JP6724228B2 - Liposomes encapsulating fats and oils - Google Patents

Description

The present invention relates to liposomes and the like encapsulating oil and fat components.

Liposomes are artificial capsules composed of phospholipids, which are the main constituents of biological membranes. Phospholipids have an amphipathic structure and form a lipid bilayer (in other words, a bilayer membrane). An oil-soluble substance can be incorporated into the bilayer membrane, and a water-soluble substance can be incorporated into the inner aqueous phase depending on the preparation method.

JP-A-2015-174860 International Publication No. 2008/093848

As described above, since liposomes can incorporate an oil-soluble substance inside the bilayer membrane, it is possible that liposomes can be used for stably containing an oil/fat component in an aqueous composition. Further, in recent years, attention has been focused on the efficacy of vegetable oils and fats components, and in particular, there is an increasing demand for compounding the vegetable oils and fats components with external compositions (especially aqueous aqueous compositions) such as cosmetics.

In particular, when such an aqueous composition is used for cosmetics, the appearance (transparency) is often important, and it is particularly important that the transparency is maintained. This is because consumers tend to avoid compositions that become cloudy over time (especially cosmetic compositions).

Further, it is advantageous that the size of each liposome particle is relatively large because the amount of the component that can be encapsulated increases, and as a result, the amount of the fat and oil component that can be incorporated increases.

Furthermore, the more uniform the size of each liposome particle (that is, the more uniform the liposome particles), the less likely the liposomes are to coalesce or disintegrate, and the higher dispersion stability over time tends to occur. From this viewpoint, it is preferable that the size of each liposome particle is as uniform as possible.

Therefore, the present invention provides a liposome composition encapsulating a fat and oil component, wherein the liposome-containing composition maintains transparency and liposome particle size uniformity as much as possible, and each liposome particle size is relatively large. The purpose is to

The present inventors maintain transparency and liposome particle size uniformity by using specific phospholipids and surfactants in specific ratios for liposome preparation, and contain liposomes in which each liposome particle size is relatively large. The possibility of preparing a composition was found, and further improvements were made to complete the present invention.

The present invention includes the subject matter described in the following sections, for example.
Item 1.
(A) hydrogenated phospholipids, and (B) polyoxyethylene hydrogenated castor oil having an average addition mole number of ethylene oxide of 40 to 95 are included in a mass ratio (A)/(B)=2 to 8,
Liposomes containing oil and fat components.
Item 2.
Item 2. The liposome according to Item 1, wherein the oil and fat component is at least one selected from the group consisting of rice oil, soybean oil, olive oil, medfoam oil, sunflower oil, hazelnut oil, and tocopherol.
Item 3.
Item 3. The liposome according to Item 1 or 2, wherein the hydrogenated phospholipid is hydrogenated lecithin.
Item 4.
Item 4. The liposome according to any one of Items 1 to 3, which has an average particle size of 65 nm or more.
Item 5.
Item 5. The liposome according to any one of Items 1 to 4, which has a polydispersity index (PdI) of 0.25 or less. Item 6.
Item 7. A composition containing the liposome according to any one of Items 1 to 5.
Item 7.
Item 7. The composition according to Item 6, having a 600 nm wavelength transmittance of 70% or more.
Item 8.
Item 8. The composition according to Item 6 or 7, which is an external pharmaceutical composition, an oral composition, or a cosmetic composition.

Provided are a liposome-containing composition having a relatively large liposome particle size, which maintains transparency and liposome particle size uniformity, liposomes contained in the composition, and a method for producing these. The liposome-containing composition is particularly advantageous for use as a cosmetic composition.

Hereinafter, each embodiment included in the present invention will be described in more detail. The present invention preferably includes a liposome-containing composition, a liposome contained in the composition, a method for producing these, and the like, but the present invention is not limited thereto, and the present invention is disclosed in the present specification. Includes everything that can be recognized by the trader.

