JP3385857B2 - Skin protective agent - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to suppressing skin irritation from the outside, in particular, suppressing the percutaneous absorption of a surfactant, and suppressing dermal intercellular lipids and natural moisturizing in the stratum corneum. Factors, elution of water in the stratum corneum
The present invention relates to a skin protective agent capable of effectively suppressing reduction. 2. Description of the Related Art The skin plays a role of a barrier that protects the inside of the body from the environment of the outside world. Natural moisturizing factor of the layer
It is important that there is sufficient water in the stratum corneum (izing factor: NMF). If these components are insufficient, the skin becomes rough. There are various external factors that cause such rough skin, and surfactants are particularly irritants to the skin. Surfactants are used not only in creams, lotions, body cleansers, shampoos, and rinses, but also in kitchen detergents, residential detergents, clothing detergents, softeners, and the like. Stimulation has been a problem in the past, and it has been proposed to use surfactants with low irritation as raw materials, or to use anionic, nonionic, amphoteric surfactants in combination, etc. It has also been proposed to incorporate tannic acid. [0003] However, even in these proposals,
It is difficult to sufficiently suppress the elution of lipids between stratum corneum and natural moisturizing factors in the stratum corneum and the reduction of water content in the stratum corneum by the use of surfactants, especially for people with rough skin and frequent use of shampoos. For heavy users such as hairdressers, irritation by surfactants is a serious problem. [0004] Therefore, there has been a method for effectively suppressing the elution or reduction of lipids between stratum corneum cells, natural moisturizing factors in the stratum corneum and water in the stratum corneum by an external stimulus such as the use of a surfactant. It was strongly requested. In addition, as a countermeasure against troubles on sensitive skin such as dry skin disease patients, infants, persons exposed to substances that irritate the skin such as disinfectants and disinfectants, at the same time as calming down troubles already occurring, It is important to protect the skin from irritation that causes skin troubles. The stratum corneum of the skin plays a role of protecting the inside of the body from the external environment.However, in order to fulfill its function, it is necessary to remove lipids between the stratum corneum such as cholesterol and moisture between the stratum corneum such as urocanic acid and pyrrolidone carboxylic acid. It is important that there be sufficient natural moisturizing factor (NMF) to retain. If these components are insufficient, the skin becomes rough. [0006] Anti-inflammatory agents have been used to treat such troubles, especially allergic and dry skin diseases. However, anti-inflammatory agents only suppress inflammation that has already occurred, and have a preventive effect. It is not recognized, and it is difficult to use regularly from the viewpoint of side effects. For this reason, conventionally, skin troubles have been prevented or reduced by supplementing oils and moisturizing components. However, oils and moisturizing components have no sufficient therapeutic effect on skin diseases. There is a need for a therapeutic agent that can effectively prevent and improve skin diseases. Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies in order to respond to the above demand, and as a result, the particle diameter is 1 to 1000 nm and the absolute value of the zeta potential is 3
A water-swellable clay mineral having a purity of 0 mV or more and a purity of 90% or more suppresses percutaneous absorption to external stimuli, further suppresses the elution of lipids between keratinocytes and natural moisturizing factors in the horny layer, and reduces the moisture in the horny layer. It has been found that it has an effect of suppressing a decrease in the amount, and particularly has an effect of preventing the above-mentioned adverse effects on the skin due to use of a surfactant. That is, conventionally, clay minerals have properties such as adsorptiveness, binding, suspending, swelling, film-forming properties, and viscosity increasing. Have been. When a clay mineral is blended in a cosmetic, the cosmetic is (1) non-sticky, has a smooth and refreshing feel, (2) stretches well on the skin surface, forms a film and adheres, (3) And (4) improving the stability of emulsions and suspensions, (5) improving the cleansing performance of lotions and shampoos, and (6) improving the washability with water and soap. It is known. That is, by blending the clay mineral, the liquid properties of the cosmetic can be changed, and the texture and finish after use can be improved. [0010] Furthermore, the water-swellable clay mineral imparts the above-mentioned preferable feeling of use to the cosmetic, exhibits a thickening effect equivalent to that of the polymer thickener, is inexpensive, and allows the cosmetic to be removed from the container. It has advantages such as better drainage when taking out. Therefore, water swellable clay minerals have hitherto been used in cosmetics such as foundations, packs, creams, soaps and paste-like facial cleansing agents due to the above effects. In particular, water-swellable clay minerals are known to have the effect of giving a smooth feel to washed skin even when mixed with a thing that is washed away, such as a skin cleanser, without slimy when rinsing. ing. However, the water-swellable clay mineral suppresses percutaneous absorption to external stimuli, prevents elution of lipids between keratinocytes and natural moisturizing factors in the stratum corneum, and reduces water content in the stratum corneum. Although it has not been known that it has an effect of suppressing liposomes, the present inventors have found that water-swellable clay minerals suppress percutaneous absorption by a surfactant, and lipids between keratinocytes, keratin It has been found that the elution of the natural moisturizing factor in the stratum corneum is remarkably prevented, and the effect of effectively suppressing the decrease in the amount of water in the stratum corneum is achieved, and the present invention has been accomplished. Therefore, according to the present invention, the particle size is 1 to 1000 n.
