JP2024075412A - Skin preparations - Google Patents

Abstract

[Problem] To provide an external preparation for the skin that is excellent in stability, spreads well when applied, has no oily feeling, and is pleasant to use. [Solution] An external preparation for the skin that contains an oil agent derived from degummed and decolorized Nannochloropsis oceanica. [Selected Figures] None

Description

The present invention relates to a skin preparation for external use.

Conventionally, in cosmetics for protecting and moisturizing the skin, triglycerides derived from animals and plants that are solid at room temperature, such as beeswax, shea butter, and Rhus vinifera derived from goby, or tri(caprylic acid/capric acid/myristic acid/stearic acid)glyceryl with a fatty acid composition adjusted according to the characteristics of the triglycerides, have been used to reduce stickiness when applied.
For example, Patent Literature 1 describes that an oil-based solid cosmetic preparation containing a dextrin fatty acid ester, naturally derived solid fat and/or semi-solid fat, and isoparaffin is excellent in feel when used, skin protection, and stability over time.
Patent Document 2 describes that a solid cosmetic composition containing shea butter, cocoa butter, at least one component selected from Abyssinian oil, meadowfoam oil, and an antioxidant, and a vegetable liquid oil is not sticky when applied to the skin and has high oxidation stability.
Patent Document 3 describes that an emulsion cosmetic composition containing an oily component selected from a hydrocarbon oil, a fatty acid triglyceride, and a fatty acid monoester, di(octyldodecyl/phytosteryl/behenyl) lauroyl glutamate, and water, provides excellent firmness upon application and is non-sticky after application.

JP 2017-114780 A JP 2020-63224 A JP 2021-11459 A

However, triglycerides derived from animals and plants that are solid at room temperature do not have high solubility in liquid oils, and even if they are melted at around 80°C, they may solidify and precipitate at room temperature. For this reason, formulations that take advantage of the properties of triglycerides that are solid at room temperature have been limited to solid cosmetics and formulations in combination with specific amphiphilic substances. In particular, when blending at high concentrations in liquid oil formulations and emulsion formulations, there are issues with storage stability. In addition, when blending triglycerides that are solid at room temperature, it is necessary to maintain a high temperature inside the equipment during the manufacturing process in order to uniformly dissolve the raw materials, which requires a lot of energy.

In addition, while the demand for plant-derived triglycerides that are solid at room temperature, such as those derived from palm oil, is increasing year by year, a significant increase in production is unlikely, and there are concerns about the future supply system. In particular, there are negative opinions about the continued use of triglycerides, which are recognized as edible oils such as shea butter, as cosmetic ingredients amid a global food shortage. Therefore, alternative oils are desired.
The present invention relates to an external skin preparation which is excellent in stability, feel when used and texture.

The present inventors have discovered that by using an oil that is prepared from a culture of a specific species of microalga Nannochloropsis and that has been degummed and decolorized, it is possible to obtain a skin preparation that is stable during storage, spreads well when applied, is not oily, and feels good when used, without precipitating the oil derived from Nannochloropsis, and thus has completed the present invention.

The present invention relates to a skin preparation for external use that contains an oil derived from degummed and decolorized Nannochloropsis oceanica.

The topical skin preparation of the present invention has excellent storage stability, does not cause precipitation of the oil derived from Nannochloropsis, spreads well when applied, is not sticky such as oily, and has a good feel when used.

The oil used in the present invention can be obtained from a culture of Nannochloropsis oceanica, a microalgae belonging to the genus Nannochloropsis.
Nannochloropsis is a marine organism belonging to the Heterokontophyta and Euopterygium, and is used in fish farming. Extracts of Nannochloropsis have been studied as effective ingredients for cosmetics, such as for antioxidative stress and skin tightening (JP Patent Publication No. 2006-232766 and JP Patent Publication No. 2019-532966). However, there have been no reports of Nannochloropsis extracts being used as an oily base for cosmetics, such as oil preparations and emulsion preparations.

Nannochloropsis oceanica used in the present invention can be cultured in a medium prepared by adding additives such as ammonium sulfate, calcium superphosphate, and chelating agents and buffer solutions usually used in the cultivation of algae to seawater. From the viewpoint of preventing contamination by other microorganisms and concentrating antioxidant components, it is preferable to culture the organism by a method of exposing the organism to excessive light in a closed system using a photoreactor.