The liposome included in the present invention contains (A) hydrogenated phospholipid, (B) polyoxyethylene hydrogenated castor oil having an average addition mole number of ethylene oxide of 40 to 95, and (C) an oil component. To do. Hereinafter, the liposome included in the present invention may be referred to as “the liposome of the present invention”. In addition, although not particularly limited, it is preferable that the liposome of the present invention further contains (D) cholesterol. This is because the localization of cholesterol (D) between lipids enhances the bond between liposome membranes and improves the stability of vesicles.

Preferable examples of the phospholipid of the hydrogenated phospholipid include glycerophospholipids such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol and phosphatidylic acid, and sphingolipids such as sphingomyelin. Also, lecithin (eg, soybean lecithin, corn lecithin, cottonseed oil lecithin, egg yolk lecithin, egg white lecithin, etc.) can be used. The lecithin preferably has a phosphatidylcholine content of 60% by mass or more, more preferably 65, 70, 75, 80, 85, or 90% by mass or more. This is because as the content of phosphatidylcholine increases, the liposome-forming ability is improved, and precipitation with time is not observed, and the stability is improved. In addition, phospholipid derivatives into which polyethylene glycol or aminoglycans are introduced, phosphatidylcholine hydroxide, lysophosphatidylcholine and the like are also included in the phospholipids herein.

Preferable examples of the hydrogenated phospholipid include those obtained by hydrogenating the phospholipid. Among them, for example, hydrogenated glycerophospholipids, particularly hydrogenated phosphatidylethanolamine, hydrogenated phosphatidylserine, hydrogenated phosphatidylinositol, hydrogenated phosphatidylcholine and the like are preferable. Further, hydrogenated lecithin (for example, hydrogenated soybean lecithin, hydrogenated egg yolk lecithin, hydrogenated corn lecithin, hydrogenated cottonseed oil lecithin, etc.) can also be used.

The hydrogenated phospholipids may be used alone or in combination of two or more.

The polyoxyethylene hydrogenated castor oil used for the liposome of the present invention has an average added mole number of ethylene oxide of 40 to 95 (40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, or 95). It is preferably about 45 to 90, more preferably about 50 to 80, even more preferably about 55 to 70, and even more preferably about 55 to 65. The polyoxyethylene hydrogenated castor oil can be used alone or in combination of two or more.

Examples of the oil and fat component include animal oil and fat components and vegetable oil and fat components. The animal fat component here includes not only animal fat components but also synthetic fat components known as animal fat components. Similarly, the vegetable oil/fat component here includes not only a vegetable oil/fat component but also a synthetic oil/fat component known as a vegetable oil/fat component. For example, since tocopherol is a component contained in many vegetable oils, even a synthesized tocopherol is included in the vegetable oil component here. As the oil and fat component, a vegetable oil and fat component is particularly preferable.

Examples of the vegetable oil component include rice oil, soybean oil, olive oil, medfoam oil, sunflower oil, hazelnut oil, and tocopherol (α-tocopherol is preferable, for example, D-α-tocopherol, dl-α-tocopherol, dl acetate dl. -(Alpha)-tocopherol etc. are included) etc. can be mentioned. The rice oil is preferably rice bran oil. As the rice bran oil, a rice bran oil extracted with a solvent (eg, hexane, acetone, etc.) can be used, but a rice bran oil obtained by squeezing (preferably squeezing) the rice bran is preferable. In addition, other vegetable oils and fats can be used by appropriately selecting known oils that are particularly suitable for cosmetics. Moreover, the vegetable oil component can be used individually by 1 type or in combination of 2 or more types.

