Skincare formulation

Abstract

Disclosed is a skin care composition comprising a first cosmetic active ingredient and a second cosmetic active ingredient, wherein the first and second cosmetic active ingredients are separately encapsulated within micro or nanoparticles of a matrix material, preferably protein, wherein the first cosmetic active ingredient and a second cosmetic active ingredients are targeted at treatment of different skin layers, wherein the micro or nanoparticles encapsulating the first cosmetic active ingredient have a first mean particle size and the micro or nanoparticles encapsulating the second active ingredient have a second mean particle size different to the first mean particle size; and wherein both the first and second mean particle sizes are of from 200 to 2000 nm. A method of preparing the skin care composition is also described.

Description

INTRODUCTION The invention relates to the field of skin care. Specifically, the invention relates to a new skin care composition and a method for preparing the skin care composition. BACKGROUND It is well known to provide compositions targeted at specific skin conditions such as dark spots, hyperpigmentation and discolouration. It is also known to provide compositions targeted at specific skin types. Of specific interest are compositions targeted at melanin-rich skin. The term melanin-rich skin is not confined to any one race or ethnicity; rather, this term is inclusively unified by referring to the specific skin benefits and challenges that stem from a shared or relatable melanin concentration FST (Fitzpatrick Skin Type) 2-6. Melanin is an evolutionary protective pigment whose skin function is as a physical barrier against ultraviolet (UV) solar radiation. All races have similar numbers of melanin producing cells located within the stratum basalis of the epidermis. Skin colour differences result from the pigment content and characteristics of the melanosomes produced by the melanocytes in the skin. There are a number of skin care compositions available that are targeted at skin conditions such as hyper-pigmentation in melanin-rich skin. However, these compositions are typically topical brightening treatments that fail to penetrate into deep of the skin layers, and therefore are ineffective at targeting melanocytes located in the layer of basal cells at the deepest part of the epidermis. Melanocytes are highly differentiated cells that produce the pigment melanin inside melanosomes. The production of the melanin is typically stimulated by the enzyme tyrosinase. Hyperpigmentation and discolouration in melanin rich skin is believed to be the result of inflammation and a reaction from external and internal contributing factors (e.g. UV sun damage, lifestyle choices, acne or eczema). Melanin rich skin tones typically have multiple layers of trauma to the skin with each layer of the skin being affected differently. Inflammation causes pigmentation from Melanin to prematurely darken on the skin’s surface such that it appears to have a rough texture, large open visible pores, excess sebum production, dark marks, spots or signs of hormonal ageing. The topical treatments are not effective at treating trauma in each layer and therefore are often less effective at addressing the skin conditions. As a result, there is a need for an alternative and / or improved cosmetic composition which is effective at reducing the appearance of inflammation, minimises hyperpigmentation and / or shows anti-ageing rejuvenation for the skin. SUMMARY OF INVENTION In general, the present invention proposes a skin care composition comprising multiple cosmetic active ingredients encapsulated in micro or nanoparticles of varying sizes. Without wishing to be bound by theory, this strategy is believed to maximize the penetration of the different cosmetic active ingredients to different skin layers. This approach may therefore allow each ingredient's unique benefits to be targeted to specific areas of the skin (e.g. specific layers of the dermis to reticular dermis), addressing multiple hallmarks of ageing and hyperpigmentation for both men and women. The invention may also allow for timed release of the different active ingredients in an uninterrupted sequential manner. Advantageously, the composition has be found to be highly applicable to melanin-rich skin while also being suitable for all skin tones. In particular, the composition has been found to effectively compete against the natural ligand (a-MSH) on its specific receptor (MC1-R) to prevent any further activation of the tyrosinase and as a result, block melanin synthesis and stop unwanted pigmentation. The composition may lead to improvements in skin evenness and rejuvenation of the skin, the maintenance of a healthy skin equilibrium, and may aid in restoring damaged skin barrier function from external and internal factors Accordingly, in an aspect of the invention there is provided a skin care composition comprising: a first cosmetic active ingredient and a second cosmetic active ingredient; wherein the first and second cosmetic active ingredients are separately encapsulated within micro or nanoparticles of a matrix material, preferably protein; wherein the first cosmetic active ingredient and a second cosmetic active ingredients are targeted at treatment of different skin layers; wherein the micro or nanoparticles encapsulating the first cosmetic active ingredient have a first mean particle size and the micro or nanoparticles encapsulating the second active ingredient have a second mean particle size different to the first mean particle size; and wherein both the first and second mean particle sizes are of from 200 to 2000 nm. In another aspect of the invention there is provided a method of preparing a skin care composition comprising: encapsulating a first active cosmetic ingredient within micro or nanoparticles of a matrix material, preferably protein; encapsulating a second active cosmetic ingredient within micro or nanoparticles of a matrix material, preferably protein; and mixing the micro or nanoparticles encapsulating the first active cosmetic ingredient with the micro or nanoparticles encapsulating the second active cosmetic ingredient, wherein the first cosmetic active ingredient and a second cosmetic active ingredients are targeted at treatment of different skin layers; wherein the micro or nanoparticles encapsulating the first active ingredient have a first mean particle size and the micro or nanoparticles