Powder Compositions Comprising Salts of C4 to C10 Oxocarboxylic Acids and of Unsaturated or Aromatic C6 to C10 Carboxylic Acids
20220183288 · 2022-06-16
Inventors
- Carsten Dietz (Neustadt A.d. Weinstrasse, DE)
- Malte Sietzen (Hamburg, DE)
- Markus Schröder (Hamburg, DE)
- Frank Brauns (Hamburg, DE)
- Chris Dechow (Hamburg, DE)
Cpc classification
A01N37/10
HUMAN NECESSITIES
International classification
Abstract
The present invention relates to a composition comprising (a) an alkali metal salt and/or an alkaline earth metal salt of a C4 to C10 oxocarboxylic acid and (b) an alkali metal salt and/or an alkaline earth metal salt of an unsaturated or aromatic C6 to C10 carboxylic acid, wherein (a) is present in an amount of 20 to 95 wt.-%, based on the total mass of the composition, and (b) is present in an amount of 5 to 50 wt.-%, based on the total mass of the composition, wherein the composition is present in the form of a powder, methods of its manufacture and its use for inhibiting microbial growth in cosmetic, dermatological or personal care compositions.
Claims
1. Composition comprising (a) an alkali metal salt and/or an alkaline earth metal salt of a C4 to C10 oxocarboxylic acid and (b) an alkali metal salt and/or an alkaline earth metal salt of an unsaturated or aromatic C6 to C10 carboxylic acid, wherein (a) is present in an amount of 20 to 95 wt.-%, based on the total mass of the composition, and (b) is present in an amount of 5 to 50 wt.-%, based on the total mass of the composition, wherein the composition is present in the form of a powder.
2. Composition comprising (a) an alkali metal salt and/or an alkaline earth metal salt of a C4 to C6 oxocarboxylic acid and (b) an alkali metal salt and/or an alkaline earth metal salt of an unsaturated or aromatic C6 to C10 carboxylic acid, wherein the unsaturated or aromatic C6 to C10 carboxylic acid is selected from the group consisting of benzoic acid, salicylic acid, sorbic acid, cinnamic acid and p-methoxybenzoic acid, wherein (a) is present in an amount of 20 to 95 wt.-%, based on the total mass of the composition, and (b) is present in an amount of 5 to 50 wt.-%, based on the total mass of the composition, wherein the composition is present in the form of a powder.
3. Composition comprising (a) an alkali metal salt and/or an alkaline earth metal salt of levulinic acid and (b) an alkali metal salt and/or an alkaline earth metal salt of p-methoxybenzoic acid, wherein (a) is present in an amount of 20 to 95 wt.-%, based on the total mass of the composition, and (b) is present in an amount of 5 to 50 wt.-%, based on the total mass of the composition, wherein the composition is present in the form of a powder.
4. Composition according to claim 1, wherein the composition is obtainable by spray drying a liquid mixture comprising component (a) and component (b).
5. Composition according to claim 1, wherein the composition is obtainable by combining component (a), in powder form with component (b), in powder form and subsequently mixing the two components to obtain a mixed powder, wherein the size of the powder particles of the two components in the final mixture is essentially the same.
6. Composition according to claim 1, wherein the particle size is in the range of from about 0.5 μm to about 100 μm, wherein the D90 value, as determined by static light scattering, is in the range of from 30 to 50 μm.
7. Composition according to claim 1, wherein the alkali metal is sodium or potassium.
8. Composition according to claim 1, wherein the composition consists of components (a) and (b).
9. Method for manufacturing the composition according to claim 1, wherein a liquid mixture comprising the alkali metal salt and/or the alkaline earth metal salts of the C4 to C10 oxocarboxylic acid and the unsaturated or aromatic C6 to C10 carboxylic acid is prepared by adding the corresponding acids to a solvent and further adding an alkali metal hydroxide and/or an earth alkaline metal hydroxide to form a liquid mixture and spray drying said mixture to form a spray dried powder.
10. Method for manufacturing the composition according to claim 1, wherein the alkali metal salt and/or the alkaline earth metal salt of the C4 to C10 oxocarboxylic acid in powder form and the alkali metal salt and/or the alkaline earth metal salt of the unsaturated or aromatic C6 to C10 carboxylic acid in powder form are mixed, wherein the particle sizes of the two components are essentially the same.
11. Method according to claim 9, wherein the liquid mixture used for spray drying is a solution containing water and an alcohol and an alkali metal salt.
