阅读说明：本技术 胆烷酸共轭物的纯化 (Purification of cholanic acid conjugates ) 是由 M·莫雷利 D·罗西 A·雷塞利 G·拉泽蒂 于 2020-04-08 设计创作，主要内容包括：本发明涉及以下式(I)的牛磺熊去氧胆酸的纯化方法：<Image he="396" wi="700" file="DDA0002442033740000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>(The invention relates to a method for purifying tauroursodeoxycholic acid of the following formula (I):)

1. A process for purifying tauroursodeoxycholic acid of formula (I) or a salt thereof:

the method comprises the following steps:

with C₄-C₇Extracting tauroursodeoxycholic acid of formula (I) or a salt thereof from the aqueous solution with an alcohol;

addition of a compound different from C₄-C₇An additional organic solvent for the alcohol; or alternatively to said addition, cooling the solution to a temperature of less than about 5 ℃, preferably to a temperature of about 0 ℃ or less;

-adding a protonic acid (HX) to precipitate tauroursodeoxycholic acid of formula (I), and

-isolating tauroursodeoxycholic acid of formula (I).

2. The method of claim 1, whereinSaid C is₄-C₇The alcohol is selected from the group consisting of 1-butanol, sec-butanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 1-cyclohexanol and 1-heptanol, preferably 1-butanol, 2-butanol, tert-butanol and 1-cyclohexanol, more preferably 1-butanol.

3. The method of claim 1 or 2, wherein said is different from C₄-C₇The additional organic solvent of the alcohol is selected from: polar aprotic solvents such as dimethylformamide, dimethylsulfoxide or acetonitrile; ethers such as methyl tert-butyl ether, tetrahydrofuran or dioxane; ketones such as methyl ethyl ketone, methyl isobutyl ketone or acetone; esters, e.g. straight-chain or branched C₁-C₅Acetates of alcohols, preferably ethyl acetate; chlorinated solvents, such as dichloromethane, chloroform or chlorobenzene; or a mixture of two or more, typically two or three, of said solvents.

4. The method of claim 3, wherein the is different from C₄-C₇An additional organic solvent for the alcohol is acetone.

5. The process according to claims 1 to 4, wherein the solution is concentrated by azeotropic distillation of the solvent before the addition of the protic acid (HX).

6. The process according to claims 1 to 5, wherein the protic acid (HX) is an inorganic acid.

7. The process according to claim 6, wherein the mineral acid is selected from the group consisting of sulfuric acid, phosphoric acid and hydrohalic acid, preferably hydrochloric acid.

8. The process according to claims 1 to 7, wherein the purification is carried out using from about 0.5 mol to about 4.0 mol, preferably from 0.5 mol to about 2.0 mol of protic acid (HX) per mol of tauroursodeoxycholic acid of formula (I), more preferably under about equimolar conditions.

9. The process according to claims 1 to 8, wherein the addition of the protic acid (HX) is carried out at a temperature between about 0 ℃ and the reflux temperature of the solution.

10. The process according to claims 1 to 9, wherein tauroursodeoxycholic acid of formula (I) is obtained by a process comprising the following steps:

a) salifying ursodeoxycholic acid of formula (II) with a tertiary aliphatic or heteroaromatic amine:

b) treating a salt of ursodeoxycholic acid of formula (II) with a derivative of formula (III):

Cl-COOR

(III)

wherein Cl is chlorine and R is selected from C₁-C₆Alkyl, phenyl or benzyl; and

c) reacting the mixed anhydride of formula (IV) obtained in step b):

wherein R is as defined above, and wherein,

with taurine of formula (V) or a salt thereof,

the reaction is optionally carried out in the presence of a base.

Background

Tauroursodeoxycholic acid, also known as TUDCA, is represented by the following formula (I):

tauroursodeoxycholic acid is a bile acid present in our organism and is used to treat cholestatic conditions such as primary biliary cirrhosis, primary sclerosing cholangitis, cholestasis associated with cystic fibrosis or intrahepatic families, and cholesterol stones (cholestrol stone).

On an industrial scale, tauroursodeoxycholic acid of formula (I) is prepared in different ways. Initially, the compounds were obtained from bear bile. Currently, tauroursodeoxycholic acid of formula (I) is prepared by the following method: industrial fermentation, such as described by Xu et al in micro b.cell.fact (2019)18:34, using modified e.coli (e.coli) cells; or, synthesis, for example, synthesis using ursodeoxycholic acid of formula (II) as a starting material,

for example as described in EP 0629634 or IT 1197330.

