HYDROGEL POUR APPLICATION DE PRINCIPES ACTIFS THERAPEUTIQUES ET/OU COSMETIQUES SUR LA PEAU

HYDROGEL FOR THE APPLICATION OF THERAPEUTIC AND/OR COSMETIC ACTIVE SUBSTANCES TO THE SKIN

Abrégé français

L'invention concerne des hydrogels qui constituent une forme galénique appropriée à l'utilisation de principes actifs dans le traitement médical d'affections cutanées et/ou le traitement cosmétique de zones sensibles de la peau ou des ongles. Ces hydrogels en nappe constituent des structures rigides-élastiques adaptées aux contours des parties du corps humain et contiennent des principes actifs thérapeutiques et/ou cosmétiques. Ces hydrogels peuvent être appliqués sur la peau de manière simple et hygiénique, à la place des préparations classiques semi-liquides ou liquides ou d'emplâtres, et contribuent singulièrement à la guérison d'affections cutanées et/ou au maintien des fonctions naturelles de la peau. Ces hydrogels s'utilisent également pour délivrer des principes actifs à des végétaux.

Abrégé anglais

The invention concerns the use of hydrogels as a means of applying active
substances in the therapy of skin ailments and/or in the cosmetic treatment of
sensitive areas of skin and nail. These gels are flat, stiffly flexible
structures shaped to fit the contours of particular parts of the human body
and containing therapeutic and/or cosmetic active substances. These gels can
be placed on the skin instead of the usual semi-solid or liquid preparations
and plasters, providing a simple, clean way of applying the active substances
and contributing significantly to the healing of skin ailments and/or to
maintenance of the natural functioning of the skin. The hydrogels are also
suitable for the release of active substances to plants.

Revendications

Claims
1. A hydrogel for the application of therapeutic and/or
cosmetic active substances to the skin or for the cosmetic care and
treatment of sensitive sites of the skin and nails, characterized in
that it is a sheet-like, rigid-elastic structure adapted to contours of
human body sites which comprises medicinal and/or cosmetic
active substances.
2. The hydrogel according to claim 1 characterized in that it is
provided with a pressure-sensitive adhesive surface.
3. The hydrogel according to claim 1 or 2 characterized in that
active substances contained therein are therapeutic agents to heal
skin injuries caused by lesions, UV radiation, aging, or by some
other way.
4. The hydrogel according to claim 1 to 3 characterized in that
active substances contained therein have a skin-smoothing effect
and are selected from the group consisting of vitamins,
moisturizers, and vegetable oils.
5. The hydrogels according to claim 1 - 4 characterized in that
the active substances contained therein have an effect stimulating
the skin function and are selected from the group consisting of
plant extracts and essential oils.
6. The hydrogel according to one or several of claims 1 to 5
characterized in that the side averted from the skin is provided
with a tack-free layer.
7. The hydrogel according to one or several of claims 1 to 6
characterized in that it is packaged in a waterproof and
moisture-proof package prior to application.

8. The use of the hydrogel according to any one of claims 1 to
7 to heal skin injuries.
9. The use of the hydrogel according to any one of claims 1 to
7 for cosmetic skin care, in particular to smooth and rejuvenate
the skin.
10. The use of the hydrogel according to any one of claims 1 to
7 to influence the blood circulation of the skin.
11. The use of the hydrogel according to any one of claims 1 to
7 for the care of the nails.
12. The use of the hydrogel according to any one of claims 1 to
7 for releasing active substances to plants.

Description

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Hydrogel for the application of therapeutic active substances and/or
cosmetic active substances to the skin
Specification
The present invention relates to a hydrogel used as an application
form for the use of active substances to treat skin injuries caused
by lesions, UV rays, aging, or by some other way, or sensitive
sites of the skin and nails.
Skin aging, for example, causes reducing skin elasticity. This, in
turn, is mainly due to the fact that individual collagen fibers stick
together within the reticular structure of the dermis. Diminishing
elasticity of the skin is accompanied by a reduced water-binding
capacity of the epidermis. External moisture supply is indispensa-
ble to maintain or regenerate the natural function of the skin. In
addition, the effects of active substances for skin-smoothing, care,
and stimulation may positively influence the cutaneous relief and
stimulate the circulation. Other skin injuries, i.e., sunburn, inflam-
mations, etc. require the application of curative andtor cosmetic
active substances on the surface of the skin.
Several administration forms for therapeutic agents are known to
meet these requirements. For example, emulsions, which represent
multi-phase systems, may be applied on the skin as creams or lo-
tions. Oils, which represent single-phase systems comprising only
lipid-soluble raw materials, may also be applied on the skin in liq-
uid state. Moreover, semisolid transparent gels hav~ng a creamy
consist~ncy are known as curative and/or care-giving substances.- - ~
In practice, it is frequently extremely difficult to use such healing
and care substances on the skin surface. Excessive substance

