JP6234752B2 - Bacteriostatic agents against acne-causing bacteria - Google Patents

Description

  The present invention relates to a bacteriostatic agent for acne-causing bacteria, and in particular, to a bacteriostatic agent for acne-causing bacteria that has low skin irritation and high safety.

  In general, microorganisms called skin resident bacteria live on the surface of human healthy skin. By the action of the skin resident bacteria, the pH of the skin surface is kept weakly acidic, and the skin homeostasis is maintained by its barrier function. However, if the balance of this skin resident bacteria is lost, it is considered that it causes skin diseases such as acne and inflammation. In particular, acne (acne vulgaris) is said to develop due to an increase in sebum secretion, infection with acne-causing bacteria (such as Acne bacteria).

  As conventional techniques related to bacteriostatic agents and skin external products for acne-causing bacteria, the proportion of anti-acne bacteria composition (patent document 1) characterized by containing polyglycerin fatty acid ester, metal oxide, and monoester body A skin external preparation composition (Patent Document 2), which is an acne treatment drug containing 55 to 100% by mass of a sucrose fatty acid ester and isopropylmethylphenol and having a pH of 2 or more and less than 7, has been disclosed. There has been a need for a more preferred bacteriostatic agent for acne causing bacteria.

JP 2007-77086 A JP 2009-149568 A

  It is an object of the present invention to provide a bacteriostatic agent for acne-causing bacteria that is weak in skin irritation and highly safe.

As a result of intensive studies in order to solve the above problems, the present inventor has found that propylene glycol fatty acid esters under certain conditions solve the above problems. Based on these findings, further studies have been made and the present invention has been completed.
That is, the present invention
(1) Acne characterized in that it is a propylene glycol fatty acid ester containing one or more fatty acids having 8 to 14 carbon atoms as a constituent fatty acid and having a monoester content of 90% by mass or more. Bacteriostatic agent against causative bacteria,
(2) A skin external preparation for acne, comprising the bacteriostatic agent according to (1) above,
It is made up of.

  The bacteriostatic agent for acne-causing bacteria of the present invention is highly safe because of its weak skin irritation and has the effect of effectively bacterizing acne-causing bacteria.

  The bacteriostatic agent for acne-causing bacteria of the present invention contains one or more fatty acids having 8 to 14 carbon atoms as the constituent fatty acid, and a monoester content of propylene glycol fatty acid of 90% by mass or more. Ester.

  The fatty acid having 8 to 14 carbon atoms constituting the propylene glycol fatty acid ester may be either a saturated fatty acid or an unsaturated fatty acid, and preferably a linear saturated fatty acid having 8 to 14 carbon atoms (for example, caprylic acid, (Largonic acid, capric acid, lauric acid, myristic acid, etc.), more preferably caprylic acid, pelargonic acid, capric acid and lauric acid. When the number of carbon atoms of the fatty acid is less than 8, the resulting propylene glycol fatty acid ester has a strong unpleasant odor and skin irritation, and when the number of carbon atoms of the fatty acid exceeds 14, the resulting propylene glycol fatty acid ester is Since the bacteriostatic effect is weak or disappears, it is not preferable.

  The fatty acid having 8 to 14 carbon atoms can be used singly or in combination of two or more, preferably about 50% by mass or more, more preferably about 70% by mass or more, and still more preferably about 90% by mass in the whole fatty acid. % Fatty acid or fatty acid mixture.

