Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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SKIN CARE PRODUCT AND PROCEDURE FOR ITS PRODUCTION
FIELD OF THE INVENTION
[0001] The present invention relates to lipid particles, particularly for use
in skin care
products.
BACKGROUND OF THE INVENTION
[0002] In recent times, have become widespread skin care products, such as
creams, lotions
or serums, composed of a fluid substance, usually a gel, which incorporates
lipid particles
containing one or more molecules of cosmetic active ingredients
[0003] Examples of the aforesaid active ingredients are vitamins, such as for
example
vitamins A, C, E and their derivatives, coenzyme Q10, minerals, antioxidants,
natural
extracts and peptides.
[0004] Among the factors known to cause damage to the skin are the so-called
"free
radicals". These are responsible for lipid peroxidation. Among these, in
particular the so-
called ROS (Reactive Oxygen Species) containing molecular oxygen with an
electron
deficiency ("peroxyl"), when in excess, cause damage, the most serious of
which is
premature aging of the skin.
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[0005] In the process of lipid peroxidation the lipids containing unsaturated
fatty acids and
their esters are directly oxidized by molecular oxygen and the damage is able
to propagate
through a chain reaction, as the electron-deprived lipids tend to reintegrate
the loss by
subtracting electrons from the contiguous molecules, up to also involving the
proteins of the
central nucleus and DNA.
[0006] Following these reactions, some of the possible damages are therefore:
lipid
peroxidation, peroxidation of amino acids and proteins, enzymatic alterations
and damage to
protein structures.
[0007] ROS generated within mitochondria can retroact and directly damage
mtDNA and
other mitochondrial components. ROS can also damage nuclear DNA.
[0008] For all these reasons, the oxidative modification of some proteins can
be an
important aging factor. Therefore, products containing anti-oxidant active
ingredients
capable of interacting with ROS and inhibiting their activity are known and
widespread. For
example, those products are commercialized as:
[0009] - Revitalift Derm Intensives 10% Pure Vitamin C (L'Oreal Paris),
[0010] - Resveratrol B E Antioxidant Night concentrate (Skinceuticals)
[0011] - DayWear Advanced Multi-Protection Anti-Oxidant Creme SPF 15 (Estee
Lauder)
[0012] - Anthelios AOX Daily Antioxidant Serum with Sunscreen (La Roche-Posay)
[0013] However, the products available today to reduce ROS in the skin have
limitations.
For example, these products, while comprising active ingredients sensitive to
ROS, have the
drawback that the latter are either in the free state or incorporated in lipid
particles that have
a stable matrix, i.e. a containment envelope, designed to protect the content,
or to vehicle it in
a controlled and specific manner but not to have affinity towards ROS.
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[0014] This matrix generally consists of predominantly saturated polymers
and/or lipids
stable to oxidation (Comunian et al. "Protection and controlled release of
vitamin C by
different micro/nanocarriers", Crit Rev Food Sci Nutr. 2020, Dec 22;1-22).
[0015] The matrices used in the products known to date have the purpose of
protecting the
active ingredients incorporated, making them more bioavailable, that is able
to reach the
circulatory system, and increasing skin penetration and gradual release
[0016] For these reasons, however, the activity of the active ingredients is
expressed equally
on the entire area of skin where the product is applied regardless of the
localized
concentration of ROS and not preferentially in the areas with a higher
concentration of ROS,
which are those in which there would be a greater need.
[0017] Furthermore, for the production of similar products, it is necessary to
use organic
solvents, such as dichloromethane, chloroform, diethyl ether and ether-
methanol mixtures
which can be toxic, or high temperatures, higher than 60 C and up to 100 C
(Ghasemiyeh et
al., "Solid lipid nanoparticles and nanostructured lipid carriers as novel
drug delivery
systems: applications, advantages and disadvantages", Res Pharm Sci.2018 Aug;
13(4):288-
303). This results in an economically and energetically expensive process.
BRIEF SUMMARY OF THE INVENTION
[0018] In light of the limitations of the prior art described above, the main
aim of the
present invention is to provide a product for skin care and a process for its
manufacture
which are capable of improving the prior art in one or more of the aspects
indicated above.
[0019] Within this aim, an object of the invention is to provide lipid
particles which have a
high sensitivity to ROS and are able to convey the active ingredients
incorporated therein in
the areas which have ROS and in particular in those with a higher
concentration of ROS.
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[0020] Another object of the invention is to provide a skin care product with
a greater
affinity for ROS than similar products known to date. Another object of the
invention is to
provide a method for manufacturing a skin care product that does not provide
for the use of
organic solvents and the use of high temperatures.
[0021] Not the least object of the invention is to provide a product for skin
care and a
process for its manufacture which are highly reliable, relatively easy to
implement and at
competitive costs.
