Pest repellent for humans

Abstract

A human-use pest repellent for use on humans, comprising a repellent effective component (a), a diacyl glutamic acid lysine salt (b), and water.

Description

Technical Field

[0001] This disclosure relates to a human pest repellent that can be used on humans. More specifically, it relates to a human pest repellent that, while reducing the amount of surfactant added, exhibits excellent stability over time and can be used without shaking. Background Technology

[0002] Traditionally, skin repellents used to repel pests such as mosquitoes have been widely sold, containing ethanol and applied directly in liquid form. However, these liquid repellents have several drawbacks: they often drip during application, making it difficult to apply evenly to the skin. Furthermore, the high ethanol content can sometimes cause irritation, dryness, and tightness. Therefore, a method is currently being developed to emulsify and disperse the hydrophobic repellent active ingredient in water without adding ethanol. For example, Patent Document 1 proposes a method that emulsifies and disperses the repellent active ingredient using at least one nonionic surfactant selected from the group consisting of polyoxyethylene hydrogenated castor oil and fatty acid polyoxyethylene hydrogenated castor oil. Patent Documents 2 and 3 propose methods for emulsifying and dispersing the repellent active ingredient using a three-phase emulsification method.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-026603

[0006] Patent Document 2: Japanese Patent Application Publication No. 2017-185474

[0007] Patent Document 3: Japanese Patent Application Publication No. 2022-072114 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] However, in Patent Document 1, although a nonionic surfactant is contained, there is a possibility of irritation due to the presence of the nonionic surfactant. Furthermore, in Patent Document 2, while it eliminates the need for conventional surfactants and thus has the advantage of being less irritating, it requires the preparation of closed vesicles formed from amphiphilic substances that spontaneously form closed vesicles, or particles of condensation polymers with hydroxyl groups, which necessitates special processes for preparation. Additionally, in Patent Document 3, due to coacervation (not oil-water separation caused by emulsification instability, but rather apparent liquid layer differences caused by the specific gravity difference of individual emulsion particles), the product is in a separated two-layer state before use, requiring shaking of the container for mixing.

[0010] This disclosure was made to solve the above-mentioned technical problems, and its purpose is to provide a human pest repellent with excellent stability over time that can be used without shaking.

[0011] Technical solutions for solving technical problems

[0012] To achieve the above objectives, one aspect of this disclosure is based on a human-use insect repellent suitable for human use. The human-use insect repellent, for example, comprises a repellent active ingredient (a), a diacylglutamic acid lysine salt (b), and water.

[0013] The repellent active ingredient (a) is, for example, at least one selected from the group consisting of icoplanin, DEET, IR3535, and p-menthane-3,8-diol.

[0014] The concentration range of the repellent active ingredient (a) can be set to 3% by mass or more and 30% by mass or less.

[0015] The diacylglutamic acid lysine salt (b) may also be, for example, dilauryl glutamic acid lysine salt.

[0016] The concentration range of the diacylglutamic acid lysine salt (b) can be set to 0.0009% by mass or more and 0.5% by mass or less.

[0017] Human insect repellents may also contain a thickener (c) as an optional ingredient. The concentration of the thickener (c) can be set to a range of 0.01% by mass or more and 5.0% by mass or less.

[0018] Human insect repellents may also contain polyol (d) as an optional component. The concentration of said polyol (d) can be set to 15% by mass or less.

[0019] The effects of the invention

[0020] According to this disclosure, a human pest repellent can be provided that, although the amount of surfactant added is reduced, exhibits excellent stability over time and can be used without shaking. Detailed Implementation

[0021] The embodiments of the present invention will now be described in detail. It should be noted that the following description of preferred embodiments is merely illustrative and is not intended to limit the invention, its application, or its uses.

[0022] The insect repellent for human use described in this embodiment is an insect repellent that can be used on humans, comprising the repellent active ingredient (a), diacylglutamic acid lysine salt (b), and water. The insect repellent for human use may also contain a thickener (c) as an optional ingredient. Furthermore, the insect repellent for human use may also contain polyols (d) as optional ingredients. Additionally, the insect repellent for human use may contain other ingredients besides thickeners (c) and polyols (d) as optional ingredients.

