Field of the invention

The present invention relates to an invention in the field of skin moisturization. It more particularly relates to compositions capable of imparting a moisturizing effect to the skin and which are capable of keeping the skin moisturized for long hours.

Background of the invention

Physiologically, the skin is an organ composed of several layers, of tissue, the most external of which is called the stratum corneum. Underlying the stratum corneum is a basal layer which in turn is followed by a layer known as the dermis. The entire skin organ functions as a primary moisture reservoir for the body as well as a protective mantle. The outermost layer, the stratum corneum plays its most significant role in controlling the level of moisture in the skin and is composed of keratinized cells, a natural moisturizing factor, and lipids. All of these, function together as a protective coating, as well as a moisture barrier to retain moisture within the skin. Water is extremely important to the proper physical condition and appearances of the skin. Dry and chapped skin is largely the result of an insufficient level of moisture in the stratum corneum. Dry skin is usually characterized by at least one of the following signs or symptoms: (a) rough and flaky appearance, (b) reduced flexibility, or (c) surface fissures. In general, however, soft, pliable and healthy skin cannot be maintained in the absence of the proper level of moisture in the stratum corneum. The level of moisture in the skin is dependent upon a number of factors among which are the water binding potential of the stratum corneum, the rate at which water is supplied to the internal layers of the stratum corneum, and the rate at which water is lost from the skin via external evaporation. Under normal conditions the water content and vapor pressure of the epidermis are higher than those of the surrounding air which results in the evaporation of water from the skin surface. Replenishment of this lost water is normally carried out by the body; however, the ability to replenish this water diminishes with age resulting in the general loss of skin softness and pliability with maturation. Additionally, skin can become dry because of excessive loss of water due to exposure to low humidities, continuous use of soaps or detergents, and contact with solvents or anhydrous materials. With these factors in mind, investigators have for a long time been actively searching for ways to maintain proper levels of moisture in the skin. Since there appears no doubt that the water content of the stratum corneum is a very important factor in maintenance of normal soft flexible skin, most efforts have been directed to means for replenishment of this water from an external source. The treatment of dry skin involves the use of basic ingredients that have come to be known as emollients. While the evidence points to the fact that water alone might suffice as a treatment agent there has been great difficulty in achieving any significant result via this agent alone. The difficulty arises in the application itself since only a very thin film of water can be made to adhere to the skin. Due to the competing physical forces, evaporation will take place before any emollient effect can take place. Prolonged immersion in large quantities of water to overcome the problem of evaporation presents the danger of over hydration resulting in swelling of the corneum, possible cellular damage and even exacerbation of the original condition. These problems have been overcome by incorporating water in various cosmetically acceptable bases that will allow availability of water to the stratum corneum and regulate water take-up.

Humectants were originally employed to control moisture exchange between the product and the air, both in storage and on the skin. Typical humectants used in the past did decrease the rate of water loss from the vehicle itself and did prevent crust formation; however, they did not do one of two 25 things: decrease the rate of water loss from, or increase the water content of, the stratum corneum. I 1. Shelmire Jr., J. B.; "Archives of Dermatology, " 82:24- 31, 1960.

Moisturizing compositions can be used independently as creams and lotions or may comprise a part of other formulations that have another primary purpose such as makeup compositions, sunscreens, tanning lotions, skin treatment formulations to treat a particular aspect of the skin, and so on. It also becomes difficult to confer moisturizing properties to such formulations having a primary objective other than moisturization but nonetheless require moisturization benefit to prevent or counter the side-effects of the other harsh/artificial ingredients of the formulation, such as long wear makeup or to enhance the benefits of the formulations such as in skin treatment compositions.

Therefore, there is a need for a composition that provides moisturization for long hours.

There is also a need of a composition that is capable of Summary of the invention

According to the first aspect, the present invention relates to a moisturizing composition comprising: a. a saccharide based humectant in the range of 0.01 to 10 wt%; b. and a glucosamine glycan based moisturizing agent in the range of 0.01 to 10 wt%; c. an antioxidant in the range of 0.01 to 10 wt%; and d. a water based carrier.

These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilized in any other aspect of the invention.

The term "comprising" is meant not to be limiting to any subsequently stated elements but rather to encompass non-specified elements of major or minor functional importance. In other words the listed steps, elements or options need not be exhaustive. Whenever the words "including" or "having" are used, these terms are meant to be equivalent to "comprising" as defined above. In other words, the listed steps or options need not be exhaustive It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated.

Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description and claims indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about".

Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated. It should be noted that in specifying any range of concentration or amount, any particular upper concentration can be associated with any particular lower concentration or amount.

For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of preferred embodiments.

Detailed description of the invention

The present invention relates compositions capable of imparting a moisturizing effect to the skin and which are capable of keeping the skin moisturized for long hours.

The present invention provides a moisturizing composition comprising: a. a saccharide based moisturizing agent in the range of 0.01 to 10 wt%; b. and a glucosamine glycan based moisturizing agent in the range of 0.01 to 10 wt%; c. an antioxidant in the range of 0.01 to 10 wt%; and d. a water based carrier.

The moisturizing compositions of the present invention are capable to keeping the skin moisturized for long hours. These compositions are also suitable for incorporating into cosmetic formulations.

It was also surprising finding of the present invention that when the composition of the present invention was used in a facial cosmetic composition, the skin remained moisturized during the time that the facial composition remained on the skin and even long after the removal of the facial composition.

Moisturizing composition

The present invention provides compositions capable of imparting a moisturizing effect to the skin and which are capable of keeping the skin moisturized for long hours. The compositions of the present invention are suitable for skin treatment compositions or cosmetic formulations that require moisturizing effect either as a need or an added benefit. It is preferable that the compositions of the present invention are suitable for cosmetic formulations.

It is preferable that the compositions of the present invention are intended for use as foundation. By the term ‘foundation’ it is meant that the composition is used as a base or a pre-makeup base on the face before makeup is applied. The foundation can also be used to even out the skin tone and/or to conceal any flaws and give a uniform appearance to the face.

The compositions of the present invention comprises a saccharide based moisturizing agent, a glucosamine glycan based moisturizing agent, an antioxidant and a water based carrier.

It is preferable that the weight ratio of the saccharide based moisturizing agent to antioxidant is in the range of 1 : 10 to 10: 1.

It is preferable that the weight ratio of glucosamine glycan based moisturizing agent to antioxidant is in the range of 1:10 to 10:1.

It is preferable that the weight ratio of sum of wt% of antioxidant and wt% of saccharide based moisturizing agent to wt% of glucosamine glycan based moisturizing agent is in the range of 30:1 to 15:1.

Saccharide based moisturizing agent

The present invention comprises a saccharide-based moisturizing agent. It is preferred that the saccharide based moisturizing agent is in the range of 0.01 to 10 wt% by weight of the composition.

Preferably, the composition comprises saccharide based moisturizing agent in amounts from 0.001 to 10 wt%, more preferably from 0.01 to 8 wt%, even more preferably from 0.1 to 7 wt%, furthermore preferably from 0.1 to 5 wt% and still more preferably from 0.1 to 3 wt% by weight of the composition. It is highly preferred that the saccharide based moisturizing agent of the present invention is saccharide isomerate.

Preferably, the composition comprises saccharide isomerate in amounts from 0.001 to 10 wt%, more preferably from 0.01 to 8 wt%, even more preferably from 0.1 to 7 wt%, furthermore preferably from 0.1 to 5 wt% and still more preferably from 0.1 to 3 wt% by weight of the composition.

Saccharide isomerate is a complex mixture of hydrating corn-derived sugars which have moisture-binding (humectant) properties. The sugars are then isomerized, a process in which rearranges molecular structure to change the way a substance works and/or the results it has. In this case, the result closely matches the carbohydrates naturally present in skin’s natural moisturizing factor, NMF.

Saccharide isomerate is commercially available under trade name ‘Pentavitin®’ (from DSM), under trade name Waterin (from Clariant), under trade names ‘EPS3 Powder’, ‘EPS4 Powder’, ‘EPS5 Powder’ and‘EPS15 Powder’ (all from Codif) and under trade name'Hyanify’ (from Lipotec S.A.).

Glucosamine glycan based moisturizing agent

The present invention comprises a humectant comprising a glucosamine glycan based moisturizing agent. It is preferred that the glucosamine glycan based moisturizing agent is in the range of 0.01 to 10 wt% by weight of the composition.

Preferably, the composition comprises glucosamine glycan based moisturizing agent in amounts from 0.001 to 10 wt%, more preferably from 0.01 to 8 wt%, even more preferably from 0.1 to 7 wt%, furthermore preferably from 0.1 to 5 wt% and still more preferably from 0.1 to 3 wt% by weight of the composition.

