IONIC LIQUID AS AN ANTIPERSPIRANT

Abstract

The invention relates to an aluminum salt-free, antiperspirant, deodorizing, cosmetic and/or dermatological composition comprising at least one antiperspirant active ingredient, wherein the antiperspirant active ingredient is selected from the group of ionic liquids.

Claims

1. An aluminum salt-free, antiperspirant and cosmetic and/or dermatological composition comprising at least one antiperspirant active ingredient, characterized in that the antiperspirant active ingredient is selected from the group of ionic liquids, wherein the at least one antiperspirant active ingredient has at least one cation and at least one anion, wherein the cation is selected from the group of: imidazolium, ammonium, phosphonium, guanidinium, pyrrolidinium, piperidinium and pyridinium, wherein the specified basic structures of the cations each have one or more substituents, of which at least one substituent is an alkyl substituent having a chain length of 1 to 10 carbon atoms.

2. The composition as claimed in claim 1, characterized in that the at least one cation is an alkylpyridinium cation.

3. The composition as claimed in either of the preceding claims, characterized in that the anion is selected from the group of halides.

4. The composition as claimed in any of the preceding claims, characterized in that at least one of the antiperspirant active ingredient comprises 1-hexylpyridinium chloride.

5. The composition as claimed in any of the preceding claims, characterized in that the at least one antiperspirant active ingredient is present to an extent of 1 to 25% by weight, particularly preferably 5 to 10% by weight, based on the total weight of the composition.

6. The composition as claimed in any of the preceding claims, characterized in that the composition has a pH of 3.5 to 7.0.

7. The use of an ionic liquid as antiperspirant active ingredient, characterized in that the ionic liquid has at least one cation and at least one anion, wherein the cation is selected from the group of: imidazolium, ammonium, phosphonium, guanidinium, pyrrolidinium, piperidinium and pyridinium, wherein the specified basic structures of the cations each have one or more substituents, of which at least one substituent is an alkyl substituent having a chain length of 1 to 10 carbon atoms.

8. The use as claimed in claim 7, characterized in that the ionic liquid comprises 1-hexylpyridinium chloride.

9. The use as claimed in claim 7 or 8, characterized in that the ionic liquid is used in combination with another antiperspirant active ingredient.

10. The use as claimed in claim 6 or 7, characterized in that the ionic liquid is used as the sole antiperspirant active ingredient in a cosmetic and/or dermatological preparation.

Description

Example Formulations and Investigations of the Active Ingredient Properties

1. EXAMPLE FORMULATIONS

[0075] The % data in the formulations are to be understood as percentages by weight.

Formulation Example 1—Roll-on (5% Active Ingredient)

[0076]

TABLE-US-00001 Phase Ingredients Proportion in % by weight A Ethanol 40.0 A 3-(2-Ethylhexyloxy)propane-1,2-diol 1.0 A Triethyl citrate 4.0 A Perfume 2.0 B Water 43.5 B 75% D-Panthenol in water 0.5 B 1-Hexylpyridinium chloride 5.0 C Hydroxypropyl cellulose 2.0 C Glycerin 2.0

[0077] The ingredients of phase A and phase B are mixed within each phase respectively. Subsequently, phase A is mixed with phase B. The phase C ingredients are dispersed together. With each other. Phase AB, which corresponds to the mixture of phase A and phase B, is added to phase C and stirred until smooth. The overall formulation is adjusted to approximately pH 4.5 by adding citric acid.

Formulation Example 2—Active Ingredient Solution 7.5%

[0078]

TABLE-US-00002 Phase Ingredients Proportion in % by weight A Water 90.5 A 1-Hexylpyridinium chloride 7.5 A Hydroxypropyl cellulose 2.0

[0079] All ingredients of phase A are mixed together. The overall formulation is adjusted to approximately pH 4.5 by adding sodium hydroxide.

Formulation Example 3—Active Ingredient Solution 10%

[0080]

TABLE-US-00003 Phase Ingredients Proportion in % by weight A Water 88 A 1-Hexylpyridinium chloride 10 A Hydroxypropyl cellulose 2.0

[0081] All ingredients of phase A are mixed together. The overall formulation is adjusted to approximately pH 4.5 by adding sodium hydroxide.

