JP2021091609A - Emulsion composition - Google Patents

Abstract

To provide an emulsion composition containing pyrrolidone carboxylic acid and/or a salt thereof, the emulsion composition having excellent emulsion stability.SOLUTION: An emulsion composition containing pyrrolidone carboxylic acid and/or a salt thereof is blended with ufenamate together with the pyrrolidone carboxylic acid and/or a salt thereof, so that it has excellent emulsion stability.SELECTED DRAWING: None

Description

The present invention relates to an emulsified composition containing pyrrolidone carboxylic acid and / or a salt thereof, which is excellent in property stability.

The emulsified composition can contain an aqueous component and an oily component, can be used for various pharmaceutical formulations, and has an excellent usability when applied to the skin. Therefore, the emulsified composition is widely used in the fields of external medicines and cosmetics.

Sodium pyrrolidone carboxylate is a component to be blended as a moisturizer in an external composition, and is also blended in an emulsified composition.

For example, Patent Document 1 describes a group consisting of glycerin, fructose, trimethylglycine, sodium lactate, and sodium pyrrolidone carboxylate in an emulsified composition containing α-monoalkylglyceryl ether, waxes, and a predetermined silicone oil. It is stated that a more selected moisturizer may be incorporated. Patent Document 2 describes hyaluronic acid or hyaluronic acid in an emulsified composition containing 0.1 to 10% by mass of a water-soluble polymer obtained by mixing a predetermined agar and xanthan gum in a predetermined mass ratio and 30% by mass or more of water. It is described that one or more moisturizing agents selected from the salt, pyrrolidone carboxylic acid or a salt thereof, glycerin, diglycerin, and polyglycerin may be blended. In Patent Document 3, a composition for external use on the skin at a predetermined pH containing ascorbic acid glucoside, 2-amino-2-hydroxymethyl-1,3-propanediol, and ethylenediaminetetraacetic acid or a salt thereof is prepared as an emulsifying composition. It is described that pyrrolidonecarboxylic acid or a salt thereof may be blended.

International Publication No. 97/044001 International Publication No. 2011/111854 Japanese Unexamined Patent Publication No. 2014-129278

Although it is described that the emulsified composition described in Patent Documents 1 to 3 may contain pyrrolidone carboxylic acid or a salt thereof, the emulsified composition when pyrrolidone carboxylic acid or a salt thereof is actually blended. The property stability of the product has not been investigated. The present inventor has faced a problem that when an emulsified composition containing pyrrolidone carboxylic acid or a salt thereof is prepared, separation occurs after storage and the properties become unstable.

Therefore, an object of the present invention is to provide an emulsified composition containing pyrrolidone carboxylic acid or a salt thereof, which has excellent emulsification stability.

The present inventor has diligently studied an emulsified composition containing pyrrolidone carboxylic acid or a salt thereof, and found that by blending ufenamate, which has not been known to have an emulsifying stabilizing effect, excellent emulsifying stability is provided. I found that unexpectedly. The present invention has been completed by further studies based on this finding.

That is, the present invention provides the inventions of the following aspects.
Item 1. An emulsified composition containing pyrrolidone carboxylic acid and / or a salt thereof, and ufenamate.
Item 2. Item 2. The emulsified composition according to Item 1, which contains 0.001 to 10% by weight of the pyrrolidone carboxylic acid and / or a salt thereof in total.
Item 3. Item 2. The emulsified composition according to Item 1 or 2, wherein the ufenamate is contained in an amount of 1.5 parts by weight or more per 1 part by weight of the total amount of the pyrrolidone carboxylic acid and / or a salt thereof.
Item 4. An emulsification stabilization method in which ufenamate is blended together with the pyrrolidone carboxylic acid and / or a salt thereof in an emulsification composition containing a pyrrolidone carboxylic acid and / or a salt thereof.

According to the present invention, an emulsified composition containing pyrrolidone carboxylic acid or a salt thereof can be provided with excellent emulsification stability.

1. 1. Emulsifying Composition The emulsifying composition of the present invention is characterized by containing pyrrolidone carboxylic acid and / or a salt thereof, and ufenamate. Hereinafter, the emulsified composition of the present invention will be described in detail.

Pyrrolidone carboxylic acid and / or a salt thereof The pyrrolidone carboxylic acid and / or a salt thereof contained in the emulsifying composition of the present invention is a known component as a moisturizer. Pyrrolidone carboxylic acid and / or a salt thereof destabilizes the properties of the emulsified composition after storage, but the emulsified composition of the present invention exhibits excellent emulsification stability.

