Preparation method and application of 2Z isomer impurity in epalrestat

Abstract

The invention relates to the technical field of medicine synthesis, in particular to a preparation method and application of a 2Z isomer impurity in epalrestat. The structural formula of the impurity is shown as a formula I: # imgabs0 #. The epalrestat 2Z isomer impurity is prepared for the first time, and efficient preparation, separation and identification of the impurity have important significance on subsequent quality control of epalrestat raw material medicine and preparations thereof. The preparation method provided by the invention is simple and feasible, a liquid phase does not need to be prepared, and the high-purity epalrestat 2Z isomer impurity can be obtained through a simple process. According to the invention, convenience is provided for impurity analysis and research of epalrestat raw material medicines and preparations thereof, and a detection method and a judgment basis are provided for production and medication safety of epalrestat.

Description

Technical Field

[0001] The present invention relates to the technical field of drug synthesis, and in particular to a preparation method of a 2Z isomer impurity in epalrestat and application thereof. Background Art

[0002] Epalrestat is a reversible non-competitive inhibitor of aldose reductase, mainly used to treat diabetic neuropathy, especially diabetic peripheral neuropathy. Aldose reductase plays a role in converting glucose into sorbitol in the human body, and in diabetic patients, due to the hyperglycemic state, the activity of aldose reductase may increase, resulting in the accumulation of sorbitol in cells. This accumulation can damage nerve cells, thereby causing diabetic neuropathy. Epalrestat protects nerve cells from damage by inhibiting the activity of aldose reductase and reducing the generation and accumulation of sorbitol. Clinically, Epalrestat is often used to treat diabetic patients' neuropathy symptoms, such as numbness, pain, and paresthesia in the hands and feet. In addition, it also helps to improve the nerve conduction velocity of diabetic patients and improve the quality of life of patients. The preparation of its impurities has important applications for drug quality control, impurity limit research and drug safety evaluation.

[0003] As an impurity reference substance, epalrestat 2Z isomer can be used to study and control epalrestat 2Z isomer in epalrestat API and pharmaceutical composition. By using epalrestat 2Z isomer reference substance, researchers can understand the existence state, source and properties of epalrestat 2Z isomer, so as to take corresponding measures to control the production and content of epalrestat 2Z isomer. This helps to ensure the safety and effectiveness of drugs.

[0004] The 2Z isomer of epalrestat can be used as an impurity reference substance to determine the stability and composition of epalrestat drug products to determine the maximum feasible limit of epalrestat drug products. In addition, the 2Z isomer of epalrestat can also be used as a reference substance to describe the process characteristics of epalrestat ingredients and to evaluate the change trend of inactive ingredients in drugs.

[0005] In the production process of epalrestat, epalrestat 2Z isomer can be used as a reference substance to monitor the stability of the epalrestat production process and product quality. By comparing the properties and contents of epalrestat 2Z isomer with those of samples in actual production, problems in the process can be discovered in a timely manner, and corresponding measures can be taken to adjust and optimize. This helps to improve the production efficiency and product quality of the drug. As an impurity reference substance, epalrestat 2Z isomer can be used to formulate corresponding standards and reference bases for the epalrestat production process to ensure the quality consistency between different batches of drugs.

[0006] In the field of drug testing, epalrestat 2Z isomer can be used as a standard and reference for epalrestat testing.

[0007] In view of the high medicinal value of epalrestat, it is necessary to conduct quality research on epalrestat API or preparation. However, when conducting quality research on epalrestat API or preparation, there is still a lack of high-purity reference substances for relevant major degradation impurities. In the process of drug development, the lack of impurity reference substances may become a serious bottleneck, which has an unignorable impact on drug quality control and R&D progress. Impurity reference substances play a vital role in ensuring the safety, stability and effectiveness of drugs. Summary of the invention

[0008] In view of the problems existing in the prior art, the present invention provides a method for preparing a new impurity epalrestat 2Z isomer, and the 2Z impurity can be used as a reference substance for quality research of epalrestat raw materials or preparations thereof.

[0009] Another object of the present invention is to provide the use of the above-mentioned epalrestat 2Z isomer impurity as a reference substance in the quality control of epalrestat raw materials and preparations thereof.

