JPH0725816A - Polyenoic acid clathrate - Google Patents

Abstract

PURPOSE:To obtain a polyenoic acid clathrate which can reduce smell, increase stability, solubility in water and absorption in living bodies by including polyenoic acids as a medicine for thrombosis or arteriosclerosis or as a starting substance for food products in a specific dextrin. CONSTITUTION:At least one selected from the group consisting of polyenoic acids of 18 to 22 carbon atoms, their alkali metal salts and their lower alkyl esters is included in methylated (alpha-, beta-or gamma-)cyclodextrin to give the objective clathrate of a polyenoic acid, for example, 2,6-di-O-methyl-alpha-dextrin clathrate of methyl eicosapentaenoate. The clathrate is obtained by bringing 1 mole of a polyenoic acid into contact with 6 to 8-fold molar amount of methylated (alpha-, beta-or gamma-)cyclodextrin, stirring them in the presence of water in an inert gas atmosphere and separating the precipitate by filtration and drying it under reduced pressure. The clathrate can readily be used as an injection solution and can resist to oxidation of the polyenoic acid, when it is prepared into an ointment.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyenoic acid having 18 to 22 carbon atoms (hereinafter referred to simply as polyenoic acid) which is clathrated with methylated (α-, β-, γ-) cyclodextrin. The present invention relates to an inclusion compound and a method for dissolving polyenoic acids in water by including them with methylated (α-, β-, γ-) cyclodextrin.

[0002]

2. Description of the Related Art Typical examples of polyenoic acids having 18 to 22 carbon atoms include arachidonic acid (eicosatetraenoic acid, AA) and eicosapentaenoic acid (EP).
A) and docosahexaenoic acid (DHA). Polyenoic acids, especially EPA, are contained in the fish oil of blue fish such as sardines, mackerel, and saury, and are known to have an arteriosclerosis-preventing action, a platelet aggregation-inhibiting action, a blood cholesterol-lowering action, a triglyceride-lowering action, etc. In recent years, pharmaceuticals for the purpose of prevention or treatment of rapidly increasing thrombosis and arteriosclerosis,
Attention has been paid to its usefulness as a raw material for foods.

However, since EPA is oily and has low water solubility, it is very difficult to handle, and further, it has an odor peculiar to raw blue fish such as sardines, mackerel, and saury. It is difficult to include it in food. Also, EPA is extremely unstable due to the double bond present in the molecule. That is, EPA easily absorbs oxygen in the air to generate harmful peroxides and various aldehydes and ketones which are decomposition products thereof.
In addition, harmful cyclic compounds and polymers are also produced by the action of light, oxygen and heat, and double bond rearrangement is likely to occur.

Therefore, in order to deodorize and stabilize the unstable EPA having these unpleasant odors without impairing its useful physiological activity, cyclodextrin (α-,
It has been proposed to make an inclusion compound with β-, γ-cyclodextrin (JP-A-58-13541, JP-A-58-13541).
60-34156 publication). A kneading method and a saturated aqueous solution method are used for these inclusion methods. The kneading method only involves contacting cyclodextrin and EPA in the presence of water,
Although it is the simplest method for obtaining an inclusion compound, it is difficult to obtain an inclusion powder excellent in oxidation stability by this method. On the other hand, the method of obtaining the clathrate compound by the saturated aqueous solution method is to dissolve the cyclodextrin and EPA in a hydroalcoholic solution with stirring under heating, and then slowly cool the clathrate compound at a constant rate over 5 to 7 hours to form crystals of the clathrate compound. To generate. However, this method takes a long time to produce and requires tight control over the cooling rate. Furthermore, since a 50 to 70% aqueous alcohol solution is used during heating and stirring, equipment for fire prevention is also required at the time of production, resulting in high production cost. In addition, the conventional EPA cyclodextrin inclusion compound obtained by the above method does not become an emulsion depending on the amount of water added at the time of inclusion because of its low solubility in water, and EPA as an oily substance There is a problem of floating on the surface of the water. In addition, since it has low solubility in water, when it is used as a drug or food containing it,
Depending on the form, a sufficient amount cannot be included, and the absorption rate in the body is low. As means for improving the solubility of EPA in water, branched cyclodextrins (α-, β-, γ-cyclodextrin, etc., and one or two molecules α-1 of a small sugar such as glucose, maltose, maltotriose, etc. , 6-bonded) (Japanese Unexamined Patent Publication No. 4-178348), but its solubility is not sufficient.

