JPH0558914A - Skin external preparation - Google Patents

Abstract

PURPOSE:To obtain a skin external preparation having quickly drying properties and capable of improving adhesiveness to skin and simultaneously preventing whitening by mixing pyroxylin with polyvinyl pyrrolidone at a definite ratio as a coating film forming agent with a mixed solvent consisting of acetone and lower alcohol. CONSTITUTION:A skin external preparation obtained by dissolving pyroxylin and polyvinyl pyrrolidone as a coating film forming agent in a mixed solvent of acetone and lower alcohol (especially preferably ethanol) at a wt. ratio of pyroxylin/polyvinyl pyrrolidone of 3.5-0.5. The mixed solvent consists of acetone and ethanol contained at a wt. ratio of 0.1-0.4 or methylethyl ketone, ethanol and acetone, preferably at a wt. ratio of methylethyl ketone/ethanol of 1.0-1.4 and acetone/ethanol of 0.7-0.9.

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 improvement of a collodion-based external preparation for skin.

[0002]

2. Description of the Related Art Conventionally, so-called collodion, in which pyroxylin is dissolved in an organic solvent, has been widely used as an external skin preparation such as a keratin remover, and a film is formed on the skin to promote the drug effect of salicylic acid or the like.

As a general collodion, one in which pyroxylin is dissolved in a mixed solvent of ethanol and ether is used, but ether is highly flammable and has anesthesia, so it is dangerous to handle it by a manufacturing operator or a user. At the same time, it has been pointed out that since the ether is highly volatile, the medicinal component is concentrated and deposited during use, which makes it unusable. In order to improve such a point, a solvent using a mixed solvent of ethyl acetate and ethanol as a solvent for pyroxylin, or a mixed solvent of acetone and a lower alcohol has been developed (JP-A-47-39621, etc.).

[0004]

However, the collodion using the mixed solvent of ethyl acetate and ethanol has a problem that it is insufficient in quick-drying property and adhesion to the skin. On the other hand, collodion using a mixed solvent of acetone and lower alcohol may cause browning during storage, and when it is used as a keratin-removing agent in which salicylic acid is dissolved, the salicylic acid precipitates on the skin and becomes white. There was a problem of becoming The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to obtain an external preparation for skin which does not use ether and is excellent in quick-drying and adhesiveness to the skin.

[0005]

Means for Solving the Problems As a result of intensive studies by the present inventors in order to achieve the above object, as a film-forming agent, pyroxylin and polyvinylpyrrolidone are blended in a fixed ratio in a mixed solvent consisting of acetone and a lower alcohol. As a result, they have found that the quick-drying property and the adhesion property to the skin can be improved, and whitening can be prevented, and the present invention has been completed.

That is, in the external preparation for skin according to claim 1 of the present application, the weight ratio of 1 to 8% by weight of pyroxylin and the pyroxylin is such that pyroxylin / polyvinylpyrrolidone = 3.5 to 0.5. Polyvinylpyrrolidone blended, and is dissolved in a mixed solvent of acetone and lower alcohol.

The external preparation for skin according to claim 2 is characterized in that the lower alcohol comprises ethanol and that acetone / ethanol is 0.1 to 0.4.

Further, in the external preparation for skin according to claim 3, the mixed solvent comprises methyl ethyl ketone, ethanol and acetone, and methyl ethyl ketone / ethanol = 1.0-
1.4, Acetone / Ethanol = 0.7-0.9 weight ratio.

The structure of the present invention will be described below. The pyroxylin used in the present invention is preferably from 1 to 8% by weight, and when it is less than 1% by weight, a film is not formed well, and when it exceeds 8% by weight, browning is likely to occur during storage. In addition, polyvinylpyrrolidone is the same as the above-mentioned pyroxylin, pyroxylin / polyvinylpyrrolidone =
It is preferable that the blending amount be 3.5 to 0.5, and particularly preferably 3.0 to 1.0. If the ratio exceeds 3.5, browning is likely to occur during storage, and if it is less than 0.5, stickiness may occur after coating and drying.

