Note: Descriptions are shown in the official language in which they were submitted.
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OIL-BASED COSMETICS CONTAINING WATER-SOLUBLE ACTIVES
Field of the Invention
The invention relates to cosmetic compositions. More
specifically, the invention relates to cosmetic compositions
containing water-soluble active ingredients.
Background of the Invention
It is not uncommon, in this age of value-added
cosmetics, that most formulations will contain one or more
active ingredients. In addition to the benefit obtained
from the standard cosmetic components, such as emollients
and moisturizers, the actives generally provide an added
measure of utility in their biological activity, for
example, antioxidant or free-radical scavenging activity,
keratolytic activity, or antiirritant or antiinflammatory
activity. Active components come in many forms, however,
and a compound having a desired activity may not be
compatible with the vehicle of choice.
A particular problem can arise in connection with lip
products. Lipsticks, lip glosses and the like are, to a
large extent, almost exclusively based on anhydrous
formulas. The combination of waxes, oils and pigments used
in these products results in a product that is easy to
apply, gives good color coverage, and feels moist on the
lips both during and after application. However, these
constituents are normally highly hydrophobic. Thus, the
formula cannot ordinarily readily accommodate elements that
are not oil soluble. Water soluble components, such as
water-soluble actives, as well as other water soluble
components such as flavorings, are incompatible with this
type of system, and thus, the typical lip formulation is
very limited in the variety of components that can be added.
The ability to incorporate water soluble ingredients
into anhydrous formulas would provide a great advantage.
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The present invention now makes this possible, by providing
a means for rendering water-soluble components compatible
with an oil-based vehicle.
Summary of the Invention
The invention relates to anhydrous cosmetic and
pharmaceutical compositions comprising an oil phase, the
composition containing a least one water-soluble component
rendered compatible with the oil phase. The water soluble
component is rendered compatible with the oil phase by being
complexed with a polyhydric alcohol and a polyglycerol fatty
acid ester. The invention also relates to a method for
making an anhydrous cosmetic composition containing a water
soluble active comprising dissolving the water soluble
active in a polyhydric alcohol to form a solution, mixing
the solution with a polyglycerol fatty acid ester to form an
oil-compatible complex, and adding the complex to an
anhydrous cosmetically acceptable vehicle. The complexes so
formed are useful in a variety of different types of oil-
based cosmetics.
Detailed Description of the Invention
The present invention is based on the observation that
it is possible to render a water soluble active component
compatible with an oil base by first dissolving the active
in a polyhydric alcohol, and then complexing the solution
with a polyglycerol fatty acid ester. The active component
in the complex then behaves substantially as an oil soluble
component, with virtually no incompatibility problems in an
anhydrous base. The first step to accomplishing this oil
compatible complex is the dissolution of the water-soluble
active in the polyhydric alcohol. The alcohol chosen can be
any polyhydric alcohol that is capable of solubilizing a
water soluble active. The preferred polyhydric alcohol is a
C2-C6 alcohol, containing from 2-6 hydroxyl groups. Examples
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of such alcohols include, but are not limited to, propylene
glycol, dipropylene glycol, butylene glycol, or glycerol.
Particularly preferred for use in the invention is glycerol.
The amounts used of each of the polyhydric alcohol and active
are not absolute, but will be determined routinely on a case-
by-case basis depending upon the active chosen and the
solubility of the active in the chosen polyhydric alcohol.
The overall goal is to get as much active dissolved into the
alcohol as possible, so as to permit flexibility in
incorporation of adequate amounts of the active in the final
solution. It is preferred to have at least about 50o active
in the alcohol solution, and more preferred to have at least
about 70o and most preferred to have about 90o active in the
alcohol solution. Dissolution of the active material in the
alcohol ordinarily will be conducted at a temperature of
about 50°-100°C, taking into account the temperature
sensitivity of the active, with stirring until uniform.
Once the polyhydric alcohol/active solution has been
formed, the solution is then combined with the polyglycerol
fatty acid ester. The preferred polyglycerol is a
hexaglycerol, an octaglycerol or a decaglycerol. The fatty
acid ester is prepared by reaction of the polymeric glycerol
with either a saturated or unsaturated fatty acid, resulting
in the substitution of the fatty acid moiety on one or more,
preferably two or more, more preferably four or more, of the
hydroxyl sites on the glycerol molecule. Examples of useful
fatty acids are C12-C22 fatty acids, e.g., oleic acid,
linoleic acid, stearic acid, palmitic acid, myristic acid or
lauric acid. Particularly preferred is an ester formed
between a polyglycerol and an unsaturated fatty acid,
particularly oleic acid. Many polyglycerol fatty acid esters
are commercially available; just two examples are Caprol
10G40 from Abitec(Ohio), and Net-DGPO from Barnet(Ohio).
The complex is formed by adding the active/polyhydric
alcohol solution to the polyglycerol fatty acid ester at the
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same temperature as was used to prepare the solution, under
continuous agitation until the mixture is clear. The
relative amounts of active-containing solution and ester are
not critical, and can range from about 10:90 to 50:50
solution: ester. Once the clear mixture has been obtained,
the complex is oil-compatible, and can be incorporated into
an appropriate anhydrous base.
The application of this technique is not limited to any
particular type of active, i.e., it is useful with any number
of different types of water-soluble active ingredients.
