JPH07267985A - Production of tauroursodeoxycholic acid hydrate - Google Patents

Abstract

PURPOSE:To simply obtain a tauroursodeoxycholic acid hydrate from an aqueous solution of tauroursodeoxycholic acid on an industrial scale at a low cost without using an organic solvent. CONSTITUTION:This method for producing a tauroursodeoxycholic acid hydrate is to condense taurine with ursodeoxycholic acid in an organic solvent, then distill away the organic solvent, add an acid such as dilute sulfuric acid or dilute hydrochloric acid to the resultant aqueous solution of the tauroursodeoxycholic acid, deposit a crystal of the tauroursodeoxycholic acid hydrate and wash the formed crystal thereof with water.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing tauroursodeoxycholic acid hydrate which exhibits an effective pharmacological action such as a hypolipidemic action in blood.

[0002]

2. Description of the Related Art 1 g of tauroursodeoxycholic acid is 1
It easily dissolves in ml and is extremely soluble in water,
It is very difficult to extract crystals directly from an aqueous solution efficiently and with high purity. Regarding the method for producing tauroursodeoxycholic acid hydrate, see JP-A 63-14689.
5 and JP-A-3-17096. Both are methods in which inorganic salts generated by the reaction and unreacted taurine are removed by filtration, and then tauroursodeoxycholic acid is precipitated with a large amount of an organic solvent.

[0003]

The problem with the above method is that (1) the operation of removing the inorganic salt using an organic solvent is repeated, so the operation is complicated, and the inorganic salt produced by the reaction and unreacted It is difficult to completely remove the taurine and ursodeoxycholic acid from (2)
It requires a large amount of organic solvent and is difficult to carry out industrially. (3) Drying under reduced pressure after the condensation reaction of taurine and ursodeoxycholic acid is dangerous in operation.

As a result of intensive studies to solve these problems, the inventors have found that tauroursodeoxycholic acid hydrate is inexpensive and convenient on an industrial scale without using an organic solvent from an aqueous solution of tauroursodeoxycholic acid. The present invention has been invented.

[0005]

According to the present invention, in the method for producing tauroursodeoxycholic acid, (1) a step of subjecting taurine and ursodeoxycholic acid to a dehydration condensation reaction in an organic solvent which may contain water. , (2) a step of washing the aqueous solution obtained by distilling off the organic solvent to remove unreacted ursodeoxycholic acid, (3) adjusting the pH by adding an acid to the aqueous solution of tauroursodeoxycholic acid There is provided a method for producing tauroursodeoxycholic acid hydrate, which comprises a step of crystallizing tauroursodeoxycholic acid hydrate.

In the present invention, the dehydration condensation reaction can be carried out by a method commonly used for peptide synthesis such as a mixed acid anhydride method or an active ester method (Izumiya et al., "Peptide Synthesis",
Maruzen Co., Ltd., 1975). As the solvent used in the dehydration condensation reaction, any solvent can be used as long as it does not inhibit the dehydration condensation reaction, and for example, n-hexane,
Hydrocarbons such as benzene, halogenated hydrocarbons such as dichloromethane, chloroform, diethyl ether, 1,2-
Examples thereof include chain ethers such as dimethoxyethane, cyclic ethers such as dioxane and tetrahydrofuran, and esters such as ethyl acetate and butyl acetate. As the dehydration condensing agent, in the mixed acid anhydride method, ethyl chlorocarbonate,
Examples thereof include carbonic acid monoalkyl esters such as isobutyl chlorocarbonate, and p-nitrophenyl ester, chlorinated phenyl ester, 2-ethoxy-1- (2H) -quinolinecarboxylic acid ester and the like in the active ester method. The reaction can be carried out under anhydrous condition or under water containing condition, but when carried out under anhydrous condition, water may be added after completion of the reaction.

The acid used for pH adjustment is not particularly limited, but examples thereof include mineral acids such as hydrochloric acid and sulfuric acid. The pH is acidic, preferably 3 or less.

The organic solvent for removing ursodeoxycholic acid may be any solvent that is not miscible with water and dissolves ursodeoxycholic acid. For example, hydrocarbons such as n-hexane, benzene, etc., dichloromethane, chloroform, etc. Examples thereof include halogenated hydrocarbons, ethers such as diethyl ether and diisopropyl, and esters such as ethyl acetate and butyl acetate.

According to this method, crude tauroursodeoxycholic acid can also be purified. That is,
Crude tauroursodeoxycholic acid is dissolved in water to remove the ursodeoxycholic acid from the resulting aqueous solution with an organic solvent to obtain an aqueous solution of tauroursodeoxycholic acid.
This is a purification method in which an acid is added to this to crystallize tauroursodeoxycholic acid hydrate.

[0010]

EXAMPLES Representative examples of the method of the present invention will be shown below. In the following examples, the content of inorganic salts or taurine, which are the main impurities in this production method, was measured by applying the sulfate test method described in the 12th revised Japanese Pharmacopoeia.
The purity of tauroursodeoxycholic acid was obtained by mixing Kieselgel 60F254 (trademark: manufactured by Merck) as a thin plate and chloroform: ethanol: ethyl acetate: acetic acid: water (8: 6: 5: 4: 1) as a developing solvent. It was measured by thin layer chromatography using a solvent.