The (A) hydrogenated phospholipid and (B) polyoxyethylene hydrogenated castor oil having an average added mole number of ethylene oxide of 40 to 95 are contained in a mass ratio (A)/(B) of 2 to 8. The lower limit of the mass ratio range is, for example, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1. It may be 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, or 3.9. The upper limit of the mass ratio range is, for example, 7.9, 7.8, 7.7, 7.6, 7.5, 7.4, 7.3, 7.2, 7.1, 7, 6. .9, 6.8, 6.7, 6.6, 6.5, 6.4, 6.3, 6.2, 6.1, 6, 5.9, 5.8, 5.7, 5 .6, 5.5, 5.4, 5.3, 5.2, 5.1, 5, 4.9, 4.8, 4.7, 4.6, 4.5, 4.4, 4 It may be .3, 4.2, or 4.1. The mass ratio range is, for example, preferably 2.5 to 6, and more preferably 3 to 5.

The form in which (A), (B), and (D) are contained in the liposome is not particularly limited. For example, when they are present in the hydrophilic region or hydrophobic region formed inside the liposome, The case of being attached to the surface of the outermost membrane of the body and the like are included, but the case of coexisting with the membrane constituent substance of the liposome (particularly contained in the liposome as a membrane constituent component of the liposome) is preferable.

The amount of the (C) oil/fat component encapsulated in the liposome of the present invention can be appropriately set, but for example, (C):(A) is preferably about 1:1 to 10 in terms of mass ratio, and 1:2-8. Or about 1:2.5 to 6 is more preferable, and about 1:3 to 5 is further preferable. When (D) is included, the mass ratio of (C) and (A) described above is preferable, and the mass ratio of (C):(A+D) is more preferably about 1:1 to 10. , 1:2 to 8 or 1:2.5 to 6 are more preferable, and 1:3 to 5 or 1:4 to 5 are even more preferable.

The liposomes are classified into two types, multilamellar liposomes (MLV) and unilamellar liposomes, based on the number of lipid bilayers. The unilamellar vesicles are further classified into SUV (small unilamella vesicle), LUV (large unilamella vesicle), GUV (giant unilamella vesicle), etc. according to their size. Any of these can be preferably used as the liposome of the present invention. Of these, multilamellar vesicles (MLV) are more preferable. When the mass ratio is within the range of (A)/(B), MLV tends to be formed. Further, as the size (particle size) of the liposome of the present invention, those having an average particle diameter (meaning an average outer diameter when not having the spherical particle shape) are preferably 65 nm or more, 66, More preferably, 67, 68, 69, 70, 71, 72, 73, 74, or 75 or more. The upper limit of the average particle diameter is not particularly limited. For example, 150 nm or less is exemplified. In addition, about 140 nm, 130 nm, 120 nm, 110 nm, 100 nm, or about 90 nm or less can be exemplified. When the average particle diameter is in the above range, a sufficient amount of oil and fat component can be retained in the liposome. When the average particle size is less than the lower limit, the amount of the oil/fat component retained becomes small and the liposome particles are apt to aggregate, so that the stability of the composition decreases. If the average particle size exceeds the upper limit, the liposome particles aggregate, and further, the transdermal absorbability is reduced as compared with particles having a small size.

The polydispersity index (PdI) of the liposome of the present invention is preferably 0.25 or less, and more preferably 0.24, 0.23, or 0.22 or less. The polydispersity index (PDI) is an index for evaluating the width of the particle size distribution and takes a value in the range of 0 to 1. It can be said that the closer to 0, the more uniform the dispersion. The more uniform the dispersion, the less likely the liposomes will coalesce or disintegrate, and the higher the dispersion stability over time.

The average particle diameter and PdI are values measured by the dynamic light scattering method. For example, it can be measured using a particle size distribution analyzer by dynamic light scattering.

Further, the liposome of the present invention preferably has a pH of about 6 to 7.5. The liposome having such a pH range is preferable because the temporal dispersion stability is further increased. A liposome having such a pH range can be prepared, for example, by adjusting the pH of the composition used for liposome preparation in advance to the pH range. A pH adjuster can be used to adjust the pH. Examples of the pH adjusting agent include sodium hydroxide and potassium hydroxide.

