Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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CLEAR SUNSCREEN GELS AND METHODS OF USE THEREOF
FIELD OF THE INVENTION
The present invention relates to skin care cosmetic compositions and methods
of using
the same. In particular, the present invention relates to novel clear, alcohol-
free sunscreen gels
and methods of use thereof.
BACKGROUND OF THE INVENTION
The negative effects of exposure to sunlight are well known. For example,
prolonged
exposure to sunlight can cause short term damage such as sunburn and premature
aging of the
skin when skin is exposed to UV radiation having a wavelength of from about
290 nm to abut
400 nm. Moreover, long term damage can lead to serious conditions such as skin
cancer.
As a result of such health hazards caused by excessive sun exposure, sunscreen
products
continue to be in demand. Therefore, the market provides a variety of
sunscreen products,
including daily wear products which contain sunscreens. With the increased use
of such
sunscreen products, consumer demands require the development of sunscreen
product that are
not only effective shields against the sun's rays, but also are aesthetically
pleasing upon
application to the skin.
Clear cosmetic compositions are commonly used for antiperspirants and hair
gels.
Such compositions typically comprise polyols and silicone emulsifiers whose
refractive
indices are matched to provide transparent emulsions, otherwise known as gels.
However, in
conventional clear sunscreens, the silicone elastomers normally used do not
thicken the
sunscreen component sufficiently, so that additional waxes are needed.
Unfortunately, the
additional waxes destroy the clarity of the conventional clear sunscreen
compositions and
result in compositions that are often too thick and therefore unappealing to
the consumer.
Moreover, the conventional sunscreen compositions typically contain alcohols,
which may
cause irritation and dry the skin upon application of the sunscreen products.
Therefore, there remains a need for improved clear sunscreen gel compositions
that
have sufficient thickness but at the same time maintain the desired clarity
and are aesthetically
pleasing to the consumer. Further, there is a need for improved clear
sunscreen gel
compositions that are essentially free of alcohol and therefore non-irritating
to the skin.
SUMMARY OF THE INVENTION
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The present invention at one aspect relates to a cosmetic composition
comprising at
least one chemical ultra-violet (UV) light absorber, at least one solvent and
at least one
diphenyl silicone elastomer gellant, wherein the composition is transparent
and is essentially
free of alcohol.
The term "transparent" as used herein refers to a composition or material
having a
refractive index (RI) that matches the RI of its surroundings, i.e., such a
composition or
material is transparent within and relative to its functional environment.
Preferably, a
transparent composition or material as described by the present invention
exhibits a light
transmission value of greater than about 70%, more preferably greater than
about 75%, and
will not exhibit any light scattering property.
The term "essentially free of alcohol" as used herein refers to a composition
or
material having an ethyl alcohol content of less than about 0.5% by total
weight of the
composition or material.
At another aspect, the present invention relates to a method of using the
above-
described transparent cosmetic composition for protecting skin against harmful
effects of UV
radiation, by applying such a transparent cosmetic composition to the skin.
Other aspects and objectives of the present invention will become more
apparent from
the ensuring description, examples, and claims.
2o DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS
THEREOF
Except in operating and comparative examples, or where otherwise explicitly
indicated, all numbers in this description indicating amounts or ratios of
material or conditions
of reaction, physical properties of materials and/or use are to be understood
as modified by the
word "about." All amounts are by weight of the final composition, unless
otherwise specified.
In the present invention, it has been surprisingly found that by combining a
specific
diphenyl silicone elastomer gellant and one or more specific non-alcohol
solvent(s) with a
chemical UV light absorber, a stable, alcohol-free, and transparent cosmetic
composition can
be formed, which is particularly useful as an aesthetically appealing clear
sunscreen gel. The
term "stable" as used herein refers to a composition having sufficient
physical and chemical
stability so that the composition does not separate or precipitate when all of
the components
are added. The term "aesthetically appealing" as used herein refers to a
composition having a
powdery, velvety, and silky texture upon application onto the skin.