[0023] Human insect repellents can be marketed as insect repellent products in the form of containers. The dosage form of human insect repellents can be any of the following: liquid, emulsion, cream, gel, spray, aerosol, metered-dose aerosol, patch, or tissue. Containers for human insect repellents can include trigger spray containers, atomizing spray containers, pump spray containers, and aerosol containers. When human insect repellents are contained in metered-dose aerosols, the spray volume can be set to any amount. In the case of aerosol containers, the propellant used to spray the human insect repellent is also contained in the container. In the case of patches or tissues, human insect repellents can be contained in bags or the like in a state of being soaked or attached to the patch or tissue for market distribution.

[0024] This product can be used by applying the insect repellent to human skin. In the case of aerosol or spray products containing the insect repellent, it can be applied to the skin by spraying. Alternatively, if the insect repellent is in liquid, lotion, cream, or gel form, it can be applied to the skin. Furthermore, if the insect repellent is soaked or attached to patches or tissues, these patches or tissues can be used to adhere it to the skin. Additionally, the insect repellent can be applied to items such as clothing.

[0025] <Repellent active ingredient (a)>

[0026] Repellent active ingredient (a) is an ingredient that has a repellent effect on pests. Pests refer to, but are not limited to, mosquitoes, etc. Agents that can repel various pests can be used as repellent active ingredient (a).

[0027] Examples of repellent active ingredients (a) include: icosamide, DEET (diethyltoluamide), ethyl 3-(Nn-butyl-N-acetyl)aminopropionate (IR3535), p-menthane-3,8-diol, 2-ethyl-1,3-hexanediol, butyl 3,4-dihydro-2,2-dimethyl-4-oxo-2H-pyran-6-carboxylate, n-hexyl triethylene glycol monoether, and methyl 6-n-pentyl-cyclohexene-1-carboxylate (methyl Insect repellent ingredients include 6-n-pentyl-cyclohexene-1-carboxylate, dimethyl phthalate, eucalyptol, α-pinene, geraniol, citronellol, camphor, linalool, terpineol, carvone, dioctyl phthalate, dibutyl phthalate, naphthalene, cinnamon, camphor, lemongrass, clover, thyme, geranium, bergamot, bay leaf, pine, ternstroemia gymnanthera, peppermint oil, eucalyptus, and azadirachta indica. Pyrethroid insecticides include natural pyrethroids, pyrethroids, allethrin, phthalthrin, benzalkonium chloride, propargite, permethrin, cyphenothrin, propargite, propargite, and tetrafluorobenzyl pyrethrin. Human insect repellents may contain only one of these as the active repellent ingredient (a), or a mixture of two or more of these as the active repellent ingredient (a).

[0028] <Diacylglutamate lysine salt (b)>

[0029] The insect repellent for human use, by including diacylglutamic acid lysine salt (b), can become a stable emulsified repellent. Furthermore, as described later, even with the inclusion of diacylglutamic acid lysine salt (b), the repellent effect of the active ingredient (a) can still be fully exerted, ensuring the long-lasting duration of its repellent effect.

[0030] The following components can be cited as diacylglutamic acid lysine salts (b) contained in human insect repellents. Fatty acid residues constituting the acylglutamic acid lysine salts contained in human insect repellents can be, for example, fatty acid residues with 8 or more carbon atoms and 22 or fewer. Specifically, examples include: caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, linoleic acid, behenic acid, etc. These can be derived from plants and animals, or are fatty acids from coconut oil, palm oil, hardened tallow, etc. Furthermore, their salts can include: salts of alkali metals such as sodium and potassium, organic amine salts such as triethanolamine, and salts of basic amino acids such as arginine.

[0031] Diacylglutamate lysine salt (b) may, for example, contain one or more selected from the group consisting of sodium dilauroyl glutamate lysine, sodium dimyristoyl glutamate lysine, sodium distearate glutamate lysine, and sodium dilinoleoyl glutamate lysine, preferably sodium dilauroyl glutamate lysine.

[0032] Diacylglutamic acid lysine salt (b) can be synthesized, for example, by reacting L-lysine hydrochloride with N-fatty acid acyl-L-glutamic anhydride. Alternatively, commercially available products such as Pellicer L-30 (trade name: sodium dilauroyl glutamic acid lysine, effective content 29%, water 71%) and Pellicer LB-10 (trade name: sodium dilauroyl glutamic acid lysine, effective content 10%, 1,3-butanediol 10%, water 71%) manufactured by Asahi Kasei Fine Chemicals Co., Ltd.