The present invention also includes a liposome composition containing the liposome of the present invention. The liposome composition is preferably an aqueous composition. In addition, the composition is preferably used as, for example, a pharmaceutical composition for external use, a composition for oral cavity, and a cosmetic composition.

The liposome of the present invention and a composition containing the liposome (liposome composition) can be prepared, for example, by stirring a composition containing the liposome raw material and water, and further subjecting the composition to high-pressure treatment if necessary. ..

As the raw material of the liposome, the contents described above can be preferably applied as they are. For example, a composition obtained by mixing (A), (B), and (C) above, and optionally (D) and other components (for example, a polyhydric alcohol, preferably propylene glycol) with water. The product can be prepared and used. With respect to each condition such as the amount of each component used, the above description of the liposome raw material can be preferably applied as it is. It is also preferable to adjust the pH of the composition to about 6 to 7.5 in advance. As described above, a pH adjuster (eg, sodium hydroxide, potassium hydroxide, etc.) can be used to adjust the pH.

As the stirring treatment, known stirring treatment used in the liposome preparation field can be preferably used. For example, a homomixer can be used to stir at a rotation speed of 3000 to 10000 rpm, preferably 4000 to 6000 rpm for about 2 to 10 minutes. By the stirring treatment, liposomes can be usually prepared.

Further, as the high-pressure treatment, known stirring treatment used in the field of liposome preparation can be preferably used. For example, a method of subjecting the agitated composition to high pressure treatment using a wet atomization device can be mentioned. STARBURSTmini (Sugino Machine Co., Ltd.) is exemplified as such a wet atomizer. Examples of the high pressure treatment include treatment at 100 to 400 MPa (preferably 150 to 300 MPa). The high-pressure treatment can usually reduce the particle size of liposomes and make each particle size more uniform.

The liposome suspension thus obtained can be used as it is as a liposome composition containing the liposome of the present invention.

The liposome and the liposome composition of the present invention may contain components other than the above-mentioned components as long as the effects of the present invention are not impaired. For example, oily components, lipids, water-soluble substances, physiologically active substances and the like are included. In particular, components known to be used in external medicines or cosmetics can be preferably used. For example, bactericides (especially phenolic bactericides such as isopropylmethylphenol); antioxidants such as ascorbic acid; organic acids such as lactic acid and citric acid; alkaline compounds such as potassium hydroxide and sodium hydroxide; phosphatidyl glycerol; Lipids such as phosphatidylethanolamine; natural polymers such as chitosan, fucoidan, hyaluronic acid; synthetic polymers such as polyethylene glycol and carboxyvinyl polymer; sugars such as trehalose, lactulose and maltitol; polyols such as glycerin. ..

Each of the components used in the liposome and the liposome composition of the present invention is a known component, and a commercially available product can be purchased and used, for example.

Further, the liposome composition of the present invention preferably has a 600 nm wavelength transmittance of 70% or more, more preferably 71, 72, or 73% or more. The transmittance is a transmittance (%) at a wavelength of 600 nm (generally used for measuring turbidity) measured using a spectrophotometer (for example, UV-2600: SHIMAZU). It can be said that the higher the transmittance, the more transparent.

Although not particularly limited, propylene glycol, hydrogenated lecithin, rice oil, polyoxyethylene hydrogenated castor oil having an average addition mole number of ethylene oxide of 55 to 65, and cholesterol are included in one embodiment of a particularly preferred liposome composition of the present invention. The thing contained is mentioned. Of these, components other than propylene glycol form liposomes.

In this case, the content ratio of each component to the liposome composition is 10 to 15% by mass of propylene glycol, 2 to 5% by mass of hydrogenated lecithin, and 0.5 to 4% by mass of rice oil (preferably 0. 8 to 2% by mass), 0.5 to 5% by mass of polyoxyethylene hydrogenated castor oil having an average addition mole number of ethylene oxide of 55 to 65, and cholesterol of 0.1 to 1.5% by mass (preferably 0.2). Is about 1% by mass), and the mass ratio (a)/(b) of (a) hydrogenated lecithin, and (b) polyoxyethylene hydrogenated castor oil having an average addition mole number of 55 to 65 of ethylene oxide is 2). It is especially preferable that it is -8.

