KR102440905B1 - Pickering emulsion composition - Google Patents

Abstract

The present invention relates to a composition of a Pickering emulsion formulation with improved storage stability, and more particularly, to a composition for preparing a Pickering emulsion stabilized by an aggregate formed by a host-guest action between cyclodextrin and a specific ester oil, It relates to a Pickering emulsion composition comprising CD and an ester oil in isoform at both ends.
In addition, the CD-based Pickering emulsion composition according to the present invention does not use an emulsifier, so it has good skin safety, and the storage stability of the Pickering emulsion formulation can be improved by changing the oil composition.

Description

Pickering emulsion composition

The present invention relates to a Pickering emulsion composition having improved storage stability.

Pickering emulsion is an emulsion form in which the interface is stabilized by solid particles. It was discovered by Pickering in 1907, and a lot of research has been conducted after it was recently lit up about Pickering emulsion 20 years ago. When the solid particles are in the form of Janus particles, that is, powder particles having both hydrophilic and hydrophobic properties, an effective Pickering emulsion can be formed. The material capable of forming the Pickering emulsion is a hydrophobic material, and fumed silica in which a part of the particles is substituted is representative. In addition, various materials such as latex, synthetic polymer, metal oxide, graphene, etc. can be used. .

Pickering emulsion has the advantage of less irritation to the skin and less risk of environmental pollution because it can make an emulsion form without using an emulsifier. It has been reported that the skin delivery of caffeine, a model drug, effectively occurs in the case of a Pickering emulsion composed of silica particles, as well as a good feeling of use due to strong thixotropy (Non-Patent Document 1). Nevertheless, in order to apply Pickering emulsion to products, it is one of the challenges in the industry to solve the stability problem due to shear stress and the long-term stability problem.

Cyclodextrin (CD) has a hydrophobic structure inside and hydrophilic outside, so it is used for encapsulation through host-guest action and protects, stabilizes, solubilizes, and deodorizes target substances. , handling, etc. In addition, it has been reported that CD forms an inclusion complex (IC) with a linear oil (eg, hydrocarbon oil) and main action, and microcrystals capable of maintaining Pickering emulsion through IC stacking are reported. Professor Saito's group in Japan reported that the emulsion of β-CD/hydrocarbon oil became more stable as the molecular weight of hydrocarbon oil increased (Non-Patent Document 2). It was found that the stability of the emulsion was increased due to a decrease in the size of the crystal (Non-Patent Document 3).

However, it is difficult to apply only hydrocarbon oil to the formulation, and there is a disadvantage in that the stability of the emulsion is actually lowered by temperature, salt, and urea.

Therefore, through the present invention, it was attempted to increase the storage stability of the Pickering emulsion composed of CD and oil by diversifying the composition of the oil.

Inter. J. Pharm., 2009, 368, 7-15 J Oleo Sci. 2009, 58(2), 85-90. Phys. Chem. Chem. Phys., 2013, 15, 17903-17914

Therefore, the present inventors studied to improve the storage stability of the Pickering emulsion formulation composed of β-CD and oil through a change in oil composition to solve the problem of long-term storage stability of the existing Pickering emulsion formulation composed of β-CD and hydrocarbon oil. As a result, the present invention was completed by developing a Pickering emulsion composition with improved storage stability including ester oil (especially, isoform ester oil) and cyclodextrin.

Accordingly, an object of the present invention is to provide a Pickering emulsion composition with improved storage stability.

As a means for solving the above problems, the present invention provides a Pickering emulsion composition with improved storage stability comprising an ester oil and a cyclodextrin.

The CD-based Pickering emulsion composition according to the present invention does not use an emulsifier, so it has good skin safety, and it is expected that the storage stability of the Pickering emulsion formulation consisting of β-CD and ester oil can be improved through the change in oil composition. It is expected.

1 is a result of observing the stability of Pickering emulsion prepared using β-CD aqueous solution and hydrocarbon oil ((A) Dodecane, (B) Tetradecane, (C) Hexadecane) after storage at room temperature for 6 months.
2 is a result of observing the stability of Pickering emulsion prepared using β-CD aqueous solution, hydrocarbon oil ((A) Hexadecane), and ester oil ((B) Dicaprylyl carbonate) after storage at room temperature for 6 months.
3 is a result of observing the stability of a Pickering emulsion prepared using a β-CD aqueous solution and hydrocarbon oil ((A) Hexadecane, (B) Isododecane, (C) Squalane) after storage at room temperature for 6 months.
4 is a β-CD aqueous solution, a hydrocarbon oil ((A) Hexadecane), and a Pickering emulsion prepared using an isoform ester oil ((B) Isostearyl isostearate) was observed for stability after storage at room temperature for 6 months.
Figure 5 is a β-CD aqueous solution and hydrocarbon oil ((A) Dodecane, (B) Hexadecane), ester oil ((C) Dicaprylyl carbonat), isoform ester oil ((D) Isostearyl isostearate) This is the result of observing stability after adding 0.5 ml of 8 M urea to the emulsion.
6 is a result of evaluating storage stability according to the degree of phase separation after preparing a Pickering emulsion composed of a β-CD aqueous solution, various hydrocarbon oils, and ester oils.