encapsulating the second active ingredient have a second mean particle size different to the first mean particle size; and wherein both the first and second mean particle sizes are of from 200 to 2000 nm. DEFINTIONS As used herein the term “cosmetic active ingredient” refers to a compound which is capable of showing efficacy in treatment of skin conditions. For example a material that shows anti-inflammatory, anti-hyperpigmentation and anti-ageing effects. As used herein the term “targeted at treatment of a different skin layers” means that the two or more ingredients show their beneficial or optimum efficacy at a different levels of penetration into the skin. As used herein the term “mean particle size” refers to the mean size (diameter) determined from dynamic light scattering as described in the examples section below. As used herein the term “microparticle” refers to a particle having an average diameter of 0.1 to 100 microns. Typically particle size is determined by dynamic light scattering as described below. As used herein the term “nanoparticle” refers to a particle having an average diameter of up to 500 nm. Typically particle size is determined by dynamic light scattering as described below Unless otherwise stated percentages provided herein are given as %weight / volume (w / v) in g / ml. i.e. the percentage is calculated by dividing the mass of the solute in grams by the volume of solution in millilitres then multiplying this by 100. DETAILED DESCRIPTION OF THE INVENTION Embodiments of the various aspects of the invention are described below. For the avoidance of doubt, it will be appreciated, where appropriate, that any embodiments as described herein in relation to one aspect of the present invention will also apply to the other aspects of the present invention. Cosmetic active ingredients As described above, the present invention proposes a skin care composition comprising at least two cosmetic active ingredients encapsulated in micro or nanoparticles of varying sizes. Preferably, the skin care composition comprises three cosmetic active ingredients. Further preferably, the skin care composition comprises four cosmetic active ingredients. Further preferably, the skin care composition comprises five cosmetic active ingredients. Further preferably, the skin care composition comprises six cosmetic active ingredients. Further preferably, the skin care composition comprises seven cosmetic active ingredients. Further preferably, the skin care composition comprises eight cosmetic active ingredients. Preferably, each of the cosmetic active ingredients is targeted at a different skin layer or a different skin penetration depth. Optionally each of the cosmetic active ingredients is separately encapsulated within micro or nanoparticles of a matrix material, preferably protein. Preferably, the cosmetic active ingredients are selected from Kojic Acid, Tranexamic Acid, L-Glutathione, y-Aminobutyric Acid, Epigallocatechin Gallate, Alpha-Bisabolol, Magnolia Officinalis Bark Extract and Glabridin. It will be appreciated that the two, preferably three, four, five, six, seven or eight cosmetic active ingredients could be selected from any combination of the above list. Optionally, the composition comprises all of these cosmetic active ingredients. It will also be appreciated that Magnolia Officinalis Bark Extract refers to any or all compounds that may be extracted for Magnolia Officinalis Bark, such as magnolol and / or honokiol. Advantageously, these cosmetic active ingredients, otherwise known as actives, have been observed to provide one or more of the following properties; the capability to inhibit tyrosinase activity, the promotion of tyrosinase degradation, down regulatation of gene expression that promotes melanogenesis, inhibiting pro- melanogenetic effects of UV, inhibiting melanosome transfer from melanocyte to keratinocyte, increasing exfoliation of pigmented keratinocytes, countering the inflammation stimulus of UV and other stresses. They are therefore highly suited to skin care products targeted to a melanin-rich skin. Without wishing to be bound by theory these cosmetic ingredients are believed to function in the following manner: Kojic Acid is a fungal metabolite of certain species of Acetobacter, Aspergillus, and Penicillium. Its depigmenting ability originates from a potent inhibition of tyrosinase by chelating copper at the active site of the enzyme. Kojic acid has been found to prevent the formation and accumulation of melanin in which the copper irons are chelated for the tyrosinase activity. An effective tyrosinase inhibitor that stunts melanin production, it is a useful skin conditioning agent that functions as an antioxidant (eliminating free radicals) and effectively fades pigmentation visibly appearing as damaged clusters of melanin in the skin. It can inhibit tyrosinase activity, preventing the production of melanin. This action can reduce the appearance of freckles, age spots, and other unwanted pigmentation such as photo-aging. It also eliminates free radicals and strengthens cell activity, prohibiting the activity of tyrosinase and is ideal for melaninrich skin of colour. Tranexamic Acid slows the production of melanin by inhibiting a pathway known as the plasminogen / plasmin pathway. By doing so, it reduces the interactions between pigment-producing cells (melanocytes) and skin cells (keratinocytes) and this leads to a reduction in pigmentation, particularly in melasma. L-Glutathione is a tripeptide comprised of three amino acids (Cysteine, Glutamic Acid, and Glycine). Cysteine is important in collagen production, as well as skin elasticity and texture. Glutamic acid is an amino acid that helps aid skin hydration. Glycine has the ability to improve moisture retention, increase collagen production, and promote skin repair and regeneration. L-Glutathione inhibits the synthesis and agglutination of melanin by interrupting the binding between tyrosinase and L-DOPA and acting as an antioxidant, a free radical scavenger, and a detoxifying agent. y-Aminobutyric Acid (GABA), a non-protein amino acid, is naturally present in the human body. It can also be produced by lactobacillus fermentation, and when purity is higher than 98% is an ideal anti-ageing ingredient. It can penetrate into skin, relaxing tense muscles and reducing small wrinkles. In epidermis, GABA can repair cuticle barriers because GABA can promote the epidermal cell proliferation and the production of involucrin and glutathione. In