After culturing Nannochloropsis oceanica, the algae may be concentrated by centrifugation, filtration, etc., if necessary, or may be sterilized by heating or other methods. In addition, methods for obtaining oils include squeezing, solvent extraction using hexane or ethyl acetate, and squeezing.

Nannochloropsis oceanica-derived oil (hereinafter referred to as "Nannochloropsis-derived oil") is used after degumming and bleaching. Degumming can be performed using water, an aqueous solution of phosphoric acid or citric acid, or an enzyme solution, as necessary. Bleaching can be performed using an adsorbent such as activated carbon. In addition, deodorization can be performed in combination with exposure to water vapor or heating.

The Nannochloropsis-derived oil used in the present invention is a partially melted solid at 20° C., but can melt at a lower temperature than other solid fats commonly used in cosmetics, such as beeswax.
The temperature at which most of the Nannochloropsis-derived oil used in the present invention melts and becomes fluid is preferably 45°C or lower, more preferably 20 to 40°C.

In the skin topical preparation of the present invention, the content of the Nannochloropsis-derived oil is preferably 0.01 to 35% by mass, and more preferably 0.1 to 25% by mass, of the total composition from the viewpoints of preventing precipitation of the Nannochloropsis-derived oil, improving storage stability, improving spreadability upon application, and reducing stickiness such as an oily feel.

When the skin topical preparation of the present invention is a non-aqueous oil preparation, the content of the Nannochloropsis-derived oil in the total composition is preferably 0.1 to 35% by mass, more preferably 1 to 33% by mass, and even more preferably 8 to 25% by mass.

The skin external preparation of the present invention can be made into an emulsified preparation by using a Nannochloropsis-derived oil together with water and a surfactant.
When the skin topical preparation of the present invention is an emulsion preparation, the content of the Nannochloropsis-derived oil is preferably 0.01 to 20% by mass, more preferably 0.02 to 10% by mass, even more preferably 0.03 to 5% by mass, and even more preferably 0.04 to 1% by mass, of the total composition.

As the surfactant, an ionic surfactant or a nonionic surfactant can be used.
Examples of nonionic surfactants include polyoxyethylene hydrogenated castor oil, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, polyoxyethylene alkanol ether, polyglycerin fatty acid ester, sucrose fatty acid ester, polyoxyethylene sorbit beeswax, glycolipids, etc. Among these, from the viewpoint of preventing the precipitation of the oil agent derived from Nannochloropsis, improving storage stability, improving spreadability at the time of application, and reducing stickiness such as oily feeling, it is preferable to contain one or more selected from polyoxyethylene hydrogenated castor oil, polyoxyethylene alkyl ether, and polyoxyethylene fatty acid ester, more preferably to contain one or more selected from polyoxyethylene hydrogenated castor oil and polyoxyethylene alkyl ether, and even more preferably to contain polyoxyethylene hydrogenated castor oil.
Examples of the ionic surfactant include hydrogenated soybean phospholipid, egg yolk lecithin, acyl glutamate, sodium surfactin, and acyl sulfate.

When the topical skin preparation of the present invention is an oil-in-water emulsion preparation, it is preferable to use a nonionic surfactant. The HLB of the nonionic surfactant is preferably 9 to 18, and from the viewpoint of causing a change in the feel of the cosmetic preparation during application, an HLB of 11 to 16 is more preferable, and an HLB of 12 to 15 is even more preferable.
When the skin topical preparation of the present invention is a water-in-oil type emulsion preparation, it is preferable to use a nonionic surfactant, the HLB of which is preferably 1 to 9, more preferably 2 to 8, and even more preferably 3 to 7.

Here, HLB (Hydrophilic-Lipophilic Balance) indicates the molecular weight of the hydrophilic group portion in the total molecular weight of the surfactant, and is calculated by Griffin's formula. When a surfactant is composed of two or more nonionic surfactants, the HLB of the mixed surfactant is calculated as follows. The HLB of the mixed surfactant (mixed) is the phase arithmetic average of the HLB values of the individual nonionic surfactants based on their blending ratio.
Mixed HLB = Σ(HLBx × Wx)/ΣWx
HLBx indicates the HLB value of nonionic surfactant X.
Wx represents the mass (g) of the nonionic surfactant X having the HLBx value.