Therefore, the object of the present invention is not only to reduce odor and improve stability, but also to further improve solubility in water and increase absorbability in vivo by oral administration.
An object is to provide a cyclodextrin inclusion compound of polyenoic acids such as EPA, and to provide a method for dissolving polyenoic acids in water.

[0006]

Means for Solving the Problems In view of the above circumstances, the inventors of the present invention have conducted extensive studies and as a result, have found that polyenoic acids are identified as inclusion compounds of methylated (α-, β-, γ-) cyclodextrin. By doing so, they have found that the above problems can be solved, and completed the present invention.

The polyenoic acids referred to in the present invention include arachidonic acid (eicosatetraenoic acid, AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), or salts thereof (for example, sodium, potassium salts, etc.), or Their lower alkyl esters (eg C1-C4)
Alkyl esters of methyl, ethyl, propyl,
Butyl ester) is also included.

In the present invention, the cyclodextrin which can form the inclusion compound of the above polyenoic acids and can achieve the object of the present invention is a methylated (α-, β-, γ-) cyclodextrin, specifically, 2,6-di-O-methyl-
(Α, β, γ) -cyclodextrin, 2,3-di-O-methyl- (α, β, γ) -cyclodextrin, 3,6-di-
O-methyl- (α, β, γ) -cyclodextrin, 2,
3,6-tri-O-methyl- (α, β, γ) -cyclodextrin and the like.

The clathrate compound of polyenoic acid of the present invention is usually 1 to 10 times mol, preferably 6 to 8 times mol of methylated (α-, β-, γ-) cyclodextrin per mol of polyenoic acid. And are brought into contact with each other in the presence of water to obtain a constant temperature (30
(° C) Shaking in a shaking water tank under an inert gas stream for 24 to 48 hours, the clathrate compound precipitated is collected by filtration, and dried under reduced pressure.

The inclusion compound of the polyenoic acid of the present invention obtained as described above has a significantly improved solubility in water as compared with the inclusion compound using the conventional α-cyclodextrin or the like.

Further, in order to investigate the content of polyenoic acid in the clathrate compound of the present invention, this clathrate compound is washed with hexane to remove the polyenoic acid adhering to the crystal surface of the clathrate compound. After removal, water-soluble organic solvent
Dissolve in water mixture and perform HPLC analysis. The organic solvent that dissolves the clathrate is preferably one that freely dissolves in water, preferably methanol, ethanol, acetone, or tetrahydrofuran, but a 1: 1 methanol-water system is particularly preferably used.

The amount of polyenoic acid contained in the inclusion compound of polyenoic acids obtained as described above is 1 to 15% by weight,
It is preferably 1 to 10% by weight, more preferably 4 to 9% by weight.

The clathrate compound of polyenoic acids obtained in the present invention can be taken as it is, but it is dried and powdered by a known method to form powders, granules, capsules, tablets, etc. For example, minerals, vitamins, etc. can be further fortified and formulated to be orally administered. The compound can also be parenterally administered as an injection or an ointment. Further, the clathrate compound of polyenoic acid obtained in the present invention can be contained in various foods such as health foods (beverages, confectionery, meat products, dairy products, etc.).
INDUSTRIAL APPLICABILITY The clathrate compound of polyenoic acid of the present invention, and the pharmaceuticals and foods containing the clathrate compound are useful for the prophylactic treatment of thrombosis, arteriosclerosis and the like.

[0014]

The clathrate compound of polyenoic acid obtained according to the present invention has much higher solubility in water than conventional clathrate compounds. Therefore, the compound of the present invention can be used as a medicine (tablets containing polyenoic acid, powders, granules, capsules, etc.) and as an additive to foods, and is highly soluble in water. The absorbability of in vivo is improved. Further, since polyenoic acids are not soluble in water, conventionally, in the case of making an injection, a method such as a fat emulsion has been proposed, but the compound of the present invention can be provided as an injection instead of this, more simply. To Further, when used as an ointment, the polyenoic acid is suppressed from being oxidized because it is less in contact with the outside air.