the dermis, GABA can promote fibroblast proliferation and synthesis of HA and collagen, as a result it improves the skin moisture and elasticity, revealing younger, fresher looking skin. Epigallocatechin Gallate (EGCG) is a polyphenol that is abundant in Green Tea extract and the most active in the depigmenting catechin group. This makes it effective at reducing sebum excretions in the skin, the oily substance that human sebaceous glands secrete to moisturise the skin. It also has significant inhibitory activity of melanin synthesis (reduces hyperpigmentation by lowering the amount of melanin, MITF and tyrosinase found in the skin cells) with positive effects against oxidative stress and inflammation. OH Alpha-Bisabolol is the major active component of Chamomile. An effective active in hyperpigmentation and inflammation, it inhibits the rate of a-MSH, decreasing melanogenesis and skin darkening pigmentation. Its anti-inflammatory action comes from inhibiting the metabolism pathway of arachidonic acid through the presence of lipoxygenase and cyclooxygenase enzymes. As skin pigmentation experiences hormonal imbalances, a-MSH hormone present in melanocytes has great importance in the regulation of melanin rich skin of colour. The a-MSH through the MC1-R (a-MSH receptor gene) activates adenyl cyclase (AC) and increasing intracellular cAMP (cyclic adenosine monophosphate), resulting in the production of dark pigment eumelanin. Alpha-Bisabolol has the capabilities to biosynthesise leukotrienes and prostaglandins that are important chemical mediators of inflammation. Promoting the inhibition of a-MSH rate, anti-inflammatory Alpha-Bisabolol discourages melanin synthesis and pigment transfer to keratinocytes decreasing melanogenesis and skin discolouring. The constituents of Magnolia Officinalis Bark Extract, magnolol and honokiol, may be able to stop NF-KB, which plays a role in both inflammation and skin ageing. Obtained from the stem bark of the magnolia tree, the natural extract has been developed and proven effective against Propionibacterium sp. The extract is obtained from the bark of the Magnolia officinalis plant with anti-inflammatory properties of magnolol and honokiol that effectively help to fight and inhibit the activation of NF-KB, a key facilitator in the aging and chronic inflammation processes. Both magnolol and honokiol, and the Bark Extract as a whole, are anti-inflammatory and highly effective anti-aging agents and strong antioxidants. Further Magnolia Officinalis Bark Extract is a plant derived ingredient that inhibits testosterone deficiency. Male skin is different to female skin as it comprises thicker layers of skin, giving it a different physical makeup that requires a different approach, similar to that of melanin rich skin when it comes to anti-ageing treatments. The gradual loss of testosterone usually begins to have a noticeable effect on the skin in the early 30s as it relaxes, becoming more sensitive to external forces. Magnolia Bark is a hormone boosting ingredient based on the principles followed by female hormone replacement. Magnolia bark extract targets the depletion of a combination of major processes in the make skin ageing process: sex hormone binding Globulin (SHBG), 5-Alpha-reductase and aromatase. The ingredients work through enzymatic inhibition and process to be a decoy for the depletion of SHBG, regulating hormones available into the skin cells. Glabridin is a component of Licorice and a tyrosinase inhibitor that has the capability to reduce UVB pigmentation with suppressing effects in melanin production. As is the main ingredient in Licorice extract with dual pigment modulating and anti-inflammatory properties, it inhibits the tyrosinase activity of melanocytes without cytotoxicity or affecting DNA synthesis rates. Preferably each of the cosmetic active ingredients is present in the composition in at least 0.01% (weight / volume) For example, each of the cosmetic active ingredients may be present in at least 0.02% (w / v), 0.05% (w / v), or 0.1% (w / v). Preferably each of the cosmetic active ingredients is present in the composition in present in no more than 10% (w / v). For example, each of the cosmetic active ingredients may be present in no more than 7% (w / v), 5% (w / v) or 2% (w / v). Preferably each of the cosmetic active ingredients is present in the composition in the range of 0.01 to 10% by (w / v). Further preferably each of the cosmetic active ingredients is present in the composition in the range of 0.02 to 5% (w / v). Further preferably each of the cosmetic active ingredients is present in the composition in the range of 0.05 to 3% (w / v). Optionally each of the cosmetic active ingredients is present in the composition in the range 0.02 to 3%, 0.05 to 2%, 0.5 to 5%, 0.01 to 2.5%, or 0.5 to 10% (w / v). In embodiments comprising Kojic Acid, the Kojic Acid is preferably in a concentration of 0.5 to 2% (w / v). In embodiments comprising Tranexamic Acid, the Tranexamic Acid is preferably in a concentration of 1 to 3% (w / v). In embodiments comprising L-Glutathione, the L-Glutathione is preferably in a concentration of 0.5 to 5% (w / v). In embodiments comprising y-Aminobutyric Acid, the y-Aminobutyric Acid is preferably in a concentration of 0.05 to 0.3% (w / v). In embodiments comprising Epigallocatechin Gallate, the Epigallocatechin Gallate is preferably in a concentration of 0.05 to 2% (w / v). In embodiments comprising Alpha-Bisabolol, the Alpha-Bisabolol is preferably in a concentration of 0.1 to 1% (w / v). In embodiments comprising Magnolia Officinalis Bark Extract, the Magnolia Officinalis Bark Extract is preferably in a concentration of 0.1 to 0.5% (w / v). In embodiments comprising Glabridin, the Glabridin is preferably in a concentration of 0.02 to 0.5% (w / v). Advantageously, these amounts have been found to be a safe and effective amount for each active component within the composition. It will be appreciated that the percentage of each component determines the concentration of the active ingredient that will be delivered to the skin and a well-calibrated concentration can achieve desired results without causing irritation or any adverse reactions. However, it will also be appreciated that the precise percentage will vary depending on the specific active ingredient, the encapsulation technique, the targeted skin layer and the overall formulation strategy. Preferably, the composition comprises: Kojic Acid in a concentration of 0.5 to 2% (w / v); Tranexamic