Pyrrolidone carboxylic acid is a component also called pyroglutamic acid or pyrramic acid. The three-dimensional structure of the pyrrolidone carboxylic acid is not particularly limited, and may be any of D-pyrrolidone carboxylic acid, L-pyrrolidone carboxylic acid, and DL-pyrrolidone carboxylic acid.

The salt of pyrrolidone carboxylic acid is not particularly limited as long as it is pharmaceutically or cosmetically acceptable, but it is an alkali metal salt such as a sodium salt, a potassium salt or a lithium salt; an alkali such as a calcium salt or a magnesium salt. Earth metal salts; ammonium salts, alkanolamine salts and the like can be mentioned. As the salts of these pyrrolidone carboxylic acids, one type may be used alone, or a plurality of types may be used in combination. Among these pyrrolidone carboxylic acids, an alkali metal salt is preferable, and a sodium salt is more preferable.

Since the emulsified composition of the present invention is excellent in emulsification stability after storage, it is possible to effectively obtain emulsification stability even if more electrolytes that easily cause aggregation of emulsified particles coexist. From this point of view, it is even more preferable that the emulsified composition of the present invention contains a salt of pyrrolidone carboxylic acid and a salt of pyrrolidone carboxylic acid which produces more electrolyte by complete ionization among the salts of pyrrolidone carboxylic acid.

The content of pyrrolidone carboxylic acid and / or a salt thereof in the emulsified composition of the present invention is not particularly limited and can be appropriately determined depending on the moisturizing property to be imparted and the like, but the total amount of pyrrolidone carboxylic acid and its salt thereof. For example, 0.001 to 10% by weight can be mentioned. From the viewpoint of obtaining even more preferable emulsion stability, a preferred example of the content of pyrrolidone carboxylic acid and / or a salt thereof is 0.001 to 5% by weight. Further, since the emulsified composition of the present invention is excellent in emulsification stability after storage, it is possible to effectively obtain emulsification stability even if a relatively large amount of pyrrolidone carboxylic acid and / or a salt thereof is contained. From this point of view, as a preferable example of the content of pyrrolidone carboxylic acid and / or a salt thereof in the emulsified composition of the present invention, 0.1 to 10% by weight, preferably 1 to 10% by weight, more preferably 2. 10% by weight is mentioned.

Ufenamate Ufenamate contained in the emulsified composition of the present invention, also referred to as butyl flufenamic acid, is a component known as a poorly water-soluble non-steroidal anti-inflammatory drug. The emulsified composition containing pyrrolidone carboxylic acid and / or a salt thereof has unstable properties after storage, but the emulsified composition of the present invention exhibits excellent emulsification stability by blending ufenamate.

The content of ufenamate in the emulsified composition of the present invention is not particularly limited and is appropriately set according to the emulsification stability to be imparted, but is, for example, 1 to 20% by weight, preferably 2 to 10% by weight, more preferably. Is 3 to 7% by weight.

In the emulsified composition of the present invention, the ratio of ufenamate to pyrrolidone carboxylic acid and / or a salt thereof is determined according to each content of each of the above components, but from the viewpoint of obtaining even better emulsification stability, for example. The content of ufenamate per 1 part by weight of the total amount of pyrrolidone carboxylic acid and / or a salt thereof includes, for example, 1.5 parts by weight or more, preferably 1.8 parts by weight or more, and more preferably 2 parts by weight or more. The upper limit of the range of the content of ufenamate per 1 part by weight of the total amount of pyrrolidone carboxylic acid and / or a salt thereof is not particularly limited, but for example, 40 parts by weight or less, preferably 20 parts by weight or less, more preferably 10 parts by weight or less. , More preferably 5 parts by weight or less.

Oil content The emulsified composition of the present invention contains an oil content as a base component of the oil phase. The oil content is not particularly limited as long as it is pharmaceutically or cosmetically acceptable, and examples thereof include liquid oils, solid oils, and higher alcohols. These oils may be used alone or in combination of two or more.

The oil content in the emulsified composition of the present invention may be appropriately set according to the emulsified type, form, use, etc. of the emulsified composition, and is, for example, 2 to 60% by weight, preferably 4 to 30% by weight. , More preferably 4 to 15% by weight, still more preferably 6 to 8% by weight.