The present invention relates to a Pickering emulsion composition comprising an ester oil and a cyclodextrin with improved storage stability.

"Cyclodextrin (CD)" in the present invention means a round hollow molecule formed by gathering n dextrins, wherein n is not particularly limited thereto, but preferably an integer of 1 to 10,000, More preferably, it may be 6-8, and most preferably, it may be 7. The CD[n] can form a complex by strongly interacting with various guest molecules using the hydrophobic space inside, and the guest molecule is not particularly limited thereto, but hydrocarbon oil, ester oil, PEG, polyamine, It may be an amino acid, etc., but is not particularly limited thereto.

The term "hydrocarbon oil" in the present invention is a compound consisting of only hydrogen and carbon. In general, C _n H _{2n +2} , C _n H _{2n ,} C _n H _{2n - 2} is a compound of the form, wherein n is not particularly limited thereto, but is preferably an integer of 1 to 1,000, more preferably 8 to 30 this can be

In the present invention, "ester oil" refers to a compound in which a substance having an alcohol group and a carboxyl functional group forms an ester (-COO-) bond. Generally, it is a compound of the form represented by the following formula (1):

[Formula 1]

C _n H _{2n + 1} COOC _m H _{2m +1}

In Formula 1, n and m are not particularly limited thereto, but preferably an integer of 1 to 1,000, more preferably an integer of 5 to 100, and most preferably an integer of 8 to 30.

The term "a substance having an alcohol group" and a "functional group of carboxy" refers to a compound in which alcohol (OH) and carboxy (COOH) are present in a hydrocarbon chain, respectively. In general, it is a compound in the form of C _n H _{2n + 1} OH or C _n H _{2n + 1} COOH, wherein n is not particularly limited thereto, but preferably an integer of 1 to 1,000, more preferably 8 to 30. have.

In particular, it is more preferable that the ester oil has an isoform at both ends because it may have an advantage in that the bonding force between CD and oil is stronger.

In addition, the ester oil is preferably used in an amount of 20 wt% to 80 wt% (preferably 40 wt% to 70 wt%) based on the total Pickering emulsion composition. If its content is less than 20% by weight, it is difficult to form an emulsion, and if it exceeds 80% by weight, there is a problem in formulation and formulation stabilization.

In addition, the cyclodextrin is preferably used in an amount of 0.01 wt% to 20 wt% (preferably 0.1 wt% to 10 wt%) based on the total Pickering emulsion composition. If its content is less than 0.01% by weight, it is difficult to form an emulsion, and if it exceeds 20% by weight, there is a problem in formulation and formulation stabilization.

The Pickering emulsion composition according to the present invention may consist of an aqueous phase component including cyclodextrin and purified water, and an oil phase component including oil.

The purified water is preferably used in an amount of 25 wt% to 55 wt% (preferably 30 wt% to 50 wt%) with respect to the total Pickering emulsion composition.

In particular, a water-soluble polymer may be additionally included in the aqueous component for a feeling of use. As the water-soluble polymer, polyacrylate [carbopol, Aronvis, TR-2, etc.], xanthan gum [Keltrol, Merezan, Rhodicare, etc.], ammonium acryloyldimethyltaurate copolymer [ Aristoflex, Botanimulse, Acudyne SCP, SUpolymer G-1, etc.], acrylamide copolymer [Simulgel, Creasparkles, Flocare, Oristar], Natrozol, cellulose and cellulose derivatives [Natrosol, AEC hydroxyethylcellulose, alcoramnosan] , cellosize, HEC CF, Tylose, Methocel, etc.], chitosan, hyaluronic acid, PEG and PEG derivative copolymers [Poloxamer, TMCM, Pepol, etc.], Phthalilc anhydride derivatives and copolymers [Beckosol], dimer Dimethicone and dimethicone derivative copolymers [Xiameter, Botanisil, Siltext RT, etc.] may be used, but is not limited thereto. The water-soluble polymer may be included in an amount of 0.01 to 1% by weight based on the total composition of the Pickering emulsion.