In addition, in this specification, "comprising" includes "consisting essentially of" and "consisting of." is also included including "consisting essentially of" and "consisting of". Further, the invention includes all combinations of the constituent elements described in this specification.

Further, various characteristics (properties, structures, functions, etc.) described in the above-described embodiments of the present invention may be combined in any manner to specify the subject matter included in the present invention. That is, the invention includes all subject matter that is made up of any combination of the combinable properties described herein.

Hereinafter, the present invention will be described more specifically, but the present invention is not limited to the following examples.

Liposome suspensions were prepared according to the compositions shown in Table 1, Table 2 and Table 3. The value of each component in the table is% by mass. In each table, "PG" represents propylene glycol, "lecithin" represents hydrogenated lecithin (hydrogenated lecithin phosphatidylcholine content 70% by mass), rice bran oil was rice oil (Sambran rice oil (pressed rice bran oil): Sanwa Yushi Co., Ltd.), “HCO-60” represents polyoxyethylene hydrogenated castor oil having an average addition mole number of ethylene oxide of 60, and “Prince M” represents methyl paraoxybenzoate.

More specifically, the preparation is carried out in accordance with the composition described in each table according to the composition of propylene glycol, hydrogenated lecithin (hydrogenated lecithin), rice oil (Sambran rice oil (pressed rice bran oil): Sanwa Yushi Co., Ltd.), ethylene oxide Polyoxyethylene hydrogenated castor oil having an average added mole number of 60, cholesterol, and methyl paraoxybenzoate are dissolved (heating at 80° C.), and water (potassium hydroxide is dissolved) heated at 80° C. is added thereto. Then, the pH was adjusted to about 7, the mixture was stirred at 5000 rpm for 5 minutes, and a high-pressure treatment of 200 MPa was further performed to prepare the liposome suspensions of Examples and Comparative Examples. The stirring process was performed using a homomixer (Homomixer MARK II: PRIMIX). The high-pressure treatment was performed by using a wet atomization device (STARBURSTmini: Sugino Machine Ltd.).

The average particle diameter and polydispersity index (PdI) of the liposomes contained in each of the obtained liposome suspensions were measured using a particle size distribution analyzer (Zetasizer nano: Malvern) by dynamic light scattering. Specifically, each liposome suspension was diluted 100-fold with distilled water, and the diluted solution was put in a cuvette and placed in the particle size distribution meter for measurement. Furthermore, with respect to each liposome suspension, the transmittance (%) at a wavelength of 600 nm (wavelength generally used when measuring turbidity) was measured using a spectrophotometer UV-2600 (SHIMAZU). ..

Furthermore, in each of the obtained liposome suspensions, whether or not a liposome structure was actually formed was observed by a negative staining method using a transmission electron microscope (HT-7700: Hitachi High Technologies).

The liposome suspensions in Table 1, Table 2 and Table 3 were evaluated based on the average particle diameter, polydispersity index (PdI), transmittance (%) and the result of transmission electron microscope observation. The evaluation was performed according to the following evaluation criteria.
Each measurement result and evaluation result are also shown in each table.

<Average particle size>
A: 75 nm to 90 nm
◯: 65 nm to 100 nm
Δ: 100 nm to 150 nm
X: less than 65 nm or more than 150 nm

<Polydispersity index (PdI)>
◎: 0.22 or less ○: 0.25 or less ×: 0.25 or more

<Transmittance (%)>
◎: 73% or more ○: 70% or more ×: Less than 70%

<Formation of liposome>
A: Formation of multilamellar liposomes (MLV) is observed.
◯: Formation of unilamellar vesicles is observed.
X: No liposome formation is observed.