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As a first essential component of the transparent cosmetic composition of the
present
invention, a chemical UV light absorber is used. The chemical UV light
absorber can be any
suitable chemical UV light absorbers commonly used in cosmetic compositions.
Specific
examples of suitable chemical UV light absorbers include, but are not limited
to:
benzophenone-3, homosalate, ethylhexyl methoxycinnamate, avobenzone,
ethylhexyl
salicylate and octocrylene and combinations thereof. Preferably, the chemical
UV light
absorber is present in the transparent cosmetic composition of the present
invention at an
amount ranging from about 1% to about 20%, more preferably from about 2% to
about 15%,
by total weight of the composition. Particularly, the transparent cosmetic
composition of the
present invention does not include any physical UV absorbers, such as titanium
oxide and zinc
oxide, which are known to destroy the clarity of the composition.
As a second essential component of the transparent cosmetic composition of the
present invention, at least one solvent system is used. The solvent system can
comprise any
suitable solvent or solvents for solubilizing and carrying the chemical UV
light absorber.
Specific examples of suitable solvents include, but are not limited to:
dimethicone (such as
DM-fluid A-6CS available from Shin-Etsu Chemical Co., Ltd. at Tokyo, Japan),
dicaprylyl
carbonate (such as cetiol CC available from Cognis Corporation at Cincinnati,
OH), lauryl
lactate (such as ceraphyl 31 available from International Specialty Products
at Wayne, NJ),
neopentyl glycol diheptanoate (such as Lexfeel 7 available from Inolex
Chemical Co. at
Philadelphia, PA), glycerin, and combinations thereof. Preferably, but not
necessarily, the
composition of the present invention comprises a silicone-based solvent, such
as dimethicone,
which is particularly compatible with the chemical UV light absorbers
described hereinabove.
The solvent(s) may be present in an amount ranging from about 1% to about 30%,
preferably,
from about 10% to about 29%, and most preferably from about 15% to about 28%,
by total
weight of the composition.
It is known that chemical UV light absorbers are mostly in powder form with
low
clarity. High amounts of ethyl alcohol have been used in conventional
sunscreen
compositions to enhance solubility of such chemical UV light absorbers.
However, sunscreen
compositions with high ethyl alcohol content usually causes irritation upon
application of the
compositions to the skin. In the present invention, it has been surprisingly
discovered that a
third essential ingredient, i.e., a diphenyl silicone elastomer gellant, and
more specifically, a
diphenyl silicone elastomer gellant comprising diphenylsiloxy phenyl
trimethicone, can be
used to effectively enhance the solubility of the chemical UV light absorbers,
in the absence of
ethyl alcohol. While not wishing to be bound by any theories, it is believed
that the diphenyl
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group of the silicone elastomer gellant interacts with the diphenyl group of
the UV absorber
and thereby enhancing solubility of the UV absorber in the composition. The
total amount of
diphenylsiloxy phenyl trimethicone in the sunscreen composition of the present
invention may
range from about 1% to about 50% by total weight of the composition.
In one specific embodiment of the present invention, the diphenyl silicone
elastomer
gellant comprises a mixture of diphenylsiloxy phenyl trimethicone and
dimethicone/phenyl
vinyl dimethicone crosspolymer. Preferably, such a mixture comprises from
about 80% to
about 90% of diphenylsiloxy phenyl trimethicone and from about 10% to about
20% of
dimethicone/phenyl vinyl dimethicone crosspolymer by total weight of the
mixture. For
example, KSG-18A available from Shin-Etsu Chemical Co., Ltd. at Tokyo, Japan,
which is a
mixture comprising about 85 wt% of diphenylsiloxy phenyl trimethicone and
about 15 wt% of
dimethicone/phenyl vinyl dimethicone crosspolymer, is used as the diphenyl
silicone
elastomer gellant in the compositions of the present invention. If KSG-18A is
used in the
composition of the present invention as the gellant, it may present in an
amount ranging from
35% to about 55%, more preferably about 40% to about 50%, and most preferably
from about
44% to about 46%, by total weight of each composition.
