STABLE COMPOSITION OF SOAP FOR PERSONAL WASHING AND PROCESS FOR PREPARING THE SAME The present invention relates to soap compositions for personal washing and, in particular, to stable soap compositions for personal use which essentially incorporate a skin lightening agent, niacinamide. , and also to its manufacturing process. The soap composition for personal washing of the invention allows the direct incorporation of the agent for the benefit of the skin, niacinamide, in soaps at higher levels to impart better properties of the bar for lightening the skin, and will still be stable, maintaining the product attributes desired by the consumer even in prolonged storage in hot and humid conditions. Usually, sunscreen and skin lightening agents, such as niacinamide and Parsol, are agents that benefit the skin and are incorporated into highly compatible cosmetic compositions. Skin lightening agents, such as niacinamide, lactic acid and others, are generally unstable at an alkaline pH. Personal wash formulations are usually based on soap, and have an alkaline pH that can prove to be detrimental to formulations containing skin lightening agents. Therefore, it is a problem to formulate a wash product comprising these skin lightening agents. Importantly, it is not possible to deliver skin lightening agents, such as niacinamide, into personal washing baths processed in a conventional manner at substantive levels where the total fat is in the range of 30% to 80%, since these compounds are unstable in an alkaline p H at an elevated temperature. Usually, therefore, to deliver skin benefit agents through washing products, it has been found that it is necessary to use a delivery system such as those that include a cationic polymer. WO 01/82884 A1 discloses a detergent bar comprising from 1% to 85% active detergent and from 0.1% to 20% skin lightening agents. Preferably, the skin lightening agent is incorporated into the detergent bar at a temperature of about 20 to 60 ° C. Importantly, this formulation was directed to synergistic soap / detergent formulations which would provide a delivery Improved skin lightening agents, ie, niacinamide, on the applications in which they are applied, thus obtaining the maximum effective value of the benefit agents used in such formulations. Although the prior art of the preceding paragraph provides soap / detergent formulations that allow the incorporation of active ingredients, such as niacinamide, into such a base formulation, and also although such selective synergistic formulations also provide improved delivery of agents beneficial to the skin, such as niacinamide, it has been found that there are still problems in the incorporation of active ingredients, such as niacinamide, in such formulations. This is due to the fact that it leads to the loss of storage stability of the product, especially under wet conditions. In particular, it has been found that formulations which include soap containing unsaturated fat which have such sunscreen benefit agents or skin brighteners, such as, for example, niacinamide, show discoloration on prolonged storage. , especially under hot and humid conditions. Thus, such soap bars of protection and care with sunscreens are known to develop discoloration by storage for a long time in hot, humid and sensitive conditions. Particularly, fas soap bases are that they contain soaps or unsaturated fatty acids with 0. 1% to 5% niacinamide show discoloration under hot, humid and sensitive conditions, typically in approximately 30 to 40 days. Importantly, it has also been found that in the case of formulations involving soaps derived from an unsaturated fatty acid (eg, oleic acid) with niacinamide, the discoloration and stripping patterns still appear at 0.5 or a percentage. in lower weight r of niacinamide at room temperature. For the foregoing reasons, it has been found especially that soaps derived from unsaturated fatty acids are not compatible with skin benefit agents, such as niacinamide, and have been found to usually lead to discoloration and loss of product attributes. for the consumer.
