Title - STABLE SKIN-LIGHTENING COSMETIC COMPOSITION

Abstract

This is a multi-skin-lightening cosmetic composition comprising ascorbic acid stably delivered in high concentration and, optionally, other complementary active ingredients.

Description

-03'00' STABLE SKIN LIGHTENING COSMETIC COMPOSITION FIELD OF THE INVENTION The present invention relates to a multi-skin-lightening cosmetic composition comprising ascorbic acid stably delivered in high concentration and, optionally, other complementary active ingredients. FUNDAMENTALS OF THE INVENTION Ascorbic acid, known as vitamin C, is an antioxidant capable of fighting free radicals and promoting skin lightening, both of normal skin, giving a lighter and brighter tone, and of skin with dark spots caused by the excessive production and deposition of melanin (melasma). Ascorbic acid has this effect on dark spots because it inhibits the production of tyrosinase, the enzyme that transforms tyrosine into melanin, creating pigmentation. Since it is water-soluble and not synthesized within the human body, it must be taken orally as a supplement. Topically, creams and serums containing small amounts of ascorbic acid have been widely used for promoting a range of skin benefits. In addition to lightening dark spots, it also stimulates collagen production, smoothing fine lines and even combating deep wrinkles. It so happens that ascorbic acid, in general, reacts with oxygen from water or air, leading to oxidation and darkening of compositions containing it, especially at high concentrations, compromising its effectiveness. For this reason, to maintain its stability, it has been used in its pure form or in carriers in IF-2019-79629068-APN-ANP#INPI Page 1 of 6 anhydrous formulations, in the dispersed form in high concentration, with the consistency of fine grains that act as exfoliants on the skin, generally, in a silicone medium. However, it is known that efficient clearing action would be achieved with ascorbic acid in its soluble form, allowing it to act on the deeper layers of the skin. In an attempt to overcome these transportation and solubilization problems, the state of the art suggests, as a means of transportation and stabilization of ascorbic acid, the use of silicones or polyhydric alcohols, as well as the use of heating to promote its solubilization. The ingredient is also sensitive to temperatures above 40°, which limits its processing possibilities at high temperatures for the purpose of solubilization. Most priorities dictate the use of ascorbic acid as the active ingredient responsible for the effect, or in complex compositions for that same purpose. It is frequently mentioned in water-in-oil compositions, at very low concentrations, performing functions other than skin lightening, in its dispersed (and not solubilized) form, intended for uses outside of cosmetics, or even including specific stabilizing ingredients (some harmful to the skin, especially in the long term). Due to limitations in the use of ascorbic acid at the desired concentration, it has frequently been used in combination with other lightening ingredients, for example, ferulic acid. Thus, there remains a need for new cosmetic compositions aimed primarily at skin lightening, which allow the incorporation of ascorbic acid in high concentrations and even combine it with other complementary active ingredients, while maintaining its stability. IF-2019-79629068-APN-ANP#INPI Page 2 of 6 BRIEF DESCRIPTION OF THE FIGURES Figure 1 shows the integrity of vitamin C (ascorbic acid) in the T91 study = 24-month validity. In this graph, the theoretical result represents the concentration added to the formulation (first bar) and the actual result represents the concentration obtained in dosage result 9 (second bar). Figure 2 shows the percentage of Vitamin C (ascorbic acid) decay in the T91 study - 24-month validity. DESCRIPTION OF THE INVENTION The present invention relates to a stable skin-lightening cosmetic composition comprising a high concentration of solubilized and stabilized ascorbic acid, particularly associated with other complementary lightening ingredients. This desired efficiency is achieved by using a specific ratio of propylene glycol and propanediol in a silicone medium, which is free of other essential complementary agents such as carbonate, providing protection against degradation to oxygen and temperatures above 40 °C, as well as a suitable medium for the solubilization and stabilization of high amounts of ascorbic acid. The stable skin-lightening cosmetic composition according to the present invention consists particularly of a multi-lightening serum in the form of a silicone-in-glycol emulsion that allows the delivery of a high dosage of ascorbic acid, i.e., above 5%, preferably 8 to 15%, more preferably 10% of ascorbic acid, which is adequately solubilized in a high concentration (30 to 40%) of glycols, particularly IF-2019-79629068-APN-ANP#INPI Page 3 of 6 selected from propylene glycol and propanediol. The