[0033] <Water>

[0034] The water contained in human pest repellents can be any of the following: tap water, ion-exchanged water, purified water, etc.

[0035] <Thickener (c)>

[0036] Thickener (c) included in human insect repellents can include the following components: Thickener (c) can be any of a natural thickener, a semi-synthetic thickener, a synthetic thickener, or an inorganic thickener. Alternatively, thickener (c) can be a mixture of any two or more of the natural thickener, semi-synthetic thickener, synthetic thickener, and inorganic thickener, or it can be a mixture of all of the natural thickener, semi-synthetic thickener, synthetic thickener, and inorganic thickener.

[0037] Examples of natural thickeners include: arabic gum, tamarind gum, tragacanth gum, galactomannan, guar gum, xanthan gum, carob gum, locust bean gum, ark sylvestris gum, carrageenan, pectin, agar, quince seeds, algaecide, starch, and other plant-based macromolecules; dextran, dextrin, succinoglycan, pullulan, and other microbial macromolecules; and collagen, casein, albumin, gelatin, and other animal-based macromolecules. Thickener (c) can include either any single substance selected from these or a mixture of any two or more selected substances.

[0038] Examples of semi-synthetic thickeners include: starch-based polymers such as carboxymethyl starch and methyl hydroxypropyl starch; cellulose-based polymers such as methyl cellulose, nitrocellulose, ethyl cellulose, methyl hydroxypropyl cellulose, hydroxyethyl cellulose, sodium cellulose sulfate, hydroxypropyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, crystalline cellulose, and cellulose powder; and alginate-based polymers such as sodium alginate and propylene glycol alginate. Thickener (c) can include either any one of these selected substances or a mixture of two or more selected substances.

[0039] Examples of synthetic thickeners include: vinyl polymers such as polyvinyl alcohol, polyvinyl methyl ether, polyvinylpyrrolidone, and carboxyvinyl polymers (carbomer); polyoxyethylene polymers such as polyethylene glycol (molecular weights of 1500, 4000, 6000, etc.); polyoxyethylene-polyoxypropylene copolymers; acrylic polymers such as sodium polyacrylate, polyethyl acrylate, and acrylic / alkyl methacrylate copolymers; and polyethyleneimine and cationic polymers. Thickener (c) can include either a single selected substance or a mixture of two or more selected substances.

[0040] Examples of inorganic thickeners include bentonite, magnesium aluminum silicate, laponite, hectorite, and silicic anhydride. Thickener (c) can be any single substance selected from these, or it can be a mixture of two or more selected substances.

[0041] <Polyols (d)>

[0042] Examples of polyols (d) contained in insect repellents for human use include: glycerol, diglycerol, triglyceride, polyglycerol, 3-methyl-1,3-butanediol, 1,3-butene glycol (1,3-BG), isopentyl glycol, polyethylene glycol, 1,2-pentanediol, 1,2-hexanediol, propylene glycol, dipropylene glycol, polypropylene glycol, ethylene glycol, diethylene glycol, neopentyl glycol, maltitol, reducing syrup, sucrose, lactitol, palaginitol, erythritol, sorbitol, mannitol, xylitol, xylose, glucose, lactose, mannose, maltose, galactose, fructose, inositol, pentaerythritol, maltotriose, sorbitan, trehalose, starch hydrolysate, starch hydrolysate reducing alcohol, etc. The polyol (d) may include only one of these selected substances, or it may include a mixture of two or more selected substances. From the viewpoint of the long-term stability of the insect repellent for human use, polyols with a total carbon number of 5 or less are preferred, and polyols with a total carbon number of 3 or less are more preferred.

[0043] <Propellant>

[0044] When a human-use insect repellent is contained in an aerosol container, the propellant is also contained in the aerosol container. Examples of propellants include liquefied petroleum gas (LPG), dimethyl ether (DME), and compressed gases (carbon dioxide, nitrogen). Either a single selected substance can be included as the propellant, or a mixture of two or more selected substances can be included. The ratio of human-use insect repellent to propellant can be arbitrarily set considering factors such as the effectiveness of the human-use insect repellent.