The method described in EP 0629634 or IT 1197330 comprises: the salt of ursodeoxycholic acid of formula (II) is reacted with a halocarbonyl ester, for example with a derivative of formula (III),

Cl-COOR

(III)，

wherein Cl is chlorine and R is selected from C₁-C₆Alkyl, phenyl or benzyl to give the mixed anhydride of the formula (IV)

Reacting the mixed anhydride of formula (IV) with taurine of formula (V),

finally, the tauroursodeoxycholic acid shown as the formula (I) is obtained.

The tauroursodeoxycholic acid of formula (I) thus obtained must be separated from the salts formed during the reaction, from the unreacted taurine of formula (V) and bile acids, for example from the unreacted ursodeoxycholic acid of formula (II), and/or from further bile acids which may optionally be present in the reaction mixture.

EP 0400695 and EP 0629634 describe methods for the purification of tauroursodeoxycholic acid of formula (I) by chromatography, for example by using an ionic resin.

The process disclosed in IT 1197330 is a process for the purification of tauroursodeoxycholic acid of formula (I), which comprises: an acid was added to the reaction solution to lower the pH to about 2, and the mixture was concentrated. The resulting residue is dissolved in ethanol, unreacted taurine of formula (V) is removed by filtration, and tauroursodeoxycholic acid of formula (I) is precipitated by adding acetone, ethyl acetate or a mixture thereof.

EP 2137206 discloses a process for separating salts and unreacted taurine from alkali metal salts or alkaline earth metal salts of tauroursodeoxycholic acid of the formula (I), which is carried out as follows: add 0.8-1.4 equivalents of acid and let the solution stand for 10-180 minutes. The precipitated taurine is isolated and subsequently an organic solvent is added, resulting in the precipitation of tauroursodeoxycholic acid of formula (I).

However, there is still a need to find a new safe alternative method for purifying tauroursodeoxycholic acid of formula (I) in high yield and particularly suitable for industrial production. In particular, there is still a need for a process which not only allows the isolation of tauroursodeoxycholic acid of formula (I) from the salts present in the reaction mixture, in particular unreacted (V) taurine, but also from other cholanic acids, such as unreacted ursodeoxycholic acid of formula (II) or other cholanic acids present as impurities in the starting product.

Brief description of the invention

The object of the present invention is a process for the purification of tauroursodeoxycholic acid or a salt thereof of formula (I) below:

it includes:

with C₄-C₇Extracting tauroursodeoxycholic acid of formula (I) or a salt thereof from the aqueous solution with an alcohol;

addition of a compound different from C₄-C₇An additional organic solvent for the alcohol; or alternatively to said addition, the solution isCooling the liquid to a temperature of less than about 5 ℃, preferably to a temperature of about 0 ℃ or less;

-adding a protonic acid (HX) to precipitate tauroursodeoxycholic acid of formula (I), and

-isolating tauroursodeoxycholic acid of formula (I).

The process allows tauroursodeoxycholic acid of formula (I) to be separated from the salts present in the reaction mixture and from the taurine of formula (V), and from other cholanic acids, such as ursodeoxycholic acid of formula (II). The operations described herein allow to safely obtain a surprisingly highly pure product, which is able to comply with the regulatory requirements required by APIs.

Detailed Description

The object of the present invention is a process for the purification of tauroursodeoxycholic acid or a salt thereof of formula (I) below:

it includes:

with C₄-C₇Extracting tauroursodeoxycholic acid of formula (I) or a salt thereof from the aqueous solution with an alcohol;

addition of a compound different from C₄-C₇An additional organic solvent for the alcohol; or alternatively to said addition, cooling the solution to a temperature of less than about 5 ℃, preferably to a temperature of about 0 ℃ or less;

-adding a protonic acid (HX) to precipitate tauroursodeoxycholic acid of formula (I), and

-isolating tauroursodeoxycholic acid of formula (I).

The salt of tauroursodeoxycholic acid of formula (I) is preferably a pharmaceutically acceptable salt. Examples of pharmaceutically acceptable salts include salts derived from a suitable base, such as an alkali metal salt (e.g. sodium or potassium), alkaline earth metal salt (e.g. calcium or magnesium), ammonium or NR'₄ ⁺Wherein R' is C₁-C₄An alkyl group.

The tauroursodeoxycholic acid of formula (I) in the starting aqueous solution may be concentrated to a solution of 0.1% -70% w/w, typically 2% -50% w/w, for example about 5%, 10%, 20%, 30% or 40% w/w.