One or more types of surfactants can be used in combination, and the content is preferably 0.05 to 6 mass% of the total composition, more preferably 0.1 to 5 mass%, even more preferably 0.3 to 4 mass%, and even more preferably 0.5 to 3.5 mass%, from the viewpoints of preventing precipitation of the oil derived from Nannochloropsis, improving storage stability, improving spreadability during application, and reducing stickiness such as oiliness.

When the topical skin preparation of the present invention is an emulsion preparation, the water content is preferably 20 to 99% by mass, more preferably 35 to 98% by mass, of the total composition.

When the topical skin preparation of the present invention is formulated as an emulsion preparation, it may further contain a polyhydric alcohol, which can improve spreadability upon application and reduce stickiness such as oily feeling.
The polyhydric alcohol is a compound having two or more hydroxyl groups in the molecule, and any of those commonly used in external skin preparations may be used.
Examples of dihydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, butylene glycol, and propanediol. Examples of trihydric alcohols include glycerin and trimethylolpropane. Examples of tetrahydric alcohols include diglycerin and erythritol. Examples of polyhydric alcohols having a valence of five or more include polyglycerin such as triglycerin; sugars and sugar alcohols such as glucose, maltose, maltose, sucrose, xylitol, sorbitol, malbitol, polyoxyethylene methyl glucoside, polyoxyethylene ethyl glucoside, and polyoxyethylene propylene glucoside.

One or more types of polyhydric alcohols can be used in combination. The content is preferably 0.5 to 50% by mass, more preferably 1 to 40% by mass, and even more preferably 2 to 30% by mass in the total composition, from the viewpoint of improving spreadability during application and reducing stickiness such as oiliness.

The topical skin preparation of the present invention may further contain a thickener, which prevents the oil derived from Nannochloropsis from precipitating, improves storage stability, improves spreadability upon application, and reduces stickiness such as an oily feel.
The thickener increases the viscosity of the topical skin preparation by swelling in the continuous phase, water or oil, and may be any of those commonly used in topical skin preparations.
Examples of thickeners include polysaccharides such as xanthan gum, carrageenan, and Tremella fuciformis polysaccharide; modified polysaccharides such as carboxymethylated glucan, hydroxypropylmethylcellulose, and ethylcellulose; and synthetic polymers such as carboxyvinyl polymers, acyl-modified carboxyvinyl polymers, and sodium polyacrylate.

As the thickener, it is preferable to contain xanthan gum, from the viewpoints of preventing the precipitation of the Nannochloropsis-derived oil, improving storage stability, improving spreadability upon application, and reducing stickiness such as an oily feel.
The content of the thickener is preferably 0.01 to 1 mass % of the total composition, more preferably 0.05 to 0.7 mass %, and even more preferably 0.1 to 0.3 mass %, from the viewpoints of preventing precipitation of the Nannochloropsis-derived oil, improving storage stability, improving spreadability upon application, and reducing stickiness such as oily feeling.

The topical skin preparation of the present invention may further contain, in addition to the Nannochloropsis-derived oil, an oil that is liquid at 25°C. This is preferable from the standpoint of preventing the Nannochloropsis-derived oil from precipitating, improving storage stability, improving spreadability upon application, reducing stickiness such as an oily feel, and from the standpoint of reducing energy consumption and simplifying the manufacturing process.
The term "liquid" refers to something that has fluidity, and includes a paste-like state.
The oily agents that are liquid at 25° C. include those commonly used in external skin preparations, such as hydrocarbon oils, ester oils, ether oils, silicone oils, and higher fatty acids.

Examples of the hydrocarbon oil include squalane, liquid paraffin, liquid isoparaffin, light liquid isoparaffin, heavy liquid isoparaffin, and α-olefin oligomers.
The hydrocarbon oil preferably contains one or more selected from squalane and α-olefin oligomers, and more preferably contains squalane.