[0022] This task, as well as these and other purposes which will be apparent
later, are
achieved by lipid particles wherein each of said particles comprises:
[0023] - (a) a matrix, comprising:
[0024] (i) from greater than or equal to 20% to less than or equal to 60% by
weight on the
total weight of the lipid particle, of a lipid component characterized by a
melting temperature
from greater than or equal to 40 C to less than or equal to 55 C;
[0025] (ii) from greater than or equal to 20% to less than or equal to 30% by
weight on the
total weight of the lipid particle of one or more unsaturated fatty acids;
[0026] (iii) from greater than or equal to 10% to less than or equal to 12% by
weight on the
total weight of the lipid particle of one or more excipients selected from
surfactants,
suspending agents, humectants and their mixtures;
[0027] and (b) at least one antioxidant agent, incorporated in said matrix.
[0028] The aims and objects of the present invention are also achieved by a
process for the
preparation of lipid particles according to the invention, comprising the
steps of:
[0029] (i) melting the lipid component;
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[0030] (ii) dispersing the one or more unsaturated fatty acids in the fused
lipid component
of step (i);
[0031] (iii) dispersing in water previously heated to a temperature from
greater than or
equal to 40 C to less than or equal to 50 C:
[0032] - the at least one antioxidant agent; and
[0033] - the one or more excipients;
[0034] (iv) adding said dispersion obtained in step (ii) to said aqueous
dispersion obtained
in step (iii), under stirring, obtaining an emulsion;
[0035] (v) cooling the emulsion obtained in step (iv) to a temperature from
greater than or
equal to 5 C to less than or equal to 15 C, obtaining an emulsion consisting
of lipid particles
in an aqueous phase.
[0036] Furthermore, the tasks and purposes of the invention are also achieved
by lipid
particles for use in the topical treatment of a condition associated with an
accumulation of
ROS ("Reactive Oxygen Species") in the skin of a patient, wherein each of said
lipid
particles comprises:
[0037] (a) a matrix comprising:
[0038] (i) a lipid component;
[0039] (ii) one or more unsaturated fatty acids;
[0040] (iii) one or more excipients selected from surfactants, suspending
agents, humectants
and their mixtures;
[0041] and
[0042] (b) at least one antioxidant agent, incorporated in said matrix.
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[0043] The aims and objects of the present invention are also achieved by a
skin care
product comprising the lipid particles according to the invention.
[0044] Finally, the aims and objects of the invention are also achieved by
lipid particles
according to the invention or a skin care product according to the invention
for use in the
topical treatment of a condition associated with an accumulation of ROS in a
patient's skin.
[0045] Further characteristics and advantages of the invention will become
clearer from the
following detailed description.
DETAILED DESCRIPTION
[0046] In a first aspect, the present invention relates to lipid particles
wherein each of said
particles comprises a matrix and at least one antioxidant agent incorporated
therein.
[0047] The matrix of the lipid particles of the invention comprises from
greater than or
equal to 20% to less than or equal to 60% by weight on the total weight of the
lipid particle,
of a lipid component having a melting temperature from greater than or equal
to 40 C to less
than or equal to 55 C.
[0048] Advantageously, the aforementioned melting temperature is closer to the
temperature of the skin (37 C) than the melting temperatures of other waxes
used to create
lipid particles such as microcristalline wax, carnauba wax, bees wax, that
have a melting
temperature above 65 C.
[0049] In a preferred embodiment, the lipid component is a mixture of at least
two of
mimosa wax (acacia decurrens), jojoba seed wax, sunflower seed wax,
polyglycerol,
pentaerythrityl distearate, and transesterification products of polyglycerol
and at least one
wax chosen from jojoba wax, mimosa wax and sunflower seed wax.
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[0050] Furthermore, the matrix of the lipid particles according to the
invention comprises
(ii) from greater than or equal to 20% to less than or equal to 30% by weight
on the total
weight of the lipid particle of one or more unsaturated or preferably
polyunsaturated fatty
acids which by having a high affinity towards ROS, provide the lipid particles
of the
invention with the property of interacting with ROS, releasing the active
ingredients in a
targeted manner. The lipid particles of the invention have a matrix therefore
characterized by
a high affinity towards ROS.
[0051] In the present description, the term "affinity" means the tendency that
the active
principles or lipid particles that comprise them have to interact with ROS.
[0052] As described above, ROS affinity is measured by the iodine index.
[0053] As described above, the lipid particles commonly used today have an
oxidation
stable matrix.
[0054] In the present description, the expression "stable matrix" means a
matrix stable to
oxidation and, in the case of a lipid matrix, this means an iodine index less
than 60g
Iodine/100g, where the iodine index is measured according to ASTM D1959-97
standard.
[0055] In a preferred embodiment, the matrix of the lipid particles according
to the
invention has an iodine index higher or equal to 60g Iodine/100g where the
iodine index is
measured according to the ASTM D1959-97 standard.
