JP2964183B2 - External preparation for skin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external preparation for skin, and more particularly to an external preparation for skin which normalizes keratinization of the epidermis.

[0002]

2. Description of the Related Art The skin has an appearance and appearance.
It has an important function as a boundary wall between a living body and the outside world. The skin intrinsically prevents the loss of water and various biological components from tissues, controls the evaporation of water on the body surface, and maintains the body temperature constantly, while the physical and chemical stimuli (temperature , Humidity, ultraviolet rays, and various chemical substances). Thus, the skin plays a very important role in the vital activity of living organisms due to its physiological functions.

[0003] However, changes in the external environment or changes in physiological functions (due to diseases or aging) cause abnormalities in the skin tissue, often leading to epidermal thickening and parakeratosis due to enhanced skin turnover. You. Such interactions of internal and external factors result in various vulnerable skin problems such as dry or greasy skin and dandruff.

[0004] In order to improve such skin troubles and maintain healthy skin, such skin troubles must be eliminated or eliminated by adding or applying certain components, or by removing or reducing certain substances or events. Can be considered. Conventionally, the main methods of preventing and improving these skin problems are a method of applying a synthetic or natural moisturizing component to prevent the skin from drying and increasing the moisturizing ability of the skin, or applying a blood circulation promoting agent to the blood circulation of the skin. Attempts have been made to improve by promoting effect.

[0005]

However, the above-mentioned conventional methods not only evaluate the effectiveness of preventing and improving various skin problems, but also maintain the effect, and furthermore, the stability and safety of the drug. There are a number of problems in this regard. In particular, since the conventional method generally involves replenishing moisture or moisturizing components on the surface of the stratum corneum,
Its effect or effect is only temporary, and a permanent improvement effect cannot be expected. Therefore, a prompt solution to this problem has been desired.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above circumstances, and have found that sphingosines, which are physiologically active components present in the epidermis, enhance the turnover of the epidermis caused by ultraviolet rays and various components. (Epidermal hyperplasia, parakeratosis, abnormalities in epidermal lipid metabolism, etc.) and found to have the effect of normalizing epidermal keratinization, and completed the present invention.

That is, the present invention relates to dihydrosphingosine, phytosphingosine, dehydrosphingosine,
Dehydrophytosphingosine, sphingadienin,
It is intended to provide a skin external preparation characterized by containing sphingosines selected from these N-methyl or N, N-dimethyl forms, N-methylsphingosine and N, N-dimethylsphingosine.

[0008] The sphingosines used in the present invention include:
The carbon chain preferably has 12 to 24 carbon atoms. These sphingosines can be obtained by using a natural (D (+)) optically active substance or a non-naturally occurring (L (+)) optically active substance, and furthermore by using a natural or non-natural type. May be used. The relative configuration of the above compound may be a natural configuration, another non-natural configuration, or a mixture thereof.

The structural formula of sphingosines used in the present invention is shown below, taking as an example a compound having 18 carbon atoms.

[0010]

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Among the above sphingosines, those which exist in nature extract phospholipids / ceramides containing the respective compounds from an appropriate tissue (for example, bovine brain).
It is obtained by extraction with an organic solvent after hydrolysis.

Further, the Journal of the American Chemical Society (J. Am. Chem. So
c. 95, 4098 (1973), Journal of Lipid Research (J. Lipid Re).
s. 19, 250 (1978), Tetrahedron Letters.
29, 239 (1988), tetrahedron (T
etrahedron) 42, 5961 (1986)
Year)). In addition, as for these N-methyl form and N, N-dimethyl form, these sphingosines are used in biochemistry (Bioc).
Chemistry, Vol. 7, p. 2192 (1968) and the like, and can be synthesized by N-methylation.

The amount of the sphingosine compound in the skin preparation for external use is not particularly limited, but is usually 0.001 to 5% by weight (hereinafter referred to as%) of the total composition in the case of an emulsified skin external preparation. And particularly preferably 0.01 to 1%. In the case of an oily skin external preparation based on a liquid hydrocarbon such as squalane, the content is usually 0.01 to 10%, particularly 0.03%.
5 to 2% is preferred.

The external preparation for skin of the present invention comprises:
Various forms of use such as external preparations for cosmetics and cosmetics can be adopted.

Examples of the external preparation for medicated skin and the external preparation for skin for cosmetics include various ointments containing a medicinal ingredient. The ointment may be any of those based on an oily base and those based on an oil / water or water / oil type emulsified base. The oily base is not particularly limited and includes, for example, vegetable oil, animal oil, synthetic oil, fatty acid, and natural or synthetic glyceride.
The medicinal component is not particularly limited, and for example, an analgesic / inflammation agent, an antipruritic, a bactericidal disinfectant, an astringent, an emollient, a hormonal agent, and the like can be used as needed.