Acid in a concentration of 1 to 3% (w / v); L-Glutathione in a concentration of 0.5 to 5% (w / v); Y-Aminobutyric Acid in a concentration of 0.05 to 0.3% (w / v); Epigallocatechin Gallate in a concentration of 0.05 to 2% (w / v); Alpha-Bisabolol in a concentration of 0.1 to 1% (w / v); Magnolia Officinalis Bark Extract in a concentration of 0.1 to 0.5% (w / v); and Glabridin in a concentration of 0.02 to 0.5% (w / v). Preferably the micro or nanoparticles each comprise between 1 and 40% (w / v) of the cosmetic active ingredient, such as between 2 and 30%. Optionally the micro or nanoparticles each comprise between 5 and 30% (w / v) of the cosmetic active ingredient, such as between 10 and 30% or between 5 and 20% (w / v). Particle size As described above, the skin care composition comprises two mean particle sizes. A first mean size for the micro or nanoparticles encapsulating the first active ingredient and a second mean particle size different to the first mean particle size for the micro or nanoparticles encapsulating the second active ingredient. Preferably the composition comprises at least three, preferably four, five, six, seven or eight, different mean particle sizes within the composition. In embodiments comprising three cosmetic active ingredients and comprising micro or nanoparticles encapsulating each of the three ingredients, the skin care composition preferably comprises three different mean particle sizes (i.e. a first mean size for the micro or nanoparticles encapsulating the first active ingredient, a second mean particle size different to the first mean particle size for the micro or nanoparticles encapsulating the second active ingredient and a third mean particle size different to the first and second mean particle sizes for the micro or nanoparticles encapsulating the third active ingredient). In embodiments, comprising four cosmetic active ingredients and comprising micro or nanoparticles encapsulating each of the four ingredients, the skin care composition preferably comprises four different mean particle sizes. In embodiments, comprising five cosmetic active ingredients and comprising micro or nanoparticles encapsulating each of the five ingredients, the skin care composition preferably comprises five different mean particle sizes. In embodiments, comprising six cosmetic active ingredients and comprising micro or nanoparticles encapsulating each of the six ingredients, the skin care composition preferably comprises six different mean particle sizes. In embodiments, comprising seven cosmetic active ingredients and comprising micro or nanoparticles encapsulating each of the seven ingredients, the skin care composition preferably comprises seven different mean particle sizes. In embodiments, comprising eight cosmetic active ingredients and comprising micro or nanoparticles encapsulating each of the eight ingredients, the skin care composition preferably comprises eight different mean particle sizes (i.e. a first mean size for the micro or nanoparticles encapsulating the first active ingredient, a second mean particle size for the micro or nanoparticles encapsulating the second active ingredient, a third mean particle size for the micro or nanoparticles encapsulating the third active ingredient, a fourth mean particle size for the micro or nanoparticles encapsulating the fourth active ingredient, a fifth mean particle size for the micro or nanoparticles encapsulating the fifth active ingredient, a sixth mean particle size for the micro or nanoparticles encapsulating the sixth active ingredient, a seventh mean particle size for the micro or nanoparticles encapsulating the seventh active ingredient, and an eighth mean particle size for the micro or nanoparticles encapsulating the eighth active ingredient, wherein all the mean particle sizes are different). As described above, the first mean size and the second mean particle size are of from 200 to 2000 nm. Advantageously, micro or nanoparticles of these sizes may permeate through the different skin barriers, reaching lower layers without being adversely affected by skin enzymes, microbiota, and / or pH. This may allow for an appropriate dose to reach the correct layer of the skin and therefore may provide a targeted cosmetic effect without undue skin irritation. These sizes also differs from those typically used in medical treatments which use smaller particle sizes. In embodiments, comprising three optionally four, five, six, seven or eight cosmetic active ingredients and comprising micro or nanoparticles encapsulating each of the ingredients, the micro or nanoparticles encapsulating the third, and optionally the fourth, fifth, sixth, seventh and eighth cosmetic active ingredients, may also have a mean particle size of from 200 to 2000 nm. It will be appreciated that the exact penetration capabilities vary based on factors such as the specific type of nanoparticles, the formulation and the condition of the skin. However, in general, it has been observed that nanoparticles with larger sizes interact with the upper layers of the epidermis, while nanoparticles with smaller sizes are useful for targeting deeper skin layers. In particular, particles with an average size of around 400 nanometers have been found to have the ability to penetrate the epidermis, which is the outermost layer of the skin. This layer consists of several sublayers, including the stratum corneum, stratum granulosum, stratum spinosum and basal layer. Particles with sizes of less than 400 nm have the potential to reach the basal layer, which is the deepest part of the epidermis. The basal layer is responsible for producing new skin cells and contains melanocytes that produce melanin, the pigment responsible for skin colour. Preferably the first and second mean particle sizes (an optionally the third, fourth, fifth, sixth, seventh and eighth mean particle sizes) are of from 200 to 1500 nm. Preferably the first and second mean particle sizes (an optionally the third, fourth, fifth, sixth, seventh and eighth mean particle sizes) are of from 200 to 800 nm. Optionally the first and second mean particle sizes (an optionally the third, fourth, fifth, sixth, seventh and eighth mean particle sizes) are of from 400 to 2000 nm, 600 to 2000 nm, 800 to 2000 nm, 1000 to 2000 nm, 1500 to 2000 nm, 200 to 1500 nm nm, 400 to 1500 nm, 600 to 1500 nm, 800 to 1500 nm, 1000 to 1500 nm, 200 to 800 nm, 400 to 800 nm, 600 to 800 nm, 200 to 600 nm, or 400 to 600 nm. Preferably the size of the micro