[0056] The matrix of the particles of the invention comprises one or more
unsaturated fatty
acids, preferably selected from the group consisting of C16-C24 unsaturated
fatty acids and
their mixtures. In a preferred embodiment, said one or more unsaturated fatty
acids are
selected from the group consisting of linoleic acid, linolenic acid, alpha
linolenic acid, oleic
acid and their mixtures.
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[0057] Preferably the one or more unsaturated fatty acids of the matrix
comprise at least
60% by weight of polyunsaturated fatty acids on the total weight of the
unsaturated fatty
acids.
[0058] The lipid particles of the invention comprise at least one antioxidant
agent,
incorporated in the matrix.
[0059] Preferably the at least one antioxidant agent is selected from the
group consisting of
BHT (butylhydroxytoluene), vitamin E, vitamin C, BHA (butylhydroxyanisole),
polyphenols, carotenoids, superoxide dismutase and bisulfites.
[0060] In the context of the present description, the term "vitamin C" refers
to ascorbic acid
and its derivatives such as, for example, sodium ascorbyl phosphate, ascorbyl
tetraisopalmitate, 3-0-cetyl ascorbic acid and ascorbyl glucoside.
[0061] The matrix of the lipid particle, rich in unsaturated and
polyunsaturated fatty acids
which provide a high affinity towards ROS, therefore allows to selectively
convey the
antioxidant agents incorporated in it, and to act as "scavengers" in skin
areas rich in ROS
allowing therefore to neutralize them.
[0062] Preferably in the lipid particles of the invention the at least one
antioxidant is in an
amount comprised from greater than or equal to 5% to less than or equal to 20%
by weight
on the total weight of the lipid particle.
[0063] The matrix of the lipid particles according to the invention further
comprises (iii)
from greater than or equal to 10% to less than or equal to 12% by weight on
the total weight
of the lipid particle of one or more excipients selected from surfactants,
suspending agents,
humectants and their mixtures.
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[0064] Preferably, the at least one excipient is selected from the group
consisting of
polysorbates, polyacrylates, xanthan gum, alkyl glucosides and glycols.
[0065] Furthermore, the lipid particles of the invention can further comprise
one or more
active ingredients incorporated in said matrix, wherein the one or more active
ingredients are
selected from the group consisting of vitamins, peptides, minerals, growth
factors and natural
extracts.
[0066] The aforementioned active ingredients have the function of restoring
the
physiological balance, repairing and stimulating the autogenous repair
mechanisms of the
skin damaged by excessive concentrations of ROS.
[0067] The term "active ingredient" in this description refers to a substance
which possesses
a biological activity or which influences the appearance and conditions of the
skin.
[0068] With the expression "biological activity", in the present description,
it is meant that
this substance has an effect on a biological tissue, in this case the skin, or
a cosmetic effect
on it.
[0069] In a second aspect, the present invention relates to a process for the
preparation of
lipid particles according to the invention, comprising the steps of:
[0070] (i) melting the lipid component;
[0071] (ii) dispersing the one or more unsaturated fatty acids in the fused
lipid component
of step (i);
[0072] (iii) dispersing in water previously heated to a temperature from
greater than or
equal to 40 C to less than or equal to 50 C:
[0073] - the at least one antioxidant agent; and
[0074] - the one or more excipients;
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[0075] (iv) adding said dispersion obtained in step (ii) to said aqueous
dispersion obtained
in step (iii), under stirring, obtaining an emulsion;
[0076] (v) cooling the emulsion obtained in step (iv) to a temperature from
greater than or
equal to 5 C to less than or equal to 15 C, obtaining an emulsion consisting
of lipid particles
in an aqueous phase.
[0077] In step (iv) the stirring is preferably carried out at a constant speed
between 1000
and 8000 revolutions per minute.
[0078] Preferably, before step (v) the emulsion obtained in step (iv) is
sieved through a net
with holes ranging in size from greater than or equal to 0.1 to less than or
equal to 50 m,
obtaining an emulsion consisting of lipid particles in an aqueous phase with a
size ranging
from greater than or equal to 0.1 to less than or equal to 50 m. Said
emulsion, after cooling
in step (v), can then be dried under vacuum at a temperature below 40 C and/or
stabilized by
adding preservatives such as, for example, sodium benzoate, potassium sorbate,
isothiazolinones, phenoxyethanol, formaldehyde eliminators, chelating agents.
[0079] In a preferred embodiment of the process according to the invention,
the lipid
component is a mixture of at least two of mimosa wax (acacia decurrens),
jojoba seed wax,
sunflower seed wax, polyglycerol, pentaerythrityl distearate,
transesterification products of of
polyglycerol 3 and at least one wax chosen from jojoba wax, mimosa wax and
sunflower
seed wax;
[0080] The choice of the above described mixture of waxes advantageously
allows the
particles to be prepared with a process which does not require high
temperatures or organic
solvents.