12. Method according to claim 9, wherein levulinic acid and p-methoxybenzoic acid are first dissolved and/or dispersed in water and/or an alcohol, followed by addition of an alkali metal hydroxide, to obtain the liquid mixture for spray drying.
13. Method according to claim 9, wherein the liquid mixture has the following composition: Anisic acid: 5-15 wt-%, levulinic acid: 15-40 wt %, alkali or alkaline earth metal salt: 5-15 wt-%.
14. Method of inhibiting microbial growth in cosmetic, dermatological or personal care compositions comprising adding a composition according to claim 1 to said cosmetic, dermatological or personal care compositions.
15. Method of claim 14, wherein the alkali metal salt and/or the alkaline earth metal salt of the C4 to C10 oxocarboxylic acid is sodium levulinate and wherein the alkali metal salt and/or the alkaline earth metal salt of the unsaturated or aromatic C6 to C10 carboxylic acid is sodium p-methoxybenzoate.
16. Composition according to claim 1, wherein component (a) comprises the alkali metal salts and/or the alkaline earth metal salts of levulinic acid and component (b) comprises the alkali metal salts and/or the alkaline earth metal salts of p-methoxybenzoic acid.
17. Composition according to claim 16, comprising alkali metal salts, wherein the alkali metal is sodium.
18. Composition according to claim 2, wherein component (a) comprises the alkali metal salts and/or the alkaline earth metal salts of levulinic acid and component (b) comprises the alkali metal salts and/or the alkaline earth metal salts of p-methoxybenzoic acid.
19. Composition according to claim 18, comprising alkali metal salts, wherein the alkali metal is sodium.
20. Composition according to claim 3, wherein component (a) comprises the alkali metal salts and/or the alkaline earth metal salts of levulinic acid and component (b) comprises the alkali metal salts and/or the alkaline earth metal salts of p-methoxybenzoic acid.
Description
SHORT DESCRIPTION OF THE FIGURES
[0022]
[0023]
[0024]
[0025]
DETAILED DESCRIPTION OF THE INVENTION
[0026] Component (a) of the composition of the present invention is an alkali metal and/or alkaline earth metal salt of a C.sub.4 to C.sub.10 oxocarboxylic acid, preferably a C.sub.4 to C.sub.8 oxocarboxylic acid, more preferably a C.sub.4 to C.sub.6 oxocarboxylic acid and most preferably levulinic acid. Component (b) of the composition of the present invention is an alkali metal salt and/or an alkaline earth metal salt of an unsaturated or aromatic C.sub.6 to C.sub.10 carboxylic acid, preferably a C.sub.6 to C.sub.8 aromatic acid which may be substituted with a hydroxyl, a methoxy or an acrylic group (—OH, —OCH.sub.3, —CHCHCOOH), more preferably substituted with hydroxyl or methoxy, most preferably 4-methoxybenzoic acid (also termed para- or p-methoxybenzoic acid or p-anisic acid). Specific examples of the aforementioned acids which are used for preparing the salts are levulinic acid, benzoic acid, salicic acid, sorbic acid, cinnamic acid and 4-methoxybenzoic acid. The metal salt is preferably an alkali metal salt, more preferably an alkali metal salt selected from the group consisting of sodium and potassium, and is most preferably sodium.
[0027] Antimicrobial efficiency of a solid mixture according to the present invention containing levulinic acid and p-methoxybenzoic acid salts as preferred active ingredients was compared to that of the corresponding liquid mixture according to the state of the art by challenge by testing according to the standard procedure described in the European Pharmacopeia (8.8.0). The results are shown in
[0028] Specifically,
[0029] Furthermore,
[0030] Notably, the solubility of the powder mixture according to the present invention is excellent both in water and in the most common personal care formulations such as emulsions, shampoos or shower gels. For example, while sodium p-methoxybenzoate may be dissolved and then transferred into the antimicrobially active acid by decreasing the pH value, there is at least one polymorphic crystal modification of this compound that displays a low solubility (under such conditions) and tends to precipitate in higher concentrations or at low temperatures (see EP 1 709 955 A1). Surprisingly, the present inventors found that this behavior does not occur when using the salt mixture of the present invention. Without wishing to be bound by theory, this may be due to the different physical properties of both acids and their corresponding salts. Furthermore, levulinic acid shows good water solubility and a low melting point (33-35° C.) while p-methoxybenzoic acid shows low water solubility and a high melting point (183° C.). The sodium salt of p-methoxybenzoate is easier to produce because the sodium salt of levulinic acids shows a much higher hygroscopicity. It appears that the presence of levulinic acid salts is able to avoid the formation of low soluble crystal modifications of p-Methoxybenzoic acid. This is another advantage associated with the present invention.