[0010] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: The structural formula of the epalrestat 2Z isomer impurity prepared by the present invention is shown in Formula I: The present invention provides a method for preparing epalrestat 2Z isomer, comprising the following steps: (1) dissolving epalrestat in a first solvent and reacting under light and / or heating conditions to obtain a reaction solution; (2) adding the second solvent to the reaction solution, crystallizing, filtering with suction, and drying the filter cake to obtain a crude product of epalrestat 2Z isomer; (3) Adding the crude epalrestat 2Z isomer to the third solvent, heating and stirring, filtering while hot, cooling the filtrate and crystallizing, filtering and vacuum drying to obtain epalrestat 2Z isomer.

[0011] Preferably, in step (1), the first solvent is one or more of DMF, tetrahydrofuran, methanol, ethanol, acetone, dichloromethane, chloroform and DMSO; preferably, the first solvent is DMF; the mass ratio of epalrestat to the first solvent is 1:5-20; preferably, the mass ratio is 1:5.

[0012] Preferably, in step (1), the illumination is performed at an illumination of 100 Lx or more; preferably, the illumination is 10,000 to 60,000 Lx; and the total illumination received by the reaction substrate is not less than 1.44*10 6 Lx, preferably (3.6~6.0)*10 6 Lx*h.

[0013] Preferably, in step (1), the heating temperature is 30-150° C., preferably 70-80° C.; and the reaction time is 48 h to 144 h, preferably 48-72 h.

[0014] Preferably, in step (2), the second solvent is a mixture of one or more solvents selected from the group consisting of purified water, n-hexane, petroleum ether, ethanol, methanol, dichloromethane, chloroform, ether and isopropanol; preferably, the second solvent is purified water or isopropanol; the mass ratio of the second solvent to the first solvent is 1:5-40, preferably, the mass ratio is 1:20.

[0015] Preferably, in step (2), the crystallization time is 1-5 hours; preferably, the crystallization time is 3 hours.

[0016] Preferably, in step (3), the third solvent is one or a mixture of several solvents selected from the group consisting of DMF, tetrahydrofuran, methanol, ethanol, acetone, dichloromethane, chloroform and DMSO; preferably, the third solvent is ethanol or methanol; and the mass ratio of the crude epalrestat 2Z isomer to the third solvent is 1:1 to 20, preferably 1:5.

[0017] Preferably, in step (3), the heating and stirring conditions are: heating to 40-80°C and stirring for 1-5 hours; preferably, heating to 50-60°C and stirring for 2 hours.

[0018] Preferably, in step (3), the crystallization temperature is 0°C to 50°C, preferably 25°C to 35°C.

[0019] The preparation method provided by the present invention has a reaction scheme as shown below: The high-purity epalrestat 2Z isomer (cis-trans isomers of epalrestat) prepared by the present invention is used as a reference substance. This impurity is one of the main degradation impurities of epalrestat and its impurity limit shall not exceed 0.2%; and this impurity will significantly increase under accelerated conditions during the stability placement period, posing certain safety hazards to the human body.

[0020] In some embodiments, the specific application of epalrestat 2Z isomer in the quality control of epalrestat bulk drug is included, and the epalrestat 2Z isomer is used as an impurity reference substance for epalrestat bulk drug.

[0021] The present invention also provides a method for determining the 2Z isomer impurity of the epalrestat bulk drug, the method comprising: Provide test products, self-reference products and 2Z isomer standards of epalrestat API; The presence and amount of the 2Z isomer in the epalrestat drug substance were determined by chromatography of the test, reference and standard substances.

[0022] In a preferred embodiment of the present invention, the method for determining the 2Z isomer of the epalrestat drug substance comprises: Provide standard products of epalrestat API; Provide a 2Z isomer reference; Analyze the 2Z isomer reference substance by HPLC to determine the retention time of the 2Z isomer; The test sample of the epalrestat bulk drug substance was analyzed by HPLC to determine whether the test sample contained a substance whose retention time was substantially consistent with the retention time of the 2Z isomer, thereby determining the presence of the 2Z isomer in the epalrestat bulk drug substance.

[0023] The beneficial effects of the present invention are: (1) The present invention prepares the epalrestat 2Z isomer impurity for the first time. The efficient preparation and separation and identification of the impurity are of great significance for the subsequent quality control of the epalrestat API and its preparations.