The propylene glycol fatty acid ester is obtained by removing as much as possible unreacted substances and diester form from the esterification product of propylene glycol and the above fatty acid, and purifying the monoester form content to 90% by mass or more. , Esterification reaction, removal and purification can be produced by methods known per se.
The outline of the production method of the propylene glycol fatty acid ester is as follows.
For example, an ordinary reaction vessel equipped with a stirrer, a heating jacket, a baffle plate, etc. is charged with propylene glycol and a fatty acid having 8 to 14 carbon atoms in a molar ratio of about 1: 0.2 to 1.5. The esterification reaction is carried out, and after completion of the reaction, the catalyst remaining in the reaction mixture is neutralized to obtain a reaction solution. The heating temperature for the esterification reaction is usually in the range of about 180 to 260 ° C, preferably in the range of about 190 to 210 ° C. The reaction pressure is under reduced pressure or normal pressure, and the reaction time is about 0.5 to 15 hours, preferably about 1 to 10 hours. The obtained reaction liquid is a mixture containing unreacted fatty acid, unreacted propylene glycol, propylene glycol monofatty acid ester, propylene glycol difatty acid ester, and the like. This reaction solution is distilled under reduced pressure to distill off unreacted propylene glycol, followed by molecular distillation using, for example, a falling film molecular distillation device or a centrifugal molecular distillation device, or column chromatography or By purifying using a method known per se such as liquid-liquid extraction, a propylene glycol fatty acid ester containing 90% by mass or more of a monoester is obtained.

  As said propylene glycol fatty acid ester, what is manufactured and sold commercially can be used, for example, Riquemar PL-100 (trade name; Propylene glycol laurate monoester content by Riken Vitamin Co., Ltd. about 95 Mass%).

  The thus obtained bacteriostatic agent for acne-causing bacteria according to the present invention has an effect on acne-causing bacteria such as Propionibacterium acnes, Propionibacterium avidum, Staphylococcus epidermidis, especially Propionibacterium avidum, Staphylococcus.

  An external skin preparation for acne containing a bacteriostatic agent for acne-causing bacteria of the present invention is also one form of the present invention. The topical acne skin preparation is a general term for preparations used externally to the skin for the purpose of preventing or treating acne, and is used as a medicine or cosmetic. When used as a medicine, it can be in the form of an ointment, stick, liquid, extract, lotion, emulsion, cataplasm, and the like. For example, in the case of an ointment, any of those based on an oily base and those based on an oil-in-water or water-in-oil emulsified base may be used. Examples of oily bases include vegetable oils, animal oils, Examples include synthetic oils, fatty acids, and natural or synthetic glycerides. In addition, other medicinal ingredients such as analgesic / anti-inflammatory agents, bactericidal / disinfectants, astringents, emollients, hormones, antibiotics, and the like can be appropriately blended with the medicament.

  When used as a cosmetic, various forms such as oil-in-water or water-in-oil emulsified cosmetics, creams, gels, cosmetic emulsions, lotions, oily cosmetics, facial cleansers, foundations, packs, poultices , Spray, mist, skin cleanser and the like. The cosmetics are further commonly used as cosmetic ingredients, such as oils, ceramides, coagulated ceramides, sterols, moisturizers, antioxidants, singlet oxygen scavengers, powder ingredients, colorants, UV absorbers. , Whitening agents, alcohols, chelating agents, pH adjusters, preservatives, thickeners, pigments, fragrances, plant extracts, various skin nutrients, and the like can be combined in any combination.

  The present invention will now be described by way of examples, which are merely illustrative of the invention and do not limit the invention.

<Production of bacteriostatic agent against acne-causing bacteria>
[Production of prototype 1]
A 3 L four-necked flask equipped with a stirrer, thermometer, gas blowing tube and water separator was charged with 1080 g of propylene glycol, 1320 g of capric acid and 0.24 g of zinc oxide and heated to 195 ° C. while introducing nitrogen gas. Reaction was performed for 7 hours to obtain 2140 g of a reaction solution having an acid value of 1.2. After 900 g of this reaction liquid was distilled under reduced pressure (100 ° C., 250 Pa) to remove unreacted propylene glycol, it was further distilled under reduced pressure (150 ° C., 120 Pa) to obtain 430 g of propylene glycol capric acid ester (Example Product 1). It was. The monoester content was 95% by mass.