When used as cosmetics, oils, humectants, ultraviolet absorbers, alcohols, chelating agents, pH adjusters, preservatives, thickeners, pigments generally used as cosmetic ingredients are used. Flavors and the like can be arbitrarily combined and blended. As cosmetics, various uses and forms, for example, water / oil, oil / water emulsified cosmetics, creams,
It can be used as a cosmetic emulsion, lotion, oily cosmetics, lipstick, foundation, skin cleanser, hair tonic, hair styling agent, hair restorer, hair restorer and the like. The external preparation for skin of the present invention can be prepared into the above various forms by a conventional method.

[0017]

The external preparation for skin of the present invention has a remarkable inhibitory effect on parakeratosis, epidermal hyperplasia, abnormal lipid metabolism, etc. due to the influence of ultraviolet rays and various other factors. It restores function and contributes to maintaining homeostasis.

[0018]

EXAMPLES The present invention will be described below in detail with reference to examples, but it goes without saying that the present invention is not limited to these examples.

Example 1 Inhibitory effect of sphingosines on DNA synthesis of keratinocytes (1) Method a) Culture of human keratinocytes Epidermal keratinocytes are human normal keratin cells sold by Kurabo Industries, Ltd. Purified cells (trade name: Epipack) were purchased and used. The cells were maintained and passaged using a medium for human normal keratinocytes (trade name: K-GM) sold by the company. b) Measurement of DNA synthesis (thymidine incorporation measurement) Keratinocytes cultured in a proliferating state in a 24-well plate were used. First, the medium in each well was removed by suction, and 450 μl of K-GM to which no pituitary extract was added was added to replace the medium. Thereafter, sphingosines were added. Further, 0.2 μCi / ml [ ³ H] thymidine was added over time, followed by incubation for 4 hours. after that,
The supernatant is removed by suction, and washed three times with PBS (-).
μl of 2N NaOH was added. After incubation at 37 ° C. for 10 minutes, the same amount of 2N HCl was added to neutralize,
4 ml of ice-cooled 10% trichloroacetic acid was added and left for 30 minutes. After collecting the precipitate with a glass filter,
Washed three times with 3 ml of 0% trichloroacetic acid. After washing the filter once with 3 ml of ice-cold ethanol, the glass filter was air-dried and its radioactivity was measured with a liquid scintillation counter to calculate the amount of thymidine incorporated into the cells.

(2) Results The results are shown in FIG.

[0021] Figure 1 is dihydrosphingosine (2-amino-1,3-dodecanediol) to C _12, C ₁₂ dimethyl dihydrosphingosine [2- (dimethylamino)
1,3-dodecanediol], C ₂₀ dihydrosphingosine (2-amino-1,3-eicosanediol Sanji ol),
And C ₂₀ dimethyl dihydrosphingosine [2- (dimethylamino) -1,3-eicosanediol Sanji ol] (C _12, etc. are shown, the number of carbon atoms in the carbon chain), respectively 10 [mu] M (top), and 100 [mu] M (bottom) when added [ ³ H]
The thymidine incorporation rate (control%) is shown. In particular, when C ₁₂ dihydrosphingosine and C ₁₂ dimethyldihydrosphingosine were added at 100 μM each, a marked decrease in [ ³ H] thymidine incorporation was observed.

As described above, it was revealed that the rate of incorporation of thymidine was significantly reduced by the addition of sphingosines, that is, the DNA synthesis of human epidermal keratinocytes was significantly inhibited.

Example 2 Effect of sphingosines on transglutaminase activity of epidermal keratinocytes (1) Measurement of transglutaminase activity Keratinocytes cultured in a growth state in a 6-well plate were used. The medium in each well was removed by suction, and 2 ml of K-GM to which no pituitary extract was added was added to replace the medium.
Thereafter, sphingosines were added. 24 hours later,
After each well was washed three times with PBS (-), the cells were peeled and collected with a rubber policeman. The obtained cell suspension was centrifuged at 2,500 rpm for 10 minutes to collect a sediment. The buffer solution (a) [10 mM Tris-HCl was added to the sediment.
Buffer, 10 mM DTT, 0.5 mM EDTA;
pH 7.4], and sonicated twice by ultrasonication for 1 minute. 25,000 of the resulting suspension
After ultracentrifugation at rpm for 30 minutes, a supernatant was obtained. After dispensing a certain amount of the supernatant, each reaction solution [300 m
M Tris-HCl buffer, pH 8.1, 60 mM C
aCl ₂ 100 μl, 30 mM DTT 100 μl
1, 100 μm of distilled water containing 540 μg of dimethyl casein
1, 12 mM putrescine 50 μl, 2.5 μCi
[ ¹⁴ C] A solution obtained by mixing 50 μl of putrescine and 100 μl of distilled water] and incubated at 37 ° C. for 1 hour. Next, 600 μl of 10% trichloroacetic acid was added,
After allowing to stand for 30 minutes, the precipitate was collected using a 0.45 μm nitrocellulose membrane. After washing the membrane with 15 ml of 5% ice-cold trichloroacetic acid (containing 1% putrescine), the radioactivity on the membrane was calculated by a liquid scintillation counter.

