Emulsion structure for enhancing skin absorption and method of preparing the same

Abstract

Provided are an emulsion structure for enhancing skin absorption and a method of preparing the same. According to a composition of an aspect of the present disclosure, due to a hexagonal structure that can mimic intercellular lipid ingredients of skin, the composition has excellent formulation safety and piezoelectric properties capable of generating a microcurrent, and accordingly, the composition is able to enhance skin absorption of a physiologically active substance without damaging the skin barrier.

Claims

1. A cosmetic composition for enhancing skin absorption formulated as an emulsion having a hexagonal crystal structure, comprising: an oil phase comprising ceramides or derivatives thereof and a glucoside-based surfactant; and a liquid phase comprising polyols, wherein the glucoside-based surfactant is C.sub.12-C.sub.20 alkyl glucoside, wherein an amount of the surfactant is in a range of 1 weight % to 3 weight % based on the total amount of the cosmetic composition, and wherein an amount of the ceramides or the derivatives thereof is in a range of 0.1 weight % to 1 weight % based on the total amount of the cosmetic composition.

2. The cosmetic composition of claim 1, wherein the derivatives of the ceramides comprise at least one selected from ceramide EOP, ceramide NG, ceramide NS, ceramide NP, ceramide AS, and ceramide AP.

3. The cosmetic composition of claim 1, wherein the oil phase or the liquid phase further comprises a physiologically active substance.

4. The cosmetic composition of claim 1, wherein the cosmetic composition has a piezoelectric constant in a range of 60 pC to 120 pC.

5. The cosmetic composition of claim 1, wherein the cosmetic composition is a piezoelectric cosmetic.

6. The cosmetic composition of claim 1, wherein the cosmetic composition enhances skin absorption of the ceramides or derivatives thereof.

7. A composition for delivering a physiologically active substance to skin, the composition being formulated as an emulsion having a hexagonal crystal structure, and comprising: an oil phase comprising ceramides or derivatives thereof and a glucoside-based surfactant; a liquid phase comprising polyols; and the physiologically active substance at least one selective from the group consisting of whitening agent, a sunscreen agent, an atopy enhancer or therapeutic agent, an antioxidant, an analgesic, an anti-inflammatory agent, an anti-infective agent, a wound- or scar-healing agent, an antipyrotic, a nutritional supplement, a mineral, and a vitamin; wherein the glucoside-based surfactant is C.sub.12-C.sub.20 alkyl glucoside, wherein an amount of the surfactant is in a range of 1 weight % to 3 weight% based on the total amount of the cosmetic composition, and wherein an amount of the ceramides or the derivatives thereof is in a range of 0.1 weight % to 1 weight % based on the total amount of the cosmetic composition.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

(2) FIG. 1 is a wide-angle X-ray scattering graph of a cosmetic composition according to an embodiment; and

(3) FIG. 2 is a graph showing an in vitro skin absorption effect of a cosmetic composition according to an embodiment.

DETAILED DESCRIPTION

(4) Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

Example: Preparation of Cosmetic Composition Having Hexagonal Structure

(5) Cosmetic compositions having compositions of Table 1 below (unit: weight %) were prepared in Example and Comparative Example. In the cosmetic compositions of Comparative Example, surfactants based on cetyl palmiate, sorbitan olivate, sorbitan palmitate, or the like were used, and in the cosmetic compositions of Example, surfactants based on alkyl glucoside were used.

(6) In detail, according to each ingredient and content shown in Table 1, each raw material was weighed in a beaker, and then, Phase A (i.e., oil phase) was dissolved at a raised temperature in a range of 80° C. to about 90° C., and the resulting phase was slowly added to Phase B (i.e., liquid phase) at room temperature. Here, the mixture of Phase A and Phase B was constantly stirred, and then, Part C (i.e., a thickener) was added thereto and stirred. The resulting mixture was cooled to a temperature of 30° C., and Part D (i.e., a preservative) was added thereto. Afterwards, bubbles were removed from the cooled mixture, thereby preparing each cosmetic composition.

(7) TABLE-US-00001 TABLE 1 Content (weight %) Comparative Ingredients Example Example A Cetearyl alcohol 1.0 1.0 Cetyl palmiate 0.8 0 Sorbitan olivate 0.6 0 Sorbitan palmiate 0.6 0 C.sub.12-C.sub.20 alkyl glucoside 0 2.0 Ceramide 0.5 0.5 Caprlic/Capric triglyceride 3.5 3.5 B Purified water Suitable amount Suitable amount Glycerin 10 10 C Cabomer Suitable amount Suitable amount D Preservative Suitable amount Suitable amount

Experimental Example 1: Evaluation of Skin Safety

(8) The skin safety evaluation was performed with respect to the cosmetic compositions of Example and Comparative Example.

