JP5427422B2 - Oil-in-water emulsion composition - Google Patents

Description

  The present invention relates to an oil-in-water emulsion composition.

  It is known that an oil-in-water emulsion composition is stabilized by incorporating an anionic surfactant. The anionic surfactant in the oil-in-water emulsion composition increases the negative charge of the hydrophobic dispersed droplets and prevents the droplets from coalescing by increasing their repulsive force.

  However, when the oil-in-water emulsion composition is acidic, there is a problem that even if an anionic surfactant is added, a stable emulsion composition cannot be obtained, such as separation and creaming. This was particularly noticeable in low-viscosity emulsion compositions having a viscosity of 1000 mPa · s or less.

  In Patent Document 1, as an anionic surfactant that can be added to cosmetics, alkylbenzene sulfonate, alkyl or alkenyl ether sulfate, alkyl or alkenyl sulfate, olefin sulfonate, alkane sulfonate, unsaturated fatty acid Examples include salts, alkyl or alkenyl ether carboxylates, α-sulfo fatty acid salts or esters, N-acyl amino acid type surfactants, phosphate mono- or diester type surfactants. An oil-in-water cream containing polyoxyethylene (10) hydrogenated castor oil as an ionic surfactant, sorbitan monostearate, sodium stearoylmethyl taurate as an anionic surfactant, and sodium polyoxyethylene lauryl ether phosphate is described. Although it is an oil-in-water chestnut The viscosity of the beam is usually about 5~100Pa · s.

  Patent Document 2 describes an emulsion-type oil-in-water emulsified skin cosmetic in which hydrogenated phospholipid, polyethylene glycol monostearate (100 mol) and sodium stearoylmethyl taurate are blended as surfactants. The viscosity of the preparation is 2900 Pa · s, and from the composition, the pH of the preparation is considered not to be 5 or less.

Japanese Patent Laid-Open No. 9-208442 (paragraph 0059, Example 1) JP 2007-314442 A (Example 2-2)

  An object of the present invention is to stabilize an oil-in-water emulsion composition having a pH of 5 or less and a viscosity of 1 to 1000 mPa · s, particularly 1 to 500 mPa · s.

The gist of the present invention is as follows.
(1) An oil-in-water emulsion composition containing 0.1 to 2% by mass of an N-acyl taurine salt, having a pH of 5 or less and a viscosity of 1 to 1000 mPa · s.
(2) The oil-in-water emulsion composition according to (1), further containing pyridoxine or a salt thereof.
(3) The oil-in-water emulsion composition according to (2), which is used for improving diaper rash.
(4) The oil-in-water emulsion composition according to any one of (1) to (3), further containing petrolatum and / or liquid paraffin.
(5) The oil-in-water type according to any one of (1) to (4), wherein the N-acyl taurine salt is at least one selected from N-alkyl substituted and N-alkyl unsubstituted N-acyl taurine salts. Emulsified composition.
(6) In an oil-in-water emulsion composition having a pH of 5 or less and a viscosity of 1 to 1000 mPa · s, 0.1 to 2% by mass of N-acyl taurine salt is blended and stabilized. A method for stabilizing an oil-in-water emulsion composition.

  According to the present invention, an oil-in-water emulsion composition having a pH of 5 or less and a viscosity of 1 to 1000 mPa · s, particularly 1 to 500 mPa · s can be stabilized.

Hereinafter, the present invention will be described in detail.
The oil-in-water emulsion composition of the present invention contains an N-acyl taurine salt which is a specific anionic surfactant.

  The N-acyl taurine salt used in the present invention is not particularly limited as long as the nitrogen atom of the taurine salt or N-monoalkyl taurine salt is substituted with an acyl group and has a surface activity.

The acyl group in the N-acyl taurine salt is not particularly limited as long as the N-acyl taurine salt has a surface activity, and preferably an acyl group derived from a saturated or unsaturated fatty acid having 8 to 22 carbon atoms, Examples include lauroyl (C ₁₂ ), myristoyl (C ₁₄ ), palmitoyl (C ₁₆ ), stearoyl (C ₁₈ ), oleoyl (C _{18: 1} ), and cocoyl (coconut oil fatty acid acyl). There is no restriction | limiting in particular as an alkyl group in the said N-acyl-N-alkyl taurine salt, Preferably a C1-C3 lower alkyl group, for example, a methyl group, is mentioned.

  Examples of the salt of N-acyl taurine include sodium salt, potassium salt, ammonium salt, triethanolamine salt, diethanolamine salt, monoethanolamine salt, arginine salt, lysine salt, histidine salt, ortinine salt, and oxylysine salt.