Formulation Example 4—Active Ingredient Solution 5%

[0082]

TABLE-US-00004 Phase Ingredients Proportion in % by weight A Water 93 A 1-Hexylpyridinium chloride 5 A Hydroxypropyl cellulose 2.0

[0083] All ingredients of phase A are mixed together. The overall formulation is adjusted to approximately pH 4.5 by adding sodium hydroxide.

2. Investigation of the Active Ingredient Properties

[0084] It should be noted that the terms test product and test composition are used synonymously. The same applies to the terms composition and product, test person and test subject.

2.1 Investigation of Sweat Inhibition

2.1.1 Gravimetric Determination of the Antiperspirant Effect of a Test Product Having 5% Active Ingredient as a Roll-on (Example Formulation 1) (Short-Term Use)

[0085] The antiperspirant effect was investigated in a randomized, comparative and blinded manner on twelve test subjects, eight of whom were female and four male and all aged between 32 and 64. Three test subjects dropped out during the test.

[0086] To prepare for the test, during the so-called washout period, the test subjects were not allowed to apply any antiperspirant for 21 days. The application takes place over four consecutive days and once a day.

[0087] After applying 400-450 μL of the test product with a pipette and smearing it with a finger stall on a defined underarm, the test subjects were exposed twice for 20 minutes each time at a temperature of 38° C.±2° C. and a relative humidity of 35%±5%. The other underarm remained untreated throughout the test period.

[0088] Sweat production and sweat inhibition were measured prior to application, which corresponds to a base measurement point t0, and 24 h after the last application, which corresponds to a measurement point t24h. Sweat production was measured gravimetrically.

[0089] The direct comparison of the untreated reference measurement at the base measurement point t0 with a measurement 24 h after the last application of the product to be tested at measurement point t24h shows that the tested product causes a significant reduction in sweat.

[0090] The product tested has an average effectiveness of 87.3%. Even at low concentrations, the test product shows a relevant reduction in the amount of sweat of 13.7% after short-term use.

[0091] None of the test subjects showed a negative skin reaction during the course of the test.

2.1.2 Gravimetric Determination of the Antiperspirant Effect (Long-Term Use)

[0092] Further gravimetric investigations on sweat inhibition were performed as follows:

[0093] After a conditioning phase, in which the test subjects spent 17 days without deodorant having antiperspirant active ingredients and 5 days of those also without any deodorant, the test product was applied once a day to a defined underarm. The application period was four weeks. A reference test was analyzed after the conditioning phase and before the test product was applied for the first time, which is also referred to as the baseline sweat test, and approximately 16 hours after the last application.

[0094] The investigations were carried out randomly with respect to the test product, and a control product without an antiperspirant active ingredient, on the right and left underarms on a total of five test subjects, three female and two male aged 30 to 47 years. Only subjects who sweated at least 100 mg per underarm under the study conditions were included.

[0095] The sweat secreted from the underarms was determined gravimetrically in each case during intensive sporting activity, for example in the form of 30 minutes on a cross-trainer under defined conditions, without using the product to be tested as a reference study, and after a four-week application phase. For this purpose, cotton pads having a certain weight were attached beneath both underarms of the test subjects. The sweat absorbed by the cotton pads under stress conditions was determined gravimetrically.

2.1.2.1 Result of the Gravimetric Determination of the Antiperspirant Effect of a Test Product Having 5% Active Ingredient (Example Formulation 4)

[0096] Comparison of a baseline sweat test, which was carried out prior to the application period without using the test product, and a sweat test 16 hours after completion of the application of the test product resulted in a reduction in the amount of sweat in the test area in relation to the control area of 32% on average across the test subjects.

2.1.2.2 Result of the Gravimetric Determination of the Antiperspirant Effect of a Test Product Having 7.5% Active Ingredient (Example Formulation 2)

[0097] Comparison of a baseline sweat test, which was carried out prior to the application period without using the test product, and a sweat test 16 hours after completion of the application of the test product resulted in a reduction in the amount of sweat in the test area in relation to the control area of 39% on average across the test subjects.