With C₄-C₇Alcohol extraction from the aqueous solution allows tauroursodeoxycholic acid of formula (I) to be enriched in said C₄-C₇In alcohol; at the same time, conversely, the salts present in the reaction mixture, in particular the taurine of formula (V), remain in the aqueous phase.

Said C of the invention₄-C₇The alcohol may be linear, branched or cyclic. Said C is₄-C₇The alcohol may be selected from, for example, 1-butanol, sec-butanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 1-cyclohexanol and 1-heptanol; preferably 1-butanol, sec-butanol, tert-butanol and 1-cyclohexanol; more preferably 1-butanol.

Said is different from C₄-C₇Additional organic solvents for the alcohol may be: polar aprotic solvents such as dimethylformamide, dimethylsulfoxide or acetonitrile; ethers such as methyl tert-butyl ether, tetrahydrofuran or dioxane; ketones such as methyl ethyl ketone, methyl isobutyl ketone or acetone; esters, e.g. straight-chain or branched C₁-C₅Acetates of alcohols, preferably ethyl acetate; chlorinated solvents, such as dichloromethane, chloroform or chlorobenzene; or a mixture of two or more, typically two or three, of said solvents.

One preferred is different from C₄-C₇An additional organic solvent for the alcohol is acetone.

Additional compounds other than C may be added before or after the addition of the protic acid (HX)₄-C₇An additional organic solvent for the alcohol. The protic acid (HX) may even differ from C₄-C₇A mixture of additional solvents of alcohol.

In a preferred aspect, said other than C is added to the extracted reaction mixture before said protic acid (HX) is added₄-C₇An additional organic solvent for the alcohol.

In a further preferred aspect, the solution is concentrated and then the protic acid (HX) is added.

The solution may be distilled, e.g. by co-distillationBoiling, distilling and concentrating. At the C₄-C₇In the case where the alcohol is 1-butanol, the azeotropic distillation is carried out at a temperature of between about 70 ℃ and reflux temperature, preferably between about 80 ℃ and about 115 ℃, for example about 90 ℃, 100 ℃ or 110 ℃. The distillation can be carried out at ambient pressure or under reduced pressure.

In a further preferred aspect, the solution is concentrated and then said other than C is added₄-C₇Additional organic solvent of alcohol, and finally the protic acid (HX).

In the mixture of C₄-C₇The ratio between the alcohol and the further organic solvent as defined above may typically be about 10:1 (C)₄-C₇The volume of the alcohol to the volume of the further organic solvent, v: v) to 1:10000(v: v), preferably between about 5:1(v: v) to about 1:1000(v: v), more preferably between about 2:1(v: v) to about 1:100(v: v), for example in a ratio of 1:1(v: v), 1:2(v: v), 1:5(v: v), 1:10(v: v) or 1:50(v: v). In the case of concentrating the extraction solution, the ratio refers to the ratio in the mixture after the concentration step of the extraction solution.

The cooling of the extraction solution comprising tauroursodeoxycholic acid of formula (I) may be carried out at a temperature below 5 ℃, preferably at a temperature of about 0 ℃ or lower, for example at-5 ℃, -10 ℃ or-20 ℃. The solution may be cooled slowly, for example at a rate of between about 0.1-0.4 deg.C/minute.

The addition of the protic acid (HX) leads to the precipitation of tauroursodeoxycholic acid of formula (I), but not, or only to a minor extent, other cholanic acids, in particular ursodeoxycholic acid of formula (II).

The protic acid (HX) may be an inorganic acid or an organic acid.

The inorganic acid may be, for example, an acid selected from sulfuric acid, phosphoric acid and hydrohalic acid, preferably hydrochloric acid.

The organic acid may be, for example, an acid selected from: a sulfonic acid, typically camphorsulfonic acid, p-toluenesulfonic acid, methanesulfonic acid or trifluoromethanesulfonic acid; aryl carboxylic acids, typically benzoic acid; and C₁-C₄Alkyl carboxylic acid, wherein said C₁-C₄The alkyl group may be linear or branched and is optionally substituted by one or more halogen atoms, preferably 1 to 3 chlorine or fluorine atoms, typically acetic acid or trifluoroacetic acid.

The protic acid (HX) may be used in an approximately stoichiometric amount, in excess or in an insufficient amount relative to the tauroursodeoxycholic acid of formula (I). Typically, the protic acid (HX) may be in an amount of about 0.5 to about 4.0 moles, preferably about 0.5 to about 2.0 moles, more preferably about equimolar, for example 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.5, 3.0, 3.5 or 4.0 moles of protic acid (HX)/mole of tauroursodeoxycholic acid of formula (I) per mole of tauroursodeoxycholic acid of formula (I).