In another specific embodiment of the present invention, the diphenyl silicone
elastomer gellant comprises a mixture of diphenylsiloxy phenyl trimethicone,
dimethicone/phenyl vinyl dimethicone crosspolymer, and methyl trimethicone.
Preferably,
such a mixture comprises from about 10% to about 15% of diphenylsiloxy phenyl
trimethicone, from about 25% to about 35% of dimethicone/phenyl vinyl
dimethicone
crosspolymer, and from about 55% to about 60% of methyl trimethicone, by total
weight of
the mixture. For example, X-21-5652D available from Shin-Etsu Chemical Co.,
Ltd. at
Tokyo, Japan, which is a mixture comprising about 13 wt% of diphenylsiloxy
phenyl
trimethicone, about 30 wt% of dimethicone/phenyl vinyl dimethicone
crosspolymer, and about
57 wt% of methyl trimethicone, is used as the diphenyl silicone elastomer
gellant in the
compositions of the present invention. If X-21-5652D is used in the
composition of the
present invention as the gellant, it may present in an amount ranging from
about 5% to about
25%, more preferably from about 7% to about 20%, and most preferably from
about 10% to
about 17% by total weight of the composition.
In yet another embodiment of the present invention, the diphenyl silicone
elastomer
gellant may comprise a first mixture of diphenylsiloxy phenyl trimethicone and
dimethicone/phenyl vinyl dimethicone crosspolymer (e.g., KSG-18A), and a
second mixture
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of diphenylsiloxy phenyl trimethicone, dimethicone/phenyl vinyl dimethicone
crosspolymer,
and methyl trimethicone (e.g., X-21-5652D), as described hereinabove.
In order to further improve the texture of the transparent cosmetic
composition of the
present invention, a hybrid silicone powder with a silicone rubber core coated
with a silicone
resin shell can optionally be added to such composition. Specific examples of
hybrid silicone
powders suitable for use in the present invention include, but are not limited
to the KSP- 100
powders available from Shin-Etsu Chemical Co., Ltd. at Tokyo, Japan, which
comprise a vinyl
dimethicone/methicone silsesquioxane crosspolymer. The KSP-100 hybrid silicone
powders
provide a uniquely soft, silky feel with good dispersibility/spreadability and
reduced
agglomeration. If KSP-100 is used in the composition of the present invention,
it may present
in an amount ranging from about 0.5 % to about 10%, more preferably from about
1% to about
5%, by total weight of the composition.
Further, the transparent cosmetic composition of the present invention may
optionally
comprise a thickener for improving the viscosity of the composition without
adversely
affecting its clarity and aesthetical appeal to customers. Preferably, the
thickener comprises a
dimethicone/phenyl vinyl dimethicone crosspolymer. More preferably, the
thickener
comprises a mixture of the dimethicone/phenyl vinyl dimethicone crosspolymer
with phenyl
trimethicone, such as the KSG- 18 silicone paste available from Shin-Etsu
Chemical Co., Ltd.
at Tokyo, Japan. If KSG-18 is used in the composition of the present invention
as the gellant,
it may present in an amount ranging from 35% to about 55%, more preferably
about 40% to
about 50%, and most preferably from about 44% to about 46%, by total weight of
each
composition.
The transparent cosmetic composition of the present invention as described
hereinabove is preferably anhydrous, i.e., containing less than about 0.5% of
water by total
weight of the composition, and alcohol-free, i.e., containing less than about
0.5% of ethyl
alcohol by total weight of the composition. More preferably, the composition
of the present
invention is in form of a gel emulsion and has a viscosity in the range of
16,000 cps to 28,000
cps.
