DE102009034771B4 - Skin protectant - Google Patents

Abstract

Skin protection agent for protection against water-insoluble substances, characterized in that it is a salt of a fatty acid, a fatty acid mixture, an alkali salt of a fatty acid or mixtures thereof with a basic amino acid or the acid salt of a basic amino acid and at least one emulsifier capable of film formation with an HLB value in the range of 12 to 25.

Description

The present invention relates to skin protection agents.

Practical work with soiled objects causes soiling of the hands and other, possibly exposed parts of the body surface. The term dirt in the context of this patent means primarily so-called "Liposchmutz", d. H. Contamination of the human body surface with non-water-soluble and / or non-polar substances. These include, for example: engine oil, oil pollution in general, greases, paints and coatings, as far as they are not water-based, shoe polish, bituminous products for underbody preservation of cars, but also dusts such as soot, graphite, rust and other metal oxides.

The cleaning of the skin from such contamination is complicated and tedious. Often this means must be used, which strain and damage the skin to be cleaned. As an example, washing pastes with rubbing agents or technical solvents may be mentioned. It can be said without exaggeration that the removal of such contaminants for unprotected affected skin areas is often a greater burden and may have a greater dermatological damage potential than the contact with the dirt.

In order to minimize the stress on the skin with "lipo-soiling", so-called "personal protective equipment" is used in the professional work process (to be provided by the employer). These include u. a. Protective gloves and skin protection products, in the latter preferred cosmetic barrier preparations.

The concept of protecting the skin against soiling by means of a barrier-forming preparation has long been the practice in various branches of industry. The hands are z. Greased with soft soap (i.e., the potassium salt of fatty acid mixtures). This forms a film after drying, which prevents the direct contact between skin and "lipo dirt". This means that dirt is not deposited directly on the skin, but on the film. In addition to being able to form a protective barrier, soft soap is amphiphilic and therefore washable. If pre-treated hands with soap, washed with "Liposchmutz" are washed, the "Liposchmutz" is emulsified by the protective film and can then be rinsed off.

The concept of a barrier against soiling of the skin by means of soft soap was taken up and led to the development of formulations for a wide range of applications. For skin protection preparations of this purpose, the term "invisible glove" (English "invisible glove") was coined. Such products are for. B. Evonik Stockhausen / Krefeld (www.stoko.de), Greven GmbH (www.petergrevenhautschutz.de) or Ursula Rath GmbH / Senden (www.rath.de) available.

It has long been noted that the presence of sodium waterglass often added as a diluent to soaps results in the formation of particularly effective barriers to "lipo-soiling". This effect is based on the unique effect of a skin protection product marketed under the name PR 88 by Ursula Rath GmbH, Senden. The standard of this product is not yet reached by any of the many generic drugs on the market.

Due to the use of soda water glass, the product PR 88 has a pH> 11. This fact has alarmed occupational physicians and dermatologists who suspect damage to the so-called acidic protective film of the skin when using the PR 88. This assumption is underlined by the fact that PR 88 is used as a "leave-on" preparation during the work process regularly and over long periods of time.

The assumption of a neutralizing and thus detrimental effect of alkaline barrier preparations on acid skin hydrolipids is logical, but apparently based only on chemical-theoretical considerations. It must be emphasized that since its market entry almost five decades ago, the PR 88 has been sold and used in very large quantities worldwide, without any case of skin damage becoming known even after long-term use. Nevertheless, the considerations regarding the skin compatibility of clearly alkaline barrier preparations gave rise to the formulation of guidelines which stipulate a pH of 9.5 as the upper limit for such preparations (Prevention Guideline Skin Protection of the Expert Committee "Personal Protective Equipment", Hauptverband der gewerblichen Berufsgenossenschaften, Jan 2006).

In anticipation of a general liability of that directive, a number of barrier preparations have been developed, the formulation of which, although using sodium silicate, has lowered the pH to below the aforementioned limit of pH 9.5 by adding fatty acids (mostly stearic acid) and other ingredients.

The DD 254142 A1 describes skin protection agent as O / W emulsion containing triethanolamine and stearic acid. From the GB 2 326 338 A For example, long-chain fatty acid barrier preparations are known with mono- or triethylamine together with an emulsifier, a sunscreen, silicone oils, and liquid paraffin or waxes, with both the soaps and the emulsifiers having structures other than the invention. The US 2002/0054895 A1 relates to the combination of allantoin and a metabolic product against skin irritation and various emulsifiers in an O / W emulsion. From the WO 96/166351 A1 is the topical application of ceramides, emulsifiers and triethanolamine stearates known to repair damaged skin lipid barrier.