  Examples of the N-acyl taurine salt used in the present invention include N-lauroyl taurine sodium, N-myristoyl taurine sodium, N-cocoyl taurine sodium, N-oleoyl taurate sodium, N-palmitoyl taurate sodium, N-lauroyl- Examples include sodium N-methyltaurine, sodium N-myristoyl-N-methyltaurine, sodium N-cocoyl-N-methyltaurine, and the like. These N-acyl taurine salts can be used alone or in admixture of two or more.

  The compounding quantity of the N-acyl taurine salt in the oil-in-water emulsion composition of this invention needs to be 0.1-2 mass%. When the blending amount of the N-acyl taurine salt is less than the lower limit, the effect of stabilizing the oil-in-water emulsion composition is insufficient, and when the upper limit is exceeded, foaming may occur when dissolved and used. When directly applied to the skin, the skin irritation is increased, which is not preferable.

  When the oil-in-water emulsion composition is acidic and has a low viscosity, it is difficult to stabilize even if an anionic surfactant is added. Therefore, the present invention has a pH of 5 or less and a viscosity of The target is oil-in-water emulsion compositions having a viscosity of 1 to 1000 mPa · s, particularly 1 to 500 mPa · s.

The oil-in-water emulsion composition of the present invention exhibits an effect of improving diaper rash by adding pyridoxine (vitamin B ₆ ) or a salt thereof. The pyridoxine salt used here is an acid addition salt, for example, an inorganic acid salt such as hydrochloride, sulfate, phosphate, acetate, maleate, fumarate, tartrate, citrate, lactate, etc. Organic acid salts of

  When pyridoxine or a salt thereof is blended in the oil-in-water emulsion composition of the present invention, the blending amount is usually 0.001 to 5% by mass, preferably 0.005%, based on the oil-in-water emulsion composition of the present invention. It is 05-1 mass%.

  The oil-in-water emulsion composition of the present invention preferably further contains a bactericidal agent from the viewpoint of improving the effect of improving diaper rash. The bactericidal agent is not particularly limited as long as it can be blended into a skin external preparation. For example, isopropylmethylphenol, salicylic acid or a salt thereof, hinokitiol, photosensitizer, cetylpyridinium chloride, benzalkonium chloride, triclosan, guaiazulene, chlorhexidine hydrochloride Preferably, isopropylmethylphenol is used.

  When mix | blending a disinfectant with the oil-in-water type emulsion composition of this invention, the compounding quantity is 0.001-1 mass% normally with respect to the oil-in-water type emulsion composition of this invention, Preferably 0.05- 0.8% by mass.

  The dosage form of the oil-in-water emulsion composition of the present invention is not particularly limited as long as it is a preparation having a viscosity of 1 to 1000 mPa · s, particularly 1 to 500 mPa · s. For example, a liquid agent, a suspension agent, an emulsion, an aerosol agent And lotions.

  The oil-in-water emulsion composition of the present invention is preferably adjusted to have a pH of 2 to 5 from the viewpoint of the stability of the component when pyridoxine or a salt thereof is blended.

  The oil-in-water emulsion composition of the present invention is preferably used as a bathing agent or a wiping agent composition from the viewpoint that it can be easily applied during routine diaper changes or bathing.

  In addition to the above components, the oil-in-water emulsion composition of the present invention may contain an organic acid and / or a salt thereof, a nonionic surfactant, and an oil component.

  Examples of the organic acid include glycolic acid, lactic acid, malic acid, citric acid, ascorbic acid, benzoic acid, fumaric acid, tartaric acid, malonic acid, adipic acid, pyrrolidone carboxylic acid, salicylic acid, and succinic acid. Or in combination of two or more. As the salt of the organic acid, a salt of an aqueous solution, for example, an alkali metal salt such as a sodium salt is preferable.

  Examples of the nonionic surfactant include glycerin fatty acid ester, propylene glycol fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, tetraoleic acid polyoxyethylene sorbitol, polyoxyethylene alkyl ether, polyoxyethylene polyoxy Examples include propylene alkyl ether, polyethylene glycol fatty acid ester, polyoxyethylene hydrogenated castor oil, and polyglycerin fatty acid ester.