The emulsified composition of the present invention preferably contains a liquid oil among the above oils. The liquid oil is an oil that maintains a liquid form at 25 ° C. The liquid oil may be any liquid oil usually used for cosmetics, external medicines, etc. For example; fatty acids such as oleic acid and instearic acid; cetyl ethylcaproic acid, ethylhexyl palmitate, octyldodecyl myristate, myristic acid. Isopropyl, neopentyl glycol diethylcaproate, glyceryl tri2-ethylhexanoate, octyldodecyl oleate, isopropyl myristate, glyceryl triisostearate, dibaramethoxysilicic acid? Ester oils such as glyceryl monoethylhexanoate; silicone oils such as dimethylpolysiloxane, methylhydrodienepolysiloxane, methylphenylpolysiloxane, octamethylcyclotetrasiloxane; liquid hydrocarbon oils such as liquid paraffin, squalane, squalane, etc. Be done.

These liquid oils may be used alone or in combination of two or more.

Among these liquid oils, ester oils, silicone oils and liquid hydrocarbon oils are preferable, and octyldodecyl myristate, isopropyl myristate, dimethylpolysiloxane and liquid paraffin are more preferable. Further, among these liquid oils, liquid hydrocarbon oil is preferably mentioned, and liquid paraffin is more preferable, from the viewpoint of obtaining even more preferable emulsion stability.

When the emulsification stabilizer of the present invention contains a liquid oil, the content thereof is not particularly limited and may be appropriately set according to the emulsification type, form, application, etc. of the emulsification composition. .5 to 30% by weight, preferably 1 to 20% by weight, more preferably 3 to 10% by weight, still more preferably 5 to 8% by weight.

Emulsion composition of the water present invention comprises water as a base component of the aqueous phase. The water content in the emulsified composition of the present invention may be appropriately set according to the emulsified type, form, application, etc. of the emulsified composition, and is, for example, 30 to 95% by weight, preferably 30 to 90% by weight. More preferably, it is 30 to 80% by weight, and further preferably 30 to 75% by weight.

Further, since the emulsified composition of the present invention has excellent emulsification stability that suppresses aqueous phase separation after storage, even when a large amount of water is contained, which is inherently more likely to cause aqueous phase separation. , It becomes possible to obtain excellent emulsification stability. In view of such effects of the present invention, a preferred embodiment of the emulsified composition of the present invention is an emulsified composition having a relatively high water content. More specifically, as a preferable example of the water content in the emulsified composition of the present invention, for example, 40 to 95% by weight, preferably 45 to 95% by weight, more preferably 50 to 95% by weight, still more preferable. Is 55 to 95% by weight, more preferably 60 to 95% by weight.

Surfactant The emulsifying composition of the present invention contains a surfactant as a component for emulsifying the oil phase and the aqueous phase. The surfactant is not particularly limited as long as it is pharmaceutically or cosmetically acceptable, and for example, a nonionic surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant. And so on.

Examples of the HLB value of the surfactant include 10 to 19, preferably 13 to 17.5, and more preferably 13.5 to 15.5 from the viewpoint of obtaining even more excellent emulsion stability. The HLB value is a value calculated according to the Kawakami method (HLB value = 7 + 11.7 log (sum of formulas of hydrophilic part / sum of formulas of lipophilic part)).

Among these surfactants, a nonionic surfactant is preferable from the viewpoint of obtaining more excellent emulsion stability.

