JPS627A - Skin external agent containing incorporated urea - Google Patents

Abstract

PURPOSE:The titled skin external agent, containing urea and obtained by incorporating a specific polyhydric alcohol with a skin external agent containing urea useful as a remedy for keratosis, etc., as a principal active constituent and capable of synergistically enhancing the humectant action of the urea and suppressing side effects of the urea at the same time. CONSTITUTION:A skin external agent obtained by incorporating 5-90wt%, preferably 10-50wt%, particularly 10-30wt% polyhydric alcohol having >=3 hydroxyl groups in the molecule thereof, e.g. glycerol, polyglycerol such as di-tetraglycerol, threitol, erythritol, fructose, xylitol, sorbitol, maltotriose, glucose, maltitose and/or maltitol, etc., as an essential component in a skin external agent containing 2-30wt%, preferably 5-20wt% urea as a principal active constituent and capable of synergistically enhancing the humectant action of the urea and improving feeling of pricking or smarting peculiar to urea against the skin at the same time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a urea preparation used as a keratosis treatment, etc., containing a polyhydric alcohol having three or more hydroxyl groups in the molecule. This topic relates to a urea-containing external skin preparation that synergistically enhances the moisturizing effect of urea and suppresses one of the side effects of urea, tingling and irritation, on the skin.

[Prior art] Urea exists in living organisms, and as a result of changing protein polypeptides, it increases its solubility, and has antibacterial effects, proteolytic denaturing effects, hydration phenomenon, that is, enhancement of water retention ability, etc. It has an important pharmacological effect on skin chemistry, and is generally used as a treatment for ichthyosis, progressive palmar angle syndrome, senile xeroderma, rough fingers, and keratosis of the elbows, knees, heels, and sections.
It is used at a concentration of 20% by weight.

[Problems to be Solved by the Invention] However, one of the side effects of urea is a tingling or stinging sensation on the skin, although it is temporary.

It is known that urea is easily hydrolyzed by acids, alkalis, heat, etc. in the coexistence of water and generates ammonia. To date, little research has been done on restoring the effect or suppressing the prickling and stinging sensation of urea on the skin.

[Means for Solving the Problems] In view of these circumstances, the inventor has conducted extensive research and has found that:
By adding a polyhydric alcohol having three or more hydroxyl groups in the molecule to a urea preparation, the moisturizing effect is synergistically enhanced compared to the addition of only urea or only the polyhydric alcohol, and the tingling sensation unique to urea is achieved. The present invention was completed based on the discovery that the tingling and stinging could be reduced.

That is, the present invention provides an external skin preparation containing urea as a main active ingredient, which is characterized by containing one or more polyhydric alcohols having three or more hydroxyl groups in the molecule. be.

The amount of urea added is generally 2 to 30% of the total amount of the skin external preparation.
% by weight, preferably from 5 to 20% by weight.

If it is less than 2% by weight, the moisturizing effect of urea cannot be expected much;
Moreover, a blend exceeding 30% by weight is not preferable because urea crystals tend to precipitate and stinging and tingling sensations cannot be suppressed.

Examples of polyhydric alcohols having three or more hydroxyl groups in the molecule include polyglycerin such as glycerin, diglycerin, triglycerin, and tetraglycerin, threitol, erythritol, fructose, xylitol, sorbitol, maltotriose, glucose, multidose,
maltitol, etc., and one or more of these may be used.

The blending amount is 5 to 90% by weight, preferably 10 to 50% by weight.
, more preferably 10 to 30% by weight.

More favorable results can be obtained by adding an oily component in addition to the above essential components. Oily ingredients are commonly used medicinal and cosmetic oily ingredients, and in particular branched saturated aliphatic alcohols such as diisopropyl adipate and diethyl sebacate, saturated aliphatic dibasic acids, or malic acid, tartaric acid, and citric acid. Ester oils and silicone oils are preferred.

Among these, those with low viscosity are desirable.

The oily component also has the effect of improving the feel of the external skin preparation of the present invention, mainly the sticky feeling.

The blending amount is 10 to 60% by weight, preferably 15 to 40% by weight.

In addition to this, the skin external preparation of the present invention may include drugs,
Preservatives, antioxidants, thickeners, colorants, fragrances, ammonium salts as urea stabilizers, buffers, surfactants, other humectants, etc. may be added.