It is well known from silicate chemistry that monomeric sodium silicate and smaller oligomers thereof (ie the principal constituents of soda waterglass) are not stable below a pH of 10.5 (see, for example, US Pat. US2007 / 0161539 A1 ), but with the release of water condense to higher molecular weight species. It can be assumed that this is the reason why all barrier preparations in which water glass (partially) was neutralized to lower the pH with fatty acids, have a significantly worse effectiveness than the PR 88, which is the only one with a pH above the resistance limit the orthosilicic acid possesses.

From the above, the object is to provide for industrial skin protection a barrier preparation against the contamination of the skin, especially the hands, against "Liposchmutz". This preparation should have compared to "Liposchmutz" an effectiveness that the PR 88 as the "gold standard" of z. Z. Barrier preparations in the market comes close without the principle disadvantages of the PR 88 d. H. primarily the dermatologically unacceptably high pH value.

Further, PR 88 has a partially frothed, otherwise gelatinous, consistency which makes its use in dosing dispensers virtually impossible. A preparation should therefore have a consistency that allows the use of dosing dispensers.

It is also essential that a barrier preparation against "Liposchmutz" as a regular and applied for long periods, cosmetic "leave-on" preparation must be particularly skin-friendly.

It has now surprisingly been found that preparations containing salts of fatty acids with certain amines have excellent barrier functions against "lipo contamination".

The above objects are therefore achieved by a skin protection agent for protection against non-water-soluble substances which comprises a product of a fatty acid, a fatty acid mixture, an alkali salt of a fatty acid or mixtures thereof with a basic amino acid or acid salt of a basic amino acid and at least one emulsifier capable of film formation an HLB value in the range of 12 to 25.

Such salts are known per se and some are commercially available. Ajinomoto (outside Europe) markets a liquid soap base called the Aminosine AR12, which consists of the arginine salt of coconut fatty acids. According to the product data sheet, this soap has a pH of 8.0-9.5. In US 6,284,749 B1 ; US Pat. No. 6,444,710 B1 and WO 00/24375 A1 For example, salts of basic amino acids with fatty acids are described as preservatives for pharmaceutical purposes. The DE 3633453 A1 describes the use of lysine or arginine salts of fatty acids as z. As plasticizer, emulsifier or antioxidant for cosmetic, dermatological or food purposes.

As starting material for the preparation of the barrier-forming skin protection agents according to the invention are fatty acids, saturated, monounsaturated or polyunsaturated, individually or as a mixture for use. The fatty acid or fatty acid mixture should preferably give a clear water-soluble fatty acid soap. Fatty acids or fatty acid mixtures with a melting point of 15 to 40 ° C, especially from 20 to 35 ° C are therefore particularly suitable. For saturated fatty acids, an average chain length, e.g. From C6 to C14, especially C8 to C12. For mono- or polyunsaturated fatty acids, those having a chain length of C ₈ to C _{18 are} preferred, or a mixture of two, three or more of these Fatty acids. Fatty acid mixtures are particularly preferred; coconut fatty acids, palm oil fatty acids or palm kernel fatty acids, also in hardened form, may be mentioned by way of example.

Particularly preferred is the fatty acid mixture obtained from palm kernel oil. It is commercially available at low cost. Another advantage is that, when reacted with arginine, lysine, TRIS or meglumine, each gives a fatty acid soap which becomes plastic on the skin at body temperature and therefore both gives a pleasant feeling to the skin and favorably influences the mechanical properties of the barrier.

In principle, all amino acids capable of forming salts with fatty acids and suitable for cosmetic purposes are suitable as amino acids. With regard to the pH of the skin protectants, the pK value should be in the range of about 7.5 to about 12.5 and, in addition, the isoelectric point should be above 7. The basic amino acids such as arginine and lysine should be mentioned here. Preferably, such amino acids are used, which are approved for cosmetic purposes or pharmaceutical purposes, ie, for. B. in the INCI list are also amino acid mixtures can be used.

The formation of the salts according to the invention of the fatty acids, hereinafter referred to as aminoseifen, takes place by reaction of the fatty acid (s) with the amino acid in a molar ratio of 1: 2 to 2: 1, preferably 1.5: 1 to 1: 1, 5 and in particular in approximately stoichiometric amounts. It is possible to form the aminose in situ in the manufacture of the skin protection agent, i. H. Add amino acid and fatty acid as a single substance. In addition, it is possible to use an alkali salt of the fatty acid or of the fatty acid mixture, such as. As a sodium salt, with an acid salt of the amino acid such as. As the hydrochloride, implement. In this case, the skin protection agent contains in addition to the fatty acid salt and the alkali metal salt of the acid, eg. B. NaCl. The skin protection agents thus prepared are more viscous at the same concentration of amino acid.