Specific examples of the nonionic surfactant include polyoxyethylene hydrogenated castor oils (for example, PEG-40 hydrogenated castor oil, PEG-50 hydrogenated castor oil, PEG-60 hydrogenated castor oil, and PEG-80. Hydrogenated castor oil, PEG-100 hydrogenated castor oil,); sorbitan fatty acid esters (eg, sorbitan monooleate, sorbitan monoisostearate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan sesqui Oleate, sorbitan trioleate, penta-2-ethylhexylate diglycerol sorbitan, tetra-2-ethylhexylate diglycerol sorbitan, etc.); glycerin fatty acid esters (eg, monocotton oil fatty acid glyceryl, monoerucate glyceryl, sesquioleate glyceryl, Glyceryl monostearate (glycerin stearate), α, α'-glyceryl pyroglutamate oleate, glycerin maloic acid, etc.); propylene glycol fatty acid esters (eg, propylene glycol monostearate, etc.); glycerin alkyl ether; Steareth-2; Polyoxyethylene sorbitan fatty acid esters (eg, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tetraoleate, etc.); Polyoxyethylene sorbitan fatty acid esters (eg, polyoxyethylene sorbitan tetraoleate, etc.) Polyoxyethylene sorbit monolaurate, polyoxyethylene sorbit monooleate, polyoxyethylene sorbit pentaoleate, polyoxyethylene sorbit monostearate, etc.); Polyoxyethylene glycerin fatty acid esters (eg, polyoxyethylene glycerin monosteare) Rate, polyoxyethylene glycerin monoisostearate, polyoxyethylene glycerin triisostearate, etc.); Polyoxyethylene fatty acid esters (eg, polyoxyethylene monooleate, polyoxyethylene monostearate, polyoxyethylene distea) Rate, polyoxyethylene monodiolate, ethylene glycol distearate, etc.); Polyoxyethylene alkyl ethers (eg, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene behenyl ether) , Polyoxyethylene 2-octyldodecyl ether, polyoxyethylene cholestanol ether, etc.); Pluronic types (eg, Pluronic, etc.); Polyoxyethylene / polyoxypropylene alkyl ethers (eg, polyoxyethylene / polyoxypropylene-) Cetyl ether, polyoxyethylene / polyoxypropylene-2-decyltetradecyl ether, polyoxyethylene / polyoxypropylene monobutyl ether, polyoxyethylene / polyoxypropylene hydrogenated lanolin, polyoxyethylene / polyoxypropylene glycerin ether, etc.) ; Stairless-21 and the like can be mentioned.

These surfactants may be used alone or in combination of two or more.

Among these nonionic surfactants, polyoxyethylene hydrogenated castor oils, polyoxyethylene sorbitan fatty acid esters, and polyoxyethylene fatty acid esters are preferable from the viewpoint of obtaining more excellent emulsion stability. Preferred include PEG-60 hydrogenated castor oil, polyoxyethylene sorbitan monostearate, and polyoxyethylene monostearate. Further, among these nonionic surfactants, polyoxyethylene sorbitan fatty acid esters are mentioned, and more preferably, polyoxyethylene sorbitan monostearate is mentioned from the viewpoint of obtaining even more excellent emulsion stability.

In the emulsified composition of the present invention, the content of the surfactant may be appropriately set according to the type of the surfactant to be used and the like, and is, for example, 0.5 to 7% by weight, preferably 1 to 5% by weight. %, More preferably 2 to 5% by weight, still more preferably 3 to 5% by weight.

Other Ingredients In addition to the above-mentioned ingredients, the emulsified composition of the present invention may contain other commonly used additives, if necessary. Such additives include, for example, polyhydric alcohols, thickeners, pH regulators, buffers, solubilizers, chelating agents, preservatives, preservatives, antioxidants, stabilizers, fragrances, colorants. And so on.

The polyhydric alcohol is not particularly limited as long as it is pharmaceutically or cosmetically acceptable, and for example, propylene glycol, 1,3-butylene glycol, ethylene glycol, isoprene glycol, diethylene glycol, dipropylene glycol and the like. Divalent alcohols; trihydric alcohols such as glycerin, polyethylene glycols such as macrogol 4000 and macrogol 6000, and the like. These polyhydric alcohols may be used alone or in combination of two or more. Among these polyhydric alcohols, from the viewpoint of obtaining more excellent emulsion stability, dihydric alcohols and trihydric alcohols are preferable, and 1,3-butylene glycol and glycerin are more preferable.

When the emulsified composition of the present invention contains a polyhydric alcohol, the content thereof may be appropriately set according to the type of the polyhydric alcohol used, for example, 1 to 20% by weight, preferably 5. ~ 18% by weight, more preferably 10 to 16% by weight.

The thickener is not particularly limited as long as it is pharmaceutically or cosmetically acceptable, and for example, carboxyvinyl polymer, hypromellose, polyvinylpyrrolidone, sodium alginate, ethyl cellulose, sodium carboxymethyl cellulose, xanthan gum, carrageenan, etc. Can be mentioned. Among these thickeners, xanthan gum is preferably mentioned from the viewpoint of obtaining more excellent emulsion stability. Further, among these thickeners, the carboxyvinyl polymer undergoes an extreme decrease in viscosity in the coexistence with pyrrolidone carboxylic acid and / or a salt thereof, and therefore has a normal emulsification composition containing pyrrolidone carboxylic acid and / or a salt thereof. When blended in a product, the storage stability is significantly reduced. However, since the emulsified composition of the present invention has excellent emulsification stability after storage, the emulsification stability can be effectively obtained even if a carboxyvinyl polymer is contained. be able to. In view of such effects of the present invention, it is preferable that the emulsified composition of the present invention contains at least a carboxyvinyl polymer as a thickener.