[0024] (2) The 2Z isomer of epalrestat provided by the present invention can be used to detect and control the content of the 2Z isomer produced during the preparation or storage of the epalrestat API and its pharmaceutical composition, and control the content of related impurities in the epalrestat API and its pharmaceutical composition to meet the required standards, and also provide a reference for process condition control and storage condition control. The method is simple and feasible, does not require the preparation of liquid phase, and can obtain a high-purity epalrestat 2Z isomer reference substance through a simple crystallization process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the HPLC determination chart of the epalrestat 2Z impurity in the epalrestat raw material. DETAILED DESCRIPTION

[0026] The present application is further described in detail below in conjunction with specific examples, which are not intended to limit the present invention. The examples described are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1 Preparation of Epalrestat 2Z Isomer Take 50 ml of DMF and 10 g of epalrestat, add them into the reaction bottle, start stirring, and place under light with an illumination of 6*10 4Lx and heated at 70 ° C for 100 hours. After the reaction, take an appropriate amount of the reaction solution for liquid chromatography analysis and detection. The control purity of the 2Z isomer of epalrestat is 76.42%. Add 1000 ml of purified water to the reaction solution of the 2Z isomer of epalrestat for crystallization, filter after 3 hours, and vacuum dry the filter cake at 50 ° C for 5 hours to obtain 8.16 g of crude 2Z isomer of epalrestat. Add 8.16 g of crude 2Z isomer of epalrestat to 40 ml of ethanol solution, heat to 50 ° C, stir for 2 hours, filter while hot, cool the filtrate to 30 ° C for crystallization, and filter after 1 hour to obtain 2.13 g of golden 2Z isomer of epalrestat. The target compound was analyzed by liquid chromatography, and the purity was 99.23%. 1 H-NMR (600MHz, DMSO-d6, 25℃) δ:1.800(s,3H),1.938(s,3H),3.976(s,1H),4.568~4.644(m,2H),5.209(s,1H),6.653(s,1H) ,7.216~7.364(m,10H) ,7.657(s,1H),13.458(s,2H) 13 C-NMR(600MHz,DMSO-d6,25℃) δ:21.946,45.395,123.566,129.012,129.088,129.996,131.682,133.017,136.358,142.551,167.014,167.701,193.552.

[0028] LC-MS (m / z) : 320.0 [M+H] + .

[0029] HPLC purity(99.23)%.

[0030] Embodiment 2: Take 50 ml of DMF and 10 g of epalrestat, add them into the reaction bottle, start stirring, and place under light with an illumination of 5*10 4Lx and heated at 70 ° C for 72 hours. After the reaction, take an appropriate amount of the reaction solution for liquid chromatography analysis and detection. The central control purity of the 2Z isomer of epalrestat is 66.48%. 1000 ml of purified water was added to the reaction solution of the 2Z isomer of epalrestat for crystallization. After 3 hours, the filter cake was vacuum dried at 50 ° C for 5 hours to obtain 7.87 g of the crude 2Z isomer of epalrestat. 7.87 g of the crude 2Z isomer of epalrestat was added to 35 ml of methanol solution, heated to 45 ° C, stirred for 2 hours and filtered while hot, and the filtrate was cooled to 30 ° C for crystallization. After 1 hour, the filtrate was filtered to obtain 1.83 g of the golden 2Z isomer of epalrestat. The target was analyzed by liquid chromatography, and the purity was 98.64%.

[0031] Effect Example 3: HPLC Determination of Epalrestat 2Z Isomer Impurity in Epalrestat API (1) Accurately weigh 5 mg of epalrestat API, place it in a 100 ml volumetric flask, dilute to the mark with mobile phase A, shake well, and place in a dark place for 1 hour as the test solution. Take an appropriate amount of epalrestat 2Z isomer impurity reference substance, accurately weigh it, place it in a 50 ml volumetric flask, add mobile phase A to dissolve and quantitatively dilute it to make a solution containing about 50 μg of impurities per 1 ml as the impurity stock solution; accurately weigh an appropriate amount of epalrestat reference substance, add the impurity stock solution, and dilute it with mobile phase A to make a solution containing about 0.5 mg of epalrestat and 1 μg of epalrestat 2Z isomer impurity per 1 ml as the system suitability solution.

[0032] (2) Determined according to high performance liquid chromatography (Chinese Pharmacopoeia 2020 Edition Part IV General Chapter 0512). Octadecylsilane bonded silica gel is used as the filler (Waters Symmetry C18 250mm×4.6mm, 5cm or chromatographic column of equivalent performance); phosphate buffer (0.06mol / L potassium dihydrogen phosphate solution adjusted to pH 7.6 with 0.06mol / L disodium hydrogen phosphate solution)-acetonitrile (3:1) is used as mobile phase A; phosphate buffer (0.06mol / L potassium dihydrogen phosphate solution adjusted to pH 7.6 with 0.06mol / L disodium hydrogen phosphate solution)-acetonitrile (2:8) is used as mobile phase B; gradient elution is performed according to the table below; the flow rate is 1.0ml per minute; the detection wavelength is 280nm; and the column temperature is 25℃.