[0031] Generally, the compositions of the present invention comprise the alkali metal salt and/or the alkaline earth metal salt of the C.sub.4 to C.sub.10 oxocarboxylic acid such as levulinic acid in an amount of 20 to 95 wt.-%, based on the total mass of the composition. Preferred amounts are 40 to 90 wt.-% or, more preferably, 60-80 wt.-%. The alkali metal salt and/or the alkaline earth metal salt of the unsaturated or aromatic C.sub.6 to C.sub.10 carboxylic acid such as p-methoxybenzoic acid is present in an amount of 5 to 80 wt.-%, based on the total mass of the composition. Preferred amounts are 10 to 60 wt.-% or, more preferably, 20-40 wt.-%.
[0032] Two manufacturing methods of compositions according to the present invention are disclosed.
[0033] The methods are described with regard to the salts of the preferred acid mixture of the present invention, i.e., levulinic acid and paramethoxybenzoic acid. However, it is to be understood that the following disclosure also applies to the more general definitions of components (a) and (b) of the compositions of the present invention.
[0034] In one embodiment of the invention, the alkali metal salts and/or the alkaline earth metal salts of levulinic acid and p-methoxybenzoic acid, such as in particular the sodium or potassium salts, in particular the sodium salts, are produced separately and subsequently combined by mixing the two components in the form of powders. Two problems that might occur are: 1) The Brazil nut effect caused by different particle sizes resulting in unintended segregation and 2) The different hygroscopicities of both salts. According to the present invention, the Brazil nut effect is avoided by grinding the mixture so that a uniform particle size is obtained. Of course, a person of skill in the art will appreciate that the particles will show a certain size distribution. However, said distribution is sufficiently narrow that the above-mentioned problems do not occur. This can be controlled by visual inspection or well-known methods for determining particle size distributions such as static light scattering (laser diffraction). For example, particle size distribution can be determined according to ISO 13322 “Particle Size Analysis—Laser Diffraction Methods” using as the analyzer the instrument Bettersizer 2600 suitable for particle size and shape measurements in the range of from 0.02 to 2,600 μm available from 3P Instruments GmbH & Co. KG, Odelzhausen, Germany. Grinding of highly hygroscopic substances like sodium levulinate can be accomplished by operating the mixing vessel under the atmosphere of a water-free gas such as dried air, nitrogen or argon. The water content of the gas should be below 100 ppm. Elevated temperatures should be avoided, as they promote water uptake. The presence of a non-hygroscopic p-methoxybenzoate salt further helps to reduce the hygroscopicitiy of the mixture. The compositions of the mixture comprise the alkali metal salt and/or the alkaline earth metal salt of levulinic acid in an amount of 20 to 95 wt.-%, based on the total mass of the composition. Preferred amounts are 40 to 90 wt.-% or, more preferably, 60-80 wt.-%. The alkali metal salt and/or the alkaline earth metal salt of p-methoxybenzoic acid is present in an amount of 5 to 80 wt.-%, based on the total mass of the composition. Preferred amounts are 10 to 60 wt.-% or, more preferably, 20-40 wt.-%. A particle size range of about 0.5 μm to about 100 μm is generally achieved, as determined by using a Bettersizer 2600 and DIN ISO 13320. A small percentage of particles may have a size of below or above the indicated range. Usually, the percentage of such particles is about 1% or lower.
[0035] More specifically, a preferred particle size distribution is characterized by the following D values: D10: 4-10 μm; D50: 10-25 μm; D90: 30-50 μm. The D value means the weight percentage of particles having a size of or below the indicated value. It is determined based on the method as disclosed hereinabove.
[0036] In another embodiment of the invention, the composition is produced by spray-drying. In a first step both acids are added into a suitable solvent such as water and/or an alcohol such as ethanol. An alternative solvent is a mixture of water and alcohol because p-methoxybenzoic acids shows a much better solubility in ethanol (50 mg/ml at 20° C.) than in water (0.3 mg/ml at 20° C.). Preferred mixtures are aqueous solutions consisting of 70-90 wt.-% water and 10-30 wt.-% alcohol. In a second step, the pH value is increased by adding an alkali metal base and/or an alkaline earth metal base until the salts of both acids are formed. Tests revealed that the total concentration of acids should be less than 35 wt.-%, if water is used as a solvent, because at higher concentrations they tend to precipitate. A suitable composition of the solution consists of 30 wt.-% acids, 9.75 wt.-% sodium or potassium hydroxide and 60.25 wt.-% water. This mixture is then spray dried. Spray drying as such is known in the art.
