CN102993037B - Preparation method of L-ornithine phenylacetate - Google Patents

Abstract

The invention belongs to the field of medicine and chemical industry, and relates to a preparation method of L-ornithine phenylacetate. The method comprises the following steps: mixing free L-ornithine aqueous solution and phenylacetic acid solution, stirring and reacting, and then crystallizing the obtained L-ornithine phenylacetic acid salt solution to precipitate in the form of crystals. The invention is a one-step reaction with a simple and mild process, which provides an effective reference for the high-purity and industrialized preparation of L-ornithine and phenylacetic acid. The product has low toxic and side effects and ensures the safety of clinical medication. In comparison, the preparation method of the present invention has low cost, high yield and high product purity, and is suitable for industrialized production.

Description

A kind of preparation method of L-ornithine phenylacetate

technical field

The invention belongs to the field of medicine and chemical industry, and relates to a preparation method of L-ornithine phenylacetate.

Background technique

Hepatic encephalopathy is a central nervous system dysfunction syndrome based on metabolic disorders caused by various subspecies of liver diseases clinically. It is caused by liver detoxification insufficiency and failure. Its clinical manifestations include disturbance of consciousness, abnormal behavior, coma, and elevated blood ammonia. When the liver fails, the ability of the liver to synthesize urea and remove ammonia decreases or even disappears, so that the ammonia from the intestinal tract directly enters the human circulation without detoxification by the liver, increasing blood ammonia, and high blood ammonia is toxic to the central nervous system Therefore, reducing blood ammonia is one of the effective measures for the treatment of hepatic encephalopathy.

L-ornithine and phenylacetate can be used separately or in combination to treat hyperammonemia and hepatic encephalopathy, and there are also patents and literature describing L-ornithine and phenylacetate for the treatment of hepatic encephalopathy Compositions. However, certain salts, especially sodium or chloride salts, have disadvantages when they are used in the treatment of diseases related to liver disease, such as hepatic encephalopathy. Firstly, due to the high concentration intake of some salts (such as sodium salt), it is very dangerous for patients with liver disease who may already have ascites, fluid overload or electrolyte imbalance; secondly, due to the increase of osmotic pressure, intravenous injection becomes It is more difficult to administer, and diluting with a large volume of solution for intravenous injection can cause fluid overload. Therefore, there is a need for synthetic preparation of L-ornithine and phenylacetate to facilitate the treatment of hepatic encephalopathy.

Studies have shown that L-ornithine and phenylacetate have good water solubility and can be used orally or intravenously. It can stably reduce the blood ammonia concentration in patients with hepatic encephalopathy. The mechanism is: L-ornithine can promote the synthesis of glutamine, and the human body mainly reduces blood ammonia through the synthesis of glutamine when liver dysfunction occurs. Too much glutamine in the body is not only harmful to the human body, but also decomposes in the intestinal tract to produce ammonia, which makes the blood ammonia concentration rise. In the presence of phenylacetic acid, phenylacetic acid can synthesize phenylacetylglutamine in the kidney with glutamine, which is excreted from the body with urine to reduce the toxic level of ammonia.

The preparation method of L-ornithine phenylacetate reported abroad at present is: start with L-ornithine hydrochloride, first add silver benzoate to separate silver chloride and precipitate to obtain L-ornithine benzoic acid, then add Sodium phenylacetate produces L-ornithine phenylacetate, the process is complex, and the research route is cumbersome, such as (patent CN 102421432A) introducing heavy metal ions such as silver ions, which has large toxic and side effects and has a great influence on the clinical effect of the drug. Influence.

Contents of the invention

The object of the present invention is to provide a kind of preparation method of L-ornithine phenylacetate to above-mentioned technical problem.

The purpose of the present invention is achieved through the following technical solutions:

A preparation method of L-ornithine phenylacetate, the method is first to mix free L-ornithine aqueous solution and phenylacetic acid solution, stir and react, and then the obtained L-ornithine phenylacetate What is necessary is just to crystallize a solution and precipitate in the form of crystal.

The preparation method, wherein the free L-ornithine aqueous solution can be obtained by dissolving L-ornithine salt in water, adjusting the pH to 1.5-3, putting it on a cation exchange resin column, and then washing the column with water to remove impurities (such as salt ions and other impurities), and then elute L-ornithine with ammonia water, and concentrate the eluent under reduced pressure to obtain free L-ornithine aqueous solution; the cation exchange resin column is preferably JK006 cation exchange resin column.