Ester oils include monoester oils, diester oils, triester oils and tetraester oils.
Examples of monoester oils include monoesters of aliphatic or aromatic monocarboxylic or dicarboxylic acids having 2 to 24 carbon atoms. Specific examples include cetyl 2-ethylhexanoate, cetyl octanoate, isononyl isononanoate, isotridecyl isononanoate, hexyl laurate, isopropyl myristate, octyldodecyl myristate, myristyl myristate, 2-hexyldecyl myristate, isopropyl palmitate, octyldodecyl palmitate, and the like. Examples of the isocetyl oleate, isodecyl benzoate, octyl methoxycinnamate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, lanolin acetate, 2-ethylhexyl succinate, 2-hexyldecyl adipate, alkyl benzoate (C12 to C15), ethylhexyl methoxycinnamate, and jojoba oil.
The monoester oil preferably contains one or more selected from ethylhexyl methoxycinnamate and jojoba oil, and more preferably contains jojoba oil.

Diester oils include diesters of dicarboxylic acids having 3 to 18 carbon atoms, difatty acid esters of polyhydric alcohols, etc., and specific examples include propylene glycol dicaprylate, neopentyl glycol dicaprate, glycol distearate, propylene glycol diisostearate, glyceryl diisostearate, glyceryl monomyristate monoisostearate, glycerin di-2-heptylundecanoate, di-2-ethylhexyl succinate, diisopropyl sebacate, diisostearyl malate, ethylene glycol di-2-ethylhexanoate, diisobutyl adipate, di-2-heptylundecyl adipate, di-2-ethylhexyl sebacate, etc.

Examples of triester oils include tri-fatty acid esters of trivalent or higher polyhydric alcohols. Specific examples of such oils include glycerin triisopalmitate, glycerin tri-2-heptylundecanoate, trimethylolpropane triethylhexanoate, trimethylolpropane trioctanoate, tri(caprylic/capric acid)glycerin, trioleate, glycerin tri-2-ethylhexanoate, and glycerin triisostearate, as well as vegetable oils such as olive oil, macadamia nut oil, meadowfoam oil, castor oil, safflower oil, sunflower oil, avocado oil, canola oil, apricot kernel oil, rice germ oil, and rice bran oil.
The triester oil preferably contains one or more types selected from vegetable oils, more preferably contains one or more types selected from olive oil and macadamia nut oil, and even more preferably contains olive oil.

Tetraester oils include tetra fatty acid esters of polyhydric alcohols with 4 or more valences, specifically pentaerythritol tetra (behenic acid/benzoic acid/ethylhexanoic acid), pentaerythritol tetraethylhexanoate, pentaerythritol tetraoctanoate, and pentaerythritol tetra 2-ethylhexanoate.

Ether oils include dialkyl ethers, specifically dihexyl ether, dicaprylyl ether, cetyl-1,3-dimethylbutyl ether, etc.

Examples of silicone oils include volatile and non-volatile linear dimethylpolysiloxanes such as dimethylpolysiloxane (1 cs), dimethylpolysiloxane (1.5 cs), dimethylpolysiloxane (2 cs), dimethylpolysiloxane (6 cs), dimethylpolysiloxane (20 cs), and dimethylpolysiloxane (100 cs); branched siloxanes such as methyltrimethicone, tris(trimethylsilyl)methylsilane, and tetrakis(trimethylsilyl)silane; cyclic dimethylsiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane; methylphenylpolysiloxanes such as crosslinked methylpolysiloxane, net-type methylpolysiloxane, methyltrimethicone, and diphenylsiloxyphenyl trimethicone; and higher alcohol-modified organopolysiloxanes.
The silicone oil preferably contains one or more selected from linear dimethylpolysiloxane and methylphenylpolysiloxane, more preferably contains one or more selected from non-volatile linear dimethylpolysiloxane and methylphenylpolysiloxane, and even more preferably contains methylphenylpolysiloxane.

Higher fatty acids include oleic acid, isostearic acid, undecylenic acid, etc.