or nanoparticles are selected based on a target level of penetration into the skin. Preferably the first mean particle size is of from 200 to 600 nm and of the second mean particle size is of from 400 to 800 nm. As explained above, using a combination of particles of different sizes has advantageously been found to allow penetration of the various active ingredients to different layers of the skin. This allows for a targeted release of said actives to a given area in order to address specific skin conditions (e.g. conditions associated with melanin-rich skin of colour). Optionally the first mean particle size is of from 200 to 400 nm and of the second mean particle size is of from 400 to 800 nm. Optionally the first mean particle size is of from 200 to 400 nm and of the second mean particle size is of from 600 to 800 nm. Optionally the first mean particle size is of from 400 to 600 nm and of the second mean particle size is of from 600 to 800 nm. Optionally the first mean particle size is of from 200 to 600 nm and of the second mean particle size is of from 400 to 2000 nm. Optionally the first mean particle size is of from 200 to 600 nm and of the second mean particle size is of from 600 to 1200 nm. In compositions comprising a third mean particle size (for micro or nanoparticles encapsulating a third active ingredient), the first mean particle size may be of from 200 to 600 nm, the second mean particle size may be of from 400 to 800 nm and the third mean size may be of from 800 to 2000 nm. Put another way, in embodiments, comprising three cosmetic active ingredients and comprising a first mean size for micro or nanoparticles encapsulating the first active ingredient, a second mean particle size for micro or nanoparticles encapsulating the second active ingredient and a third mean particle size for micro or nanoparticles encapsulating the third active ingredient, the first mean particle size may be of from 200 to 600 nm, the second mean particle size may be of from 400 to 800 nm and the third mean size may be of from 800 to 2000 nm. In further embodiments, comprising four, five, six, seven or eight cosmetic active ingredients, and comprising micro or nanoparticles encapsulating each of the cosmetic active ingredients, the fourth, fifth, sixth, seventh and eighth mean sizes may fall within either 200 to 600 nm, 400 to 800 nm or 800 to 2000 nm. Matrix material According to the present invention the first and second cosmetic active ingredients are separately encapsulated within micro or nanoparticles of a matrix material. The matrix material may comprise protein (i.e. may comprise one or more proteins). The matrix material may consist of protein (i.e. may consist of one or more proteins). The matrix material may consist of protein derived from a single source. Advantageously, forming the micro or nanoparticle from protein has been found to provide micro and nanoparticles that forms a dry powder. This allows the micro and nanoparticles to be mixed into a wide range of cosmetic formulations, including balms and creams. Alternatively the matrix material may comprise lipids. In embodiments comprising a third fourth, fifth, sixth, seventh and / or eighth active ingredient and where the third fourth, fifth, sixth, seventh and / or eighth active ingredient are separately encapsulated in a matrix material, the matrix material of the third fourth, fifth, sixth, seventh and / or eighth active ingredient may also comprise protein. Preferably the protein encapsulating the first active ingredient is the same as the protein encapsulating the second active ingredient Optionally the protein encapsulating the first active ingredient is the same as the protein encapsulating the third, fourth, fifth, sixth, seventh and / or eighth active ingredient. Preferably the protein(s) encapsulating the cosmetic active ingredients is / are plant-based protein(s). This allows the composition to be suitable for use by vegans. Preferably, protein(s) is selected from rice, fava, pea, zein or lentil protein. Advantageously, nanoparticles formed from plant based materials such as the proteins described above facilitate interaction with the skin's barriers and enhance penetration by using ingredients that improve adhesion and permeation. Further details on some of these materials can be found in Gupta S et al, Nanocarriers and nanoparticles for skin care and dermatological treatments. Indian Dermatol Online J. 2013 Oct;4(4):267-72; Anton, N. et al, Design and production of nanoparticles formulated from nano-emulsion templates—A review. Journal of controlled release, 2008, 128(3), pp.185-199; Akbarzadeh, A. et al; Liposome: classification, preparation, and applications. Nanoscale Research Letters. 2013, 8, 102 and Pueknang, et al. Stability and Anti-Aging of Encapsulated Ferulic Acid in Phosphorylated Rice Starch. Molecules 2022, 27, 3463 Alternatively the matrix material may comprise lipids or carbohydrates. Encapsulation Preferably, the micro or nanoparticles encapsulating the first and second active ingredients, and optionally also the third, fourth, fifth, sixth, seventh and eighth cosmetic active ingredients, are further encapsulated in a microsphere ranging from 1 to 100 microns. It will be appreciated that a microsphere relates to a single micro particle in the size ranges specified above that contains a plurality of the micro or nanoparticles encapsulating the cosmetic active ingredients. Preferably the microsphere comprises one or more proteins. Optionally, the microsphere comprises the same protein as the protein encapsulating the first and / or second active ingredient. Advantageously, encapsulation in a single microsphere can allow for the cosmetic active ingredients to be released gradually over a specific period of time. Other components Preferably, the composition comprises one or more excipients (i.e. one or more constituents that are not cosmetic active ingredients). The composition may also comprise the same cosmetic active ingredients as those encapsulated by the micro or nanoparticles in a non-encapsulated form. The composition may also comprise other cosmetic active ingredients. Preferably the one or more excipients comprises glycerine. Certain excipients, known as penetration enhancers, can also be included in formulations to temporarily disrupt the skin's barrier, allowing nanoparticles to penetrate more effectively. A modified surface of nanoparticles impacts their interaction with skin components, promoting deeper penetration