percentages as expressed here are in relation to the weight of the final composition. The appropriate amounts of propylene glycol and propanediol can vary from 1.5:1 to 1:1.5, preferably being 18% propylene glycol and 22% propanediol. The stable skin-lightening cosmetic composition according to the present invention may be anhydrous or non-anhydrous, i.e., it may contain small concentrations of water (up to 2%), for example, from other raw materials incorporated into the composition, without impairing the stability of ascorbic acid. In another embodiment, the present invention further provides a stable, multi-skin-lightening cosmetic composition, which, in addition to the high concentration of ascorbic acid, also comprises other additional active ingredients that provide the selected lightening effects from one or more of the following: - 0.01 to 1%, preferably 0.5% of ferulic acid; - 0.01 to 1%, preferably 0.35% of Schinus terebinthfolius (lentisk) leaf extract; - 0.01 to 2%, preferably 1.5% of hydrolyzed extract of Candida saitoana] - 0.01 to 3%, preferably 2% of plankton extract; - 0.01 to 1%, preferably 0.5% of alpha-bisabolol. - 0.01 to 6%, preferably 4% glycolic acid. Thus, in addition to the multi-lightening effect, the compositions according to the present invention also have antioxidant, anti-aging, anti-wrinkle, anti-blemish, anti-inflammatory and / or exfoliating effects. IF-2019-79629068-APN-ANP#INPI Page 4 of 6 The following examples, without imposing any limitation, describe particular embodiments of the present invention. EXAMPLES Example 1. Skin lightening cosmetic composition according to the present invention. The table below illustrates one form of embodiment of the cosmetic composition according to the present invention, which was prepared by the emulsion preparation technique known to the technician in the art. Table______1. Cosmetic composition according to the present invention Ingredient Weight in relation to final composition Propanediol 22.0 Propylene glycol 18.0 Caprylyl methicone, PEG-12 dimethicone / PPG-20 crosspolymer 13.1 Ascorbic acid 11.0 Dimethicone 10.2 PEG-10-dimethicone 5.5 Dimethicone-50 4.3 Glycolic acid 2.9 Silica dimethyl silylate 2.0 Plankton extract 1.9 Candida saitoana extract 1.4 Ethoxy diglycol 1.0 Ferulic acid 0.5 Bisabolol 0.5 IF-2019-79629068-APN-ANP#INPI Page 5 of 6 Schinus terebinthifolius leaf extract 0.2 Perfume 0.2 Example 2. Stability of the composition The stability of the composition of the present invention was analyzed in accordance with example 1. To guarantee the stability and validity time of the formula (24 months), the rules of the stability guide recommended by the National Health Surveillance Agency of Brazil - ANVISA were observed, where it is recommended to expose the formulation to different temperatures (5°C, 25°C and 40°C) at different times (T0, T7, T14, T21, T28, T63, T91). Considering that 25°C and 40°C could be more aggressive temperatures for the product with ascorbic acid, the dosages were carried out in the following protocol: -Time 0 (T0); Time 28 days (T28), Time 91 days (T91); - Oven temperatures: 25°C and 40°C. For dosage calculations, a deviation error of 10% above or below the percentage of added ascorbic acid was considered for the HPLC method. Therefore, in Figures 1 and 2, the drop obtained at T91 at 40°C is highly positive since it did not reach a 10% drop. The person skilled in the art will be able to quickly assess, through the teachings contained in the text and the examples presented, the advantages of the invention and propose equivalent variations and alternative embodiments, without going outside the scope of the invention, as defined in the attached claims. IF-2019-79629068-APN-ANP#INPI Page 6 of 6 Argentine Republic - National Executive Branch 2019 - Year of Exports Additional Signature Sheet Graphic Report Number: IF-2019-79629068-APN-ANP#INPI CITY OF BUENOS AIRES Tuesday, September 3, 2019 Reference: 20190101774 The document was imported by the GEDO system with a total of 6 page(s). Digitally signed by GESTION DOCUMENTAL ELECTRONICA - GDE DN: cn=ELECTRONIC DOCUMENTARY MANAGEMENT - GDE, c=AR, o=GOVERNMENT SECRETARY OF MODERNIZATION, ou=ADMINISTRATIVE MODERNIZATION SECRETARY, serialNumber=CUIT 30715117564 Date: 2019.09.03 10:44:46-03'00' Marcelo Esteban Rubino Administrative Assistant National Patent Administration National Institute of Industrial Property Digitally signed by GESTION DOCUMENTAL ELECTRONICA GDE DN: cn=GEST10N ELECTRONIC DOCUMENTARY - GDE, c=AR, o=GOVERNMENT SECRETARY OF MODERNIZATION, ou=ADMINISTRATIVE MODERNIZATION SECRETARY, serialNumber=CUIT 30715117564 Date: 2019.09.03 10:44:47 -03'00'

Claims

1. A stable skin-lightening cosmetic composition, characterized in that it comprises at least 5% ascorbic acid solubilized and stabilized in 30 to 40% glycols; wherein the composition is in a silicone medium; wherein the glycols are propylene glycol and 1,3-propanediol in a weight ratio of 1.5:1 to 1:1.

5. Five claims follow.