[0015]

EXAMPLES In order to explain the present invention in more detail, examples will be given, but the present invention is not limited thereto.

Example 1 Preparation of Inclusion Compound of Ethyl Eicosapentaenoic Acid (EPA Ethyl Ester) 30 mg of EPA ethyl ester contained 0.12 mol / l of 2,6-
Di-O-methyl-α-cyclodextrin aqueous solution 10 m
1 was added and shaken in a constant temperature shaking water bath (30 ° C.) for 24 hours under an argon stream. The precipitated complex was collected by filtration and dried at room temperature for 68 hours under reduced pressure to obtain an inclusion compound of EPA ethyl ester. The content of EPA ethyl ester in this clathrate compound was determined by adding 2 ml of a methanol / water mixture (methanol: water = 1: 1) to 5 mg of the clathrate compound and dissolving it. It was obtained by comparing with the analysis result of. As a result, the content of EPA ethyl ester per solid of inclusion compound was about 4%.
Met. Powder X-ray diffraction measurement of this clathrate compound (Fig. 1)
And the Fourier transform infrared spectrum (FIG. 2) by the diffuse reflection method were measured.

Reference Example 1 Preparation of Inclusion Compound (Conventional Product) of Eicosapentaenoic Acid Ethyl (EPA Ethyl Ester) 0.02 mol / l α-in 30 mg of EPA ethyl ester
Cyclodextrin, β-cyclodextrin, and γ-cyclodextrin aqueous solution (23 ml) were added, and the mixture was shaken in a constant temperature shaking water tank (30 ° C.) under an argon stream for 24 hours. The deposited complex was collected by filtration and dried under reduced pressure at room temperature for 68 hours to obtain an inclusion compound of EPA ethyl ester.

Test Example 1 (Solubility Test) The inclusion compound prepared in Example 1 (EPA ethyl ester-2,6-di-O-methyl-α-cyclodextrin inclusion compound) and Reference Example 1 were prepared. 5 mg of water was added to 20 mg of each clathrate compound using α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin as clathrates.
1 was added, and the mixture was shaken in a constant temperature shaking water tank (30 ° C.) under an argon stream for 24 hours, the supernatant was filtered through an aqueous membrane filter, and the filtrate was subjected to HPLC analysis to measure the EPA ethyl ester concentration. The results are shown in Table 1.

[0019]

[Table 1]

Example 2 Eicosapentaenoic acid (EP
Preparation of clathrate compound of A) In the same manner as in Example 1, a clathrate compound of EPA was obtained. Its solubility in water was very good.

Example 3 Preparation of Inclusion Compound of Eicosapentaenoic Acid Sodium Salt In the same manner as in Example 1, an inclusion compound of EPA sodium salt was obtained. Its solubility in water was very good.

[Brief description of drawings]

FIG. 1 shows a powder X-ray diffraction pattern of 2,6-di-O-methyl-α-cyclodextrin and EPA ethyl ester-2,6-di-O-methyl-α-cyclodextrin inclusion compound.

FIG. 2 EPA ethyl ester, 2,6-di-O-methyl-
1 shows a Fourier transform infrared absorption spectrum of α-cyclodextrin and an EPA ethyl ester-2,6-di-O-methyl-α-cyclodextrin inclusion compound by a diffuse reflection method.

Claims (2)

[Claims] 1. A methylated (α-, β-, γ-) cyclodextrin containing at least one compound selected from the group consisting of polyenoic acids having 18 to 22 carbon atoms, alkali metal salts thereof, and lower alkyl esters thereof. A clathrate compound of polyenoic acids which is clathrated by. 2. A methylated (α-, β-, γ-) cyclodextrin is prepared from at least one compound selected from the group consisting of polyenoic acids having 18 to 22 carbon atoms, alkali metal salts thereof, and lower alkyl esters thereof. A method for dissolving a polyenoic acid in water by including it with water.