[0037]
[0038] Significant advantages of this embodiment of the production method of the present invention are that, on the one hand, a Brazil nut effect is impossible because every particle consists of the final mixture of both acids. Furthermore, the presence of the salt of levulinic acid prevents the formation of low soluble p-methoxybenzoic acid salt crystals.
[0039] According to the present invention, the handling and application of levulinic acid and p-methoxybenzoic acid in personal care formulations have been greatly improved. Freight costs, transportation mediated environmental impact, packing materials and storage area can be reduced dramatically, while simultaneously avoiding palm-oil derived raw materials. At the same time, no deficits regarding antimicrobial efficiency or convenience of use are to be expected.
[0040] The present invention is further illustrated by the embodiments disclosed in the following examples.
EXAMPLES
[0041] In the following, application examples in personal care formulations of one embodiment of the present invention are given. The solid antimicrobial mixture is a combination of sodium levulinate and sodium p-methoxybenzoate in a ratio of 4:1 to 2:1, preferably 3:1. The fluffy white solid mixture is produced by spray drying and shows a particle size distribution in the range of about 0.5 μm to about 100 μm.
[0042] Specifically, the particle size distribution was determined using DIN method ISO 13320 and a Bettersizer 2600 available from 3P Instruments suitable for particle size measurements in the range of from 0.02 to 2,600 μm (wet dispersion) and 0.1 to 2,600 μm (dry dispersion over a large scattering angle range (0.016° to 165°) with high detector density (92 pieces)). In the present examples, the specific particle size distribution as determined by using the above instrument is reproduced in
Example 1—Anti-Aging Serum
[0043] The components of the anti-aging serum of Example 1 are listed below:
TABLE-US-00003 Phase Ingredient INCI % A Demin. Water Aqua Ad. 100 A Glycerin Glycerin 5.00 A Cosphaderm ® Propanediol Propanediol 2.00 natural A Cosphaderm ® Sodium Sodium Hyaluronate 0.30 Hyaluronate high A Cosphaderm ® Sodium Sodium Hyaluronate 0.20 Hyaluronate low B Cosphaderm ® Sodium LAAS Sodium Levulinate, 1.00 Sodium Anisate
[0044] This formulation can be prepared at room temperature. All ingredients of phase A are combined and stirred until everything is completely dissolved. Cosphaderm® Sodium LAAS is added to phase A and pH is adjusted to 5.5±0.05 if necessary.
Example 2—Conditioning Shampoo
[0045] The components of the conditioning shampoo of Example 2 are listed below:
TABLE-US-00004 Phase Ingredient INCI % A Demin. Water Aqua Ad. 100 A Cosphaderm ® Propanediol natural Propanediol 3.00 A Glycerin Glycerin 3.00 A Cosphaderm ® Sodium LAAS Sodium Levulinate, Sodium Anisate 1.00 A Cosphaderm ® X 34 Xanthan Gum 1.00 B Sodium Coco Sulfate Sodium Coco-Sulfate 6.50 B Lauryl Glucoside Lauryl Glucoside, Aqua 7.36 B Cocamidopropyl Betaine Cocamidopropyl Betaine, Aqua 4.88 B Plantacare 818 UP Coco Glucoside, Aqua 2.50 B Cosphaderm ® E NGM Lysolecithin 1.00 B Cosphaderm ® Magnolia Extract 98 Magnolia Officinalis Bark Extract 0.05
[0046] Phase A is combined and stirred until everything is dissolved. Phase B is combined and both phases are heated separately up to 50° C. Phase A is added to phase B under soft stirring. Air bubbles are to be avoided. The pH is adjusted to 5.0±0.05.
Example 3—Micellar Water
[0047] The components of the micellar water of Example 3 are listed below:
TABLE-US-00005 Phase Ingredient INCI % A Demin. Water Aqua Ad. 100 A Aloe Vera Gel (0.5%) Aqua, Aloe Barbadensis 50.00 Leaf Juice Powder A Cosphaderm ® Propanediol 3.00 Propanediol natural A Glycerin Glycerin 5.00 A Cosphaderm ® PA ECONAT Phytic Acid, Aqua 0.10 A Decyl Glucoside Decyl Glucoside, Aqua 3.80 B Cosphaderm ® Sodium Sodium Levulinate, 1.00 LAAS Sodium Anisate
[0048] All ingredients of phase A are mixed at room temperature under slow stirring. Phase B is added to phase A. The pH is adjusted to 5.5±0.05.