m, absolute value of zeta potential is 30 mV or more, purity is 90%
Skin that suppresses percutaneous absorption to external stimuli containing the above water-swellable clay mineral as an active ingredient and suppresses the dissolution and reduction of lipids between keratinocytes, natural moisturizing factors in the stratum corneum and water in the stratum corneum Provide protective agent. Here, as the water-swellable clay mineral, natural or synthetic smectite clay, particularly non-organic modified smectite clay which is not organically modified, is preferably used.
Examples include hectorite, sauconite, and stevensite, and swelling mica can also be used. Of these, montmorillonite and saponite are preferred. In addition, these clay minerals are used by being supported on a supporting substance as necessary, but the supporting substance is not particularly limited. The water-swellable clay mineral has an average particle diameter of 1000 nm or less as measured by a dynamic light scattering method and an absolute value of zeta potential of 3 or less as measured by an electrophoretic light scattering method.
0 mV or more, purity determined by powder X-ray diffraction method is 9
Use the one with 0% or more. When the average particle diameter of the clay mineral exceeds 1000 nm, the surface area per unit weight of the clay mineral is small and the contact area of the skin surface is small, so that the effect of suppressing percutaneous absorption to external stimuli and the effect of suppressing the elution of keratinocyte components are reduced. Inferior. The preferred average particle size is in the range of 500 nm or less. The absolute value of the zeta potential is 30 mV or more based on the amount of (water-swellable) clay mineral adsorbed on the skin surface. Furthermore, clay minerals, especially those collected from nature, contain non-swelling impurities such as calcite, tridymite, cristobalite, quartz and various inorganic substances, and these impurities are abundant. In this case, the above effect is insufficient. From this point, the purity of the clay mineral needs to be 90% or more, and particularly preferably 95% or more. The above-mentioned agent for inhibiting elution / decrease of components between skin keratinocytes and in the stratum corneum or the skin protective agent of the present invention is a composition containing an external stimulus, particularly a surfactant, particularly a surfactant containing an anionic surfactant, for example, Suppresses the percutaneous absorption of surfactants by using creams, lotions, body cleansers, shampoos, rinses, kitchen detergents, household detergents (bactericide), lipids between keratinocytes, natural in the horny layer It is used to suppress or prevent the elution of moisturizing factors and the decrease in the amount of water in the stratum corneum. In this case, the protective agent of the present invention can be used by being incorporated into a surfactant-containing composition. In addition,
When the protective agent of the present invention is incorporated into a surfactant-containing composition or the like, the concentration is preferably 0.001% by weight or more, particularly preferably 0.1% by weight or more, from the viewpoint of exhibiting its effect effectively. is there. EFFECT OF THE INVENTION The use of the protective agent of the present invention reduces the external stimulus, in particular, the absorption into the skin via the use of a surfactant, and reduces lipids between keratinocytes, It is possible to remarkably prevent the moisture retention factor and the water content in the stratum corneum from decreasing. EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. A water-swellable clay mineral (using natural montmorillonite (supporting Na)) was added to a body soap having the composition shown in Table 1. The water-swellable clay mineral has an average particle size of 500 nm and an absolute value of zeta potential of 45 m.
V, those having a purity of 93% were used. [Table 1] The body soap of the above example has less surfactant percutaneous absorption than that of the comparative example, and also contains lipids between keratinocytes, natural moisturizing factors in the stratum corneum and water in the stratum corneum. Was suppressed.

Continuation of the front page (72) Inventor Haruo Kadoya 1-3-7 Honjo, Sumida-ku, Tokyo Inside Rion Co., Ltd. (56) References JP-A-64-47711 (JP, A) JP-A-64-40565 JP-A-63-51310 (JP, A) JP-A-2-267113 (JP, A) JP-A-4-334312 (JP, A) JP-A-63-66111 (JP, A) JP-A-4-187628 (JP, A) JP-A-7-258055 (JP, A) JP-A-63-139105 (JP, A) JP-A-62-48614 (JP, A) JP-A-3-20227 ( JP, A) JP-A-8-179528 (JP, A) JP-A-9-316485 (JP, A) JP-A-8-151597 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61K 7/00-7/50

Claims (1)

(57) [Claim 1] A skin protective agent comprising a water-swellable clay mineral having a particle size of 1 to 1000 nm, an absolute value of zeta potential of 30 mV or more and a purity of 90% or more as an active ingredient.