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[0081] In a preferred embodiment, the process according to the invention does
not include
the use of organic solvents.
[0082] The lipid particles of the invention obtained as described above can
then be
incorporated into a skin care product selected from the group consisting of a
serum, a cream
and a lotion, mixing them with said skin care product at a temperature less
than or equal to
40 C and a speed between 100 and 200 revolutions per minute until complete
homogenization.
[0083] The present invention therefore also relates to a skin care product
comprising the
lipid particles according to the invention. Said product, preferably chosen
from a serum, a
cream and a lotion, optionally packaged in airtight containers, is protected
from the
formation of ROS inside it.
[0084] The present invention also relates to the lipid particles described
above and to the
skin care product described above for use in the topical treatment of a
condition associated
with an accumulation of ROS in the skin of a patient.
[0085] Skin conditions associated with ROS accumulation include premature
aging, loss of
elasticity, loss of hydration, hyperpigmentation, dyschromia, acne, and
imbalance of
physiological balance.
[0086] The present invention also refers to lipid particles for use in the
topical treatment of
a condition associated with an accumulation of ROS in the skin of a patient,
wherein each
lipid particle comprises:
[0087] (a) a matrix comprising:
[0088] (i) a lipid component;
[0089] (ii) one or more unsaturated fatty acids;
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[0090] (iii) one or more excipients selected from surfactants, suspending
agents, humectants
and their mixtures;
[0091] and
[0092] (b) at least antioxidant agent, incorporated in said matrix.
[0093] The present invention relates of course also to a method for treating a
condition
associated with an accumulation of ROS in the skin of a patient, by applying
to a patient the
lipid particles or the skin care product described above.
[0094] The invention will now be described with reference to the following non-
limiting
example.
[0095] Example 1: Preparation of lipid particles of the invention.
[0096] To prepare lkg of a composition comprising the lipid particles of the
invention, to be
used as an intermediate in the preparation of cosmetic products, the procedure
was as
follows:
[0097] (i) 90g of a blend of jojoba wax, mimosa wax and sunflower seed wax
(ACTICIRE
MB, ACTICIRE-GATTE FOSSE) and 30g of a blend of natural polyunsaturated fatty
acids
obtained from safflower oil (Vitamin F forte, CLR Berlin) were melted in a
beaker by
heating at a temperature of 55 C under magnetic stirring at 200 rpm for 10
minutes until the
phase was completely melted;
[0098] (ii) 30g of a mixture of natural polyunsaturated fatty acids obtained
from safflower
oil (Vitamin F forte, CLR Berlin) were added to the melted lipid mixture
obtained in step (i),
under magnetic stirring at 200 rpm while maintaining the temperature at 55 C,
until a
homogeneous "fat" melted mixture is obtained;
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[0099] (iii) an aqueous dispersion was prepared by adding to 758m1 of water
heated to 45 C
subsequently under stirring (500 rpm for 10 min):
[00100] - 20g of decyl glucoside,
[00101] - 100g of sodium ascorbyl phosphate,
[00102] - 2g of hyaluronic acid;
[00103] (iv) the aqueous dispersion prepared in point (iii) was added to the
fat mixture
prepared in point (ii) by maintaining the temperature at 48 C under stirring
at 3500 rpm for
minutes, obtaining an emulsion of lipid particles in a aqueous phase;
[00104] (iv-a) the emulsion obtained in step (iv) was sieved through a net
with pores with a
diameter of 25 m, obtaining an emulsion of lipid particles with a diameter of
up to 25 .m in
an aqueous phase;
[00105] (v) the emulsion obtained in step (iv-a) was cooled to 10 C by means
of a water bath
to accelerate the solidification of the lipid part;
[00106] In practice it has been found that the invention achieves the intended
aim and objects
by producing lipid particles and skin care products characterized by a high
affinity for ROS
and capable of conveying the active ingredients incorporated therein into the
matrix of the
lipid particles in the areas with ROS and in particular in those with a higher
concentration of
ROS.
[00107] The skin care products which incorporate the lipid particles according
to the
invention advantageously have a greater affinity towards ROS than analogous
products on
the market today.
[00108] Furthermore, the invention has perfected a process for manufacturing a
skin care
product which does not involve the use of organic solvents and the use of high
temperatures.
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[00109] The invention thus conceived is susceptible of numerous modifications
and
variations, all of which are within the scope of the inventive concept;
moreover, all the
details can be replaced by other technically equivalent elements.
[00110] In practice, the materials employed, so long as they are compatible
with the specific
use, as well as the contingent shapes and dimensions, may be any according to
requirements
and to the state of the art.
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