Further, polyvinylpyrrolidone is insoluble in conventional collodion. Therefore, it is necessary to use a mixed solvent of acetone and a lower alcohol as a solvent for the pyroxylin and polyvinylpyrrolidone. Here, ethanol or propyl alcohol can be used as the lower alcohol, and ethanol is particularly preferable. Isopropyl alcohol may cause browning during storage, which is not preferable.

When a mixed solvent of acetone and lower alcohol is used, it is preferable that acetone / lower alcohol = 0.1-0.4. If the ratio is 0.1 or less, the quick-drying property may be poor, and if it is 0.4 or more, the productivity may be adversely affected.

Further, it is preferable that the mixed solvent further contains methyl ethyl ketone, so that the quick drying property can be further improved. In this case, methyl ethyl ketone / ethanol = 1.0 to 1.4, acetone / ethanol = 0.
It is preferably 7 to 0.9. By substituting a part of ethanol with methyl ethyl ketone in this way, fast drying property and manufacturability can be favorably maintained.

[0013]

EXAMPLES Examples of the present invention will be described below. The present invention is not limited to the examples. In addition, unless otherwise specified, the compounding amount is shown in% by weight.

In the present invention, polyvinylpyrrolidone is used as a film forming agent in addition to the conventional pyroxylin. The total of these two was set to 8%, and the characteristics were examined while changing the ratio of both. The basic composition is as follows.

Salicylic acid 10% Pyroxylin + polyvinylpyrrolidone 8% Methyl ethyl ketone 32% Ethanol 29% Acetone 21%

The browning is stored at 40 ° C.
The degree of discoloration was measured. ◎: No change at all ○: Slight discoloration is observed, but the product value is not affected ×: Discoloration is recognized and the product value is significantly reduced

The stickiness was applied to the skin, and after 5 minutes, it was examined by touch. ◎: Stickiness is not felt. ○: Some stickiness is felt, but there is no problem. X: Stickiness is strongly felt and the feeling of use is poor.

The whitening was applied to the skin, and after 5 minutes, it was visually observed and inspected. ⊚: A transparent film is formed. ○: A slightly white transparent film is formed. X: A opaque film is formed.

The test results are shown in Table 1 below.

[Table 1] ──────────────────────────────────── Pyroxyline 6.4 6.2 6.0 5.3 4.0 2.7 1.6 ──────────────────────────────────── POLYBINIL POLOLIDON 1.6 1.8 2.0 2.7 4.0 5.3 6.4 ────────────────────────────── ─────── Peroxylin / PVP 4.0 3.4 3.0 2.0 2.0 1.0 0.5 0.5 0.25 ─────────────────── ───────────────── Browning × ○ ◎ ◎ ◎ ◎ ◎ ◎ ───────────────────────── ─────────── Stickiness ◎ ◎ ◎ ◎ ◎ ◎ ○ × ─────────────────────── ───────────── Bleaching ○ ○ ◎ ◎ ◎ ◎ ◎ ◎ ───────────────────────────── ───────

From the above results, it is understood that the preferable mixture ratio of pyroxylin and polyvinylpyrrolidone is pyroxylin / polyvinylpyrrolidone = 3.5 to 0.5, especially 3.0 to 1.0. When the ratio is 4.0 or more, the usability such as stickiness is good, but browning occurs during high temperature storage and storage stability is poor. Moreover, whitening is likely to occur during use. Further, if the ratio is 0.25 or less, the stickiness becomes strong during use, which is not preferable.

If the content of pyroxylin is less than 1%, the film-forming property is deteriorated, and if it exceeds 8%, browning is likely to occur, which is not preferable. Therefore, as the film forming agent used in the present invention, pyroxylin is 1 to 8%, and the compounding ratio of pyroxylin and polyvinylpyrrolidone is pyroxylin / polyvinylpyrrolidone =
It should be 3.5 to 0.5.