[Production of prototype 2]
990 g of propylene glycol and coconut fatty acid (fatty acid composition lauric acid: 52% by mass, myristic acid: 24% by mass, capric acid: 9% by mass in a 3 L four-necked flask equipped with a stirrer, thermometer, gas blowing tube and water separator %, Palmitic acid: 9 mass%, caprylic acid: 3 mass%, oleic acid: 2 mass%, stearic acid: 1 mass%) 1410 g and zinc oxide 0.24 g were charged, and the temperature was raised to 195 ° C. while introducing nitrogen gas The mixture was heated for 6 hours to obtain 2150 g of a reaction solution having an acid value of 1.5. After 1000 g of this reaction liquid was distilled under reduced pressure (100 ° C., 250 Pa) to remove unreacted propylene glycol, it was further distilled under reduced pressure (140-200 ° C., 100-200 Pa) to produce propylene glycol palm fatty acid ester (Example Product 2). ) 390 g was obtained. The monoester content was 95% by mass.

[Production of prototype 3]
A 500 ml four-necked flask equipped with a stirrer, thermometer, gas blowing tube and water separator was charged with 106 g of propylene glycol, 294 g of capric acid and 0.04 g of zinc oxide, and heated to 195 ° C. while introducing nitrogen gas. Reaction was performed for 6 hours to obtain 360 g of propylene glycol capric acid ester (Comparative Example Product 1) having an acid value of 1.7. The monoester content was 50% by mass.

[Measurement method of monoester content]
The ester composition analysis was performed using HPLC, and the quantitative analysis was performed by the absolute calibration curve method. In other words, the peak area corresponding to the monoester form of the test sample recorded on the chromatogram by the data processor was measured, and the calibration was made using propylene glycol monolaurate purified by normal phase column chromatography as the standard sample. From the line, the monoester content of the test sample was determined. The HPLC analysis conditions are shown below.

[HPLC analysis conditions]
Equipment Shimadzu High Performance Liquid Chromatograph Pump (Model: LC-20AD; manufactured by Shimadzu Corporation)
Column oven (model: CTO-20A; manufactured by Shimadzu Corporation)
Data processing device (model: LCsolution; manufactured by Shimadzu Corporation)
Column GPC column (model: SHODEX KF-801; manufactured by Showa Denko KK) 2 linked mobile phase THF
Flow rate 1.0mL / min
Detector RI detector (model: RID-10A; manufactured by Shimadzu Corporation)
Column temperature 40 ° C
Test solution injection volume 15μL (in THF)

<Bacteriostatic test>
Using a bacteriostatic agent for acne-causing bacteria shown in Table 1 below, a bacteriostatic test for acne-causing bacteria (Propionibacterium avidum: P. avidum, Staphylococcus epidermidis: S. epidermidis) was performed.

[Preparation of bacterial solution for inoculation]
P. avidum and S. epidermidis was added to each No702 medium (polypeptone 10 g, yeast extract 2 g, magnesium sulfate heptahydrate 1 g, distilled water 1 L was prepared) to prepare a bacterial solution for inoculation having a bacterial count of 1 × 10 ⁵ CFU / mL. .

[Measurement of minimum inhibitory concentration (MIC)]
In each well of the 48-well microplate, as a culture solution, a liquid medium (No. 702 medium) 900 μL, each inoculum bacterial solution 100 μL, and the bacteriostatic agent for the acne-causing bacteria in the culture solution are 25 ppm, 50 ppm, 100 ppm, 10 μL of a solution diluted to 200 ppm, 300 ppm, and 400 ppm was dispensed and cultured at 37 ° C. for 5 days to confirm the presence or absence of bacterial growth. At this time, 150 μL of a culture solution in which growth was not observed was collected and applied to a No802 medium (adjusted with 10 g of polypeptone, 2 g of yeast extract, 1 g of magnesium sulfate heptahydrate, 1 L of distilled water, and 15 g of agar), and further 37 ° C. For 5 days. At this time, the minimum concentration at which no growth was observed was defined as the minimum inhibitory concentration (MIC). S. About epidermidis, the minimum prevention concentration of Example product 1, Comparative product 1 to 3 and Reference product 1 and 2 was measured. The results are shown in Table 2.

