Topical skin preparation

Abstract

The present invention addresses the problem of providing a novel topical skin preparation. The present invention provides a topical skin preparation or the like containing glycylglycine and retinol acetate.

Description

Topical skin preparations

[0001] This invention relates to a topical skin preparation.

[0002] Topical skin preparations contain various ingredients depending on the desired effect, such as improving or maintaining the condition of the skin. For example, Patent Document 1 lists glycylglycine as an ingredient that has a pore-reducing effect.

[0003] Patent No. 5241058

[0004] On the other hand, the inventors have discovered that by combining multiple components, it is possible to achieve excellent skin-improving effects that are difficult to obtain with each component alone.

[0005] This invention has been made in view of the above circumstances, and aims to provide a novel topical skin preparation.

[0006] As a result of the inventors' research, they discovered that the combination of glycylglycine and retinol acetate significantly promotes TGF-β2 gene expression, leading to the completion of the present invention. More specifically, the present invention provides the following:

[0007] (1) A topical skin preparation comprising glycylglycine and retinol acetate.

[0008] (2) The topical skin preparation according to (1), wherein the concentration ratio of glycylglycine to retinol acetate (glycylglycine / retinol acetate) is 0.2 to 200.

[0009] (3) The topical skin preparation according to (1) or (2), wherein the glycylglycine content is 0.01 to 3.00% by mass relative to the topical skin preparation.

[0010] (4) The topical skin preparation according to any one of (1) to (3), wherein the content of retinol acetate is 0.0001 to 0.50% by mass relative to the topical skin preparation.

[0011] (5) A topical skin preparation according to any one of (1) to (4), which is a TGF-β2 gene expression promoting agent.

[0012] (6) A topical skin preparation described in any of (1) to (4), which is an agent for improving the skin barrier function.

[0013] (7) A topical skin preparation described in any of (1) to (4), which is an agent for improving epidermal turnover.

[0014] According to the present invention, a novel topical skin preparation is provided.

[0015] This figure shows the results of the effects on TGF-β2 gene expression in the examples.

[0016] The following describes embodiments of the present invention, but the present invention is not limited thereto.

[0017] (1) Topical skin preparation In one embodiment of the present invention, the topical skin preparation of the present invention comprises glycylglycine and retinol acetate.

[0018] The inventors explored combinations of various components that can be incorporated into topical skin preparations to find those that exhibit beneficial interactions. They focused on TGF-β2 gene expression as one of the indicators for this exploration. Promoting TGF-β2 gene expression can lead to improved epidermal turnover, improved skin barrier function, and enhanced wound healing.

[0019] As a result, we discovered the unexpected finding that glycylglycine alone did not promote TGF-β2 gene expression, but when combined with retinol acetate, it exhibited a remarkable TGF-β2 gene expression-promoting effect, thus completing the present invention.

[0020] Note that "TGF-β2" is an abbreviation for "transforming growth factor-β2".

[0021] The composition of the topical skin preparation of the present invention will be described in detail below.

[0022] (1-1) Glycylglycine (CAS registration number: 556-50-3, chemical formula: C) ４ H ８ N ２ O ３Glycylglycine is a type of peptide and has been reported to have pore-reducing effects, etc. The inventors of this invention have made the surprising discovery that glycylglycine alone does not have a TGF-β2 gene expression promoting effect, but when combined with retinol acetate, it exhibits a remarkable TGF-β2 gene expression promoting effect.

[0023] The glycylglycine content in the topical skin preparation of the present invention is not particularly limited and can be adjusted as appropriate depending on the effect to be obtained. In a preferred embodiment of the present invention, the lower limit of the glycylglycine content is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.30% by mass or more, and even more preferably 1.00% by mass or more, relative to the topical skin preparation. In a preferred embodiment of the present invention, the upper limit of the glycylglycine content is preferably 3.00% by mass or less, more preferably 2.50% by mass or less, and even more preferably 2.00% by mass or less, relative to the topical skin preparation.

[0024] The amount of glycylglycine contained in topical skin preparations is determined by conventional methods such as high-performance liquid chromatography (HPLC).