involving the use of materials that have an affinity for the skin's proteins. Method of preparing the skin care composition As described above, in an aspect of the invention there is provided a method of preparing a skin care composition comprising: encapsulating a first active cosmetic ingredient within micro or nanoparticles of a matrix material, preferably protein; encapsulating a second active cosmetic ingredient within micro or nanoparticles of a matrix material, preferably protein; and mixing the micro or nanoparticles encapsulating the first active cosmetic ingredient with the micro or nanoparticles encapsulating the second active cosmetic ingredient, wherein the first cosmetic active ingredient and a second cosmetic active ingredients are targeted at treatment of different skin layers; wherein the micro or nanoparticles encapsulating the first active ingredient have a first mean particle size and the micro or nanoparticles encapsulating the second active ingredient have a second mean particle size different to the first mean particle size; and wherein both the first and second mean particle sizes are of from 200 to 2000 nm. Preferably, the method further comprises separately encapsulating a third cosmetic active ingredient within micro or nanoparticles of a matrix material. Further preferably, the method further comprises separately encapsulating a fourth cosmetic active ingredient within micro or nanoparticles of a matrix material. Further preferably, the method further comprises separately encapsulating a fifth cosmetic active ingredient within micro or nanoparticles of a matrix material. Further preferably, the method further comprises separately encapsulating a sixth cosmetic active ingredient within micro or nanoparticles of a matrix material. Further preferably, the method further comprises separately encapsulating a seventh cosmetic active ingredient within micro or nanoparticles of a matrix material. Further preferably, the method further comprises separately encapsulating an eighth cosmetic active ingredient within micro or nanoparticles of a matrix material. Preferably encapsulating an active cosmetic ingredient within micro or nanoparticles of a matrix material (e.g. protein) comprises: mixing the active cosmetic ingredient with a solution or dispersion comprising a matrix material, preferably a protein; precipitating the matrix material that is mixed with the cosmetic active ingredient; spray drying the precipitated material to form micro or nanoparticles. Advantageously, this method has been found effective at providing desirable micro or nanoparticle sizes and the ability to tune the micro or nanoparticle sizes. Preferably, the method further comprises encapsulating the micro or nanoparticles in a microsphere ranging from 1 to 100 microns, optionally wherein the microsphere is a protein. Preferably the method further comprises adding a stabiliser, preferably sodium chloride, prior to precipitation and / or spray drying the matrix material. Preferably the method further comprises adding a bulking agent, preferably mannitol, prior to precipitation and / or spray drying the matrix material. Optionally the method may also involve two separate encapsulations for one cosmetic active ingredient to provide two separate micro or nanoparticle distributions which are then combined. Utilizing this strategy may allow for the same cosmetic ingredient to reach different layers of the skin. The invention will now be described by the following non-limiting examples. EXAMPLES The materials used in the examples were all commercially available, unless otherwise stated. Measuring particle size The mean particle size (e.g. diameter) can be determined using dynamic light scattering (DLS). Specifically, the mean particle size (e.g. diameter) can be determined from an intensity-weighted particle distribution obtained from dynamic light scattering. For example, using a Malvern Zetasizer Nano ZS instrument. In DLS, the size of the particles is estimated according to the ability of particles to modify the light angle across the sample and the application of Stokes-Einstein equation. A distribution of particle sizes is obtained according to the signal intensity. The intensity distribution is weighted according to the scattering intensity of each particle fraction. The particle scattering intensity is proportional to the square of the molecular weight. The polydispersity index (PDI) is determined based on the width of the distribution (e.g. the Full width half maximum). An example procedure is described below: • Calibrate a dynamic light scattering instrument (e.g. a Malvern Zetasizer Nano ZS) using appropriate calibration standards. • Fill a clean cuvette with a sample comprising the nano or micro particles. • If the particles in the sample contains particles that settle quickly, use stirring equipment to keep the particles suspended during measurement. • Set the measurement parameters on the instrument, including the laser wavelength, scattering angle and measurement duration. • Set a scattering angle appropriate for the expected size range of particles. • Record the light scattering using a standard measurement protocol. • Generate a particle size distribution based on the scattering results. • Analyze the distribution to determine the mean size and polydispersity index (PDI). Preparation of micro / nanoparticles Protein based micro or nanoparticles encapsulating cosmetic active ingredients were formed according the protocol described below. For clarity, the micro or nanoparticles are referred to purely as nanoparticles within this examples section. A protein concentrate, such as rice protein, was initially purified by dispersing the protein in water, adjusting the pH, and removing the insoluble portion through centrifugation. The cosmetic active ingredient was then dissolved or dispersed within the purified protein concentrate. The protein was then precipitated using a either a chelating agent (e.g. CaCh) or an anti-solvent. In some examples, a stabilizer agent (e.g. NaCI) was also added in addition to the precipitating agent. After precipitation, an optional bulking agent (e.g. mannitol) was added. The precipitated protein containing this cosmetic active ingredient was then spray dried to form nano particles encapsulating the cosmetic active ingredient. The obtained product was typically a fine powder with a pale yellowish colour. The mean particles size could be controlled based on the content of the active ingredient, the