Furthermore, it should be noted that in the skin protection agents according to the invention does not necessarily have a complete reaction of fatty acid and amino acid must have taken place, it is conceivable that mixed micelles of amino acid and fatty acid are present in the solution. For the sake of simplicity, however, in the context of the present invention, only salt or aminose should be mentioned.

The formulations according to the invention are distinguished in particular by their good skin tolerance. They have a pH of about 8.0-9.0.

The amino-surfactants used according to the invention have a markedly microbicidal character, so that skin-protection preparations containing them do not have to be preserved, as was ensured by a comparative preservation stress test.

A further improvement of the efficacy results from the fact that the amino acid is combined with other skin-compatible substances which are capable of film formation and are preferably provided with emulsifying properties. Suitable for this purpose are all those emulsifiers suitable for cosmetic purposes which have an HLB value which is suitable for emulsion formation with "lipo soil". Typically, this HLB value is in the range of 12 to 25, preferably 15 to 24.

The use of poloxamers has proved to be particularly advantageous. Poloxamers are block copolymers of ethylene oxide and propylene oxide and z. B. commercially available under the trade name Pluracare from BASF SE.

Mixtures of aminose soaps with poloxamers have synergistic effects on their barrier properties. Especially at mixing ratios of amino acid fatty acid salt: Poloxamer in the range of 1: 5 to 5: 1, the barrier effect is significantly better compared with barrier preparations containing only one of the two components.

Examples of poloxamer are those having molecular weights in the range from 7,000 to 20,000, preferably in the range from 9,000 to 15,000. The proportion of ethylene oxide may preferably be 70 to 85% by weight, preferably 70 to 75% by weight.

Furthermore, it has proved to be advantageous to combine the inventive barrier formulation prepared from aminose soap with other water-soluble polar, capable of film-forming solids. A combination with polyvinylpyrrolidone (PVP) has proven particularly advantageous, as a result of which the protective film gains mechanical strength. Furthermore PVP makes because of its hygroscopic nature of the Use of skin-moisturizing formulation components such. As glycerol, propylene glycol, 1,2-pentanediol, polydiol, etc. superfluous.

Also preferred is the use of nonionic emulsifiers as coemulsifiers. These should have an HLB value in the range of 12 to 20. For example, copolymers of higher fatty alcohols, such as stearyl and cetyl alcohol, with ethylene glycol, called ceteareth-n, are suitable. Here, n is the number of ethylene glycol groups in the polyoxyethylene chain. Ceteareth-15 to ceteareth-30 are suitable; ceteareth-25 is particularly preferred.

The preparation may also contain other conventional additives to impart desired properties. These include z. As fragrances, defoamers, dyes, solids such as SiO ₂ or other particulate inorganic oxides to improve the grip strength or to modify the consistency of the preparation, skin-care additives (such as allantoin, bisabolol, panthenol, retinol, tocopherol / tocopheryl acetate, retinol, etc.) , Antioxidants, preservatives, bodying agents, pH stabilizers, foam stabilizers, thickeners and others. These are known per se and are used in the usual amounts.

The formulation of the invention was developed as a barrier preparation against "Liposchmutz" ("invisible glove", "invisible glove"). However, it is by no means excluded that the preparation may also be an effective barrier against lipophilic noxae (eg toluene, gasoline, diesel fuel or cutting oils).

Because of the aforementioned pronounced microbicidal action of medium-chain fatty acids and their soaps, it is to be expected that the preparation also has a disinfecting effect on the hands of the users, which is quite advantageous.

It is another benefit of the formulation that it can also be used as a liquid soap to remove this contamination when contaminating unprotected skin with "lipo dirt".

The skin protection agents according to the invention can be used as lotion, gel, foam, ointment, cream, etc. Typically, the skin protection agents of the invention are provided as a single phase solution of the amino acid (s) in water. The formulation or preparation of the skin protection agent is carried out in a manner known per se.

It is advantageous that the skin protection agents according to the invention contain an active substance with the aminose soaps which is well compatible with most customary ingredients in cosmetic products and therefore allows great freedom in the formulation. It should be noted that the skin protection agents of the invention have the well-known from PR 88 very good protection, without alkali silicates are included and thus without having the high pH to bring or require the alkali metal silicates.