In addition, the aqueous phase component may include a buffer solution together.

In addition, for fragrance, a fragrance component may be additionally included in the oily component.

In addition, the emulsion composition of the present invention may further include additives such as all kinds of ingredients used in conventional cosmetics, preservatives, antioxidants, and discoloration inhibitors within the range that does not impair the purpose of the present invention.

Accordingly, the present invention provides a cosmetic comprising the Pickering emulsion composition.

Hereinafter, examples and the like will be described in detail to help the understanding of the present invention. However, the embodiments according to the present invention may be modified in various other forms, and the scope of the present invention should not be construed as being limited to the following examples. The embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art.

Example One: emulsion ( 100 g ) Produce

β-CD was dissolved in purified water at room temperature for 2 hours. Oil was added to the aqueous phase, and the emulsified particles were homogenized at 20,000 rpm with an ultra-homogenizer.

Awards Purified water 44 g Cyclodextrin 0.5 g paid oil 55.5 g

Example 2: emulsion ( 100 g ) manufacturing

Polymers such as carbopol and fragrance ingredients were added to control the feeling and fragrance of the emulsion.

β-CD and polymer (Carbopol) were dissolved in purified water at room temperature for 2 hours. Flavored oil was added to the aqueous phase, and the emulsified particles were homogenized at 20,000 rpm for 10 minutes with an ultra-homogenizer. After that, Tris-buffer was added and homogenized for an additional 5 minutes.

Awards Purified water 43.19 g Tris-buffer (10%) 0.7 g Carbopol 981 0.1 g Cyclodextrin 0.5 g paid oil 55.5 g Sandalwood Incense 10 mg

Experimental example One

In order to confirm that the stability of the formulation is strengthened as the molecular weight of the hydrocarbon oil increases, 0.04 g of β-CD solution is dissolved in 4 g of purified water, and then dodecane, tetradecane, hexadecane) 6 g of each was added and 20,000 rpm was applied with an ultra-homogenizer to prepare an emulsion. Then, the storage stability of the emulsion for 6 months at room temperature was confirmed.

As a result, as reported in the previous study as shown in FIG. 1 , it was confirmed that the stability of the emulsion increased as the hydrocarbon oil having a large molecular weight was used. This is because as the molecular weight of oil with a high molecular weight increases, the number of β-CDs that one molecule can hold increases, which facilitates stacking between β-CDs and increases the intermolecular bonding force due to hydrophobic interaction. see.

Experimental example 2

When dicaprylyl carbonate with the same number of hexadecane and hydrocarbons used in Experimental Example 1, but having a strong hydrophilic structure in the molecule, was used, β-CD and the stability of the emulsion formed were compared A formulation was prepared for

First, 0.04 g of β-CD solution was dissolved in 4 g of purified water, 6 g each of hexadecane and dicaprylyl carbonate was added, and 20,000 rpm was applied with an ultra homogenizer to prepare an emulsion. .

Thereafter, the emulsion was stored for 6 months at room temperature and 7 days at 50° C. to evaluate the stability of the emulsion.

As a result, it was confirmed that the emulsion composed of dicaprylyl carbonate and β-CD was more stable than the emulsion composed of hexadecane and β-CD as shown in FIG. Since it is not expected to be maintained in its shape, a more stable method was needed to maintain the stabilized product, and the following experiment was carried out.

Experimental example 3

Among hydrocarbon oils, the dimethyl group of a polyisobutylene (PIB) molecule whose molecular weight is less than 500 enters γ-CD (cavity size, 0.88 nm), and sufficient hydrogen bonding between the oxygen atom of γ-CD and the hydrogen atom of PIB can occur. Referring to the report that trap formation is stable because the distance is secured (Macromolecules, 1996, 29, 5611), β-CD (0.7 nm) with a smaller cavity than γ-CD is an isoform with only one methyl group attached (Macromolecules, 1996, 29, 5611). isotype) was assumed to form a stable entrapment with hydrocarbon oils. Therefore, it was determined that a stable Pickering emulsion could be prepared if this assumption was used for the emulsion, and it was confirmed using Isododecane and squalane.

First, 0.04 g of β-CD solution was dissolved in 4 g of purified water, 6 g each of isododecane and squalene were added, and 20,000 rpm was applied with an ultra-homogenizer to prepare an emulsion. Thereafter, the emulsion was stored for 6 months at room temperature and 7 days at 50° C. to evaluate the stability of the emulsion.