Other biological active agents can be added to the present inventive
compositions as
desired, as long as the clarity and viscosity are not compromised. Routine
experimentation
can determine the amounts required to retain a stable composition. The type of
biological
active agent added, can be any which is beneficially used in a topical
cosmetic or
pharmaceutical composition. For example, the composition can further comprise
moisturizing
actives, agents used to treat age spots, keratoses and wrinkles, as well as
analgesics,
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anesthetics, anti-acne agents, antibacterials, antiyeast agents, antifungal
agents, antiviral
agents, antidandruff agents, antidermatitis agents, antipruritic agents,
antiemetics, antimotion
sickness agents, anti-irritant agents, anti-inflammatory agents,
antihyperkeratolytic agents,
anti-dry skin agents, antipsoriatic agents, antiseborrheic agents, antiaging
agents, antiwrinkle
agents, additional sunscreen agents, antihistamine agents, skin lightening
agents, depigmenting
agents, wound-healing agents, vitamins, corticosteroids, self-tanning agents,
or hormones.
The above-described biological active agents are only optional components of
the sunscreen
composition of the present invention and may be omitted from such composition
without
materially affecting the sun-screening function of the composition.
The sunscreen composition of the present application further comprises a
cosmetically
acceptable vehicle, as long as the clarity and viscosity are not compromised.
Substances
which may be formulated into the sunscreen composition of the present
application include,
but are not limited to: moisturizing agents, astringent agents, chelating
agents, surfactants,
emollients, preservatives, stabilizers, humectants, fragrances, etc.
Preferably, but not
necessarily, such vehicles aid the formation of a protective layer on the
skin. The vehicle or
vehicles can present in the topical composition of the present invention at an
amount ranging
from about 1% to about 99.9%, preferably from about 50% to about 99.5%, more
preferably
from about 70% to about 99%, and most preferably from about 80% to 90% by
total weight of
the topical composition.
For example, emollients which may be used in the sunscreen composition of the
present invention include, but are not limited to: stearyl alcohol, cetyl
alcohol, oleyl alcohol,
isocetyl alcohol, fatty alcohols, propane-l,2-diol, butane- 1,3-diol,
octadecan-2-ol, glyceryl
monostearate, isopropyl isostearate, stearic acid, isostearic acid, isocetyl
stearate, isopropyl
stearate, butyl stearate, isopropyl laurate, hexyl laurate, decyl oleate,
isobutyl palmitate, cetyl
palmitate, isopropyl palmitate, palmitic acid, dimethylpolysiloxane, glyceryl
monoricinoleate,
di-n-butyl sebacate, isopropyl myristate, butyl myristate, myristyl myristate,
isopropyl
linoleate, lauryl lactate, myristyl lactate, polyethylene glycol, triethylene
glycol, lanoline,
acetylated lanolin, sesame oil, coconut oil, arrachis oil, castor oil, mink
oil, mineral oil, and
petroleum.
A variety of preservatives can also be added to the sunscreen compositions of
the
present invention to provide a prolonged shelf life. Suitable preservatives
include, but are not
limited to: potassium sorbate, imidazolidinyl urea, p-hydroxy benzoate, esters
of p-
hydroxybenzoic acid, CTFA designation parabens, ethylhexylglycerin, caprylyl
glycol/phenoxyethanol/hexylene glycol, etc. Other preservatives suitable for
use in the
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sunscreen compositions of the present invention are disclosed in the
International Cosmetic
Ingredient Dictionary and Handbook, twelfth edition, 2004, the entire
disclosure of which is
herein incorporated by reference.
Humectants which may be used include, but are not limited to: polyhydric
alcohols
including glycerol, polyalkylene glycols, and alkylene polyols and mixtures
thereof,
hyaluronic acid, urea, glycerin, sorbitol, sodium 2-pyrrolidone-5-carboxylate,
soluble
collagen, dibutylphthalate and gelatin.
The transparent sunscreen composition of the present invention may optionally
comprise a fragrance in an amount sufficient to make the composition more
appealing to the
consumer. Preferably, the fragrance is in the amount of from about 0.01% to
about 10% by
total weight of the composition.
The above-described sunscreen compositions are particularly useful as skin-
protecting
or skin-treatment products for protecting the human skin against the harmful
effect of UV
radiation. Such sunscreen compositions can be applied to eyes, cheek, chin,
neck and other
facial areas, and it can also be applied to other bodily areas that are
potentially susceptible to
UV radiation.