Examples of such water-soluble materials include alpha and
beta hydroxy acids, and water-soluble derivatives thereof,
ascorbic acid (Vitamin C) and its water-soluble derivatives,
shikonin(a moisturizer), caffeine, glucuronic acid, whitening
agents such as kojic acid and phenyldithiazolyl-thiourea,
water-soluble collagen, whey protein, water-soluble plant
extracts, such as algal extracts, aloe, and green tea. The
foregoing examples are compounds that have a particular
biological activity; however, the benefit of the technique
can also be expanded to encompass other water soluble
components that, strictly speaking, are not actives, but do
confer a desirable property to the final product which is at
risk of being lost if not presented in an appropriate
vehicle. Examples of such materials include water soluble
flavorings, such as peach, pineapple, citrus, or butterscotch
flavored powders, or sweeteners, such as sodium saccharin.
Thus, for the sake of convenience, the term ~~actives" in the
present specification and claims will also be read to
encompass these water soluble flavoring and sweetening
components.
The complex of the invention can of course be applied to
any anhydrous makeup, for example, a foundation, concealer,
blush, or eyeshadow, as well as to an anhydrous skin care
product, such as an SPF/sunscreen product, in liquid, powder,
petrolatum-type gel, or solid/stick form. A particularly
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preferred use of the complex of the invention, however, is in
a lip product, such as a lipstick, lip balm or gloss; as
noted above, products of this type comprise extremely
hydrophobic materials, and therefore, it is very difficult to
incorporate into them any hydrophilic materials. With the
complex of the present invention, however, incorporation of
water soluble actives is a relatively simple matter. In one
embodiment, the lipstick or gloss may be a typical wax-based
formulation. By "wax-based" in the present context is
intended a product comprising at least about 5°s by weight or
more of wax, more preferably at least about 100, most
preferably about loo to about 30% by weight of the total
wax-based product. In the context of the present invention,
the term "wax" will be understood to encompass any organic
component that is solid at room temperature, which component
can be used to solidify the liquid components of the product
when all are heated together, then cooled to room
temperature. This definition includes waxes in the
traditional sense, i.e., those plant, animal or mineral
waxes containing primarily esters of higher fatty acids and
alcohols, free higher acids and alcohols, and saturated
hydrocarbons; examples of such traditional waxes include,
but are not limited to, carnauba wax, candelilla wax,
beeswax, synthetic wax, shellac wax, spermaceti, lanolin
wax, ozokerite, bran wax, ceresin wax, bayberry wax,
paraffin, rice wax and jojoba wax. However, it also includes
other non-traditional wax-like materials, including, but not
limited to, various fatty alcohols, fatty acids, fatty
esters, polyethylenes, polyethylene glycols, and sterols as
well as synthetic resinous products having a wax-like, i.e.,
hard, brittle, relatively non-greasy, texture, such as
silicone waxes.
In another embodiment, the complex is used in the
preparation of oil-based, gelled, substantially clear solid
or semi-solid products, particularly lip products, with or
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without waxes. The clear appearance of such products is
highly desirable, but the addition to the gels of other
materials risks the development of cloudiness in the
otherwise clear product. Retention of clarity can be
difficult even with the addition of materials that are
compatible with the base, and normally, clarity is retained
by the matching of refractive indices of the materials to be
incorporated, and/or with the addition of clarity enhancing
compounds. However, surprisingly, with the complex of the
present invention no such additional steps are required: the
complex containing the water-soluble ingredient is added
directly to the anhydrous vehicle components, and because of
the compatibility of the novel complex with the oil base, the
resulting product remains clear. The complex can be used
with any clear gelled oil-based system. Clear gelled
systems, and methods for making same, are well known in the
art, and include, but are not limited to, oil bases gelled
with dextrin fatty acid esters(e.g., JP US Patent No.
5106625, JP 9235210), dibenzyl monosorbitol acetal (DBMSA;
e.g., US Patent No. 5,610,199), or lanosterol and derivatives
thereof(e.g., JP 281887; JP 9188604). Thus, with the complex
of the present invention, it is possible to create a
substantially clear, flavored lip gloss, a lip balm with
water soluble actives, or a clear anhydrous stick product
containing water soluble skin actives without the
difficulties usually encountered in the preparation of such
products.
EXAMPLES
Example I.
This example illustrates the preparation of a complex of the
invention:
A complex containing the water-soluble saccharin is prepared
as follows:
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Material Weight percent
Glycerin 7.00
Sodium saccharin 8.00
Polyglyceryl-10 pentaoleate 85.00
The saccharin is sprinkled into glycerin and mixed by
propeller mixer at a temperature of 85°-95°C. When the
mixture is uniform, at the same temperature, the
polyglyceryl-10 pentaoleate is added to it, and mixed until
the mixture is clear.
In similar fashion, complexes containing active ingredients
are prepared:
Material Weight percent
Glycerin 10.00
Ascorbic acid 40.00
Polyglyceryl-10 pentaoleate 50.00
The same formula, containing either alpha hydroxy lauric
acid or sebacic acid is also prepared.
Example II.
This example illustrates the preparation of an oil-based
gelled lip gloss containing a complex of the invention.
Material Weight percent
Phase I
Dextrin palmitate 10.00
Hydrogenated polyisobutene 25.65
Simethicone .05
Phase II
Polybutene 52.00
BHT 0.05
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Octyl palmitate 6.00
Dh-,c.n TTT
Saccharin-containing complex
of Example I 2.00
Colorant 0.25
Phase IV
Oil-soluble flavoring 2.00
Phase V
Hydrogenated polyisobutene 2.00
Phase I components are sprinkled together and mixed by
propeller mixer at room temperature. When Phase I is
uniform the temperature is raised to 80°-100°C until the
mixture becomes clear. Phase II materials are added into
Phase I, at the same temperature, until the mixture is
clear.
Phase III materials are added to the mixture, and combined
under the same conditions of mixing and temperature, until
the colors and sweetener are evenly dispersed. Phase IV and
Phase V ingredients are then added and mixed at the same
temperature until clear.
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