Also, considering that iron (Fe) and copper (Cu) impurities in the soap formulation catalyze oxidation by the unsaturated fatty acid portion, it was found that attempts to control discoloration of such formulations of soap in the presence of niacinamide by the use of keto-ethanediamintetraacetic acid (E DTA) zetilén hydroxy diphosphonate (EHDP) agers of Fe / Cu in soap are not sufficient to avoid problems of product stability , such as decorating lotions containing niacinamide. Higher amounts such as up to 0.2% E DTA-4Na (35% solution), 1% EHDP (60% solution) could not prevent discoloration in soaps having niacin amide. Therefore, it is apparent from the foregoing, that soap formulations, such as formulations for personal washing, that involve niacinamide involving soaps derived from fatty acids especially unsaturated are subject to loss of stability by of discoloration of the product by storage, especially in hot, humid and sensitive conditions. Such discoloration of the product form, besides affecting the constitutional balance of the soap formulations and their relative loss of property is beneficial, also resulted essentially in the loss of attractiveness of the product to the consumer. Also, due to such stability problems, despite the possible formulations that involve active niacinamide in soaps especially to achieve a high rate of delivery of the active substance to the skin during its use, the use and application on a wide scale of Niacinamide at desired levels in soap formulations is a continuing problem in the art. It is then the basic objective of the present invention to be able to provide personal soap / washing compositions having soap containing unsaturated fat and skin / benefit lightening agents, such as niacinamide, which could avoid skin blemishes. Stability and discoloration during prolonged storage storage, even under hot and humid conditions. Another object of the present invention is that it is capable of providing soap formulations, especially bars for personal washing with detergent actives in the range from 1-5% and including soaps derived from unsaturated fatty acids, and a lightening agent. of skin, niacinamide, which could achieve the desired stability at an alkaline pH and high temperatures, and deliver the benefit agent to the skin through washing products without the problems of discoloration in storage, especially in hot and humid conditions . Still another objective is to be able to provide stable soap formulations during storage, free of discoloration including niacinamide, which achieve the desired stability in storage, which can not be achieved by the use of conventional EDTA / EH DP chelating agents. used to remove the trace amounts of Fe / Cu present in the soaps.
Another object of the present invention is that it is capable of providing formulations of synergistic soaps / detergents which, on the one hand, provide the same. Improved delivery of skin lightening agents on substrates in which they are applied, thereby obtaining a maximum effective value of the benefit agents used in such formulation, and on the other hand avoiding problems of stability and discoloration in storage in long periods of storage, even under conditions is hot and humid. Yet another object of the present invention is to be able to provide formulations for skin care / soaps that involve skin lightening agents, such as niacinamide and Parsof sunscreens, which maintain the desired effective levels of niacinamide and the filter solar for the intended benefit of skin protection, and at the same time avoid the problem of soap discoloration in prolonged storage, especially in hot, humid and sensitive conditions. Another objective of the present invention is to help enable the stable incorporation of niacinamide into storage soaps without the need to avoid soaps based on unsaturated fatty acids, and still achieve the desired stability in storage, even in wet and sensitive conditions. to maintain the attractiveness / ios to tributes of the product desired by the consumer, and meet the marketing demands of the same. Thus, accor to one aspect of the present invention, there is provided a storage stable personal / detergent washing composition comprising from 1 to 85% active detergent, from 0.1 to 20% foot lightening agent selected from niacin, niacinamide, its precursors and derivatives and 0.02 to 2% diethylene triaminpentaacetic acid (DTPA). The above formulation of the invention may include the other usual additives and / or foot agents beneficial for such formulations for personal washing. It was found surprisingly, by means of the present invention, that the selective incorporation of DTPA into the soap-based formulation above which niacinamide was able to avoid storage stability and discoloration problems, than the chelating agents of EDTA and EHDP usuates in trace amounts of Fe / Cu can not reach or control. Thus, accor to a preferred aspect of the present invention, there is provided a detergent composition for personal washing comprising from 1-5% to 85% active detergent, from 0. 1 to 20% niacinamide, from 0.02% to 2%. % Diethylene triaminpentaacetic acid (DTPA) and 0.2 to 0.8% of a chelating agent. Accor to a more p-referenced aspect, it was found that a combination of DTPA and EHDP in soap formulations containing niacinamide provides surprisingly improved storage stability, even in hot and humid conditions, and provides soap making comprising desired levels. of active niacinamide free from any storage discoloration problems.