The addition of the protic acid (HX) may be carried out at room temperature or at a temperature of less than or equal to about 20 ℃, preferably at a temperature between about 0 ℃ and about 20 ℃, more preferably at a temperature between about 5 ℃ and about 10 ℃. Alternatively, the addition of the protic acid (HX) may be carried out at a temperature of greater than or equal to about 30 ℃, preferably between about 30 ℃ and the reflux temperature of the mixture comprising tauroursodeoxycholic acid of formula (I), for example at about 40 ℃, at about 50 ℃, at about 60 ℃ or at about 70 ℃.

Without adding before an additional other than C₄-C₇In the case of an additional organic solvent for the alcohol, the addition of the protic acid (HX) to the extracted solution of tauroursodeoxycholic acid of formula (I) at room temperature or above does not lead to the precipitation of the product or the product precipitates only in low yields. Thus, said operations make the process impractical on an industrial level. Therefore, no additional difference from C was added before₄-C₇In the case of an additional organic solvent for the alcohol, the addition of the protic acid (HX) is typically carried out at a temperature below about 5 ℃, preferably at a temperature of about 0 ℃ or less.

Tauroursodeoxycholic acid of formula (I) may be further purified, for example by crystallization from water as described in IT 1197330 or EP 2137206 or by chromatography as described in EP 0629634 or EP 0400695.

The crystals of tauroursodeoxycholic acid of formula (I) obtained according to the process of the invention have a size characterized by D₉₀Values are between about 5 μm and about 250 μm, typically below 100 μm (as measured by a Malvern Laser Diffraction Mastersizer3000 and measurement Box (measurement cell) Hydro 3000S). If desired, the size of the crystals may be reduced by micronization or fine milling (fine milling).

The tauroursodeoxycholic acid of formula (I) obtained according to the process described herein has a purity surprisingly higher than 98%, for example a purity of 98.5%, 99.0%, 99.5% or higher than 99.9%, evaluated by HPLC analysis at 195 nm.

The tauroursodeoxycholic acid of formula (I) used as starting material may be obtained from commercial sources or may be a crude reaction product, which may be obtained, for example, according to a process comprising:

a) salifying ursodeoxycholic acid of formula (II) with a tertiary aliphatic or heteroaromatic amine:

b) treating a salt of ursodeoxycholic acid of formula (II) with a derivative of formula (III):

Cl-COOR

(III)

wherein Cl is chlorine and R is selected from C₁-C₆Alkyl, phenyl or benzyl; and

c) reacting the mixed anhydride of formula (IV) obtained in step b)

Wherein R is as defined above, and wherein,

with taurine of formula (V) or a salt thereof,

the reaction is optionally carried out in the presence of a base.

Examples of the aliphatic tertiary amine or heteroaromatic amine are triethylamine, tri-n-butylamine, methylpiperidine, ethylpiperidine or pyridine.

The taurate salt of formula (V) is preferably a pharmaceutically acceptable salt. Examples of pharmaceutically acceptable salts include salts derived from a suitable base, such as an alkali metal salt (e.g. sodium or potassium), alkaline earth metal salt (e.g. calcium or magnesium), ammonium or NR'₄ ⁺Wherein R' is C₁-C₄An alkyl group.

The optional base may be, for example: an inorganic base, typically an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide, or an alkaline earth metal hydroxide such as calcium hydroxide or barium hydroxide, more preferably sodium hydroxide, potassium hydroxide or barium hydroxide. The optional base may be, for example, C₁-C₆Alkoxides such as sodium ethoxide, potassium ethoxide, sodium tert-butoxide or potassium tert-butoxide; or an organic base, for example a tertiary amine, such as triethylamine or diisopropylethylamine.

The following examples further illustrate the invention.

Example 1 preparation of an aqueous solution of tauroursodeoxycholic acid of formula (I)

160g (0.408 mol) ursodeoxycholic acid of formula (II) are salified with about 45.0g (0.448 mol) triethylamine in 1200ml methyl isobutyl ketone. At a temperature not higher than 25 ℃, 46g (0.42 mol) of ethyl chloroformate was added to the mixture. The resulting reaction mixture was cooled to about 0 ℃ and 60g (0.40 mole) of the sodium salt of taurine dissolved in 80ml of water was added. At the end of the addition, the mixture was allowed to reach room temperature. The aqueous phase was separated and the organic phase was washed three times with 80ml of water. The aqueous phases were combined and purified as described in the examples below.