  Examples of the oil component include natural fats and oils such as soybean oil, rice bran oil, jojoba oil, avocado oil, almond oil, olive oil, cacao butter, sesame oil, persic oil, castor oil, coconut oil, mink oil, beef tallow and lard. , Hydrogenated hardened oil obtained by hydrogenation of these natural fats and oils and fats such as synthetic glycerides and diglycerides such as myristic acid glyceride and 2-ethylhexanoic acid glyceride; waxes such as carnauba wax, whale wax, beeswax and lanolin; Hydrocarbons such as paraffin, petrolatum, paraffin, microcrystalline wax, ceresin, squalane, pristane; lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, linoleic acid, linolenic acid, lanolinic acid, isostearic acid Higher fatty acids such as lauryl alcohol, Higher alcohols such as til alcohol, stearyl alcohol, oleyl alcohol, cholesterol, 2-hexyldecanol; cetyl octoate, myristyl lactate, cetyl lactate, isopropyl myristate, isopropyl palmitate, isopropyl adipate, butyl stearate, decyl oleate, Examples include esters such as cholesterol isostearate; essential oils; and silicone oils.

  In the oil-in-water emulsion composition of the present invention, in addition to the above components, if necessary, a water-soluble polymer, an inorganic pigment, a polyhydric alcohol, a preservative, a fragrance, an inorganic salt, a vitamin, a proteolytic enzyme, Other ingredients can be added.

  Examples of the water-soluble polymer include microbial polysaccharides such as dextrin and xanthan gum, plant polysaccharides such as starch, guar gum, carrageenan, agar and mannan, and animal proteins such as gelatin, casein, albumin and collagen. Natural polymers and semisynthetic polymers include celluloses such as methylcellulose, ethylcellulose, sodium carboxymethylcellulose, hydroxyethylcellulose, and cationized cellulose, starches such as soluble starch and methyl starch, alginates, propylene glycol alginate, etc. Of the alginic acid system. Examples of the water-soluble synthetic polymer include polyethylene glycol, polyvinyl alcohol, carboxyvinyl polymer, sodium polyacrylate, ammonium polyacrylate, polyvinyl methyl ether and the like.

  Examples of the inorganic pigment include titanium oxide, calcium carbonate, magnesium carbonate, zinc oxide (zinc white), talc, calcium silicate, anhydrous silicic acid, kaolin, bentonite, and mica titanium.

  Examples of the polyhydric alcohol include dihydric alcohols such as ethylene glycol, propylene glycol, 1,3-butylene glycol, and 3-methyl-1,3-butanediol; trihydric alcohols such as glycerin; saccharides such as sorbit and mannitol. Is mentioned.

  Examples of the preservative include paraoxybenzoic acid ester (for example, methylparaben), benzoic acid, benzoate, and phenoxyethanol. Examples of the fragrances include natural fragrances such as lavender oil, jasmine oil, lemon oil, orange oil, and rosemary oil, and synthetic fragrances such as geraniol, citronellol, and phenethyl alcohol.

  Examples of inorganic salts include sodium sulfate, magnesium sulfate, sodium chloride, potassium chloride, and sodium thiosulfate.

  Examples of vitamins include vitamin A; vitamin B other than pyridoxine or its salt; vitamin D, vitamin E, vitamin F, vitamin K, vitamin P, vitamin U, carnitine, ferulic acid, γ-oryzanol, lipoic acid, orotic acid And derivatives thereof. Examples of the proteolytic enzyme include pepsin, trypsin, chymotrypsin, cathepsin, papain, bromelain, ficin, bacterial yeast, and mold-derived protease.

  Examples of other components include sulfur, mineral sand, hot spring flowers, neutral white clay, egg yolk powder, iri cocoon powder, mica powder, skim milk powder, seaweed extract, and pigments.

  The oil-in-water emulsion composition of the present invention comprises an N-acyl taurine salt and, if necessary, pyridoxine or a salt thereof, a fungicide, an organic acid and / or a salt thereof, a nonionic surfactant, an oil component, The component is usually produced by mixing with water to make it liquid.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In addition, the compounding quantity (%) shown below is a mass reference | standard. Moreover, in the following examples and comparative examples, the measurement of the viscosity of the oil-in-water emulsion composition and the evaluation of the stability and foaming in bath water were performed as follows.

(1) Method for measuring viscosity Using a B-type viscometer, sample temperature: 20 ° C., rotor: No. 1 (less than 200 mPa · s) or No. 1 2 (200 to 1000 mPa · s), rotation speed: 30 rpm, measurement time: 60 seconds.

(2) Stability Evaluation Method The prepared oil-in-water emulsion composition was placed in a transparent sealed glass bottle, stored in a 50 ° C. constant temperature incubator, and the emulsified state after one month was visually evaluated.
(Criteria) ○: No change, ×: Separation

(3) Evaluation method of foaming in bath water 60 mL of each was dissolved in 40 L, 200 L bath water, and foaming at the time of reheating was visually evaluated.
(Criteria) ○: No foaming, Δ: Slightly foaming, ×: Many foams

Example 1
One month elapsed at 50 ° C. for an oil-in-water emulsion composition of 100 mPa · s or less obtained by adding 1.0% of the anionic surfactant of Table 2 to the composition shown in Table 1 and adjusting to pH 4 Later stability was evaluated. The results are shown in Table 2.