(Example 1) Ursodeoxycholic acid (2
5 g) was dissolved in dioxane (250 ml), triethylamine (10.2 ml, 1.15 equivalents) was added, and the mixture was stirred. The mixture was cooled to 10 ° and ethyl chlorocarbonate (7.0 ml, 1.15 eq) was added dropwise. Then, 1N sodium hydroxide solution (66 ml) of taurine (9.17 g, 1.15 equivalent) was added dropwise. The reaction solution was stirred for 1 hour and then distilled under reduced pressure to remove dioxane. Water was added to the residue to make an aqueous solution, and the pH was adjusted to 6 with dilute hydrochloric acid, and then unreacted ursodeoxycholic acid was removed with ethyl acetate. After further concentration under reduced pressure, diluted hydrochloric acid was added to adjust the pH to 1, and the mixture was stirred at room temperature for 2 hours to precipitate crystals.
The precipitated crystals were filtered, washed with water and dried to obtain tauroursodeoxycholic acid hydrate (27.9 g). Yield 8
It was 1.9%. The content of each of the inorganic salt and taurine was 0.1% or less, and the purity of tauroursodeoxycholic acid was 99.9% or more.

The obtained crystals have a melting point of 141 to 149 °,
The pH of a 2% aqueous solution was 1.5, and the solubility was 2.25% (w / w) at 30.5 °.

(Example 2) Ursodeoxycholic acid (1
0 g) was dissolved in ethyl acetate (100 ml), triethylamine (4.08 ml, 1.15 equivalent) was added, and the mixture was stirred. The mixture was cooled to 10 ° and ethyl chlorocarbonate (2.8ml, 1.15eq) was added dropwise. Then, 1N sodium hydroxide solution (27 ml) of taurine (3.67 g, 1.15 equivalent) was added dropwise. The reaction solution was stirred for 1 hour, adjusted to pH 5 with diluted sulfuric acid, and then separated. The aqueous layer was washed with ethyl acetate to remove unreacted ursodeoxycholic acid. After further concentration under reduced pressure, dilute sulfuric acid was added to adjust the pH to 2, and the mixture was stirred at room temperature for 2 hours to precipitate crystals. The precipitated crystals were filtered, washed with water, dried and then tauroursodeoxycholic acid hydrate (11.0 g)
Got The yield was 80.6%. The content of each of the inorganic salt and taurine was 0.1% or less, and the purity of tauroursodeoxycholic acid was 99.9% or more.

(Example 3) Ursodeoxycholic acid (2
5 g) was dissolved in ethyl acetate (250 ml), triethylamine (10.2 ml, 1.15 equivalent) was added, and the mixture was stirred. The mixture was cooled to 10 ° and ethyl chlorocarbonate (7.0 ml, 1.15 eq) was added dropwise. Then, taurine (9.17 g, 1.15 equivalents) was added dropwise to a 1N sodium hydroxide (66 ml) solution. The reaction solution was stirred for 1 hour, adjusted to pH 5 with diluted sulfuric acid, and then separated. The aqueous layer was washed with ethyl acetate to remove unreacted ursodeoxycholic acid. After further concentration under reduced pressure, diluted sulfuric acid was added to adjust the pH to 3, and the mixture was stirred at room temperature for 2 hours to precipitate crystals. The precipitated crystals were filtered, washed with water, dried and then tauroursodeoxycholic acid hydrate (26.0 g)
Got The yield was 76.3%. The content of each of the inorganic salt and taurine was 0.1% or less, and the purity of tauroursodeoxycholic acid was 99.9% or more.

(Example 4) Ursodeoxycholic acid (2
0 g) was dissolved in ethyl acetate (200 ml), triethylamine (8.16 ml, 1.15 equivalents) was added, and the mixture was stirred. The mixture was cooled to 10 ° and ethyl chlorocarbonate (5.6 ml, 1.15 eq) was added dropwise. Next, taurine (7.34 g, 1.15 equivalents) was added dropwise to a 1N sodium hydroxide (53 ml) solution. The reaction solution was stirred for 1 hour, adjusted to pH 4 with diluted sulfuric acid, and then separated. The aqueous layer was then washed with ethyl acetate to remove unreacted ursodeoxycholic acid. Concentrate under reduced pressure and add diluted sulfuric acid to adjust pH.
The crystal was precipitated by adjusting to 1 and stirring at room temperature for 2 hours. The precipitated crystals were filtered, washed with water, dried and then tauroursodeoxycholic acid hydrate (22.6
g) was obtained. The yield was 82.7%. The content of each of the inorganic salt and taurine was 0.1% or less, and the purity of tauroursodeoxycholic acid was 99.9% or more.

Claims (3)

[Claims] 1. In the method for producing tauroursodeoxycholic acid, (1) a step of subjecting taurine and ursodeoxycholic acid to a dehydration condensation reaction in an organic solvent which may contain water, and (2) distilling off the organic solvent. Washing the aqueous solution obtained by removing unreacted ursodeoxycholic acid,
(3) A method for obtaining tauroursodeoxycholic acid hydrate crystals, which comprises a step of crystallizing tauroursodeoxycholic acid hydrate by adjusting the pH by adding an acid to an aqueous solution of tauroursodeoxycholic acid. 2. The method according to claim 1, wherein the pH is 3 or less. 3. The method according to claim 1, wherein the acid to be added is dilute sulfuric acid or dilute hydrochloric acid.