The methods of use for the sunscreen compositions of the present invention
will
depend on the ultimate intended use of composition. For example, the sunscreen
composition
of the present invention may be applied to the skin on an as-needed basis to
provide occasional
protection against particularly intense sun light exposures. Alternatively and
preferably, the
sunscreen composition is applied to the skin in a regularly manner. For
example, the
sunscreen composition can be applied regularly at a frequency ranging from
about once per
week to about three times per day.
The following examples further illustrate the novel compositions and methods
of the
present invention, but the invention is not limited thereto.
EXAMPLE 1
The following compositions provide examples of several preferred embodiments
of the
present invention in the form of emulsion gels.
Composition A
TRADE NAME CTFA NAME CONC.
(wt. %)
Parsol MCX/ESCALOL 557 Ethylhexyl Methoxycinnamate 7.5000
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Phospholipon 90-H H dro enated Lecithin 0.1000
Poly-Pore 350FA Allyl Methacrylates Cross ol mer Ferulic Acid 0.3000
Nordih dro aiaretic Acid Nordih dro aiaretic acid 0.0500
Rosmarinic Acid 90% Rosmarinus Officinalis (Rosemary) Extract 0.0500
Neo Heliopan OS Eth lhex 1 Salicylate 5.0000
Eusolex HMS Homosalate 5.0000
Lexfeel 7 Neo en 1 Glycol Diheptanoate 3.0000
Parsol 1789 Avobenzone 2.0000
DM-Fluid A-6CS Dimethicone 10.999
Li on 1 Yeast AE N lon 6/12//Yeast Extract (FAEX) 0.1000
Amentoflavone Selaginella Tamariscina S ike Moss) Extract 0.0010
1, 3 Butylene Glycol Bu lene Gl col 0.5000
X-21-5652D Methyl Trimethicone//Dimethicone/Phenyl Vinyl Dimethicone 61.000
cross ol mer//Di hen lsiolox Phenyl Trimethicone
KSP-100 Vinyl Dimethicone/Methicone Silses uioxane Cross ol mer 3.5000
Ca mu1907P Propylene Glycol Heptanoate 0.6000
Castor Oil Ext. (30% Yellow 5 Castor Oil Ext. (30% Yellow 5 B3397) 0.2300
B3397)
Castor Oil Ext. (30% RED 28 Castor Oil Ext. (30% RED 28 C6529) 0.2300
C6529)
Composition B
TRADE NAME CTFA NAME CONC.
wt. %
Parsol MCX/ESCALOL 557 Eth lhex 1 Methoxycinnamate 7.5000
Phospholipon 90-H H dro enated Lecithin 0.1000
Poly-Pore 350FA Allyl Methacrylates Cross ol mer Ferulic Acid 0.3000
Nordih dro aiaretic Acid Nordih dro aiaretic acid 0.0500
Rosmarinic Acid 90% Rosmarinus Officinalis (Rosemary) Extract 0.0500
Neo Heliopan OS Eth lhex 1 Salicylate 7.0000
Eusolex HMS Homosalate 3.0000
Lexfeel 7 Neo en 1 Glycol Diheptanoate 3.0000
Parsol 1789 Avobenzone 2.0000
DM-Fluid A-6CS Dimethicone 10.999
Li on 1 Yeast AE N lon 6/12//Yeast Extract (FAEX) 0.1000
Amentoflavone Selaginella Tamariscina (Spike Moss) Extract 0.0010
1, 3 Butylene Glycol Bu lene Gl col 0.5000
KSG-18A Diphenylsiloxy Phenyl Trimethicone//Dimethicone/Phenyl Vinyl 46.000
Dimethicone Cross ol mer
X-21-5652D Methyl Trimethicone//Dimethicone/Phenyl Vinyl Dimethicone 15.000
cross ol mer//Di hen lsiolox Phenyl Trimethicone
KSP-100 Vinyl Dimethicone/Methicone Silses uioxane Cross ol mer 3.5000
Phenoxetol Phenoxyethanol 0.3000
Ca mu1907P Propylene Glycol Heptanoate 0.3000
Castor Oil Ext. (30% Yellow 5 Castor Oil Ext. (30% Yellow 5 B3397) 0.2300
B3397
Castor Oil Ext. (30% RED 28 Castor Oil Ext. (30% RED 28 C6529) 0.0700
C6529
Composition C
TRADE NAME CTFA NAME CONC.