  As shown in Table 2, among various anionic surfactants, only N-acyl taurine salts, N-lauroyl-N-methyl taurine sodium and N-stearoyl-N-methyl taurine sodium, are oil-in-water emulsified. The composition could be stabilized.

(Examples 2 and 3, Comparative Examples 1 to 3)
The composition ratio of N-lauroyl-N-methyltaurine sodium used as an anionic surfactant in Table 2 was adjusted to the composition shown in Table 1 (unblended (Comparative Example 1), 0.05% (Comparative Example 2) ), 0.2% (Example 2), 2% (Example 3), 3% (Comparative Example 3)), and an oil-in-water emulsion composition of 100 mPa · s or less obtained by adjusting to pH 4 is stable. Sex and foaming in bath water were evaluated. The results are shown in Table 3.

  As shown in Table 3, good results were obtained when the blending ratio of N-lauroyl-N-methyltaurine sodium was 0.2% (Example 2) and 2% (Example 3), and no blending (comparison) Examples 1) and 0.05% (Comparative Example 2) had a problem in terms of stability of the preparation, and 3% (Comparative Example 3) had a problem in terms of foaming in bath water.

Example 4
Improvement when used in 19 infants with mild diaper rash around 1 year old using the oil-in-water emulsion composition of Example 2 (N-lauroyl-N-methyltaurine sodium mixture ratio: 0.2%) The effect was evaluated. Group A (9 persons) used the oil-in-water emulsion composition for 7 days, and then evaluated the skin condition after 7 days of non-use. Group B (10 persons) used the oil-in-water emulsion composition for 7 days from 7 days after the unused period, and evaluated the skin condition. In addition, the subjects of the A group and the B group were arbitrarily selected. The method of using the oil-in-water emulsified composition is to wipe all babies at the time of changing diapers (dissolve 8 mL of the oil-in-water emulsified composition in 2 L of water (warm water), soak it in gauze, etc. Wiping) and bathing (dissolve in a ratio of 20 L of hot water to 8 mL of the oil-in-water emulsion composition and take a bath). Skin evaluation was performed by diagnosing erythema etc. by a dermatologist and VAS evaluation of the degree of improvement by a guardian on the skin condition when not in use (after 7 days) and when in use (after 7 days).
The results are shown in Tables 4 and 5.

  As shown in Tables 4 and 5, the preparation containing pyridoxine hydrochloride was effective in diaper rash.

(Example 5)
For the formulation of Example 2 (N-lauroyl-N-methyltaurine sodium mixture ratio: 0.2%), the formulation pH was adjusted as shown in Table 6 by adjusting the mixture ratio of citric acid and sodium citrate. did. Each sample was stored at 50 ° C., and after 3 months, the residual rate of pyridoxine hydrochloride was measured by liquid chromatography. The results are shown in Table 6.

  As shown in Table 6, pyridoxine showed excellent stability between pH 3.1 and 4.6.

Claims (7)

Oil-in-water emulsification containing 0.001 to 5% by mass of pyridoxine or a salt thereof and 0.1 to 2% by mass of an N-acyl taurine salt, having a pH of 5 or less and a viscosity of 1 to 1000 mPa · s. Composition. Claim 1 oil-in-water emulsified composition wherein the diaper rash improved. The oil-in-water emulsion composition according to claim 1 or 2, further comprising petrolatum and / or liquid paraffin. The oil-in-water emulsion composition according to any one of claims 1 to 3 , wherein the N-acyl taurine salt is at least one selected from N-alkyl-substituted and N-alkyl-unsubstituted N-acyl taurine salts. The oil-in-water emulsion composition according to claim 1, 2 or 4, comprising a bactericide, an organic acid and / or a salt thereof, a nonionic surfactant and an oil component. 6. The oil-in-water emulsion composition according to claim 5, wherein the bactericide is isopropylmethylphenol. In an oil-in-water emulsion composition containing 0.001 to 5 mass% of pyridoxine or a salt thereof, having a pH of 5 or less and a viscosity of 1 to 1000 mPa · s, 0.1 to 0.1 N-acyl taurine salt A method for stabilizing an oil-in-water emulsified composition, characterized by blending and stabilizing 2% by mass.