It is highly preferred that the glucosamine glycan based moisturizing agent of the present invention is a hyaluronate or a hyaluronic acid derivative. The term "hyaluronic acid" (also referred to as "HY" hereinafter) is used in literature to designate an acidic polysaccharide with various molecular weights constituted by residues of D-glucuronic acid and N-acetyl-D-glucosamine, which naturally occur in cellular surfaces, in the basic extracellular substances of the connective tissues of vertebrates, in the synovial fluid of joints, in the vitreous humor of the eye, in the tissue of the human umbilical cord and in cocks' combs.

Preferably, the composition comprises hyaluronate derivative in amounts from 0.001 to 10 wt%, more preferably from 0.01 to 8 wt%, even more preferably from 0.1 to 7 wt%, furthermore preferably from 0.1 to 5 wt% and still more preferably from 0.1 to 3 wt% by weight of the composition.

Antioxidant

The compositions of the present invention comprise an antioxidant capable of reversing or preventing free radicals from causing oxidative stress.

The present composition further comprises an antioxidant compound in the range of 0.01 to 10 wt% more preferably from 0.01 to 8 wt%, even more preferably from 0.1 to 7 wt%, furthermore preferably from 0.1 to 5 wt% and still more preferably from 0.1 to 3 wt% by weight of the composition.

The antioxidants for the purposes of this invention are preferably selected from the group of Vitamin B3 (niacinamide), selenium, Coenzyme Q10, Vitamin C, Vitamin E, polyphenol, resveratrol.

The most preferred antioxidants for the present invention are the vitamin-based antioxidant and among those Vitamin B3 and C are highly preferred.

Water based carrier

The moisturizing composition of the present invention comprises water based carrier. For use in cosmetic formulations, a suitable base is used to prepare the cosmetic formulations of the present invention. It is preferred that the water based carrier is an emulsion, preferably oil-in-water, water-in oil and silicone invert emulsions, and most preferably silicone invert emulsions. Alternatively, water based carrier may be water alone.

The present composition comprises a formulation base in the range of 10 to 40 wt%, more preferably 12 to 35wt% and most preferably in the range of 15 to 30 wt%.

Silicone Resins

Preferably, the composition comprises one or more silicone resins. Preferably, the one or more silicone resins are selected from silanes, siloxanes, siloxysilicates, silsesquioxanes and derivatives thereof. More preferably, the one or more silicone resins are selected from siloxysilicates and silsesquioxane and derivatives thereof.

Preferably, silsesquioxane derivative is Polymethylsilsesquioxanes (PMSQ), polypropylsilsesquioxane (PPSQ) or mixtures thereof, more preferably, PMSQ. PMSQ is silsesquioxane that do not have a substituent replacing the methyl groups.

A preferred example of a siloxysilicate derivative is trimethylsiloxysilicate (TMSS).

Most preferably, the composition comprises PMSQ and TMSS as the silicone resin.

It is highly preferred that the ratio of silsesquioxane derivative to siloxysilicate derivative in the composition of the present invention is in the range of 1:99 to 99:1.

Preferably, the composition comprises one or more silicone resin in an amount from 1 to 8 wt%, preferably from 2 to 7 wt%, even more preferably from 3 to 6 wt% and further more preferably from 4 to 5 wt%.

It has been found that the composition with low levels of silicone resin is effective as a long wear composition as it is well known in the makeup industry that only high silicone resin work to achieve a long wear facial cosmetic composition. Preferably, long wear means a duration from at least 6 hours up to 24 hours e.g. 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours; and 22 hours.

By ‘low levels’ in the context of silicone resin, it is preferably meant that silicone resins in amounts less than or equal to 8 wt% by weight of the composition. In other words, it is preferably meant that silicone resin amounts are not exceeding 8 wt% by weight of the composition. By ‘high levels’ in the context of silicone resin, it is preferably meant that silicone resin amounts are exceeding 8 wt% by weight of the composition.

Light Emollients

Light emollients having low viscosity preferably less than 50cp may be used for the composition of the present invention. The common light emollients known in the industry e.g. cyclopentasiloxane, can be used, preferably volatile emollients having flash point less than 150°C.

The present composition comprises light emollients in the range of 10 to 40 wt%, more preferably 12 to 35 wt% and most preferably in the range of 15 to 30 wt%.