When a thickener is contained in the emulsified composition of the present invention, the content thereof may be appropriately set according to the type of thickener used and the like, but from the viewpoint of obtaining better emulsification stability, the content thereof may be appropriately set. For example, 0.1 to 2% by weight, preferably 0.1 to 1.8% by weight, more preferably 0.2 to 1.5% by weight, still more preferably 0.3 to 1% by weight, still more preferably 0. 3 to 0.6% by weight is mentioned. When the emulsified composition of the present invention contains a carboxyvinyl polymer, the content of the carboxyvinyl polymer is, for example, 0.1 to 1% by weight, preferably 0.3 to 0.5% by weight, more preferably 0. .35 to 0.45% by weight. The ratio of the carboxyvinyl polymer to the pyrrolidone carboxylic acid and / or its salt is determined according to the content of each of the above components. For example, per 1 part by weight of the total amount of the pyrrolidone carboxylic acid and / or its salt. Examples of the content of the carboxyvinyl polymer include 0.01 to 0.5 parts by weight, preferably 0.03 to 0.3 parts by weight, and more preferably 0.06 to 0.2 parts by weight.

Further, the emulsified composition of the present invention may contain, if necessary, a medicinal ingredient capable of exerting a pharmaceutical or cosmetic physiological function in addition to the above-mentioned ingredients. Examples of such medicinal ingredients include steroids (dexamethasone, dexamethasone hydrochloride, dexamethasone acetate, hydrocortisone hydrochloride, prednisolone salicate, prednisolone acetate, etc.), antihistamines (diphenhydramine, diphenhydramine hydrochloride, chlorhexidine maleate, etc.), and local anesthesia. Agents (lydocaine, dibucaine, procaine, tetracaine, bupivacaine, mepivacaine, chloroprocaine, proparacaine, meprilcaine or salts thereof), salicylic acid alkyl esters (eg ethyl aminobenzoate, diethylaminoethyl parabutylaminobenzoate), orthokine, Oxesazein, oxypolyentoxydecane, funnel extract, percaminepase, tesitdecitin, etc.), anti-inflammatory agents (alantine, salicylic acid, glycol salicylate, methyl salicylate, indomethacin, fervinac, diclofenac sodium, sodium loxoprofen, etc.), bactericides (benzalconium chloride, benzalconium chloride, etc.) Dexamethasone chloride, benzethonium chloride, cetylpyridinium chloride, chlorhexidine hydrochloride, chlorhexidine gluconate, aqueous ammonia, sulfaziazine, lactic acid, phenol, etc.), antipruritic agents (crotamiton, thiantolu, etc.), skin protectants (colodione, castor oil, etc.), blood circulation promotion Ingredients (nonyl acid vanillylamide, nicotinic acid benzyl ester, capsaicin, capsicum extract, etc.), vitamins (vitamins A, B, C, D, E, etc.), mucopolysaccharides (sodium chondroitin sulfate, glucosamine, hyaluronic acid, etc.), etc. Can be mentioned. These medicinal ingredients may be used alone or in combination of two or more. In addition, when these medicinal ingredients are contained in the emulsified composition of the present invention, the content thereof may be appropriately set according to the type of the medicinal ingredient to be used, the expected effect, and the like.

Formulation Form / Use The emulsified type of the emulsified composition of the present invention may be either a water-in-oil type or an oil-in-water type. Since the emulsified composition of the present invention exhibits excellent emulsification stability that suppresses separation after storage, it originally contains a large amount of water such as an oil-in-water type, which is more likely to cause aqueous phase separation. However, it becomes possible to provide excellent emulsification stability. In view of such effects of the present invention, the preferred emulsified type of the emulsified composition of the present invention is the oil-in-water type having a relatively high water content.

The emulsified composition of the present invention can be used as an external preparation for cosmetics, quasi-drugs for external use, pharmaceuticals for external use, and the like. The product form of the emulsified composition of the present invention is not particularly limited, and examples thereof include creams, ointments, emulsions, gels, oils, lotions, liniments, and aerosols. Among these, creams, ointments, emulsions and lotions are preferable, and creams, emulsions and lotions are more preferable.