use of a stabilizing agent, or by the addition of the bulking agent. This is shown in table 1 below for cosmetic active ingredient y-Aminobutyric Acid (GABA). Example No GABA content % Additional Components Mean particle size (nm) Polydispersity index (PDI) 1 28 N / A 1118±231 0.221 ±0.179 2 16 NaCI as stabilizing agent 235 ± 16 0.218 ±0.065 3 20 41% Mannitol as bulk agent 536 ± 66 0.369 ± 0.070 4 28 23% Mannitol as bulk agent 591 ±200 0.163 ±0.095 Table 1 - Nanoparticle formation for y-Aminobutyric Acid. Nano particles for other cosmetic active ingredients were formed in a similar manner. Table 2 shows the nanoparticle sizes that were found to be preferable for the eight cosmetic active ingredients discussed above. In-vitro testing, Franz Diffusion Cell experiments and in-vivo pharmacokinetic studies have shown that these are effective at penetrating the skin and delivering active ingredients to different layers. Component Mean particle size range (nm) Alpha-Bisabolol 200 - 600 Kojic acid 800 - 2000 T ranexamic acid 400 - 800 L-glutathione 800 - 2000 y-Aminobutyric Acid (GABA) 200 - 600 Epigallocatechin Gallate 400 - 800 Magnolia Officinalis Bark Extract 200 - 600 Glabridin 200 - 600 Table 2 - Nano particles sizes found to be beneficial for various cosmetic active ingredients Formation of skin care composition 5 Skin care compositions comprising multiple cosmetic active ingredients were then obtained by mixing multiple nanoparticle populations, each encapsulating a different cosmetic ingredient. The mixed powder was then introduced to one or more excipients (e.g. glycerine) in order to arrive at the final skin care composition. The quantity of each nanoparticle population was selected such that a final skin care 10 composition contained each active ingredient in the range specified within table 3. Component Concentration range (w / v%) Alpha-Bisabolol 0.1 to 1 Kojic acid 0.5 to 2.0 T ranexamic acid 1.0 to 3.0 L-glutathione 0.5 to 5.0 y-Aminobutyric Acid (GABA) 0.05 to 0.3 Epigallocatechin Gallate 0.05 to 2.0 Magnolia Officinalis Bark Extract 0.1 to 0.5 Glabridin 0.02 to 0.5 Table 3 - Amount of each cosmetic active ingredient in final skin care composition Prior to introducing the mixed powder to one or more excipients, the nanoparticles encapsulating the different active ingredients, may be further encapsulated to form microsphere containing a plurality of the different nanoparticles. In such examples, the mixed powder is introduced to a purified protein concentrate which is then precipitated and spray dried as explained above in relation to the formation of individual nanoparticles particles. Typically sizes for the microsphere encapsulating the nanoparticles is 1 to 100 microns. Results Testing of a skin care composition A skin care composition was prepared as described above using eight nanoparticle populations each containing a different cosmetic active ingredient. The cosmetic ingredients were Kojic Acid, Tranexamic Acid, L-Glutathione, y-Aminobutyric Acid, Epigallocatechin Gallate, Alpha-Bisabolol, Magnolia Officinalis Bark Extract and Glabridin and the particles size and relative concentrations were as described in tables 2 and 3. The skin care composition was then clinical tested on a panel of 22 female and male subjects between 35 and 60 years old with all skin types (normal / sensitive), having a phototype from I to VI and displaying fine lines, wrinkles, hyper pigmentation, pigmentation, dark spots and / or blemishes. The skin care composition was applied once a day for 6 consecutive weeks after cleansing the skin and before wearing SPF. A quantitative assessment of the cosmetic efficacy was based on the following evaluations: Photographs of the eye contour taken at Day 0 (DO) and Day 42 (D42) using a Antera 3D (Miravex) camera followed by subsequent computational analysis of the images and determine the “average roughness”. Clinical grading of dark sport visibility by a trained technician. This grading constituted a visual evaluation on a scale from 0 to 9. Results from these assessments are presented in table 4. Parameter Time Mean score ± Standard Deviation % Variation vs. DO Statistical Test P value Significance Average Roughness DO 35.48 ± 8.52 N / A N / A N / A N / A D42 32.43 ± 9.10 -8.60% Wilcoxon < 0.05 Significant Dark Spot Visibility DO 7.2 ± 1.0 N / A N / A N / A N / A D42 6.4 ± 1.0 -10.8% Wilcoxon < 0.05 Significant Table 4 - Results from the quantitative assessment of the cosmetic efficacy. As can be seen, the skin care composition was observed to provide a statistically significant improvement in the average roughness and the visibility of dark sports. Without wishing to be bound by theory, this is believed to arise due to targeted delivery of different cosmetic active ingredients to different layers of the skin through the use of the nano particles of different sizes. In addition to the quantitative assessment above, the majority of subjects reported the following: - A noticeable improvement in fine lines and expression wrinkles An improvement in skin elasticity and firmness Positive effects on wrinkle depth and skin smoothness Fine lines and wrinkles were visibly reduced Their skin felt softer and looked younger - A visible reduction in expression lines and deep wrinkles - Skin felt firmer and supple Blemishes from breakouts, pigmentation and sun damage became less noticeable Visible bumps, blemishes or dark spots were faded - Visible discolouration was minimised - Visible dark spots and hyperpigmentation were minimised Sun damage on the skin was reduced - Age spots were minimised - A noticeable improvement in the texture of skin Skin stayed more hydrated for longer - Skin texture became smooth and plump Unevenness of skin tone was improved Improvement in crow’s feet and undereye wrinkles The above description is for the purpose of describing the invention to a person of ordinary skill in the art how to coherently comprehend the present invention, and it is not intended to detail all those obvious modifications and variations of it which will become apparent to the skilled worker upon reading the description. It is intended, 5 however, that all such obvious modifications and variations be included within the scope of the present invention, which is defined by the following claims. The claims are intended to cover the claimed compositions and steps in any sequence which is effective to meet the objectives there intended, unless the context specifically indicates the contrary. 10