As for the oil agent that is liquid at 25°C, from the viewpoint of making the Nannochloropsis-derived oil agent easily soluble during production, preventing the Nannochloropsis-derived oil agent from precipitating, improving storage stability, improving spreadability during application, and reducing stickiness such as oiliness, it is preferable to include one or more oils selected from hydrocarbon oils, ester oils, ether oils, and silicone oils, more preferably to include hydrocarbon oils, ester oils, and silicone oils, even more preferably to include one or more oils selected from hydrocarbon oils, monoester oils, triester oils, and silicone oils, even more preferably to include one or more oils selected from squalane, ethylhexyl methoxycinnamate, olive oil, macadamia nut oil, jojoba oil, and methylphenylpolysiloxane, and particularly preferably to include one or more oils selected from squalane, olive oil, jojoba oil, and methylphenylpolysiloxane.

The content of the oil agent that is liquid at 25°C is preferably 0.1 to 95 mass% of the total composition, more preferably 0.5 to 80 mass%, and even more preferably 1 to 75 mass%, from the viewpoints of preventing precipitation of the oil agent derived from Nannochloropsis, improving storage stability, improving spreadability at the time of application, and reducing stickiness such as oily feeling.
When the topical skin preparation of the present invention is a non-aqueous oil preparation, the content of the oil that is liquid at 25°C is preferably 50 to 95 mass% of the total composition, more preferably 60 to 93 mass%, and even more preferably 85 to 92 mass%.
When the topical skin preparation of the present invention is an emulsion preparation, the content of the oil agent that is liquid at 25° C. is preferably 0.1 to 80% by mass, more preferably 0.5 to 78% by mass, and even more preferably 1 to 75% by mass, of the total composition.

In addition to the above-mentioned components, the skin topical preparation of the present invention may contain components that are commonly used in skin topical preparations, such as oily components other than those mentioned above, monohydric alcohols such as ethanol, preservatives, antioxidants, pigments, pH adjusters, fragrances, plant extracts, colorants, powders, UV absorbers, moisturizers, blood circulation promoters, cooling agents, antiperspirants, disinfectants, skin activators, etc.

The topical skin preparation of the present invention can be manufactured by a conventional method. For example, it can be manufactured by appropriately mixing the specified components, and can be manufactured by uniformly mixing and dispersing all the components, regardless of the order of mixing. In particular, it can be prepared by low-energy manufacturing in an environment of 40°C or less, where the components are stirred with little mechanical force.

The topical skin preparation of the present invention can be used as a cosmetic, a medicinal cosmetic that is a quasi-drug, a pharmaceutical, etc., and is suitable as a cosmetic, and is more preferable as a skin care cosmetic.

The skin topical preparation of the present invention may be applied in the form of a solubilized preparation, an emulsion preparation, an oil preparation, a balm preparation, etc., preferably an emulsion preparation or an oil preparation, more preferably an oil preparation. The oil preparation is preferably a non-aqueous system, and in the non-aqueous system, the content of aqueous components in the total composition is preferably 1 mass % or less, more preferably 0.5 mass % or less, even more preferably 0.1 mass % or less, and even more preferably substantially free.

Production Example 1
(1) Cultivation, recovery and pretreatment of Nannochloropsis oceanica NIES2145 strain:
Nannochloropsis oceanica NIES2145 strain was cultured in f/2 liquid medium (75 mg _NaNO3 , ₆ mg NaH2PO4.2H2O, 0.5 μg vitamin _B12 , 0.5 μg biotin, 100 μg thiamine, 10 mg Na2SiO3.9H2O, 4.4 mg _Na2EDTA.2H2O , 3.16 mg _FeCl3.6H2O , ₁₂ μg FeCl3.6H2O, ₂₁ μg ZnSO4.7H2O, 180 μg _{MnCl2.4H2O, 7} μg CuSO4.5H2O, ₇ μg _Na2MoO4.2H2O , ₁₀ μg ZnSO4.7H2O, 180 μg MnCl2.4H2O, 10 μg CuSO4.5H2O, 10 μg Na2MoO4.2H2O, 10 _μg Na2SiO3.9H2O _{, 10 μg} Na2SiO3.9H2O, 10 μg Na2EDTA.2 ...SO4.7H2O, ₁₀ μg _Na2SO4.5H2O , ₁₀ μg Na2SO4.5H2O _{, 10 μg Na2SO4.5H2O, 10 μg Na2SO4.5H2O, 10 μg Na2SO4.5H2O} , ₁ The incubation was carried out in an artificial weather machine under the conditions of a temperature of 25°C, a carbon dioxide concentration of 0.3%, a 12-hour light-dark cycle, 120 rpm permeation, and a light intensity of about 300 μmol photon/m ² /s using 1 L of 1000 ml of water and 1 L of artificial seawater. The culture solution cultured for 2 weeks under the above conditions was used as a pre-culture solution. The main culture was cultured for 3 weeks using a culture solution 10 times the amount of the pre-culture solution, and the obtained culture solution was used as an oil and fat extraction sample.
The culture medium obtained above was centrifuged (9000 rpm, 20 minutes) to recover the algal bodies. The recovered algal bodies were dried at 50° C., and then the cells were crushed using an electric mill for pretreatment.