As a result, it was confirmed that the emulsions were more stable than hexadecane as shown in FIG. 3 . It is presumed that the isoform molecule stably formed IC with the cavity of β-CD, and thus the stability of the emulsion was also increased.

Experimental example 4

The stability of the emulsion consisting of β-CD and oil according to the molecular weight of the oil was evaluated.

If the molecular weight is higher than that of hexadecane, the melting point is higher than room temperature, so it is difficult to apply to the formulation because it exists in the form of a wax. If an oil with an ester in the middle is used, even if the molecular weight increases, it is in a liquid form at room temperature, so it was thought that it could be applied to the formulation. However, ester oil, like Myristyl myristate, exists in the form of wax when the molecular weight increases, so it is difficult to apply only ester oil to the formulation. Therefore, using the isoform of the ester oil, it was expected that a stable Pickering emulsion with β-CD could be prepared, and a Pickering emulsion was prepared using isostearyl isostearate.

First, 0.04 g of β-CD solution was dissolved in 4 g of purified water, 6 g of isostearyl isostearate was added, and 20,000 rpm was applied with an ultra-homogenizer to prepare an emulsion. Thereafter, the emulsion was stored for 6 months at room temperature and 7 days at 50° C. to evaluate the stability of the emulsion.

As a result, as shown in FIG. 4 , it was confirmed that the emulsions were maintained much more stably than when other oils were used. It is considered that the most stable Pickering emulsion composed of β-CD and oil was formed by taking the advantage of oil with a high molecular weight and the strength of the binding force between β-CD and oil due to the isotype at the same time.

Experimental example 5

Stability to urea of the emulsion according to the type of β-CD and oil was evaluated. Urea is known as a substance that causes separation of emulsions by breaking hydrogen bonds between water and emulsifiers, and is especially used to check the stability of cosmetic formulations. After preparing an emulsion by selecting 4 types of ester oil in the hydrocarbon, ester form, and iso form, it was confirmed how the stability of the emulsion was changed when urea was added.

After dissolving 0.04 g of β-CD solution in 4 g of purified water, dodecane, hexadecane, dicaprylyl carbonate, and isostearyl isostearate 6 g each Each was added and 20,000 rpm was applied with an ultra homogenizer to prepare an emulsion. Then, 0.5 ml of 8 M urea was added to the emulsion to compare the stability of the emulsion.

As a result, as shown in FIG. 5 , the emulsion composed of dodecane and β-CD having a small molecular weight was easily separated by urea, but it was also different for urea when isostearyl isostearate, an isoform oil with a large molecular weight, was used. It was confirmed that it was kept stable.

Experimental example 6

After dissolving 0.04 g of β-CD solution in 4 g of purified water, dodecane, tetradecane, hexadecane, dicaprylyl carbonate, isododecane, iso Add 6 g each of Isohexadecane, Squalene, Isononyl isononanoate, and Isostearyl isostearate, and apply 20,000 rpm with an ultra homogenizer to apply the pickering emulsion. prepared. After storage at room temperature for 6 months, stability was evaluated according to the degree of phase separation.

The emulsion stability was expressed by calculating the volume occupied by the emulsion by Equation 1 below.

[Equation 1]

Stability (%) of emulsion = (height occupied by emulsion/height of total solution) X 100

As a result of evaluating the stability as shown in FIG. 6 , it was confirmed that the greater the molecular weight of the oil and the isoform, the higher the storage stability of the emulsion.

Claims (9)

ester oils and cyclodextrins in isoforms at both ends;
The ester oil is 20 wt% to 80 wt% based on the total Pickering emulsion composition, Pickering emulsion composition with improved storage stability.
The method of claim 1,
Ester oil is a Pickering emulsion composition, which is an ester oil represented by the following formula (1):
[Formula 1]
C _n H _{2n + 1} COOC _m H _{2m +1}
In Formula 1, n and m are each an integer of 1 to 1,000.
3. The method of claim 2,
In Formula 1, n and m are each an integer of 8 to 30 Pickering emulsion composition.
delete delete The method of claim 1,
The ester oil is 40 wt% to 70 wt% of the Pickering emulsion composition based on the total Pickering emulsion composition.
The method of claim 1,
The cyclodextrin is 0.01 wt% to 20 wt% of the Pickering emulsion composition based on the total Pickering emulsion composition.
8. The method of claim 7,
The cyclodextrin is 2 wt% to 10 wt% of the Pickering emulsion composition based on the total Pickering emulsion composition.
A cosmetic comprising the composition according to claim 1.

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