2.2 Determination of Odor Intensity Via a Sniff Test

[0098] The odor intensity and the deodorizing effect of the test product that can be determined thereby were determined by means of a so-called sniff test as follows.

[0099] After a conditioning phase, in which the test subjects spent 17 days without deodorant having antiperspirant active ingredients and 5 days of those also without any deodorant, the test product with a fragrance-free formulation was applied once a day to a defined underarm. The application period was four weeks. A reference test, the so-called baseline sniff test, was analyzed after the conditioning phase and before the test product was applied for the first time, and approximately 16 hours after the last application.

[0100] A test product and a control product without antiperspirant active ingredient were applied daily, after randomization, under the right and left underarms for 28 days. A total of five test subjects, three female and two male aged between 30 and 47 years, were investigated.

[0101] The group of so-called sniffers consisted of five people, two of whom were female and three male, aged 40 to 48.

[0102] To check the effectiveness of the test product, a so-called baseline sniff test was initially conducted to determine the strength of the individual body odor of each test subject. For this purpose, each test subject had to wash both underarms with perfume-free soap and about 12 hours later specific non-scented cotton pads were attached beneath both underarms. These were worn for four hours in each case and individually sealed in airtight glass jars immediately after removal. These glass jars were labeled with numbers according to a blinding and randomization table and evaluated by to the sniffers with respect to odor intensity (baseline sniff test).

[0103] Approximately 16 hours after the last application of test product beneath an underarm, the odor intensity was determined again. Randomization and blinding were performed as described above. The sniffers independently evaluated the intensity of the sweat odor for both underarms.

2.2.1 Result of the Determination of the Odor Intensity of a Test Product Having 5% Active Ingredient (Example Formulation 4)

[0104] On average across the test subjects and sniffers, the baseline sniff test showed an odor intensity of level 2 beneath both underarms, which corresponds to a barely perceptible odor of sweat.

[0105] After the application period and 16 h after the last application of the fragrance-free test product, the odor intensity was determined again by means of the sniff test. On average across the test subjects and sniffers, there was a difference of one level of odor intensity between the odor intensity of the untreated underarm and that of the underarm previously treated with the test product. The odor intensity of the untreated underarms was evaluated at 2.2 on average, with 2 corresponding to a barely perceptible odor of sweat. The odor intensity of the underarms treated with test product was 0.9 on average, with 0 corresponding to no sweat odor.

2.2.2 Result of the Determination of the Odor Intensity of a Test Product Having 7.5% Active Ingredient (Example Formulation 2)

[0106] On average across the test subjects and sniffers, the baseline sniff test showed an odor intensity of level 2 beneath both underarms, which corresponds to a barely perceptible odor of sweat.

[0107] After the application period and 16 h after the last application of the fragrance-free test product, the odor intensity was determined again by means of the sniff test. On average across the test subjects and sniffers, there is a difference of one level of odor intensity between the odor intensity of the untreated underarm and that of the underarm treated with the test product. The odor intensity of the untreated underarms was evaluated at 1.8 on average, with 2 corresponding to a barely perceptible odor of sweat. The odor intensity of the underarms treated with test product was 1.0 on average, with 0 corresponding to no sweat odor.

2.3 Investigation of Skin Compatibility

[0108] The aim of examining skin compatibility, the so-called epicutaneous test, is to rule out primary skin irritation caused by a test product and/or existing sensitization to the test product.

[0109] The test substances are applied occlusively to the skin at suitable concentrations. The epicutaneous contact with the test product is limited in terms of location and time and is intensified by occlusion conditions, so that the absorption of the test substances is favored. The skin was examined after 24, 48 and 72 hours.

[0110] The occlusion conditions are used to allow a potential allergen to more easily penetrate through the stratum corneum to reach the effector cells that could elicit a local immune system response. A positive response occurs when a threshold level of irritation/sensitization is exceeded. A positive reaction to a correctly applied epicutaneous test is considered evidence of primary irritation by the test substance, but not necessarily evidence of sensitization.