結果より、Ｐ．ａｖｉｄｕｍに対しては、実施例品１〜３は５０ｐｐｍ以下で静菌効果を示した。比較例品１〜３は、１００ｐｐｍ未満では静菌効果が得られなかった。一般的な静菌剤である参考品１、２は２００ｐｐｍで静菌効果を示した。また、Ｓ．ｅｐｉｄｅｒｍｉｄｉｓに対しては、実施例品１は１００ｐｐｍで静菌性を示した。比較例品１〜３は、２００ｐｐｍ未満では静菌効果が得られなかった。一般的な静菌剤である参考例品１、２は４００ｐｐｍで静菌効果を示した。実施例品は、ニキビ原因菌に対し優れた静菌効果を示した。

From the results, P.I. For avidum, Examples 1 to 3 showed a bacteriostatic effect at 50 ppm or less. In Comparative Examples 1 to 3, the bacteriostatic effect was not obtained at less than 100 ppm. Reference products 1 and 2 which are general bacteriostatic agents showed a bacteriostatic effect at 200 ppm. S. For epidermidis, Example Product 1 was bacteriostatic at 100 ppm. In Comparative Examples 1 to 3, the bacteriostatic effect was not obtained at less than 200 ppm. Reference Example products 1 and 2 which are general bacteriostatic agents showed a bacteriostatic effect at 400 ppm. The example product showed an excellent bacteriostatic effect against acne-causing bacteria.

<Skin irritation confirmation test>
The skin irritation of Example Product 1 and Reference Product 1 was confirmed by a patch test (occlusion patch test method). This technique is generally used for the purpose of confirming skin irritation such as cosmetics.

[Production of diluted solution]
Distilled water (89.5 g), ethanol (10.0 g), and Example product 1 (0.5 g) were mixed to prepare Diluent 1 containing 0.5% by mass of Example product 1. In addition, a dilute solution 2 containing 0.5% by mass of the reference example product 1 was produced using the reference example product 1 instead of the example product 1.

[Implementation test for skin irritation]
The obtained dilutions 1 and 2 were each soaked in a circular filter paper having a diameter of about 5 mm, and this was pasted on the upper arm using an aluminum disk (fin chamber) having the same diameter as the filter paper and fixed for 48 hours. The filter paper affixed after 48 hours was peeled off (patch removal), and then the skin irritation state after 1 hour and 24 hours was determined. In the determination, the skin reaction was evaluated according to the determination criteria shown in Table 3. The sum of the number of people who had a reaction on the skin multiplied by the coefficient of each judgment was taken as the score, and the score was divided by the number of subjects (8 people) and multiplied by 100 to obtain the stimulation index. The stimulation index was evaluated as a safety product, 10 to 30 as an acceptable product, 10 to 30 as an acceptable product, and 30 or more as an improved product. Table 4 shows the skin reaction state determination, score, stimulation index, and evaluation.

結果より、実施例品１は、従来用いられている参考例品１（４−ヒドロキシ安息香酸プロピル）に比較して刺激性が弱く安全性が高いといえる。

From the results, it can be said that Example Product 1 is weak in irritation and high in safety compared to Reference Example Product 1 (propyl 4-hydroxybenzoate) that has been conventionally used.

<Preparation of acne skin external preparation>
[Acne skin external preparation 1]
According to the formulation shown in Table 5 below, each component was uniformly mixed to prepare an acne skin external preparation 1 containing Example Product 1.

[Acne skin external preparation 2]
According to the formulation shown in Table 6 below, each component was uniformly mixed to prepare an acne skin external preparation 2 (skin lotion) containing Example Product 1.

Claims (1)

The following acne cause characterized in that it is a propylene glycol fatty acid ester containing one or more fatty acids having 10 to 14 carbon atoms as a constituent fatty acid and having a monoester content of 90% by mass or more Bacteriostatic agent against bacteria.
Acne-causing bacteria: Propionibacterium avidum