(2) Preparation of crude oil:
The treated algae body obtained in (1) was added with 20 times the amount (weight ratio) of hexane and thoroughly stirred to perform hexane extraction. The hexane solution was subjected to suction filtration to separate the algae body, and the solvent was distilled using a rotary evaporator to recover the oil. The obtained oil was used as Nannochloropsis-derived extracted oil (crude oil).

(3) Refining of crude oil:
Phosphoric acid (2% relative to oil) was added to the crude oil obtained in (2), and degumming was performed by vigorously stirring at 70° C. for 30 minutes. Then, NaOH (7% relative to oil) was added, and deoxidization was performed by vigorously stirring at 70° C. for 30 minutes. The gum was separated by centrifugation (40° C., 8000 rpm, 30 minutes), and the degummed oil was collected.
Distilled water (10% of oil) was added to the degummed oil and the mixture was stirred vigorously at 70° C. for 30 minutes, and then the aqueous layer separated by centrifugation (40° C., 8000 rpm, 30 minutes) was removed and the mixture was washed with water.
The oil after washing was dehydrated at 70°C and 90 hpa for 30 minutes. After dehydration, activated clay (3% to oil) was added and strongly stirred at 100°C and 90 hpa for 30 minutes to decolorize. After the reaction, the activated clay and the oil were separated by filtration to obtain a decolorized oil. Steam (3%/h) was blown into the decolorized oil and distilled to deodorize. The reaction was carried out at 210°C and 150 pa with strong stirring for 1 hour to obtain a Nannochloropsis-derived oil (refined oil).

Test Example The state and stability (discoloration) at each temperature were evaluated for each component shown in Table 1. The results are shown in Table 1.

(1) Appearance at each temperature:
1 g of each component was placed in a glass bottle, the lid was closed, and the bottle was placed in a thermostatic bath at 20° C., 30° C., 40° C., or 45° C. After 4 hours, the appearance (presence or absence of precipitate) was visually observed.

(2) Stability (discoloration):
50 g of each component was placed in a glass bottle, the lid was closed, and the bottle was placed in a thermostatic bath at 45° C. After one month, the bottle was taken out and left at 25° C. for 6 hours, and then the appearance (presence or absence of discoloration) was visually observed.

The degummed and decolorized Nannochloropsis-derived oil did not discolor at high temperatures and had excellent stability.
On the other hand, the non-degummed and non-decolorized Nannochloropsis-derived oil solution was found to discolor at high temperatures and was therefore less stable.

Examples 1 to 7, Comparative Examples 1 to 13
Skin topical preparations (oil beauty essences) having the compositions shown in Table 2 were prepared and evaluated for spreadability upon application, lack of oiliness (stickiness), and stability (precipitation, separation into two phases, discoloration). The results are also shown in Table 2.

(Production method)
All the ingredients were mixed at 40°C and cooled to 32°C with stirring to obtain an external skin preparation (oil beauty essence).

(Evaluation method)
(1) Spreadability and lack of oiliness (stickiness) when applied:
A specialist appraiser applied approximately 0.4 g of each skin preparation to the skin and evaluated the spreadability upon application and the lack of oiliness (stickiness) after absorption on the skin using the following four-level scale.

(1-1) Elongation upon application:
4: Good stretch.
3: Slightly good stretch.
2: The stretch is somewhat poor.
1: Elongation is clearly poor.