Thus, according to such a preferred aspect of the present invention, a personal washing detergent composition comprising from 15 to 85% active detergent, from 0.1 to 20% niacinamide, from 0.02% to 2% diethylene triaminpentaacetic acid ( DTPA) and 0.2 to 0.8% ethylene hydroxy diphosphonate (EHDP). According to another aspect of the present invention, there is provided a process for the manufacture of a detergent composition for personal washing comprising selectively providing; i) from 15 to 85% active detergent; ii) from 0.1 to 20% of a skin-releasing agent selected from niacin, niacinamide, its precursors and derivatives; iii) selectively providing 0.02 to 2% efe DTPA with or without other usual additives, preferably a chelating agent, and obtain the soap from fos itself. It is particularly preferred that the chelating agent used be EHDP. According to another preferred aspect of the present invention, there is provided a process for the manufacture of a detergent composition for personal washing comprising: providing soap strands following the conventional process and mixing niacinamide with said DTPA and EHDP, with the addition of DTPA and EHDP before and / or at the same time adding the niacinamide to obtain the stable soap.
According to a further aspect of the present invention, there is provided an improved, storage stable delivery system of skin lightening agent, niacinamide, for use in detergent / soap formulations wherein the system comprises from 15 to 85% of active substance, from 0.1 to 20% of skin lightening agent, niacinamide, from 0.02% to 2% of DTPA and from 0.2 to 0.8% of EHDP, and, optionally, other beneficial agents / additives, where the skin lightening agent the skin, niacinamide, is incorporated into the soap at a temperature in the range of 20 to 60 ° C. It would then be possible, by means of the present invention, to effectively and advantageously provide soap with niacinamide as a skin beneficial agent, which It would be stable and free from discoloration problems in storage, even in humid and sensitive conditions. Importantly, the formulation of the invention would take care of the stability problems that the usual EDTA / EHDP used to chelate trace amounts of Fe / Cu present in the soap can not achieve, and also favors the stable incorporation of niacinamide. in soap derived from unsaturated fatty acids in storage. The selected lightening agents can be selected from niacin, niacinamide, its precursors or derivatives. Optionally, the formulation may include other beneficial agents, such as placenta extracts, hydroquinone and its derivatives (eg, Arbutin), kojic acid, dicarboxylic acids (azelaic acid, sebacic acid), represented by the formula HOOC- (CxHy) -COOH, where x = from 4 to 20 and y = from 6 to 40, ascorbic acid and its derivatives, hydroxy acids or their esters (lactic acid, giicolic acid, malic acid, tartaric acid, citric acid, etc.), ferulic acid , retinol and derivatives or any other known skin lightening agents. The above skin lightening agents can also be introduced as macro domains during slow progress. The soap used in the formulation may include soap containing unsaturated fat. The term soap indicates salts of fatty carboxylic acids. The soap can be derived from any of the triglycerides conventionally used in the manufacture of soap - consequently the carboxylate anions in the soap can contain from 8 to 22 carbon atoms.Soap can be obtained by the saponification of a fat and / or or a fatty acid The fats or oils generally used in the manufacture of soap may be such as tallow, tallow tallow, palm oil, palm stearin, soybean oil, fish oil, castor oil, bran oil rice, sunflower oil, babassu oil, palm kernel oil, and others. In the previous process, the fatty acids are derived from oils / fats selected from coconut, rice bran, peanut, bait, palm, palm kernel, cottonseed, soybean, castor, etc. The soaps of fatty acids they can also be prepared synthetically (for example, by oil oxidation or by the Fischer-Tropsch process) Resin acids, such as those present in bait oil, can be used.