The invention will be explained with reference to the following examples, but without being limited to the specifically described embodiments. Unless otherwise stated or necessarily different from the context, percentages are based on weight, in case of doubt on the total weight of the mixture.

The invention also relates to all combinations of preferred embodiments, as far as these are not mutually exclusive. The words "about" or "approximately" in connection with a numerical value mean that at least 10% higher or lower values or 5% higher or lower values and in any case 1% higher or lower values are included.

Example 1: Solution for donors

From the following components: 1. Aqua (demin.) 77.7 2. Palm kernel oil fatty acid 6.43 3. Arginine 4.53 4. polyvinylpyrrolidone 4.5 5. Poloxamer 407 3.6 6. Ceteareth-25 2.7 7. Bisabolol 0.27 8. Panthenol 0.27. a solution is prepared as follows. Position 1 is submitted, positions 4 to 8 stirred in succession, then stirred position 3 and added after their dissolution position 3 and stirred until a clear solution is present. The solution obtained could be well dosed by means of conventional dispensers.

Example 2: Foam

The following ingredients were mixed as in Example 1: 1. Aqua (demin.) 81.0 2. Palm kernel oil fatty acid 5.45 3. Arginine 3.84 4. polyvinylpyrrolidone 3.85 5. Poloxamer 407 3.08 6. Ceteareth-25 2.3 7. Bisabolol 0.24 8. Panthenol 0.24.

A solution is obtained which can be well dosed with conventional foam dispensing devices and gives a stable foam.

Example 3: Microbiological Stability

With solutions prepared analogously to the above examples, a microbial load test based on Ph. Eur. Was carried out. On the one hand, an unpreserved sample of the skin protection composition according to the invention was tested and, for comparison, a second sample, which was tested for a broadband preservative based on silver chloride and a third sample, to which a mixture of methylisothiazolinone and phenylethanol had been added. After inoculation with the usual test organisms, sterility could be regained in all three samples within two days. Since the unpreserved sample has again reached sterility, the skin protection agent according to the invention can be described as self-sterile.

Example 4: Effect Test

The formulations given in the following table were evaluated for their barrier effect by 5 persons on a scale of 1 (very good) to 5 (bad), the results (in each case averaged) are also indicated. table test soil Ex. 1 (without amino acid) Ex. 1 (without poloxamer) example 1 PR 88 graphite dust 1.7 1.2 1.0 1.0 Russöl (diesel engine) 1.8 1.6 1.0 1.0 black shoe polish 1.3 2.3 1.0 1.0 Acrylic paint spray 3.6 2.5 1.0 1,0 +

It can be seen that the aminoseifen according to the invention unfold a very good barrier effect.

Claims (10)

Skin protection agent for protection against non-water-soluble substances, characterized in that it comprises a salt of a fatty acid, a fatty acid mixture, an alkali salt of a fatty acid or mixtures thereof with a basic amino acid or the acid salt of a basic amino acid and at least one emulsifier capable of film formation with an HLB value ranging from 12 to 25. Skin protection agent according to claim 1, characterized in that the fatty acid is a saturated fatty acid having a chain length of C ₈ to C ₁₂ and / or a mono- and / or polyunsaturated fatty acid having a chain length of C ₈ to C ₁₈ , or a mixture of is two, three or more such fatty acids. Skin protection agent according to claim 1, characterized in that the fatty acid is a fatty acid mixture of palm oil, palm kernel oil or coconut fat, uncured, wholly or partially cured. Skin protection agent according to one of claims 1 to 3, characterized in that the basic amino acid is arginine or lysine or a mixture thereof. Skin protection agent according to one of claims 1 to 4, characterized in that it has a pH in the range of 8.0 to 9.0. Skin protection agent according to one of claims 1 to 5, characterized in that the emulsifier is a poloxamer or more poloxamers. Skin protection agent according to one of claims 1 to 6, characterized in that it contains as further constituent one or more polyvinylpyrrolidone (s). Skin protection agent according to one of claims 1 to 7, characterized in that it comprises salts of fatty acids from palm oil, palm kernel oil and / or coconut fat, which are completely or partially cured, with arginine or lysine. Skin protection agent according to one of claims 1 to 8, characterized in that it contains as a further constituent a nonionic emulsifier having an HLB value of 12 to 20, preferably a ceteareth and especially ceteareth-25. Skin protection agent according to one of claims 1 to 9, characterized in that it is a single-phase solution in water.