[0045] <Other Ingredients>

[0046] Human insect repellents may also contain other ingredients besides those mentioned above (other ingredients). Examples of other ingredients in human insect repellents include: other surfactants, other solvents (lower alcohols, etc.), repellent efficacy enhancers, waterproofing agents, astringents, antiperspirants, moisturizers, emollients, irritant-soothing agents, anti-inflammatory agents, barrier function repair agents, bactericides / preservatives, temperature-sensitive agents, cooling agents, deodorants, other thickeners, pigments, pH adjusters, fragrances, UV absorbers, antioxidants, plant extracts, amino acids, and touch improvers (powders), etc. Only one of these can be selected as an "other ingredient," or a mixture of two or more can be included.

[0047] <Concentration of each component>

[0048] The lower limit of the concentration of the repellent active ingredient (a) is 3% by mass or more, preferably 5% by mass or more, relative to the total mass of the human insect repellent. If the concentration of the repellent active ingredient (a) is at or above the above lower limit, the human insect repellent will more easily exert a repellent effect against insects when applied to the skin.

[0049] The upper limit of the concentration of the repellent active ingredient (a) is 30% by mass or less, preferably 25% by mass or less, and more preferably 20% by mass or less. If the concentration of the repellent active ingredient (a) is below the above-mentioned upper limit, the stability of the pest repellent for human use is better.

[0050] The lower limit of the concentration of diacylglutamic acid lysine salt (b) is 0.0009% by mass or more, preferably 0.009% by mass or more, relative to the total mass of the human insect repellent. The upper limit of the concentration of diacylglutamic acid lysine salt (b) is 0.45% by mass or less, preferably 0.18% by mass or less. If the concentration of diacylglutamic acid lysine salt (b) is less than the above lower limit or greater than the above upper limit, the stability of the human insect repellent may decrease.

[0051] The lower limit of the concentration of thickener (c) is 0.01% by mass or more, preferably 0.1% by mass or more, relative to the total mass of the human insect repellent. The upper limit of the concentration of thickener (c) is 5.0% by mass or less, preferably 2.0% by mass or less. If the concentration of thickener (c) is less than the above lower limit or greater than the above upper limit, the stability of the human insect repellent may decrease.

[0052] The concentration of polyol (d) is preferably 15% by mass or less, more preferably 10% by mass or less, relative to the total mass of the human insect repellent. By keeping the concentration of polyol (d) in the range of 15% by mass or less, the human insect repellent becomes a homogeneous emulsion, which can stably maintain an emulsified state for a long time.

[0053] <Target pests of human pest repellents>

[0054] Besides mosquitoes, other pests targeted by human insect repellents include: black flies, horseflies, dung flies, stable flies, house dust mites, bed bugs, ticks, fleas, chiggers, leeches, midges, moth flies, and red imported fire ants. Human insect repellents are also effective against these pests.

[0055] Example

[0056] The present invention, with reference to the embodiments and comparative examples, will now be described in more detail, but the present invention is not limited to these embodiments. The preparation methods described in the embodiments are merely examples, and other preparation methods may also be used.

[0057] <Preparation Methods of Examples and Comparative Examples>

[0058] (Examples 1-13, Comparative Examples 1-5)

[0059] The carboxyvinyl polymer was dissolved in ion-exchanged water and neutralized to pH 7 using a 1% sodium hydroxide aqueous solution. Then, sodium dilauroyl glutamate lysine was added and heated to 70°C. While stirring the above aqueous phase at 5000 rpm using a homogeneous mixer, the repellent active ingredient (a), which had been heated to 70°C, was added and stirred for 30 minutes.

[0060] (Examples 14-21)

[0061] The carboxyvinyl polymer was dissolved in ion-exchanged water and neutralized to pH 7 using a 1% sodium hydroxide aqueous solution. Then, sodium dilauroyl glutamate lysine and polyol (d) were added, and the mixture was heated to 70°C. While stirring the aqueous phase at 5000 rpm using a homogeneous mixer, icocarbidine, which had been heated to 70°C, was added and stirred for 30 minutes.