(9) In detail, for 20 adult men and women having no skin disease, the degree of irritation of the formulations prepared in Example e and Comparative Example was evaluated as follows. 20 μl of a sample was applied to the forearms of the testers, and then, the test site was sealed and patched for 24 hours. In 30 minutes and 24 hours after removal of the patch, the skin response was examined based on the terminology set forth in the CTFA guidelines. The skin irritation index (PII) scores of the testers obtained by the criteria were averaged and evaluated as ‘hypoallergenic’ for the average value of less than 1, ‘light irritation’ for the average value of less than 2, ‘moderate irritation’ for the average value of less than 3.5, and ‘strong irritation’ for the average value of 3.5 or greater.

(10) TABLE-US-00002 TABLE 2 Comparative Experiment item Example Example Primary Irritation No irritation No irritation Index (P.I.I)

(11) As shown in Table 2, it was confirmed that the compositions of Example and Comparative Example were products causing no irritation, and thus, may be used safely.

Experimental Example 2: Analysis of Crystal Structure of Emulsion Formulation

(12) To analyze the emulsion structure of the compositions of Example and Comparative Example, the wide angle X-ray scattering (WAXS) analysis (available by BL4C SAXS, Pohang Accelerator Laboratory) was performed, and the results are shown in FIG. 1.

(13) FIG. 1 is a wide angle X-ray scattering graph of a cosmetic composition according to an embodiment.

(14) As shown in FIG. 1, in the case of the comparative Example of the Comparative Example, peaks were observed at 1.51 Å.sup.−1 and 1.67 Å.sup.−1. When substituting the Bragg equation (d=2π/q) to obtain d-spacing which represents the size of a structure, the obtained values were 0.416 nm and 0.376 nm, which refers to a orthorhombic packing structure which is a densely packed structure.

(15) However, in the case of the composition of Example, a peak was observed at 1.52 Å.sup.−1. When substituting the Bragg equation (d=2π/q) to obtain d-spacing which represents the size of a structure, the obtained value was 0.414 nm, which refers to a hexagonal packing structure which is a relatively loosely packed structure.

(16) Therefore, it was confirmed that, depending on the types of the surfactant, the packing of the molecules at the interface varied, resulting in different structures. In addition, it was also confirmed that a cosmetic composition of an emulsion formulation having a hexagonal crystal structure was prepared herein.

Experimental Example 4: Confirmation of Skin Absorption Effect

(17) To evaluate skin absorption effect of ceramide under in vitro conditions with respect to the compositions of Example and Comparative Example, experiments using Franz cells were performed.

(18) In detail, the artificial membrane (Strat-M) manufactured by Merck Company was placed inside an open-type glass laboratory apparatus, and an appropriate amount of each of the compositions of Example and Comparative Example was applied thereon and then sufficiently absorbed. The acceptor portion was filled with 13 mL of 50:50 PBS/EtOH (v/v), and the penetration experiment was performed at a temperature of 32° C. After 1, 2, 4, and 8 hours, the receptor portion which penetrated the artificial membrane using the solvent (50:50 PBS/EtOH (v/v) was extracted, and the concentration of ceramide was measured by HPLC analysis. The conditions for HPLC analysis are shown in Table 3.

(19) TABLE-US-00003 TABLE 3 Column C.sub.15 (250 × 4.6 mm, 5 μm, 300 A, Jupiter) Detector Reversed phase high-pressure liquid chromatography (UltiMate 3000, Dionex) Flow rate 1.0 ml/min Absorbance 325 nm Mobile phase 90% methanol, isocratic elution

(20) Then, the HPLC data results are shown in FIG. 2.

(21) FIG. 2 is a graph showing in vitro skin absorption effect of a cosmetic composition according to an embodiment.

(22) AS shown in FIG. 2, the composition of Example having a hexagonal packing structure which is a relatively loose structure showed excellent skin absorption under in vitro conditions, compared to the compositions of Comparative Example having an orthorhombic packing structure which is a dense structure.

Experimental Example 5: Piezoelectricity Test

(23) To evaluate piezoelectric properties of the compositions of Example and Comparative Example, the liquid-phase piezoelectric measuring device (refer to KR10-1793902) was used to measure piezoelectric properties.

(24) In detail, 2 ml of each sample of Comparative Example and Example was placed between electrodes of the liquid-phase piezoelectric measuring device, a motor stage was moved and sampled, and then, the force was repeatedly applied to the samples at a rotation angle of 10°. Afterwards, electric charges generated in the samples were measured to measure piezoelectric properties, and the results are shown in Table 4.

(25) TABLE-US-00004 TABLE 4 Experiment Comparative item Example Example Piezoelectric 51.62 91.18 property (pC)

(26) As a result, as shown in Table 4, it was confirmed that the composition of Example having a hexagonal packing structure had high piezoelectricity. In other words, it was confirmed that, due to the relatively loose structure, molecules had increased movement and the polarization phenomenon easily occurred, resulting in strong piezoelectric properties.

(27) Regarding the composition according to an aspect of the present disclosure, the composition has a hexagonal structure that can mimic the intercellular lipid ingredients of the skin, and accordingly, the formulation of the composition is safe and the composition may have piezoelectric properties that can generate a microcurrent. Thus, the composition may have an effect that can enhance the skin absorption of the physiologically active substance without damaging the skin barrier.

(28) It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the following claims.