Production Method The emulsified composition of the present invention can be produced according to a known formulation method of an emulsified preparation according to the emulsified type. For example, in the method for producing an emulsified composition of the present invention, the components to be contained are divided into a water-soluble component and an oil-based component, an aqueous phase containing the water-soluble component and an oil phase containing the oil-based component are prepared, and these are prepared. Examples thereof include a method of emulsifying according to a known method.

2. Emulsification Stabilization Method As described above, ufenamate exhibits excellent emulsion stability in an emulsification composition containing a pyrrolidone carboxylic acid and / or a salt thereof. Therefore, the present invention further provides an emulsification stabilization method in which ufenamate is blended together with pyrrolidone carboxylic acid and / or a salt thereof in an emulsification composition containing pyrrolidone carboxylic acid and / or a salt thereof.

In the emulsification stabilization method of the present invention, emulsification stabilization means suppressing the separation of the emulsified composition after storage. Separation means that the aqueous phase and / or the oil phase are separated from the emulsified composition. A more preferable embodiment of the emulsion stabilization is to suppress the separation of the aqueous phase from the emulsified composition after storage, and a more preferable embodiment is that the emulsified state of the emulsified composition is uniform after storage. That is, the droplets in the emulsion are kept uniformly dispersed in the dispersion medium.

In the case of the above-mentioned "1. Emulsification composition", the type and content of each component used in the emulsion stabilization method of the present invention, the type and content of the component to be blended in the emulsification composition, the formulation form, etc. Is similar to.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Test Examples The emulsified compositions shown in Tables 1 and 2 were prepared. Specifically, the component (B) was added to the mixture of the components (I) and dissolved at 70 to 80 ° C. to prepare an oil phase. On the other hand, a mixture of each component of (II) was dissolved at 75 to 85 ° C., and a 50% by weight aqueous solution of component (A) was further added to prepare an aqueous phase. An aqueous phase heated to 70 to 80 ° C. was added to the oil phase heated to 70 to 80 ° C., and the mixture was stirred and emulsified using a homomixer and cooled to 35 ° C. As a result, an emulsified composition (milky lotion; oil-in-water type) was produced.

10 g of each of the obtained emulsified compositions was filled in a 15 mL transparent plastic tube, sealed, and centrifuged at 3,000 rpm for 10 minutes by a centrifuge. Each emulsified composition after centrifugation was visually observed, and the emulsified stability was evaluated based on the following criteria. The results are shown in Tables 1 and 2.
−−: Phase separation is clearly observed, and the degree of turbidity of the aqueous phase is small.
-: Phase separation is clearly observed, and the degree of turbidity of the aqueous phase is large.
+: No phase separation is observed, only creaming tendency is observed.
++: No phase separation is observed, and a slight creaming tendency is observed only at the bottom tip of the tube.
+++: No phase separation is observed and the emulsified state is uniform.
The creaming tendency refers to a non-uniform state in an emulsified state, and specifically, a state in which droplets in the produced emulsion are in the process of floating or settling due to the difference in specific gravity with the dispersion medium.

As is clear from Table 2, the emulsified state is stable in the emulsified composition containing no sodium pyrrolidone carboxylate (reference example), but the emulsified state becomes unstable in the emulsified composition containing sodium pyrrolidone carboxylate (comparison). Examples 1 and 2) were found. On the other hand, as is clear from Table 1, the emulsified state was stabilized by further adding ufenamate to the emulsified composition containing sodium pyrrolidone carboxylate (Examples 1 to 7). This effect of improving the emulsion stability was particularly remarkable in Examples 1, 4 to 7.

Formulation Examples The emulsified compositions (oil-in-water type) of the formulations shown in Tables 3 and 4 were prepared. Both emulsified compositions had excellent emulsification stability.

Claims (4)

An emulsified composition containing pyrrolidone carboxylic acid and / or a salt thereof, and ufenamate. The emulsified composition according to claim 1, which contains 0.001 to 10% by weight of the pyrrolidone carboxylic acid and / or a salt thereof in total. The emulsified composition according to claim 1 or 2, wherein the ufenamate is contained in an amount of 1.5 parts by weight or more per 1 part by weight of the total amount of the pyrrolidone carboxylic acid and / or a salt thereof. An emulsification stabilization method in which ufenamate is blended together with the pyrrolidone carboxylic acid and / or a salt thereof in an emulsification composition containing a pyrrolidone carboxylic acid and / or a salt thereof.