[Effects of the Invention] The external skin preparation of the present invention is a skin external preparation in which the moisturizing effects of urea and polyhydric alcohol have been synergistically advanced, and the prickling and stinging sensation peculiar to urea on the skin has been improved. It can be applied not only in the field of cosmetics but also in the field of cosmetics.

[Example] Next, the moisturizing enhancement effect and the reduction of stinging sensation and stinging sensation due to the combined use of urea and polyhydric alcohol of the present invention will be explained in detail in Examples.

(Left below) Prescription Example 1 Comparative Example 1 Comparative Example 2 Stearic acid 3.0 3.0 3.0 Vaseline 4.0 4.0 4.0 Isopropyl myriste 2.0 2.0 2.0-Toadipine Isopropyl acid 5.0 5.0 5.0 Dimethyl polysiloxane 2.0 2.0 2.0 (6 cs) Cetostearyl alco 4.5 4.5 4.5
-Luglyceryl monostear 2.5 2.5 2.5
Butylparaben 0.1 0.1 0.1
Ethylparaben 0.1 0.1 0.1
Propylene glycol 5.0 10.0 5.0
Glycerin 10.0 - - Sorbitol 10.0 - 20.01.3 Butylene glyco -20,0- Monolurea 10.0 10.0 -
Glycine 1.0 1.0 1.0K
OHO, 10, 10, 1 Citrate buffer Residual Residual Example 1
Cream formulations of Comparative Example 1 and Comparative Example 2 were manufactured, and the moisture content of the stratum corneum on the side of the forearm layer of a panel of healthy male subjects was compared and examined by conductance measurement.

The results are shown in Table-1.

The conductance value shows the average value of n=5, and is the value 5 hours after application. Measurements were carried out at 25°C and 50% RH.
B5-355 (manufactured by IBS), and the larger the value, the greater the stratum corneum water content.

(Leaving space below) Table-1 Prescription Measurement Conductance Example 1
Before application 10.0μΩ After application 120.
0 Comparative Example 1 Before application 9.0 After application 20.0 Comparative Example 2 Before application 12.0 After application
47.0 Control Before application 9.0 - After application 10.0 Also, regarding the stinging feeling of urea, we conducted a usage test on 6 female panels who are sensitive to everyday cosmetics, and found that polyhydric alcohol's tingling, stinging, etc. We investigated the suppressive effect of

The results are shown in Table-2.

The back of the hand was used as the test site. The use test was carried out twice a day in principle for 3 days, and the results of a total of 36 tests were judged based on the following judgment items and evaluation.

Table 2 shows the percentage of people who gave a score of 1 or higher in a total of 36 tests.

- Judgment Items - 1. Itching 2, Stinging 3, Stinging 4, Prickling 5, Soreness - Evaluation method - None...0 points Slightly present...1 points Slightly strong...2 points Strong... 3-point table-2 Itching Stinging Stinging Itching
Tingling feeling (%) Example 1 5.6 5.6 5.6 8.3
0 Comparative Example 1 13.9 16.7 5.6 2
2.2 0 Comparative Example 2 0 0 5.6
0 0 Further examples will be shown.

Example 2 Stearic acid 2% by weight squalane 5 cetostearyl alcohol 4 glycerin heptanofatty acid ester
3 POE Sorbitan Monostearate 1 Ethylparaben 0.1 Fragrance
0.2 urea
10 glycerin
201,3 Butylene glycol 10 Sodium hyaluronate 0.2 Edetic acid 2
Sodium 0.05 Ammonium carbonate 0.1 Purified water
A urea-containing cream preparation was produced according to a conventional method.

Example 2 was a cream that had an excellent moisturizing effect on the skin and did not have the prickly or stinging feeling that urea has on the skin.

Example 3 Urea 25 Propylene Glycol 5 Glycerin
45 Taurine 5
Purified water 20 (Production method) A urea-containing lotion was produced according to a conventional method.

Example 3 was a lotion that had an excellent moisturizing effect on the skin and did not have the prickly or stinging feeling that urea has on the skin.

Example 4 Urea 5 Propylene glycol 10 Glycerin
80 Taurine 1
Purified water 4 (Production method) A urea-containing lotion was produced according to a conventional method.

Example 4 was a lotion that had an excellent moisturizing effect on the skin and did not have the prickly or stinging feeling that urea has on the skin.

Claims (1)

[Claims] (1) An external skin preparation containing urea as a main active ingredient, which contains one or more polyhydric alcohols having three or more hydroxyl groups in the molecule.