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cannot - or only slowly - be absorbed by the skin. For example,
when wrinkles are treated in the sensitive lower eye region, sub-
stances may contact the eye mucosa and produce irritations there.
A known possibility of overcoming the problem of application and
dosage is the use of impregnated nonwoven pads. Their applica-
tion on the intended skin region is difficult and unclean because of
their moist, unstable construction.
It is not yet known to use rigid and sheet-like hydrogels as carriers
of active substances for their application in skin treatment or cos-
metics. So far rigid gel preparations have only been used as dos-
age form for active chemical compounds. Two different kinds of
gelatin capsules are known as dosage forms: hard and soft cap-
sules (DE-OS 2316 242). Moreover, an application system consist-
ing of gel is known (CA 2.078.960).
Additionally, rigid gel preparations are used in chromatography (US
5,277,91 5).
It is the object of the present invention to reduce difficulties in theapplication of active substances for cosmetic care and/or for the
treatment of skin injuries or sensitive skin and nail sites, to facili-
tate the use of therapeutic agents, and to contribute to the healing
and care of the skin or to the conservation of the natural skin
function.
According to the present invention, this object is achieved by the
fact that hydrogels are used as application form for the use of ac-
tive substances to treat the skin. These hydrogels are used for the
treatment of skin injuries and for the use in cosmetics. They are
sheet-like, rigid-elastic structures adapted to contours of human
body sites, which comprise suitable active substances for skin
treatment.

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To adapt to contours of human body sites, hydrogels are dimen-
sioned accordingly. For example, they are kidney-shaped for appli-
cation against wrinkles under the eyes. This shape also covers the
marginal areas of the eyes where "crow's feet" (creases) form.
When used as a cooling eye mask, the hydrogels have a round
shape; for example, that of cucumber slices. These are placed on
the closed eyes.
The advantages achieved by the present invention in particular
consist in the fact that a rigid, elastic hydrogel, which permits
clean application, is used instead of a semisolid or liquid prepara-
tion.
By providing them with a gently adhering surface, the hydrogels
adhere to the skin so that freedom of movement is not completely
restricted during the treatment. After application, the hydrogels
can be peeled off without pain and residues.
The hydrogels may be manufactured according to known tech-
niques. For example, a simple method is dispersing the starting
materials in heated water and gelling the solution with subsequent
cooling. The heated solution may be filled into a deep-drawing part
by means of an automatic metering unit. This can produce sheet-
like hydrogels having a thickness of 0.5 - 10 mm. Depending on
the purpose hydrogel structures having a thickness of 1 - 3 mm
are particularly advantageous in most cases.
The hydrogels according to the present invention may be em-
ployed in a wide range of applications by using various healing,
e.g., antiphlogistic, and/or care-giving active substances from the
groups comprising acetylsalicylic acid (ASA), vitamins, moisturiz-
ers, vegetable or essential oils, just to mention a few. An example
of app;ication is treating the skin in premature aging and wrinkle
formation that results, for example, through extensive sun expo-
sure of the skin and which is treated with hydrogels containing
vitamin E. Studies have shown that RRR-tocopherols act as

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radical absorbers of reactive compounds which form after the in-
fluence of UV rays.
Another application example is an eye mask completely covering
the eyes. The preferably transparent mask has a stimulating and
refreshing effect because of its intensive cooling property, and it
delivers care-giving substances, e.g., panthenol, to the skin.
An embodiment example of the present invention will be described
in the following:
The rigid hydrogel formation is achieved by the composition com-
prising:
Hydrogel for anti-wrinkle formation
a) Components: %-wt.
water 34.1 2
glycerol 26.66
gelatin A (Bloom value 200)15.46
saccharose 1 0.66
dexpanthenol 8.00
polyvinyl pyrrolidone 2.67
moisturizing factor 2.13
preservative 0.30
b) Production:
Polyvinyl pyrrolidone is dissolved in water under stirring.
Preservative and glycerol are added subsequently. Gelatin A
is allowed to swell in the initially introduced water for about
10 minutes, and the mixture is heated to about 65~C and
stirred until a clear solution is obtained. Final~y, saccharose,
dcxpanthenol, and cosmetic active substances are added.
An application example of the present invention is illustrated in the
drawings and will be described in greater detail in the following:

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FIG. 1 shows a top view of a deep-drawing part for hydro-
gels for anti-wrinkle treatment. It contains two hydro-
gel patches for single use under the eyes;
FIG. 2 shows a cross-section A-B of FIG. 1, showing the
wall and height of the deep-drawing part.
The present invention is not limited to the treatment of skin dam-
age caused by aging.
What is more, the active substance-containing hydrogels are to be
used for all kinds of external curative and care-giving treatment;
for example, they may be used instead of patches requiring a tem-
porary or lasting therapy of specific skin sites.
Moreover, the hydrogels are suitable for the release of active sub-
stances to plants.

Dessin représentatif