Optional Ingredients

Compositions of the present invention can include numerous cosmetically or medically acceptable ingredients selected for various desirable effects. These ingredients can be either in dry or liquid form, however, at levels that do not detract from the primary objects of the present invention. Pigments may be used in the composition of the present invention when the compositions are used in manufacture of cosmetic formulations. Pigments may be selected from a large group of materials to numerous to mention herein. Included in this group are inorganic pigments, organic pigments, and pearlescent pigments. When employed, the pigments are present in proportions depending on the color and the intensity of the color which it is intended to produce. Pigments can be used in the present invention at levels from about 0.1% to about 45%, preferably from about 5 % to about 40% and most preferably from 10 to 40wt%. Pigments are selected from the group consisting of inorganic pigments, organic lake pigments, pearlesent pigments, and mixtures thereof. Said pigments may optionally be surface-treated with a large number of materials that include, but, not limited to silicones, perfluorinated compounds, lecithin, amino acids, lauroyllisine, teflon, and esters. Included are the pigments as disclosed in U.S. Pat. Nos. 5,368.639 and 5,458,681, both to Hasegawa et at, issued Nov. 29, 1994 and Oct. 17, 1995; both herein incorporated by reference. Inorganic pigments useful in the present invention include those selected from the group consisting of rutile or anatase titanium dioxide, coded in the Color Index under the reference C 77,891; black, yellow, red and brown iron oxides, ceded under references CIT7.499, 77,492 and, 77.491 ; manganese violet (CIT7.742); ultramarine blue (CI77.007); chromium oxide (Cl 77,288); chromium hydrate (CI77.289); and ferric blue (Cl 77.510) and mixtures thereof. The organic pigments and lakes useful in the present invention include those selected from the group consisting of D&C Red No. 19 (Cl 45,170), D&C Red No. 9 (Cl 15,585).D&C Red NO. 21 (CI45.380), D&C Orange No. 4 (Cl 15,510), D&C Orange No. 5 (CI45.370), D&C Red No. 27 (Cl 45,410), D&C Red No. 13 (Cl 15,630), D&C Red No. 7 (Cl 15,850), D&C Red No. 6 (Cl 15,850), D&C Yellow No. 5 (Cl 19,140), D&C Red No. 36 (Cl 12,085), D&C Orange No. 10 (Cl 45.425), D&C Yellow No. 6 (Cl 15985), D&C Red No.30 (Cl 73.360), D&C Red No. 3 (Cl 45,430) and the dye or lakes based on Cochineal Carmine (Cl 75,570) and mixtures thereof. The pearlescent pigments useful in the present invention include those selected from the group consisting of the white pearlescent pigments such as mica coated with titanium oxide, bismuth oxychloride, colored pearlescent pigments such as titanium mica with iron oxides, titanium mica with ferric blue, chromium oxide and the like, titanium mica with an organic pigment of the above-mentioned type as well as those based on bismuth oxychloride and mixtures thereof. Any optional ingredients known to those skilled in the art may also be used in the invention. Examples of optional ingredients are disclosed in CTFA Cosmetic Ingredient Handbook, Second Edition, 1992, pages 621-622, 623-626 and 637-639; incorporated herein by reference. Some of the more frequently used components include from about 1 % to about 10% fillers and powders other than talc, including but not limited to the group consisting of treated and untreated mica, nylon, polyethylene, silica, polymethacrylate., kaolin, teflon, starch, oil absorbers and mixtures thereof. From about 1 to about 20% liquid ingredients including, but not limited to the group consisting of silicone oils; long chained fatty acid esters; glycerides; water; fragrances; skin conditioning and protective materials including, botanical or biological products as disclosed in The CTFA, Cosmetic Ingredient Handbook, Second Edition, pages 493-496; herein incorporated by reference. Other skin conditioning and protective material include, but, are not limited to panthenol, allantoin, aloe, aloeveragel, PABA, tocopheryl; and mixtures thereof. From about 0.1% to about 2% cos metic preservatives including, but not limited to the group consisting of methylparaben, propylparaben, butylparaben, ethylparaben, potassium sorbate, trisodium EDTA, phenoxyethanol, ethyl alcohol, diazolidinyl urea, imidazo lidinyl urea, quaternium-15 and mixtures thereof.

Method

The composition of the invention may be obtained according to the preparation processes conventionally used in cosmetics or dermatology.

Use

The present invention provides a moisturizing composition which is suitable for providing moisturization. The composition is also suitable for use in manufacture of a makeup base, a foundation which keeps the skin moisturized for at least 6 hours, and can provide skin moisturization up to 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours and up to 24 hours.

The composition of the present invention provides skin moisturization for at least 6 hours, and can provide skin moisturization up to 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours and up to 24 hours.

A person skilled in the art may select the appropriate presentation form, and also the method for preparing it, on the basis of his general knowledge, taking into account firstly the nature of the constituents used, especially their solubility in the support, and secondly the intended use of the composition.

