JPH0632710A - Skin external preparation - Google Patents

Abstract

PURPOSE:To obtain a skin external preparation remarkably improved in stability of retinol. CONSTITUTION:This skin external preparation is obtained by blending retinol together with one or two or more of polyethylene glycol and/or polypropylene glycol.

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 in which retinol stability is remarkably improved.

[0002]

2. Description of the Related Art Retinol is known to be an effective component for the prevention and treatment of cutaneous keratoses and the like, and the prevention and recovery of skin aging.

However, retinol is structurally extremely unstable and easily undergoes various isomerizations, decompositions, polymerizations and the like due to light, air, heat, metal ions, etc., so that it can be stably compounded in an external preparation for skin. It was difficult. Although methods such as fatty acid esterification have been attempted for the purpose of stabilization, esterification is effective for stabilization but is far inferior to retinol itself in terms of action on the skin.

[0004]

DISCLOSURE OF THE INVENTION As a result of intensive studies conducted by the present inventors in view of such circumstances, one or two of polyethylene glycol (hereinafter abbreviated as PEG) and polypropylene glycol (hereinafter abbreviated as PPG) together with retinol was found. It has been found that the stability of retinol is remarkably improved by mixing at least one species, and the present invention has been completed.

[0005]

Means for Solving the Problems That is, the gist of the present invention resides in an external preparation for skin characterized by containing retinol and one or more of PEG and PPG.

The structure of the present invention will be described in detail below.

The retinol used in the present invention is also called vitamin A, which means retinol itself having a hydroxyl group at the terminal and does not contain its fatty acid ester. All-trans type or 13-cis type is desirable, and a mixture thereof may be used.

There is no particular limitation on the amount to be added to the external preparation for skin according to the present invention, but considering the effect on the skin as retinol, it is 0.0001% by weight or more, and in order to strongly appeal the effect of retinol. Is preferably 0.00
It is 1% by weight or more. The upper limit of the compounding ratio is preferably 1% by weight in view of the property as an external preparation for skin.

The PEG and PPG blended in the present invention include PEG200, PEG300, PEG400, P
EG1500, PEG4000, PEG6000, PE
G20000, PPG400, PPG750, P
PG1200, PPG2000, PPG3000, etc. are famous.

These are blended in one kind or two or more kinds,
The amount added for the purpose of exerting the effect of the present invention is required to be 0.1% by weight or more, and an excessive amount of addition does not inhibit the effect of the present invention. However, it is necessary to exercise caution because if it is excessively blended, the quality of the external preparation for the skin may be impaired.

In the present invention, as a skin external preparation base containing retinol and PEG and / or PPG, any conventional skin external preparation base can be used.
That is, liquid, gel, paste, cream, powder, solid or the like, as a component for modifying the skin external preparation, a moisturizer, an oil, a surfactant, a thickener, a sequestering agent, etc. It goes without saying that the ultraviolet absorbers, drugs, dyes, fragrances, etc. can be used in combination.

[0012]

EXAMPLES The present invention will now be described in more detail with reference to more examples, but the present invention is not limited thereto.

[0013]

[Table 1]

In Examples 1, 2 and 3, the stability of retinol is improved as compared with Comparative Example, which is an effect according to the present invention.

Quantitative Method of Retinol Quantitative analysis was carried out by an absorbance measuring method at 325 nm using ethanol as a solvent. In the calculation, the maximum absorption was 325 nm E (1%, 1 cm) = 1835.

Example 4 Cream (wt%) A. Cetanol 3 Glyceryl monostearate 2 POE (25) cetyl ether 1 Stearic acid 3 Vaseline 3 Isopropyl myristate 5 Squalane 5 Retinol 0.1 BHT 0.05 Fragrance Suitable amount B. PEG1500 3 glycerin 9 potassium hydroxide 0.2 Purified water based on the total amount of 100 The oil phase portion of A and the water phase portion of B are dissolved by heating at 70 ° C., and A is added to B to emulsify. Then, it is cooled to obtain a cream.

Example 5 Lipstick (wt%) Solid paraffin 8 Carnauba wax 2 Candelilla wax 4 Microcrystalline wax 6 Hydrogenated lanolin 15 Isopropyl palmitate Amount based on 100 Glyceryl diisostearate 30 PPG 3000 15 Retinol 1 BHT 0 .3 Coloring agent (red) 7 Perfume Suitable amount Each of the above raw materials is heated and melted at 80 ° C., and then poured into a predetermined container to obtain a lipstick.

Example 6 Lotion (wt%) retinol 0.0001 oleyl alcohol 0.001 α-tocopherol 0.005 POE (20) octyldodecanol 0.8 ethanol 8 PEG300 3 PEG 1500 1 methylparaben 0.15 lactic acid 0. 03 Sodium lactate 0.07 Purified water 100

Example 7 Eye Wrinkle Oil (% by Weight) Olive Oil 40 2-Ethylhexanoic Acid Triglyceride 26 Squalane 30 PPG4000 2 PEG20000 0.9 δ-Tocopherol 1 Retinol 0.1

Example 8 Beauty Paste PEG300 30 PEG1500 40 PEG4000 10 Retinol 0.3 Isopropyl myristate 5 POE (25) Cetyl ether 2 Stearic acid 5 Purified water 100 parts in total

Example 9 Night Cream Squalane 15 Isopropylmyristate 5 Silicon Dioxide 3 Vaseline 6 Glyceryl Monoisostearate 2 POE (7) Hydrogenated Castor Oil 1.5 Propylparaben 0.2 Retinol 0.4 PEG6000 3 PEG400 3 Glycerin 17 Amount of purified water as 100

The skin external preparations of Examples 4 to 9 were excellent in retinol stability in daily use.

[0023]

INDUSTRIAL APPLICABILITY In the external preparation for skin of the present invention, the stability of retinol can be markedly improved by incorporating polyethylene glycol and / or polypropylene glycol.

Claims (1)

[Claims] 1. An external preparation for skin, comprising polyethylene glycol and / or polypropylene glycol mixed with retinol.