Naphthenic acids are also suitable. The tallow fatty acids can be derived from various animal sources and generally comprise from about 1 to 8% myristic acid, from about 21 to 32% palmitic acid, from about 14 to 31% stearic acid, from about 0 to 4 % palmitotheic acid, about 36 to 50% oleic acid and about 0 to 5% linoleic acid. A typical distribution is: 5% myristic acid, 29% palmitic acid, 23% stearic acid, 2% palmitoleic acid, 41.5% oleic acid and 3% linoleic acid. Other similar mixtures are also included, such as those of palm oil and those derived from tallow and butter of various animals. Coconut oil refers to mixtures of fatty acids that have an approximate carbon chain length distribution of 8% of 8 carbons, 7% of 10 carbons, 45% of 12 carbons, 17% of 14 carbons, 8% of 16 carbons, 2% 18 carbons, 7% oleic and 2% fínoléicos acids (the first six fatty acids listed are saturated). Other sources are included that have similar chain length distributions of carbons, such as palm kernel oil and babassu almond oil, within the term coconut oil. Optionally, beneficial agents such as organic solar filter, Parsol MCX (a trademarked name of Givaudan oure and chemically 2-ethyl-hexyl-methoxy cinnamate) Parsol 1789 (chemically known as buoyethoxy benzoylmethane) can be incorporated. Other beneficial agents that can be selected from humectants, emollients, moisturizers, surfactants that are not soaps, antimicrobial agents and anti-aging compounds can also be incorporated. Surfactants that are not soaps can be anionic, nonionic, cationic, amphoteric / supetionic or a mixture thereof. Examples of suitable moisturizers and humectants include polyols, glycerol, cetyl alcohol, carbopol 934, ethoxylated castor oil, paraffinic oils, lanolin and its derivatives. Silicone compounds such as silicone surfactants such as DC3225 (Dow Corning) and / or silicone emollients, silicone oil (DC200 ExDow Corning) may also be included. It is preferred to incorporate 1 to 5% of the beneficial agents at any step before the grinding step. Alternatively, some of these beneficial agents are introduced as macro-domains during slow progress. Other additives may be incorporated such as one or more water insoluble particulate materials such as talc, kaolin, polysaccharides, such as starch or modified starches and celluloses. Minor additives such as perfume, color, preservatives, opacifiers, and other conventional additives may be incorporated in 1 to 2% by weight. Personal washing products can be formulated in several ways. One of the examples of a person washing product) is a soap bar, the process of which is described herein. The soap can be prepared by neutralizing an appropriate mixture of fatty acids or toad to a suitable mixture of oils, or by saponifying a mixture of fatty acids and oil. The soap is converted to strands or noodles that typically have a water content in the range of 1 2 to 1 8%, and niacinamide is added to the strands thus produced, as the essential beneficial agent for the skin. Selective DTPA with EH DP with or without EDTA are mixed with the fibers before and / or at the same time of addition of the niacinamide to the strands. The minors are mixed, such as perfume, color, etc. Preferably, foot clarifying agents are added to the Sig mixer and mixed with the temperature during the mixing step which is in the range of 20 to 60 ° C. The mass of mixed soap is passed to subsequently grinding, stabilized and stamped to produce bars. In the case of soaps made from the saponification of oils, a similar process is followed after the recovery of glycerin from the soap dough. Pure soap is spray dried to reduce moisture, and the resulting strands are processed as described above. The appropriate equipment used for making soap is any equipment that is used in the manufacture of soap / detergent, and is preferably a mixer for kneading high shear. Preferred mixers include a grate mixer, mixers with kneading members of Sigma type, multiple contact overlap, single curve or double arm. The double-arm kneading mixers can be of overlapping or tangential design. Alternatively, the invention may be carried out in a container with helical screw stirrer or multi-head / high-shear metering pump mixer and spray-dryer combinations, as in conventional processing. The details of the invention, its objectives and advantages are explained in more detail below in relation to the example illustrations, not limiting, as below. EXAMPLES Under Examples 1 to 7 (comparative examples) a conventional washing soap composition incorporating the skin lightening agents, niacinamide, was prepared at varying levels from 0.1 to 5% with the soap including the Fe / Cu chelating agents. conventional, EDTA, in levels of 0.02 to 0.2% and