[0033] Table 1 (2) Take 20μl of the system suitability solution and inject it into the liquid chromatograph. Record the chromatogram. The 2Z isomer impurity of epalrestat and epalrestat peaks are present once. The separation between the peaks should meet the requirements. The theoretical plate number calculated based on the epalrestat peak should not be less than 5000. Accurately measure 20μl of the test solution and inject it into the liquid chromatograph. Record the chromatogram. Figure 1 .

[0034] (3) Calculation of content: The mass percentage of the epalrestat 2Z isomer impurity in the epalrestat bulk drug substance test sample was calculated according to the area normalization method. The collective experimental results are shown in Table 2: Table 2 Content of epalrestat 2Z isomer impurity in epalrestat bulk drug The results of Example 3 above show that the epalrestat 2Z isomer impurity provided by the present invention can be used as an impurity reference substance for the epalrestat bulk drug and can be used for its quality control, which plays a very important role in the quality monitoring of epalrestat or its drug combination.

[0035] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the scope of the present invention shall be based on the attached claims, and the description can be used to interpret the content of the claims.

Claims

1. A method for preparing epalrestat 2Z isomer, characterized in that: The following steps are involved: (1) dissolving epalrestat in a first solvent and reacting under light and / or heating conditions to obtain a reaction solution; (2) adding the second solvent to the reaction solution, crystallizing, filtering with suction, and drying the filter cake to obtain a crude product of epalrestat 2Z isomer; (3) Adding the crude epalrestat 2Z isomer to the third solvent, heating and stirring, filtering while hot, cooling the filtrate and crystallizing, filtering and vacuum drying to obtain epalrestat 2Z isomer.

2. The preparation method according to claim 1, characterized in that: In step (1), the first solvent is one or more of DMF, tetrahydrofuran, methanol, ethanol, acetone, dichloromethane, chloroform and DMSO; preferably, the first solvent is DMF; the mass ratio of epalrestat to the first solvent is 1:5-20; preferably, the mass ratio is 1:

5.

3. The preparation method according to claim 1 or 2, characterized in that: In step (1), the illumination is performed at an illumination of 100 Lx or more; preferably, the illumination is 10,000 to 60,000 Lx; and the total illumination received by the reaction substrate is not less than 1.44*10 6 Lx, preferably (3.6~6.0)*10 6 Lx*h.

4. The preparation method according to claim 1 or 2, characterized in that: In step (1), the heating temperature is 30-150°C, preferably 70-80°C; the reaction time is 48h-144h, preferably 48-72h.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In step (2), the second solvent is a mixture of one or more solvents selected from the group consisting of purified water, n-hexane, petroleum ether, ethanol, methanol, dichloromethane, chloroform, ether and isopropanol; preferably, the second solvent is purified water or isopropanol; the mass ratio of the second solvent to the first solvent is 1:5-40, preferably, the mass ratio is 1:

20.

6. The preparation method according to any one of claims 1 to 5, characterized in that: In step (2), the crystallization time is 1-5 hours; preferably, the crystallization time is 3 hours.

7. The preparation method according to any one of claims 1 to 6, characterized in that: In step (3), the third solvent is one or a mixture of several solvents selected from the group consisting of DMF, tetrahydrofuran, methanol, ethanol, acetone, dichloromethane, chloroform and DMSO; preferably, the third solvent is ethanol or methanol; and the mass ratio of the crude epalrestat 2Z isomer to the third solvent is 1:1 to 20, preferably 1:

5.

8. The preparation method according to claim 1 or 7, characterized in that: In step (3), the heating and stirring conditions are: heating to 40-80°C and stirring for 1-5h; preferably, heating to 50-60°C and stirring for 2h.

9. The preparation method according to claim 1, 7 or 8, characterized in that: In step (3), the crystallization temperature is 0°C to 50°C, preferably 25°C to 35°C.

10. The epalrestat 2Z isomer prepared according to the method for preparing the epalrestat 2Z isomer according to any one of claims 1 to 9, characterized in that: The epalrestat 2Z isomer has a structure shown in formula (I): 。

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