JPH06239734A - Preparation of liposome and loposome formulation - Google Patents

Abstract

PURPOSE:To make it possible to simply prepare uniform liposome having small particle diameter in large amount. CONSTITUTION:This method for preparing liposome formulation is characterized by preparing liposome by dissolving a lipid in ethanol or an ethanol aqueous solution and adding the solution to an aqueous solution or adding the aqueous solution to the lipid solution. The liposome formulation is prepared by the method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to pharmaceuticals, quasi drugs,
The present invention relates to a method for producing liposomes applied to cosmetics and the like, and a liposome preparation. More specifically, a preparation method which enables simple and large-scale preparation by dissolving a lipid in ethanol and adding the solution to an aqueous solution, or by adding an aqueous solution to the solution to prepare liposomes. And a liposome preparation prepared by the method.

[0002]

BACKGROUND OF THE INVENTION Liposomes are closed vesicles composed of a lipid bilayer. Natural biological membranes are said to have a bilayer membrane structure of lipids, and since this liposome has a structure similar to that of biological membranes, it has a high affinity for cell membranes and is a high drug carrier. Potential is expected. In recent years, the development of liposome preparations aiming at DDS has become more and more active not only in the pharmaceutical field but also in the cosmetic field.

However, when considering mass production as a commercial product, conventional methods for preparing liposomes are very difficult and not practical. For example, the following methods are typical.

(1) The lipid is added to a suitable organic solvent (for example,
Chloroform, ether, etc.), these solvents are distilled off under reduced pressure to once form a lipid thin film, and then the lipid thin film is hydrated (or swollen) in water by a mechanical stirring means.

(2) A lipid is dissolved in an organic solvent such as ether or ethanol, and the solution is injected into water warmed to a high temperature at a constant rate under pressure from a syringe or a nozzle, and the organic solvent is distilled off along with the injection. Alternatively, a method in which a lipid forms a bilayer by being diluted to prepare a liposome.

(3) Lipids are mixed with a surfactant such as cholic acid or deoxycholic acid in an aqueous solution to form mixed micelles, and the micelle solution is subjected to an operation such as dialysis or gel filtration to obtain an interface of cholic acid or deoxycholic acid. A method for preparing a liposome by removing an active agent.

(4) A lipid-dissolved organic solvent is added to the aqueous phase and ultrasonicated to once form a W / O type emulsion, and then the organic solvent is removed to form a gel,
A method for preparing liposomes by subjecting this gel to phase inversion by mechanical stirring.

In the preparation method (1) of the above preparation methods, volatile organic solvents such as chloroform and ether are used, and it is not preferable to use these solvents industrially. Further, it is not preferable to distill off these solvents under reduced pressure in view of simplicity. In the preparation method (2), the injection speed is extremely slow because it is injected by a syringe, a nozzle, or the like. The preparation method (3) is not simple because it involves operations such as dialysis and gel filtration. The preparation method of (4) also involves an operation of removing the organic solvent and is not simple.

[0009]

Therefore, the present inventors have made diligent studies to solve these problems, and as a result, the lipid is dissolved in ethanol and the solution is added to water, or the solution is added. The inventors have newly found that liposomes can be prepared by an extremely simple method of adding water to the present invention, and completed the present invention.

In the present invention described above, there is no need for any special technique in terms of equipment such as an ultrasonic irradiator, a high-pressure emulsifier, a special nozzle, or the like, and an operation technique. It is characterized in that small uniform liposomes can be prepared.

The details of the configuration of the present invention will be described below. Lipids used in the present invention, for example, phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, lysophosphatidylcholine, sphingomyelin, egg yolk lecithin,
In addition to phospholipids typified by soybean lecithin, hydrogenated egg yolk lecithin, hydrogenated soybean lecithin, etc., one or a mixture of two or more glycolipids, dialkyl, trialkyl type synthetic surfactants and the like is mainly used. It should be noted that sterols such as cholesterol and cholestanol may be added to these as film stabilizers, and dicetyl phosphate, phosphatidic acid, ganglioside, stearylamine and the like as charged substances, and α-tocopherol and the like as an antioxidant.