[0025] (1-2) Retinyl acetate Retinyl acetate (CAS registration number: 127-47-9, chemical formula: C ２２ H ３２ O ２ Retinol acetate is a form of vitamin A and has been reported to have effects such as promoting cell proliferation. The inventors of this invention have confirmed that retinol acetate alone has effects such as promoting TGF-β2 gene expression. However, they have found that the combination of glycylglycine and retinol acetate produces an even more remarkable effect in promoting TGF-β2 gene expression.

[0026] The content of retinol acetate in the topical skin preparation of the present invention is not particularly limited and can be adjusted as appropriate depending on the effect to be obtained. In a preferred embodiment of the present invention, the lower limit of the retinol acetate content is preferably 0.0001% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.05% by mass or more, relative to the topical skin preparation. In a preferred embodiment of the present invention, the upper limit of the retinol acetate content is preferably 0.50% by mass or less, more preferably 0.10% by mass or less, relative to the topical skin preparation.

[0027] The amount of retinol acetate contained in topical skin preparations is determined by conventional methods such as high-performance liquid chromatography (HPLC).

[0028] (1-3) Ratio of glycylglycine and retinol acetate The ratio of glycylglycine and retinol acetate to be incorporated into topical skin preparations is not particularly limited and can be set as appropriate depending on the effect to be obtained.

[0029] From the viewpoint of more easily achieving the effects of the present invention, it is preferable that the concentration of glycylglycine in the topical skin preparation is higher than the concentration of retinol acetate. In a preferred embodiment of the present invention, the concentration ratio of glycylglycine to retinol acetate (glycylglycine / retinol acetate) in the topical skin preparation is preferably 0.2 to 200, more preferably 2 to 150, and most preferably 20 to 120.

[0030] (1-4) Other components The topical skin preparation may contain, or may not contain, components other than glycylglycine and retinol acetate, as long as they do not inhibit the effects of the present invention.

[0031] Other components besides glycylglycine and retinol acetate can be appropriately selected depending on the form of the topical skin preparation and include any components that can be incorporated into the topical skin preparation. Examples of such components include base components, solvents, fragrances, antioxidants, excipients, colorants, surfactants, preservatives, and pH adjusters.

[0032] (1-5) Topical skin preparations In the present invention, "topical skin preparations" include any preparations that are applied to the surface of the skin of a living organism (applied, patched, sprayed, etc.).

[0033] The site to which the topical skin preparation is attached is not particularly limited, and examples thereof include sites where the epidermis is exposed (face, neck, hands, arms, legs, etc.).

[0034] The form of the topical skin preparation is not particularly limited, and examples thereof include the following: - Non-emulsified preparations (liquid preparations, etc.), emulsified preparations (oil-in-water type emulsified preparations, water-in-oil type emulsified preparations) - Solid preparations, liquid preparations, ointments, creams, sprays

[0035] The amount of use and frequency of use of the topical skin preparation are not particularly limited, and can be appropriately set according to the form of the topical skin preparation, the desired effect, etc.

[0036] (1-6) Method for producing a topical skin preparation The method for producing a topical skin preparation is not particularly limited, and any method according to the form of the topical skin preparation, etc. can be adopted.

[0037] (2) Agent for promoting TGF-β2 gene expression, agent for improving skin barrier function, and agent for improving epidermal turnover In a preferred embodiment of the present invention, the above-described topical skin preparation has an effect of promoting TGF-β2 gene expression. Therefore, the present invention includes an aspect in which the topical skin preparation is an agent for promoting TGF-β2 gene expression.

[0038] In the present invention, the "effect of promoting TGF-β2 gene expression" includes an increase in the TGF-β2 gene expression level by using the topical skin preparation of the present invention as compared with the case where it is not used. Whether the TGF-β2 gene expression has increased can be specified in an in vitro system (for example, the method shown in the examples). Further, when the topical skin preparation is applied to the skin of a living body, whether the effect of promoting TGF-β2 gene expression has increased can be indirectly determined, for example, by specifying whether the skin barrier function and epidermal turnover have been improved.