[0111] For the test, 20 mg or 20 μL of the test product is applied undiluted to a ready-made plaster, which is applied and fixed to the clinically healthy skin of the upper back. The test plaster is removed after an exposure time of 24 hours and for the first time assessed dermatologically and allergologically. A second and third assessment was made after 48 and 72 hours. The test reaction was evaluated for the first time 30 minutes after removal of the test plaster under standardized lighting.

[0112] The test group consists of 30 adult, male and female test subjects, whereby test subjects with dry, oily, normal and sensitive skin were included within the test group.

2.3.1 Investigation of the Skin Compatibility of a Test Product Having 7.5% Active Ingredient (Formulation Example 2)

[0113] When examining the skin compatibility of a test product with the composition of formulation example 2, which corresponds to an active ingredient concentration of 7.5%, there were no skin changes in the test area in 29 of 30 test subjects after 24, 48 and 72 hours. The epicutaneous tests were carried out according to the international guidelines of the International Contact Dermatitis Research Group as described above.

[0114] One test subject developed a mild reaction after 24 and 48 hours, which was no longer visible after 72 hours.

2.4 Efficacy Against Odor-Causing Bacteria

[0115] Perspiration odor is mainly caused by the resident bacteria of the human microflora. Corynebacteria and germs of the genus Staphylococcus epidermidis are mainly found in the underarm area. Therefore, the bacteriostatic effect of a composition comprising 1-hexylpyridinium chloride in water was investigated in vitro on the relevant test microbes.

[0116] The test microbes used were Staphylococcus epidermidis with the identifier DSM 20044, ATCC 14990, Corynebacterium xerosis with the identification DSM 20743, ATCC 373 and Kocuria rhizophila of the type Micrococcus with the identifier DSM 11926. Using a series of dilutions of the substance to be tested, the minimum inhibitory concentration was determined at which growth of the bacteria in suspension could no longer be detected. 1-Hexylpyridinium chloride shows a bacteriostatic effect up to a concentration of 0.4% Staphylococcus epidermidis, in the case of Corynebacterium xerosis an inhibition of bacterial growth could even be observed up to a final preparation concentration of 0.2%. Thus, an antimicrobial effect on odor-forming microorganisms and thus a deodorizing effect of the active ingredient 1-hexylpyridinium chloride is also shown in vitro.

2.5 Investigation of Protein Precipitation In Vitro

[0117] The use of aluminum chloride beneath the underarm causes a reduction of perspiration. The most common mode of action of aluminum chloride discussed in the literature explains sweat reduction as clogging of the pores by precipitation of proteins by the aluminum chloride.

[0118] Therefore, the ability of a composition comprising 1-hexylpyridinium chloride in water for protein precipitation was investigated in vitro using BSA (bovine serum albumin) gelling experiments. An aqueous solution of aluminum chloride hexahydrate was used as a positive control.

[0119] It could be shown that the composition with 1-hexylpyridinium chloride also leads to gelation of BSA. It is therefore assumed that the effect of 1-hexylpyridinium chloride is analogous to the effect also discussed for aluminum chloride and that the precipitation of proteins leads to closure of the sweat pores.

2.6 Investigation of Staining on Textiles

[0120] Potential staining of a 7.5% by weight composition. 1-hexyl pyridinium chloride in water was investigated on white and black cotton textiles. For this purpose, 2 mL of the composition was applied directly to a defined area of the respective textile and left to act for 24 hours. Thereafter, a slight, light yellow residue could be seen on the white textile, whereas no residue at all was visible on the black textile here, after the application site had dried completely.

[0121] The white textile was subjected to a washing cycle with heavy-duty detergent at 40° C. for 80 minutes, the composition being completely washed out.

[0122] The black fabric was also subjected to washing at 40° C. for 80 minutes using a color detergent. The composition did not show any white spots or flakes on the black textile even after drying the application site and before washing, and was also residue-free after washing.

[0123] In summary, direct application of the composition to white and/or black cotton textiles does not result in any permanent stains, especially after washing the textiles.

[0124] The invention is not restricted to one of the embodiments described above, but rather may be modified in a variety of ways.

[0125] All of the features and advantages resulting from the claims and the description, including use characteristics and substance properties, may be essential to the invention both individually and in a wide variety of combinations.