm thick filters (Schott Co.). Also, the biological reaction measured was not erythema as for the SPF determination, but rather pigmentation examined 2 hours after exposure ("persistent pigment darkening" or "PPD") . The PPD protection factor is the ratio of the UVA dose required to induce minimally perceptible pigment darkening for formulation protected skin (MPPDp) , divided by the UV-A dose required for unprotected skin (MPPDu) .
Table II
As indicated in Table II, Formulation No. 2, which contained both titanium dioxide and the triazine derivative TS, had a higher SPF then either Formulation No. 1, which contained the same amount of TS but no titanium dioxide, or Formulation No. 3, which contained the same amount of titanium dioxide but no TS . Formulation No. 2 further had an unexpectedly higher PPD Protection Factor that was over twice the PPD Protection Factor afforded by Formulation No. 1 and over three
times the PPD Protection Factor afforded by Formulation No. 3.
The addition of the titanium dioxide to formulations containing triazine derivatives, thus, significantly enhanced the UV-A protection (as indicated by the PPD Protection Factor) to almost double its original value without the titanium dioxide. This finding is unexpected in that the absorbance of the titanium dioxide is well known to be maximum in the UV-B portion of the spectrum rather than in the UV-A portion, where its contributions are quite small by comparison as noted by the low UV-A protection for the composition with titanium dioxide without the presence of the triazine derivative TS (e.g., only 2.8 for Formulation No . 3) .
It is understood that while the invention has been described in conjunction with the detailed description thereof, that the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims . Other aspects, advantages, and modifications are within the claims .