[0062] (Examples 22-26)

[0063] Thickener (c) was dissolved in ion-exchanged water, and sodium dilauroyl glutamate lysine was added. In the case of a carboxyvinyl polymer thickener, after dissolving in ion-exchanged water, the solution was neutralized to pH 7 using a 1% sodium hydroxide aqueous solution, and then sodium dilauroyl glutamate lysine was added. Icaridin at room temperature was added while stirring the aqueous phase at 5000 rpm using a homogeneous mixer at room temperature, and stirring for 30 minutes.

[0064] (Comparative Example 6)

[0065] Comparative Example 6 was prepared by mixing DEET (10% by mass), ethanol (40% by mass), and ion-exchanged water (50% by mass).

[0066] The "balance" of ion-exchanged water in Tables 1-5 represents the amount that brings the total amount of human-use insect repellent to 100% by mass. Emulsified repellents can be easily prepared using diacylglutamic acid lysine salt (b). It should be noted that the above preparation method is also applicable to repellent active ingredients (a) other than DEET and picaridin. The same applies to diacylglutamic acid lysine salt (b).

[0067] [Table 1]

[0068]

[0069] [Table 2]

[0070]

[0071] [Table 3]

[0072]

[0073] [Table 4]

[0074]

[0075] [Table 5]

[0076]

[0077] <Stability Test Evaluation>

[0078] The human insect repellents (Examples 1-26, Comparative Examples 1-5) prepared by the above method were stored at 50°C for one month. The state (appearance) of each human insect repellent was visually evaluated immediately after preparation and after one month of storage, and the stability of the human insect repellents was evaluated using the following criteria (stability at 50°C for one month).

[0079] The viscosity of the human-use insect repellent was measured using a Type B viscometer, TVB-10 (manufactured by Toki Sangyo Co., Ltd.). Depending on the viscosity of each human-use insect repellent, rotors M4, THM1 to THM3 were used, and the viscosity after rotating at 12 rpm for 60 seconds was taken as the measurement value. pH was measured using a pH meter, LAQUAF-72 (manufactured by Horiba Seisakusho Co., Ltd.).

[0080] (Stability evaluation criteria)

[0081] 〇: No separation has occurred; the mixture is in a uniformly emulsified and dispersed state.

[0082] △: Although relatively large oil droplets are present, they are not separated.

[0083] ×: Separated into two layers.

[0084] The results of the stability test are shown in Tables 1 to 5. In Examples 1 to 26, no separation occurred immediately after the human insect repellent was made and after it was stored at 50°C for one month. The repellent remained in a uniformly emulsified and dispersed state, or even if relatively large oil droplets were present, it did not separate. In contrast, in Comparative Examples 1 to 5, the human insect repellent separated into two layers.

[0085] As shown in Tables 1 and 2, the human pest repellents of Examples 1 to 8 exhibited good stability after one month when the concentration of the repellent active ingredient (a) was 5% by mass or more and 30% by mass or less. Other repellent active ingredients (a) also exhibited good stability after one month. On the other hand, as in Comparative Examples 1 to 4, when the concentration of the repellent active ingredient (a) was 40% by mass or more, the human pest repellent separated into two layers immediately after manufacture or after one month of storage at 50°C. Other repellent active ingredients (a) also separated into two layers immediately after manufacture or after one month of storage at 50°C when the concentration was 40% by mass or more.

[0086] As shown in Table 3, the human insect repellents of Examples 9-13 were able to emulsify and disperse the repellent active ingredient (a) when the concentration of diacylglutamic acid lysine salt (b) was 0.0009% by mass or more and 0.45% by mass or less, and the stability test results after one month were also good. The other repellent active ingredients (a) were also able to emulsify and disperse in the range of 0.0009% by mass or more and 0.45% by mass or less. On the other hand, as with the human insect repellent of Comparative Example 5, when the concentration of diacylglutamic acid lysine salt (b) was 0.9% by mass or more, the human insect repellent separated into two layers after one month of storage. The other repellent active ingredients (a) were also able to separate into two layers after one month of storage when the concentration was 0.9% by mass or more.

[0087] As shown in Table 4, polyol (d) was added as an additive in the human pest repellents of Examples 14-21. All of these examples were able to produce uniform emulsions, and the stability test results after one month were also good.