<Comprehensive evaluation>
⊚: The average particle size, polydispersity index (PdI), and permeability (%) were all evaluated as ⊚ or ◯, and the liposome formed a multilamellar liposome (MLV).
◯: The average particle diameter, polydispersity index (PdI), and transmittance (%) were all evaluated as ⊚ or ◯, and the liposome formed a single-layer liposome.
X: Poor in any of the average particle size, polydispersity index (PdI), permeability (%), and evaluation of liposome formation.

From the results, only in Examples 1 to 8 in which the (lecithin/HCO-60) mass ratio in the table is in the range of 2 to 8, the average particle diameter was 65 nm or more, and the polydispersity index (PdI) was 0.25. And the transmittance at a wavelength of 600 nm was 70% or more. Also, multilamellar liposomes (MLV) were formed in Examples 1, 2, 6, 7, and 8, and unilamellar liposomes were formed in Examples 3, 4, and 5.

Furthermore, according to the composition shown in Table 4, each liposome suspension was prepared by the same method as the composition of Tables 1-3. In addition, the value of each component in the said table shows mass %. In the table, "PG" represents propylene glycol, "lecithin 70" represents hydrogenated lecithin (hydrogenated lecithin phosphatidylcholine content 70% by mass), and "lecithin 90" represents hydrogenated lecithin (hydrogenated lecithin phosphatidylcholine content). 90% by mass), “Komenuka oil” indicates rice oil (San Bran rice oil (pressed rice bran oil): Sanwa Yushi Co., Ltd.), “soybean oil” indicates (soybean oil YM: Nisshin Oilio), "Olive oil" indicates (NIKKOL olive oil: Nikko Chemicals), "Medform oil" indicates (CROPURE MEADOWFOAM: Croda Japan), "sunflower oil" indicates (NIKKOL sunflower oil: Nikko Chemicals), and "hazelnut oil". Indicates (NIKKOL hazelnut oil: Nikko Chemicals), "DL-α-tocopherol" indicates (Nacalai Tesque), and "HCO-40", "HCO-50", "HCO-60", or "HCO-80""Indicates polyoxyethylene hydrogenated castor oil having an average added mole number of ethylene oxide of 40, 50, 60, or 80, respectively, and "Prince M" indicates methyl paraoxybenzoate. Similar to Examples 1 to 8, these liposome suspensions had an average particle size of 65 nm or more, a polydispersity index (PdI) of 0.25 or less, and a 600 nm wavelength transmittance of 70% or more. It was

The formulation examples of the composition of the present invention are shown below. In addition, the compounding quantity (%) of each prescription example shows mass %. As the "liposome containing liposomes" used in each of the following formulations, the liposome suspension of any of the above examples can be preferably used.

Prescription example 1: Lotion

Prescription example 2: Cream

Prescription example 3: mouthwash

Prescription example 4: toothpaste

Claims (7)

(A) hydrogenated phospholipids, and (B) polyoxyethylene hydrogenated castor oil having an average addition mole number of ethylene oxide of 40 to 95 are included in a mass ratio (A)/(B)=2 to 8,
Contains oil and fat components ,
The average particle size is 65 nm or more and 90 nm or less,
Liposomes. The liposome according to claim 1, wherein the oil and fat component is at least one selected from the group consisting of rice oil, soybean oil, olive oil, medfoam oil, sunflower oil, hazelnut oil, and tocopherol. The liposome according to claim 1 or 2, wherein the hydrogenated phospholipid is hydrogenated lecithin. The liposome according to any one of claims 1 to 3, which has a polydispersity index (PdI) of 0.25 or less. A composition containing the liposome according to any one of claims 1 to 4. The composition according to claim 5, which has a 600 nm wavelength transmittance of 70% or more. The composition according to claim 5 or 6 , which is an external pharmaceutical composition, an oral composition, or a cosmetic composition.