The composition according to the invention may also contain ingredients commonly used in cosmetics, such as vitamins, thickeners (especially clays, which are optionally modified), trace elements, softeners, sequestering agents, fragrances, acidifying or basifying agents, preserving agents and UV screening agents, and mixtures thereof.

Needless to say, a person skilled in the art will take care to select this or these optional additional compounds, and/or the amount thereof, such that the advantageous properties of the composition according to the invention are not, or are not substantially, adversely affected by the envisaged addition. The examples of compositions below are given for illustrative purposes and with no limiting nature.

Examples

While this invention has been described with respect to particular embodiments thereof, it is apparent that numerous other forms and modifications of the invention will be obvious to those skilled in the art. The appended claims and this invention generally should be construed to cover all such obvious forms and modifications which are within the true spirit and scope of the present invention.

Example 1

Preparation of formulations:

A cosmetic formulation was prepared using the moisturizing composition of the present invention. All the Oil Phase ingredients including the silicone resins were weighed accurately and mixed until the mixing of emulsion and oil phase ingredients is homogenous. A thixotropic gel is added and stirred continuously till homogenous dispersion is achieved. The pigments were added. Water and minors were then added to make up the composition of the present invention. Table 1 provides an exemplary composition according to the first aspect of the present invention.

Table 1

Cosmetic formulation Example 2

Consumer tests

The study was conducted to assess the retention of the product up to 24hrs with assessments at different time points. 37 female subjects aged 18-45 years (both ages inclusive) were enrolled and all the 37 subjects completed the study. Among the 37 subjects, 10 self-perceived sensitive skin subjects were included.

Visit 1- (Day 1) - Subjects were screened based on the inclusion exclusion criteria and enrolled in the study after obtaining the informed consent. Subjects were asked to report to the site without any make up/product application. Subjects washed their face with water and were acclimatized at a room temperature for 10 minutes. Baseline assessment which included Dermatologist’s visual assessment, instrument measurement (Spectrophotometer, Corneometer) and imaging (VISIA) was performed. Post baseline assessment, the test product was applied by the expert to the subjects. Timm assessment (5-10 minutes post product application) was performed which included dermatologist’s visual assessment, instrument measurement (Spectrophotometer, Corneometer) and subject self-assessment. Follow up assessment was performed at T8 and T12A. Post T12A assessment, subjects were asked to remove and reapply the test product. Subjects were instructed to return home and report to site after 12 hours. During this time, subjects were instructed not remove the product or wash their face.

On visit 2 (Day 2), subjects were reported to the site 12 hours after product application. Follow up assessment was performed at T12B, T14 hr, T16 hr, T18 hr, T20 hr and T24 hr.

Visit 3 (Day 3): Sweat room assessment

Subjects were reported to the study site without any product application for sweat assessment. Subjects washed their face with water and acclimatized at a room temperature for 10. Post this, product was applied on the subject’s face and imaging was performed. Subjects sat in the hot room for 30 minutes. After 30 minutes, subjects

Dermatological visual assessment

• Assessment for skin dryness • Assessment for skin texture

Skin Dryness

The subjects were evaluated based on the below given scale

1. Very Dry- Stretchy, scaly, peeling

2. Dry- stretchy, wrinkly without peeling

3. Normal

4. Slightly Hydrated

5. Hydrated

Summary statistics:

* Higher mean value indicates reduction in skin dryness

Table 2

Observation: There was significant increase noted in mean values of skin dryness immediately after product application and at all-time points of evaluation in comparison to baseline, implying that the test product was efficacious in reducing skin dryness for up to 24 hours, thereby implying that the moisturization effect was up to 24 hours.

Skin Texture

The subjects were evaluated based on the below given scale Table 3

* Higher mean value indicates improvement in skin texture

Observation: There was significant increase noted in mean values of skin texture immediately after product application and at all-time points of evaluation in comparison to baseline, implying that the test product was efficacious in improving skin texture, which was noted to be retained for up to 24 hours.

Instrumental Assessment

Corneometer- Skin Hydration

Corneometer- Right and left cheek were assessed

The Corneometer indicates the hydration level of the superficial layers of the skin (stratum corneum) via measurement of skin dielectric properties. The measurements were performed by the applying the probe to the skin surface. Upon contact, an electric field passes through the stratum corneum, and the dielectric constant is obtained

Table 4

* Higher mean value indicates improvement in skin hydration

Observation: There was significant increase noted in mean values of skin hydration immediately after product application and at all-time points of evaluation in comparison to baseline, implying that the test product was efficacious in providing skin hydration, which was noted to be retained for up to 24 hours.