Claims

:

1. A skin care composition comprising a first cosmetic active ingredient and a second cosmetic active ingredient;wherein the first and second cosmetic active ingredients are separately 5 encapsulated within micro or nanoparticles of a matrix material comprisingprotein;wherein the first cosmetic active ingredient and the second cosmetic active ingredient are targeted at treatment of different skin layers;wherein the micro or nanoparticles encapsulating the first cosmetic active 10 ingredient have a first mean particle size and the micro or nanoparticlesencapsulating the second cosmetic active ingredient have a second mean particle size different to the first mean particle size; andwherein both the first and second mean particle sizes are of from 200 to 2000 nm.

152. The skin care composition of claim 1 comprising three cosmetic active ingredients, wherein each cosmetic active ingredient is separately encapsulated within micro or nanoparticles of a matrix material comprising protein.20 3. The skin care composition of claim 2 wherein the composition comprises atleast three different mean particle sizes within the composition, wherein the micro or nanoparticles encapsulating each cosmetic active ingredient has a different mean particle size compared to the micro or nanoparticles encapsulating the other cosmetic active ingredients.

254. The skin care composition of any preceding claim wherein the micro or nanoparticles encapsulating the first and second active ingredients are further encapsulated in a microsphere ranging from 1 to 100 microns.30 5. The skin care composition of any preceding claim wherein the cosmetic activeingredients are selected from Kojic Acid, Tranexamic Acid, L-Glutathione, y-Aminobutyric Acid, Epigallocatechin Gallate, Alpha-Bisabolol, Magnolia Officinalis Bark Extract and Glabridin.05 09 246. The skin care composition of any preceding claim wherein the both the first and second mean particle sizes are of from 200 to 1500 nm.

7. The skin care composition of claims 2 to 6, wherein the micro or nanoparticles 5 encapsulating the third also have a mean particle size of from 200 to 2000 nm.

8. The skin care composition of any preceding claim wherein first mean particle size is of from 200 to 600 nm and of the second mean particle size is of from 400 to 800 nm. 10 9. The skin care composition of any preceding claim wherein each of the cosmetic active ingredients is present in the composition in the range of 0.01 to 10% by (w / v). 15 10. The skin care composition of any preceding claim wherein the micro or nanoparticles each comprise between 2 and 30% (w / v) of the cosmetic active ingredient.

11. The skin care composition of claims 2 to 10 comprising: 20 Kojic Acid in a concentration of 0.5 to 2% (w / v); Tranexamic Acid in a concentration of 1 to 3% (w / v); L-Glutathione in a concentration of 0.5 to 5% (w / v); y-Aminobutyric Acid in a concentration of 0.05 to 0.3% (w / v); Epigallocatechin Gallate in a concentration of 0.05 to 2% (w / v); 25 Alpha-Bisabolol in a concentration of 0.1 to 1% (w / v); Magnolia Officinalis Bark Extract in a concentration of 0.1 to 0.5% (w / v); and Glabridin in a concentration of 0.02 to 0.5 % (w / v). 30 12. The skin care composition of any preceding claim, wherein the matrix material consists of protein.

13. The skin care composition of claim 1, wherein the protein encapsulating the first active ingredient is the same as the protein encapsulating the second active 35 ingredient.05 09 2414. The skin care composition of claims 12 to 13, wherein the protein is a plantbased protein selected from rice, fava, pea, zein or lentil protein. 5 15. The skin care composition of any preceding claim, further comprising one or more excipients.

16. A method of preparing a skin care composition comprising: encapsulating a first active cosmetic ingredient within micro or 10 nanoparticles of a matrix material comprising protein; encapsulating a second active cosmetic ingredient within micro or nanoparticles of a matrix material comprising protein; and mixing the micro or nanoparticles encapsulating the first active cosmetic ingredient with the micro or nanoparticles encapsulating the second active 15 cosmetic ingredient, wherein the first cosmetic active ingredient and the second cosmetic active ingredient are targeted at treatment of different skin layers; wherein the micro or nanoparticles encapsulating the first cosmetic active ingredient have a first mean particle size and the micro or nanoparticles 20 encapsulating the second cosmetic active ingredient have a second mean particle size different to the first mean particle size; and wherein both the first and second mean particle sizes are of from 200 to 2000 nm. 25 17. The method according claims 16 further comprising separately encapsulating a third cosmetic active ingredient within micro or nanoparticles a matrix material comprising protein.

18. The method according to claim 17 further comprising separately encapsulating 30 four, five, six, seven or eight cosmetic active ingredients within micro or nanoparticles of a matrix material comprising protein.

19. The method according to claim 17 or 18 wherein the micro or nanoparticles encapsulating each cosmetic active ingredient each have a different mean 35 particle size.05 09 2420. The method according to any one of claims 16 to 19 wherein the micro or nanoparticles encapsulating each cosmetic active ingredient consist of protein.5 21. The method according to claim 20 wherein the first and second cosmetic activeingredients are encapsulated using the same protein.

22. The method according to any one of claims 16 to 21 wherein the first and second active ingredients are selected from Kojic Acid, Tranexamic Acid, L-10 Glutathione, y-Aminobutyric Acid, Epigallocatechin Gallate, Alpha-Bisabolol,Magnolia Officinalis Bark Extract and Glabridin.

23. The method according to any one of claims 16 to 22 wherein encapsulating an active cosmetic ingredient within micro or nanoparticles of protein comprises:15 mixing the active cosmetic ingredient with a solution or dispersioncomprising a matrix material comprising a protein;precipitating the matrix material that is mixed with the cosmetic active ingredient;spray drying the precipitated material to form micro or nanoparticles.2024. The method according to claims 23 further comprising adding a stabiliser prior to precipitation and / or spray drying the matrix material.

25. The method according to claim 23 or 24 further comprising adding a bulking25 agent prior to precipitation and / or spray drying the matrix material.