EHDP of 0.2 to 1%. The procedure followed is detailed below. Soap compositions for personal washing were prepared by the conventional route to obtain 78% total fat. The soap was converted into strands having a water content in the range of 12 to 8% and the strands thus produced were mixed with niacinamide, EHDP at the level of 0.2 to 1% and EDTA at the level of 0.02 to 0.2%. Then, niacinamide was added in varying amounts ranging from 0.1% to 5%, and mixed in a Sigma mixer at a temperature of 40 ° C. Then, the mixed soap was subjected to grinding, stabilization and stamping to produce bars. EDTA has been used in soaps such as EDTA-4Na, and the highest limit allowed in soap is 0.2% (35% solution) and the EHDP limit is 0.8% (60% solution). The EDTA limit is 0.5%. The various amounts of the active niacinamide used in the soap base is as detailed below in Table I. Table I
The storage stability of the above niacinamide incorporating soap formulations and the usual EHDP / EDTA iron / copper chelating agents were tested under a humid condition at 35-40 ° C. In all soap formulations such as the above, the discoloration after 40 to 50 days. The foregoing will clearly show that the conventional EDTA / EHDP generally used to chelate trace amounts of Fe / Cu present in soap are not capable of preventing discoloration in the formulation involving niacinamide. This confirms, therefore, the problems of soaps based on niacinamide to achieve the desired stability in storage and maintain the attributes of the product for the consumer. Examples 8 to 21 Under the following Examples 8 to 14, the selective formulations of the present invention involving selective DTPA in combination with EH DP, but without any EDTA, and with the varying amounts of active niacinamide as tested in the case of the examples under Table l. The amount of niacinamide and the level of DTPA and EHDP tested are reproduced hereinbelow in Table II, and that jute with EDTA is reproduced hereinbelow in Table III. Table II
[Example Niacinamide (%) DTPA (%) EH DP (%) EDTA (%)
8 0. 1 0.02 - 0.5 0.2 - 0.8 0 9 0.5 0.02 - 0.5 0.2 - 0.8 0 10 1 0.02 - 0.5 0.2 - 0.8 0 1 1 2 0.02 - 0.5 0.2 - 0.8 0 12 3 0.02 - 0.5 0.2 - 0.8 0 13 4 0.02 - 0.5 0.2 - 0.8 0 14 5 0.02 - 0.5 0.2 - 0.8 0 Table III
Exemplary formulations obtained in accordance with the present invention which incorporate niacinamide in the soap and having the combination of DTPA and EHDP of Examples 8 to 14 and 15 to 21 were then subjected to the same storage stability test as that which it was followed in the formulations of Table 1. In all example formulations of examples 8 to 14 and 15 to 21 according to the present invention, there was no discoloration even in wet condition of 35 to 40 ° C. The foregoing will clearly and sufficiently demonstrate the advantages of the selective incorporation of the combination of DTPA and EHDP with and without EDTA in soap-based personal wash compositions that allow the incorporation of the skin benefit agent, niacinamide, at levels of 0.1 to 5%, without problems of any discoloration of the soap.
Demonstration of the benefit of DTPA and EHDP on discoloration The soap formulation comprising predominantly sodium oleate soap and niacinamide in 5% together with 0.04% DTPA and 0.2% EHDP (Example 22) or 0.04% EDTA and 0.2% of EHDP (Example 23) were stored at room temperature for 1 to 3 weeks. The discoloration obtained in the absence of DTPA in the soap samples and the formulation of the invention containing DTPA are presented in Figure 1. The sample of Example 22 was clear even after storage for 3 weeks (Figure 1A), but the other control samples of Example 23, showed significant discoloration even after 1 week (Figure 1 B) which worsened after 2 weeks (Figure 1C). It is possible, then, by means of the present invention to avoid soiling problems of soaps, especially personal wash formulations involving soaps derived from unsaturated fatty acid in combination with niacinamide as a skin lightening agent. The composition of the invention would therefore allow, on the one hand, the conventional process for the preparation of soap-based washing formulations, and would make it possible in particular to obtain compositions / systems for the increased delivery of the skin-releasing agent, niacinamide, without the problems of discoloration of the product and / or loss of attribute for the consumer due to the presence of niacinamide in such base formulation. The composition of the invention, therefore, would favor the wider and more effective use / application of the skin lightening agent, niacinamide, in soaps / personal wash compositions and would avoid the limitations of the advantageous use of niacinamide in such cosmetic products. of personal washing.