[0039] The effect of improving the skin barrier function can be determined based on, for example, the trans-epidermal water loss (TEWL). If a tendency for a decrease in the trans-epidermal water loss is observed, it can be determined that the skin barrier function has been improved.

[0040] The improvement effect of epidermal turnover can be evaluated by any conventionally known method based on the epidermal turnover time (the time from the start of division in the basal layer to the shedding of the stratum corneum). If the epidermal turnover time is shortened, it can be determined that the epidermal turnover has been improved.

[0041] From the above, the present invention also includes aspects in which the external preparation for skin is an agent for improving the skin barrier function or an agent for improving epidermal turnover.

[0042] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0043] <Test 1: Gene Expression Analysis Using Keratinocytes> The effects of glycylglycine and retinol acetate on gene expression in keratinocytes were examined by the following method.

[0044] (1) Preparation of Samples The following samples were prepared and subjected to the culture test described below. - Glycylglycine (manufactured by Yoneyama Pharmaceutical Co., Ltd.) - Retinol acetate (manufactured by BASF Japan Ltd.)

[0045] (2) Culture Test Keratinocytes (manufactured by Kurabo) were seeded in a 24-well plate at a density of 5.0 × 10 ４ cells / mL in the medium, and cultured at 37°C in a 5% CO ２ atmosphere for 48 hours. The medium used was "EpiLife-KG2" medium (manufactured by Kurabo).

[0046] Next, each sample was added to the above culture to reach a predetermined final concentration, and further cultured at 37°C in a 5% CO ２ atmosphere for 18 hours. The conditions for each sample added to the medium are as follows. - Cont (control): medium only - GG (glycylglycine): final concentration 0.02% by mass (200 ppm) - AA (retinol acetate): final concentration 0.0002% by mass (2 ppm) - GGAA (glycylglycine and retinol acetate): GG final concentration 0.02% by mass, AA final concentration 0.0002% by mass, concentration ratio (glycylglycine (=200) / retinol acetate (=2)) = 100

[0047] After culturing, cells were harvested from each culture using "RLT buffer" (Qiagen), and RNA was purified from the harvested cells using "RNeasy Mini Kit" (Qiagen). The purified RNA was sequenced using "Novaseq" (Illumina). Based on the sequencing data, the expression levels of transcript units were calculated using "DRAGEN Bio-IT Platform" (Illumina). Differential gene expression extraction and pathway analysis were performed on the obtained gene list using "iDEP.96" (South Dakota State University).

[0048] The Tukey-Kramer method was used for statistical analysis of the obtained results. In both methods, we determined whether or not there was a significant improvement compared to the control group.

[0049] (3) Results Figure 1 shows the results of the TGF-β2 gene expression analysis (the vertical axis represents TPM (transcripts per million)). TGF-β2 is involved in the differentiation of epidermal cells, and it is expected that the higher the expression level of the TGF-β gene, the better the epidermal turnover and the more the skin barrier function and wound healing effect will be enhanced. A 5% significance level was observed between "GG" and "AA", "GG" and "GGAA", and "AA" and "GGAA". From this, it was found that the combination of glycylglycine (GG) and retinol acetate (AA) has a synergistic effect in promoting TGF-β gene expression.

Claims

1. A topical skin preparation containing glycylglycine and retinol acetate.

2. The topical skin preparation according to claim 1, wherein the concentration ratio of glycylglycine to retinol acetate (glycylglycine / retinol acetate) is 0.2 to 200.

3. The topical skin preparation according to claim 1, wherein the content of glycylglycine is 0.01 to 3.00% by mass relative to the topical skin preparation.

4. The topical skin preparation according to claim 1, wherein the content of retinol acetate is 0.0001 to 0.50% by mass relative to the topical skin preparation.

5. A topical skin preparation according to any one of claims 1 to 4, which is a TGF-β2 gene expression promoting agent.

6. A topical skin preparation according to any one of claims 1 to 4, which is an agent for improving the skin barrier function.

7. A topical skin preparation according to any one of claims 1 to 4, which is an agent for improving epidermal turnover.

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