(2) Results FIG. 2 shows the transglutaminase activity (control%) when sphingosine and dimethyl sphingosine were added at 10 μM, respectively. The addition of sphingosines increased the transglutaminase activity of the epidermal keratinocytes by 1.8 to 2.2 times as compared to the control. Therefore, it was revealed that sphingosines have keratinocyte differentiation-inducing activity.

Example 3 Inhibitory effect of sphingosines on epidermal thickening (1) Method After shaving the auricle of 25 4 to 6 week old white guinea pigs, ultraviolet rays (UVB: 2 to 3 MED) were irradiated. Immediately after irradiation, a squalane solution containing 0.05% sphingosine was applied once a day in 50 μl portions for one week. One week later, the pinna of the guinea pig was excised, and a section of skin tissue was prepared. Each tissue sample was photographed under a microscope, and the thickness of the epidermis was measured to examine the inhibitory effect of each evaluation sample on thickening due to ultraviolet rays. (2) Results FIG. 3 shows the skin thickness obtained by ultraviolet irradiation (control) and ultraviolet irradiation + sphingosine addition.
Sphingosines were found to suppress epidermal thickening.

[0026]

Example 5 Production of O / W cream (% by weight) (1) Polyoxyethylene (10) hydrogenated castor oil 1.0 (2) Sorbitan monostearate 0.5 (3) Sodium stearoylmethyltaurine 5 (4) Cetostearyl alcohol 2.0 (5) Stearic acid 1.8 (6) Dimethyl sphingosine 0.2 (7) Cholesterol 1.5 (8) Cholesteryl isostearate 1.0 (9) Neopentyl dicaprate Glycol 8.0 (10) Methylpolysiloxane 5.0 (11) Glycerin 5.0 (12) Purified water balance (1) to (10) are heated to 80 ° C. to dissolve, and (11) to (12) was added and mixed uniformly to prepare an O / W cream.

[0028] Production Example 6 Moisturizing Sunscreen cream (wt%) (1) C ₁₂ dihydrosphingosine (C _12; number of carbon atoms in the carbon chain) 0.2 (2) Silicone-coated zinc oxide 7.0 (3) p 2-ethylhexyl methoxycinnamate 3.0 (4) cholesteryl isostearate 1.0 (5) polyether-modified silicone 2.0 (6) methylpolysiloxane 5.0 (7) cyclic silicone 15.0 (8) Magnesium sulfate 1.0 (9) Glycerin 5.0 (10) Purified water balance Heat and dissolve (1) to (7) at 80 ° C, add (8) to (10) to this, and homogenize The mixture was mixed to prepare a moisturizing sunscreen cream.

[0029]

The skin external preparations obtained in Examples 5 and 6 are as follows:
Each had an inhibitory effect on parakeratosis, epidermal hyperplasia, abnormal lipid metabolism, etc., and contributed to the recovery of normal skin function and maintenance of homeostasis.

[Brief description of the drawings]

FIG. 1 is a graph showing a change in the thymidine incorporation rate by addition of sphingosines in Example 1.

FIG. 2 is a graph showing a change in transglutaminase activity caused by addition of sphingosines in Example 2.

FIG. 3 is a graph showing changes in skin thickness due to ultraviolet irradiation and addition of sphingosines in Example 3.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI A61K 31/13 A61K 31/13 (72) Inventor Yukihiro Ohashi 30-19 Koshidocho, Utsunomiya-shi, Tochigi Prefecture (72) Inventor Akira Kawamata Tochigi (57) References JP-A-4-193815 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) A61K 7/48 A61K 7 / 00 A61K 9/06 A61K 31/13

Claims (1)

(57) [Claims] 1. A dihydrosphingosine, phytosphingosine, dehydrosphingosine, dehydrophytosphingosine, sphingienin, N-methyl or N, N-dimethyl form thereof, N-methylsphingosine and N, N-dimethylsphingosine. An external preparation for skin characterized by containing sphingosines.