Example 4—Moisturizing Daycream
[0049] The components of the moisturizing day cream of Example 4 are listed below:
TABLE-US-00006 Phase Ingredient INCI % A Demin. Water Aqua Ad. 100 A Glycerin Glycerin 3.00 A Cosphaderm ® PA ECONAT Phytic Acid, Aqua 0.10 B Cosphaderm ® X 34 Xanthan Gum 0.20 B Aristoflex ® AVC Ammonium 1.00 Acryloyldimethyltaurate/ VP Copolymer B Cosphaderm ® Sodium LAAS Sodium Levulinate, Sodium Anisate 1.00 C Cosphaderm ® E NGM Lysolecithin 1.50 C Cegesoft ® SH Shorea Stenoptera Seed Butter 2.50 C Sunflower Oil Helianthus Annuus Seed Oil 2.00 C Jojoaba Oil Simmondsia Chinensis Seed Oil 2.00 C Softisan ® 154 Hydrogenated Palm Oil 1.00 C Cosphaderm ® AP Ascorbyl Palmitate 0.20 C Cosphaderm ® T-70 Tocopherol, Helianthus Annuus 0.30 NON GMO ECO Seed Oil C Cosphaderm ® Touch Heptyl Undecylenate 1.00
[0050] Phase A: All ingredients are mixed together.
[0051] Phase B: Cosphaderm® X 34 and Aristoflex AVC are slowly added under vigorous stirring to phase A. Stirring is continued for approx. 15 min. at 500 rpm until complete dissolution. Then, it is heated up to 80° C.
[0052] Phase C: All ingredients are mixed together and heated up to 80° C.
[0053] Phase C is added to phase A+B and homogenized via vigorous stirring for approx. 10 min.
[0054] Phase D is added below 40° C. under vigorous stirring. pH is adjusted if necessary.
Example 5—Sensitive Handwash
[0055] The components of the sensitive handwash of Example 5 are listed below:
TABLE-US-00007 Phase Ingredient INCI % A Demin. Water Aqua Ad. 100 A Cosphaderm ® Sodium Sodium Levulinate, Sodium Anisate 1.00 LAAS A Cosphaderm ® PA ECONAT Phytic Acid, Aqua 0.10 A NaCl Sodium Chloride 2.00 B Plantapon ® SF Sodium Cocoamphoacetate, Glycerin, 40.00 Lauryl Glucoside, Sodium Cocoyl Glutamate, Sodium Lauryl Glucose Carboxylate B Lamesoft ® PO 65 Coco-Glucoside, Glyceryl Oleate 2.00
[0056] The formulation can be prepared at room temperature. Phase A is combined and stirred until everything is completely dissolved. Phase B is mixed and added to phase A. The pH is adjusted under stirring to 5.5±0.05.
Example 6—Soothing 2-in-1-Makeup Remover
[0057] The components of the soothing 2-in-1-makeup remover of Example 6 are listed below:
TABLE-US-00008 Phase Ingredient INCI % A Demin. Water Aqua Ad. 100 A Glycerin Glycerin 5.00 A Cosphaderm ® PA ECONAT Phytic Acid, Aqua 0.10 A Decyl Glucoside Decyl Glucoside, Aqua 0.30 B Cosphaderm ® Sodium Sodium Levulinate, 1.00 LAAS Sodium Anisate C Cosphaderm ® Feel Triheptanoin 20.00 C Cosphaderm ® T-70 NON Tocopherol, Helianthus 0.10 GMO Annuus Seed Oil C Oil soluble color — q.s.
[0058] All ingredients of phase A are mixed at room temperature under slow stirring. Phase B is mixed until everything is completely dissolved and B is added to phase A. The pH of phase A+B is adjusted to 5.5±0.05. Phase C is combined and added to phase A+B without stirring.
LIST OF REFERENCE NUMERALS
[0059] 1: fan [0060] 2: dried goods [0061] 3: cyclon separator [0062] 4: dispenser [0063] 5: dry room [0064] 6: heater [0065] 7: pump [0066] 8: liquid container