The ethanol used in the present invention is generally used as a raw material for medicines and cosmetics, and the ethanol concentration of the aqueous ethanol solution is preferably 50 to 100% by weight. When the ethanol concentration is 50% by weight or less, lipids are not dissolved, which is not preferable. The amount of ethanol or ethanol aqueous solution used is about 1 to 1 with respect to the lipid.
It is preferably 100 times by weight. If the amount used is less than 1 times by weight, the lipid will not be dissolved, which is not preferable, and even if it exceeds 100 times by weight, improvement in solubility commensurate with the increase cannot be expected. When an oil-soluble component or an oil-soluble drug is added, it may be dissolved in this ethanol or ethanol aqueous solution together with the lipid.

As the aqueous solution to be added to the solution or to add the solution, water, physiological saline, buffer solution, sugar solution, or other aqueous solution of water-soluble component or water-soluble drug is used.

The preparation method is, for example, as follows. First of all, lipid in ethanol or ethanol aqueous solution,
A film stabilizer, an oil-soluble component, etc. are added, and heated and stirred to dissolve uniformly. The temperature at this time is preferably 50 to 80 ° C. This is a temperature above the phase transition temperature of the lipid, and the lipid is easily dissolved. Separately from this, an aqueous solution in which a water-soluble component or the like is dissolved is heated to 50 to 80 ° C. and then added to the above ethanol solution or the ethanol solution is added to the aqueous solution and stirred. In this way, uniform liposomes having a small particle size can be prepared.

To the liposome of the present invention, for example, a water-soluble polymer, a polyhydric alcohol, an antiseptic, a chelating agent, etc. can be added as a generally used formulation constituent.

[0016]

EXAMPLES Examples will be described below. In addition, wt% shown in the examples means% by weight.

Example 1 10 g of ethanol was heated to 50 ° C., 1.0 g of hydrogenated purified soybean lecithin, 0.5 g of cholesterol and 0.1 g of α-tocopherol were added and stirred to uniformly mix and dissolve them.
Separately, 88.4 g of water was heated to 60 ° C.,
This was added to the above ethanol solution and stirred. A milky white liposome solution was obtained, and the average particle size was 120 nm. In addition, electron microscopic observation (TEM) confirmed the characteristic lamellar structure of the liposome, and confirmed that uniform particles were formed.

Example 2 In Example 1, a 100 mM aqueous solution of carboxyfluorescein (CF) was used in place of water to prepare water. It was confirmed that CF was trapped in the inner phase by gel filtration of this liposome solution to remove CF in the outer phase and then measuring the fluorescence intensity before and after the addition of the Triton X-100 aqueous solution. The retention efficiency was 8.5%.

From the above, it is clear from Examples 1 and 2 that liposomes can be prepared by the preparation method of the present invention.

Example 3 20 g of a 30% aqueous ethanol solution was heated to 65 ° C., 2.5 g of hydrogenated and purified egg yolk lecithin, 1.0 g of cholesterol,
0.5 g of dicetyl phosphate was added and stirred to uniformly mix and dissolve. Separately, 3.0 g of magnesium ascorbyl phosphate and 73 g of water were heated to 60 ° C. and uniformly dissolved. The above ethanol solution was added to this aqueous solution and stirred to obtain a milky white liposome solution. Average particle size 100n
m, retention efficiency was 19.5%. A uniform liposome was confirmed by TEM.

Example 4 20 kg of 20% aqueous ethanol solution was heated to 60 ° C., 1.5 kg of hydrogenated and purified soybean lecithin, and 0.5 kg of cholesterol.
kg, 0.1 kg of α-tocopherol, and stirred,
It was mixed and dissolved uniformly. Separately, 77.9 kg of water was heated to 60 ° C., and this was added to the above ethanol solution and stirred. A milky white liposome solution was obtained, and uniform liposomes were confirmed by TEM with an average particle size of 120 nm.

Example 5 0.1 kg of glucose was dissolved in water in Example 4,
Prepared. After gel filtration, the retention efficiency was calculated to be 1
It was 2.6%.

[0023]

As described above, according to the present invention, unlike the conventional methods, it is possible to prepare a liposome in a very simple manner and in a very large amount, and to prepare a uniform liposome having a small particle size. It is clear that you can do it.

Claims (2)

[Claims] 1. A method for preparing liposomes, which comprises dissolving a lipid in ethanol or an ethanol aqueous solution and adding the solution to an aqueous solution, or adding an aqueous solution to the solution to prepare a liposome. 2. A liposome preparation prepared by the method according to claim 1.