When an acetone / ethanol system is used as a mixed solvent in the present invention, it may be slightly inferior in terms of quick-drying property to collodion using a conventional ether. Therefore, the present inventors proceeded with the study on the mixed solvent, replaced a part of ethanol with methyl ethyl ketone,
The quick-drying property was improved. It should be noted that ethanol is used for swelling pyroxylin during the production of collodion, and reducing ethanol may affect productivity. Therefore, the present inventors produced the exfoliating agents of the following respective formulations, and tested the rapid drying property and the manufacturability thereof.

The evaluations of quick-drying property and manufacturability are shown as good (⊚), acceptable (∘) and unacceptable (×), respectively.

[Table 2] ──────────────────────────────────── Salicylic acid 10.0 10.0 10.0 10.0 10.0 10.0 Pyroxyline 4.5 4.5 4.5 4.5 4.5 4.5 Polyvinylpyrrolidone 3.0 3.0 3.0 3.0 3.0 3.0 Acetone 21.0 21.0 21.0 21 0.0 21.0 Methyl ethyl ketone 36.7 35.8 33.6 31.0 27.8 Ethanol 24.5 25.4 27.6 30.2 33.4 ───────────── ─────────────────────── MEK / EtOH 1.5 1.4 1.4 1.2 1.0 0.8 ────────── ─────────────────────────── Quick drying ◎ ◎ ◎ ◎ ◎ ○ Manufacturing workability △ ○ ◎ ◎ ◎ ◎ ───────── ──── ────────────────────────

As is clear from the above results, it is understood that when the methyl ethyl ketone / ethanol ratio is 1.4 to 1.0, excellent quick-drying property and manufacturing workability can be obtained. In addition,
As a result, in the actual blending, acetone / ethanol = 0.7 to 0.9. Next, the exfoliating agent will be illustrated as a specific example of the external preparation for skin according to the present invention.

Example 1 Salicylic acid 10.0% Pyroxylin 4.5% Polyvinylpyrrolidone 3.0% Acetone 21.0% Ethanol 61.5% <Production method> Pyroxylin and polyvinylpyrrolidone are swollen in ethanol, and then acetone is added. Was dissolved, and other ingredients were added to prepare a exfoliating agent.

Example 2 Salicylic acid 10.0% Pyroxyline 3.5% Polyvinylpyrrolidone 2.5% Acetone 21.3% Methyl ethyl ketone 32.7% Ethanol 30.0% <Production method> Same as in Example 1.

Example 3 Salicylic acid 10.0% Pyroxyline 3.5% Polyvinylpyrrolidone 3.0% Acetone 20.5% Methyl ethyl ketone 29.0% Ethanol 29.0% Lactic acid 1.5% dl-camphor 3.5% < Manufacturing Method> According to Example 1.

[0028]

As described above, according to the skin external preparation of the present invention, it is easy to handle since it is prepared by blending pyroxylin and polyvinylpyrrolidone at a fixed ratio and dissolving them in a mixed solvent containing acetone and ethanol. It also has excellent quick-drying properties. Moreover, the quick-drying property can be further improved by adding methyl ethyl ketone to the mixed solvent.

Claims (3)

[Claims] 1. Pyroxyline in an amount of 1 to 8% by weight, and a polyvinylpyrrolidone compounded such that the weight ratio of the pyroxylin is pyroxylin / polyvinylpyrrolidone = 3.5 to 0.5, and acetone and A skin external preparation characterized by being dissolved in a mixed solvent of lower alcohols. 2. The external preparation for skin according to claim 1, wherein the lower alcohol is ethanol and acetone / ethanol is 0.1 to 0.4. 3. The external preparation for skin according to claim 1, wherein the mixed solvent comprises methyl ethyl ketone, ethanol and acetone, and methyl ethyl ketone / ethanol = 1.0-
1.4, Acetone / Ethanol = 0.7-0.9 weight ratio, The skin external preparation characterized by the above-mentioned.