[0088] As shown in Table 5, in the human pest repellents of Examples 22-26, thickener (c) was added as an additive. These examples all produced uniform emulsions, and the stability test results after one month were also good. In other examples, thickener (c) was added, and the stability test results after one month were also good.

[0089] <Continuous effect test of anti-sucking effect (insect repellency test)>

[0090] The human insect repellent was administered at a concentration of 1.67 μL / cm³. 2The appropriate dosage was evenly applied to the forearms of four subjects. After each time period (6 hours, 8 hours, 10 hours, and 12 hours), a glass ring containing 10 female Aedes albopictus mosquitoes was pressed against the skin for 5 minutes, and the number of mosquitoes that had fed was counted. The blood-feeding prevention rate, expressed by the following formula, was then evaluated. The insect repellent used for human use was Example 6. Additionally, as a comparative example, a 10% aqueous solution of DEET in ethanol (Comparative Example 6) was used.

[0091] [Table 6]

[0092]

[0093] It should be noted that in the following formula, "treated area" indicates the condition where a human pest repellent (Example 6 or Comparative Example 6) was applied, and "untreated area" indicates the condition where nothing was applied.

[0094] Bloodsucking prevention rate (%) = (1 - Bloodsucking mosquito rate in the treated area / Bloodsucking mosquito rate in the untreated area) × 100

[0095] The results are shown in Table 7. In Example 6, a blood-sucking prevention rate of over 90% was confirmed even 10 hours after application, while in Comparative Example 6, the blood-sucking prevention rate became less than 80% after 10 hours after application.

[0096] [Table 7]

[0097]

[0098] The above embodiments are merely illustrative in all respects and should not be construed as limiting. Furthermore, variations and modifications falling within the scope of the claims are also within the scope of this invention. For example, regarding the repellent active ingredient (a), any of the above-described repellent active ingredients (a) provides long-term stability while maintaining pest repellency, as in Examples 1-6. Similarly, regarding the diacylglutamic acid lysine salt (b), any of the above-described diacylglutamic acid lysine salt (b) provides long-term stability without significantly hindering the pest repellency effect of the repellent active ingredient (a), as in Examples 1-6. Furthermore, regarding the thickener (c), any of the above-described thickener (c) provides long-term stability without significantly hindering the pest repellency effect of the repellent active ingredient (a), as in Examples 1-6. Finally, regarding the polyol (d), any of the above-described polyol (d) provides long-term stability without significantly hindering the pest repellency effect of the repellent active ingredient (a), as in Examples 1-6.

[0099] Industrial practicality

[0100] As explained above, the human insect repellent disclosed herein can be used to repel pests such as mosquitoes, midges, horseflies, sedge flies, stable flies, house dust mites, bed bugs, ticks, fleas, chiggers, leeches, midges, moth flies, and red imported fire ants. For example, it can be used as an insect repellent applied to human skin.

Claims

1. A pest repellent for human use, characterized in that: The insect repellent for human use contains an effective repellent ingredient (a), diacylglutamic acid lysine salt (b), and water.

2. The insect repellent for human use according to claim 1, characterized in that: The repellent active ingredient (a) is at least one selected from the group consisting of icoplanin, DEET, IR3535, and p-menthane-3,8-diol.

3. The insect repellent for human use according to claim 1, characterized in that: The concentration range of the repellent active ingredient (a) is above 3% by mass and below 30% by mass.

4. The insect repellent for human use according to claim 1, characterized in that: The diacylglutamic acid lysine salt (b) is dilauroylglutamic acid lysine salt.

5. The insect repellent for human use according to claim 1, characterized in that: The concentration range of the diacylglutamic acid lysine salt (b) is above 0.0009% by mass and below 0.5% by mass.

6. The insect repellent for human use according to claim 1, characterized in that: The insect repellent for human use also contains a thickener (c).

7. The insect repellent for human use according to claim 6, characterized in that: The concentration range of the thickener (c) is 0.01% by mass or more and 5.0% by mass or less.

8. The insect repellent for human use according to claim 1, characterized in that: The insect repellent for human use also contains polyols (d).

9. The insect repellent for human use according to claim 8, characterized in that: The concentration range of the polyol (d) is below 15% by mass.

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