(1-2) Lack of oily (sticky) feeling after application to skin:
4: No oily feeling.
3: Almost no oily feeling.
2: Feels oily.
1: Feels very oily

(2) Stability:
50 g of each topical skin preparation was placed in a glass bottle, the lid was closed, and the bottle was stored at 25° C. for one month. After that, the appearance (precipitation/separation into two phases) and the appearance (discoloration) were visually evaluated according to the following four-point scale.

(2-1) Stability (precipitation/two-phase separation):
4: There is absolutely no precipitation and no separation of the liquid into two phases.
3: There is very little precipitation, but the liquid does not separate into two phases.
2: Clear precipitation or separation into two liquid phases is observed.
1: Precipitation occurred and the entire composition was solidified.

(2-2) Stability (discoloration):
4: No change from the start of saving.
3: There is a slight change in color from the beginning of storage.
2: There is a slight change in color from the start of storage.
1: There is a clear change in color from the start of storage.

From the results in Table 2, all of the topical skin preparations in the Examples had a good feel and excellent stability. In contrast, when a Nannochloropsis-derived oil (crude oil) that had not been degummed or bleached, or a water-soluble Nannochloropsis extract was used, a stable topical skin preparation could not be obtained. In addition, when other solid fats such as shea butter were used, a topical skin preparation with good stability and feel could not be obtained.

Examples 8 to 12, Comparative Examples 14 to 16
Oil-in-water emulsion cosmetics (oil-in-water emulsion serums) having the compositions shown in Table 3 were produced, and the spreadability upon application, lack of oiliness (stickiness), and stability (precipitation/two-phase separation) were evaluated in the same manner as in Examples 1 to 7. The results are also shown in Table 3.

(Production method)
Phase A and Phase B were each heated and stirred at 40°C, then Phase B was added to Phase A and mixed, and cooled to 25°C with stirring to obtain an oil-in-water emulsion cosmetic preparation (oil-in-water emulsion beauty serum).

The results in Table 3 show that all of the oil-in-water emulsion cosmetics of the Examples had a good feel and excellent stability. In contrast, when other solid fats such as shea butter were used, it was not possible to obtain a cosmetic that was good in terms of spreadability upon application, lack of oiliness (stickiness), and stability (precipitation/separation into two phases).

Example 13
Water-in-oil emulsion cosmetics (water-in-oil emulsion serums) having the compositions shown in Table 4 were produced in the same manner as in Examples 8 to 12, and evaluated for spreadability upon application, lack of oiliness (stickiness), and stability (precipitation/two-phase separation). The results are also shown in Table 4.

The results in Table 4 show that the obtained water-in-oil emulsion cosmetic (water-in-oil emulsion serum) had excellent spreadability when applied, no oily feeling (no stickiness), and stability (no precipitation or separation into two phases).

Prescription Examples 1 to 10
External skin preparations having the compositions shown in Tables 5 to 14 were prepared.
All of the obtained skin preparations for external use spread well when applied, were not oily (sticky), did not precipitate or separate into two phases, and were excellent in stability.

*1: ECOLANO CLE-NH, manufactured by Nippon Fine Chemicals Co., Ltd.
*2: NIKKOL Sugar Squalane, manufactured by Nippon Surfactant Co., Ltd.
*3: Croda Japan Co., Ltd., Cropure OL-LQ-(JP),
* 4: Dow Toray, DOWSIL FZ-209 (-G),
*5: Nippon Fine Chemical Co., Ltd., PRESOMER RK-2)
*6: PLANDOOL-MAS, manufactured by Nippon Fine Chemicals Co., Ltd.
* 7: Hyaluronic acid FCH (FCH-SU), manufactured by Kikkoman Biochemifa Corporation
*8: Immunotect B, manufactured by Ichimaru Pharcos,
* 9: Dismutin-JPF, manufactured by DSM Nutritional Products,
*10: Surfmellow-BBG (III), manufactured by Toyobo Co., Ltd.

Claims (3)

A topical skin preparation containing an oil derived from degummed and decolorized Nannochloropsis oceanica. The topical skin preparation according to claim 1, wherein Nannochloropsis oceanica is cultivated in a photoreactor. The topical skin preparation according to claim 1 or 2 further contains an oil that is liquid at 25°C.