(wt.%)
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Parsol MCX/ESCALOL 557 Eth lhex 1 Methoxycinnamate 7.5000
Neo Heliopan OS Eth lhex 1 Salicylate 7.0000
Eusolex HMS Homosalate 3.0000
Lexfeel 7 Neo en 1 Glycol Diheptanoate 3.0000
Parsol 1789 Avobenzone 2.0000
DM-Fluid A-6CS Dimethicone 12.628
KSG-18 Phenyl Trimethicone//Dimethicone/Phenyl Vinyl Dimethicone 46.500
Cross ol mer
X-21-5652D Methyl Trimethicone//Dimethicone/Phenyl Vinyl Dimethicone 15.000
crosspolymer//Diphenylsioloxy Phenyl Trimethicone
KSP-100 Vinyl Dimethicone/Methicone Silsesquioxane Crosspolymer 2.5000
Capmu1907P Propylene Glycol Heptanoate 0.3000
Castor Oil Ext. (30% Yellow 5 Castor Oil Ext. (30% Yellow 5 B3397) 0.2300
B3397)
Castor Oil Ext. (30% RED 28 Castor Oil Ext. (30% RED 28 C6529) 0.0420
C6529)
Phenoxetol Phenoxyethanol 10.3000
EXAMPLE 2
The following example shows comparative results of compositions using varying
gelling materials (marked in bold). All of the ingredients were mixed together
and observed
over a 24 hour period for clarity and stability.
TABLE 1
TRADE NAME CTFA NAME 1 2 3 4 5
Parsol MCX Ethylhexyl Methoxycinnamate 7.5 7.5 7.5 7.5 7.5
Neo Heliopen Ethylhexyl Salicylate 5 5 5 5 5
Eusolex Homosalate 5 5 5 5 5
Parso11789 Avobenzone 2 2 2 2 2
Phenyl
KSG-18 Trimethicone//Dimethicone/Phenyl 65.5 80.5 0 0 0
Vinyl Dimethicone Crosspolymer
gel
Methyl
T rimethicone//Dimethicone/Phenyl
X-21-5652D Vinyl Dimethicone 15 0 0 0 80.5
cro sspolymer//D iphenylsioloxy
Phen 1 Trimethicone
Gransil DM5 Dimethicone gel 0 0 80.5 0 0
Gransil TMG Cyclopentasiloxane gel 0 0 0 80.5 0
Observations clear not clear, not clear not clear clear
unstable
As seen from Table 1 above, the compositions comprising the inventive diphenyl
silicone elastomer gellant (i.e., the X-21-5652D gellant) were the only
compositions that
remained clear with sufficient stability.
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EXAMPLE 3
The following example shows comparative results of compositions containing
various
different solvents in the base composition 1 of Example 2 described
hereinabove. Each
solvent was mixed into the base composition 1 of Example 2 and observed over a
24 hour
period for clarity and stability
TABLE 2
SAMPLE# SOLVENT NAME SOLVENT % OBSERVATIONS
1 Dimethicone 5 Ok
2 Cetiol CC 5 Ok
3 Ceraa h 131 5 Ok
4 Lexfeel 7 5 Ok
5 Glycerine 5 Ok
6 Cetiol HE 12 50C unstable
7 Olive oil 12 Stable but not a gel
8 Hydrovance 12 Not stable
9 Fitoderm 12 Stable but not a gel
Cera h 1 12 Stable but not a gel
As seen from Table 2 above, only certain specific solvents provide stable,
clear gels,
while others solvents either destroy stability of the composition or do not
create a gel
composition.