The preparation method of described L-ornithine phenylacetate, wherein said L-ornithine salt is sulfate, nitrate, acetate, oxalate, formate of L-ornithine , Hydrochloride, Citrate, Carbonate, Benzoate, Succinate, Tartrate, Ascorbate, Aspartate, Bicarbonate, Maleate, Glutamate, Fumarate , one or more of methanesulfonate, besylate, p-toluenesulfonate or phosphate.

The preparation method, wherein the solvent system of the phenylacetic acid solution is selected from one or more of water, methanol, ethanol, acetone, ether or acetonitrile.

The preparation method, wherein the molar ratio of L-ornithine to phenylacetic acid in the reactant is 2:1 to 1:2; the stirring reaction temperature of L-ornithine aqueous solution and phenylacetic acid solution is controlled at 10°C ~75°C, the stirring rate is controlled at 80rpm~200rpm.

In the above preparation method, the crystallization method may adopt methods such as adding anti-solvent to the solution, evaporating solvent, lowering the temperature, or adding seed crystals, or a combination of these methods.

The preparation method, wherein the anti-solvent can be selected from one or more of the following substances: cyclohexane, ethanol, isopropanol (IPA), 1-acetone, acetone, dimethyl carbonate, benzonitrile, N -Methylpyrrolidine (NMP), Dichloromethane (DCM), Diethyl ether, Dimethylsulfoxide (DMSO), 2-Butanol, Ethyl acetate (EtOAc), Cumene, Acetonitrile, Ethyl formate, Methyl acetate, isobutyl acetate, nitromethane, 3-methyl-1-butanol, tert-butyl methyl ether, anisole, tetrahydrofuran, toluene, diisopropyl ether; The volume ratio of amino acid phenylacetic acid solution is 1:9～9:1.

In the preparation method, the crystallization method is preferably adding anti-solvent isopropanol, cooling to 2-6° C., and standing for 2-4 hours to crystallize. The volume ratio of isopropanol to L-ornithine phenylacetic acid solution is preferably 4 to 1.

In the preparation method, the temperature is controlled at 1° C. to 20° C. by lowering the temperature for crystallization.

In the preparation method, the amount of seed crystals added is 0.1-10wt% of the content of L-ornithine phenylacetic acid in the L-ornithine phenylacetic acid solution, preferably 0.5-5wt%.

Beneficial effects of the present invention:

The process route invented is a one-step reaction, the process is simple and mild, and provides an effective reference for the high-purity and industrialized preparation of L-ornithine and phenylacetic acid. The product has low toxic and side effects and ensures the safety of clinical medication. Compared with the process technology, the preparation method of the present invention has low cost, high yield and high product purity, and is suitable for industrialized production.

Specific implementation method

The present invention will be further described below through the examples, but the protection scope of the present invention is not limited to the following examples.

Example 1

Dissolve 16.8g of L-ornithine hydrochloride (containing 13.2g of free L-ornithine) in 500mL of water, adjust the pH to 2, and flow through the column filled with JK006 cation exchange resin. Rinse the column with 300mL of water to remove impurities such as chloride ions, then elute L-ornithine with 400mL of 2mol/L ammonia water, and concentrate the eluate to 200mL under reduced pressure to obtain free L-ornithine Aqueous solution (containing L-ornithine 0.1mol). Dissolve 6.8g of phenylacetic acid in 400mL of water at 75°C in a water bath, control the stirring rate at 80rpm in the aqueous solution of phenylacetic acid at 75°C, and add the above-mentioned free L-ornithine aqueous solution (L-ornithine) while stirring Acid to phenylacetic acid molar ratio is 2:1), after stirring for 20 minutes, evaporate and concentrate to 24mL, while stirring at room temperature, slowly add acetone 56mL, so that the volume ratio of acetone to the above mixed aqueous solution is 7:3, stir for 30min After cooling to 1°C, add 0.2 g of seed crystals, and after standing at 1°C for 3 hours, a crystalline solid (L-ornithine phenylacetate) precipitates, and the crystals are separated by vacuum filtration, washed with acetone, and kept at 45°C Blow drying overnight to obtain 8.8 g of L-ornithine phenylacetate. The purity was determined to be 98.5%, and the yield was 44%.

Example 2

Dissolve 20g of L-ornithine hydrochloride (containing 15.7g of free L-ornithine) in 500mL of water, adjust the pH to 2, and flow through the column filled with JK006 cation exchange resin. Rinse the column with 300mL of water to remove impurities such as chloride ions, then elute L-ornithine with 400mL of 2mol/L ammonia water, and concentrate the eluate to 200mL under reduced pressure to obtain free L-ornithine Aqueous solution (containing L-ornithine 0.119mol). Add 16.2g of phenylacetic acid (the molar ratio of L-ornithine to phenylacetic acid is 1:1) into 100mL of ethanol, and stir to dissolve. Add the ethanol solution of phenylacetic acid to the aqueous solution of L-ornithine at room temperature and control the stirring speed at 140 rpm, and stir for 20 min. Concentrate the stirred mixed solution to about 55mL under reduced pressure, and slowly add 220mL of isopropanol while stirring at room temperature, so that the volume ratio of isopropanol to the above mixed aqueous solution is 4:1, and cool to 4 after stirring for 30 minutes. ℃, add 0.638g of seed crystals, and after standing at 4℃ for 3 hours, a crystalline solid (L-ornithine phenylacetate) precipitates, and the crystals are separated by vacuum filtration, washed with isopropanol, and blown at 45℃ After drying overnight, 22.3 g of L-ornithine phenylacetate was obtained. The purity was determined to be 98.9%, and the yield was 69.9%.

Example 3

Dissolve 20g of L-ornithine nitrate (containing 13.5g of free L-ornithine) in 500mL of water, adjust the pH to 2, and flow through the column filled with JK006 type cation exchange resin to wash away impurities such as nitrate ions , and then eluted L-ornithine with 400 mL of 2 mol/L ammonia water, and concentrated the eluate to 200 mL under reduced pressure to obtain free L-ornithine aqueous solution (containing 0.102 mol of L-ornithine). Add 27.9g of phenylacetic acid (the molar ratio of L-ornithine to phenylacetic acid is 1:2) into 100mL of methanol, and stir to dissolve. The methanol solution of phenylacetic acid was added into the L-ornithine aqueous solution while stirring at room temperature under a controlled stirring rate of 200 rpm, and stirred for 20 min. Concentrate the stirred mixed solution to about 50ml under reduced pressure, and slowly add 250mL dimethyl sulfoxide while stirring at room temperature, so that the volume ratio of dimethyl sulfoxide to the above mixed aqueous solution is 5:1, after stirring for 30min Cool to 15°C, add 0.82 g of seed crystals, and stand at 15°C for 3 hours to precipitate a crystalline solid (L-ornithine phenylacetate), separate the crystals by vacuum filtration, wash with dimethyl sulfoxide, and Dry overnight at 45°C to obtain 14.7 g of L-ornithine phenylacetate. The purity was determined to be 98.7%, and the yield was 35.6%.

Claims (7)

1. a preparation method of L-ornithine phenylacetate is characterized in that first free L-ornithine aqueous solution is mixed with phenylacetic acid solution, stirred and reacted, then the obtained L-ornithine phenylacetate The salt solution is crystallized so that it can be precipitated in the form of crystals; Among them, the crystallization method is to add anti-solvent isopropanol, and cool to 2-6 ℃, stand for 2-4 hours to crystallize; the volume ratio of isopropanol to L-ornithine phenylacetic acid solution is 4 to 1; When, adding seed crystals to the solution, the amount of added seed crystals is 0.1-10 wt% of the content of L-ornithine phenylacetic acid in the L-ornithine phenylacetic acid solution. 2. The preparation method according to claim 1, characterized in that the free L-ornithine aqueous solution is obtained by dissolving L-ornithine salt in water, adjusting the pH to 1.5-3, and putting it on a cation exchange resin column , and then wash the column with water to remove impurities, then elute L-ornithine with ammonia water, and concentrate the eluent under reduced pressure to obtain free L-ornithine aqueous solution. 3. The preparation method according to claim 2, characterized in that the cation exchange resin column is a JK006 type cation exchange resin column. 4. according to the preparation method of the L-ornithine phenylacetate described in claim 2, it is characterized in that described L-ornithine is sulfate, nitrate, acetic acid of L-ornithine Salt, oxalate, formate, hydrochloride, citrate, carbonate, benzoate, succinate, tartrate, ascorbate, aspartate, bicarbonate, maleic acid One or more of salt, glutamate, fumarate, methanesulfonate, besylate, p-toluenesulfonate or phosphate. 5. The preparation method according to claim 1, characterized in that the solvent system of the phenylacetic acid solution is selected from one or more of water, methanol, ethanol, acetone, ether or acetonitrile. 6. The preparation method according to claim 1, characterized in that the molar ratio of L-ornithine to phenylacetic acid in the reactant is 2:1～1:2; L-ornithine aqueous solution and phenylacetic acid solution The temperature of the stirring reaction is controlled at 10° C. to 75° C., and the stirring rate is controlled at 80 rpm to 200 rpm. 7. The preparation method according to claim 1, characterized in that the amount of the added seed crystal is 0.5-5 wt% of the content of L-ornithine phenylacetic acid in the L-ornithine phenylacetic acid solution.