Separation method of sulindac and impurities thereof

Abstract

The invention discloses a method for separating sulindac and impurities thereof. The method comprises the step of determining impurities of sulindac in a test sample by using a high performance liquid chromatograph. The separation and detection method disclosed by the invention is good in separation degree, simple to operate, short in peak appearance time and short in detection time, and also has good method reproducibility and stability.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical analysis, and in particular to a method for the separation and detection of sulindac impurities. Background Technology

[0002] Sulindac is a low-activity prodrug that is metabolized in the body into an active sulfide. This active sulfide inhibits cyclooxygenase and reduces prostaglandin synthesis, making it a relatively new antipyretic, analgesic, and nonsteroidal anti-inflammatory drug (NSAID). Clinically, sulindac is used for anti-inflammatory and analgesic purposes in various types of chronic arthritis (such as rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, and periarthritis of the shoulder). It is particularly beneficial for the elderly, those with potential renal insufficiency, and those experiencing pain from various causes, such as dysmenorrhea, toothache, traumatic and postoperative pain, as well as mild to moderate cancer pain.

[0003] The production process of sulindac's active pharmaceutical ingredient (API) may introduce impurities such as starting materials. Furthermore, byproducts or other degradation products may be generated during the production, storage, and transportation of the API. Therefore, quality control of its starting materials is extremely important. Thus, it is necessary to study these impurities, clarify their structures, and establish detection methods to ensure the quality and safety of sulindac. Summary of the Invention

[0004] In order to effectively control the quality of sulindac, in view of the above-mentioned problems in the existing technology, The purpose of this invention is to provide a method for separating and detecting sulindac and its related impurities. This method has high sensitivity and strong specificity.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On one hand, the present invention provides a method for separating sulindac and its impurities, the method comprising using a high-performance liquid chromatograph to determine sulindac impurities in a test sample.

[0006] Preferably, the mobile phase A of the high-performance liquid chromatography is water-formic acid, and the mobile phase B is acetonitrile-formic acid. Preferably, the volume ratio of water to formic acid in mobile phase A is 100:1, and the volume ratio of acetonitrile to formic acid in mobile phase B is 100:1.

[0007] Preferably, the detection wavelength of the high-performance liquid chromatograph is 330 nm.

[0008] Preferably, the impurities include: impurity A, impurity B, impurity C, impurity D, and impurity E.

[0009] Preferably, the elution conditions of the high-performance liquid chromatograph are as follows: Time (min) A% B% 0 70 30 5 70 30 25 65 35 50 30 70 55 30 70 57 70 30 65 70 30 Preferably, the column temperature of the high-performance liquid chromatograph is 40°C.

[0010] Preferably, the injection volume of the high-performance liquid chromatograph is 20 μl.

[0011] Preferably, the isocratic elution time of the high performance liquid chromatograph is 65 min.

[0012] On the other hand, the present invention provides the application of the method according to any one of the above in the preparation of sulindac active pharmaceutical ingredient.

[0013] The effects of the invention This invention provides a method for separating and detecting sulindac and its impurities, which has good separation, simple operation, fast peak elution time, short detection time, and good method reproducibility and stability. Attached Figure Description

[0014] Figure 1 HPLC chromatogram of sulindac test solution (elution condition 2) Figure 2 HPLC chromatogram of the specificity experiment in Example 2 of this invention Figure 3 Structural diagram of impurity A Figure 4 Structural diagram of impurity B Figure 5 Structural diagram of impurity C Figure 6 Structure diagram of impurity D Figure 7 Structural diagram of impurity E Detailed Implementation

[0015] The following examples are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0016] Information on impurities involved in this application is shown in the table below: impurity code Chemical name Sources of impurities Remark Impurity A (E)-(±)-5-fluoro-2-methyl-1-[[4-(methylsulfinyl)phenyl]methylene]-1H-ethylidene-3-acetic acid Process impurities / cis-trans isomerism API byproducts Impurity B 5-Fluoro-2-methyl-1-[(Z)-4-(methanesulfonyl)benzylidene]-1H-indene-3-acetic acid Degradation impurities / process impurities API intermediates Impurity C (Z)-5-fluoro-2-methyl-1-[[4-(methylthio)phenyl]methylene]-1H-indene-3-acetic acid Degradation impurities / process impurities API byproducts Impurity D (Z)-2-(5-fluoro-2-methyl-1-(4-(methylsulfinyl)benzyl)-1H-inden-3-yl)methyl acetate Degradation impurities Oxidative degradation products of active pharmaceutical ingredients Impurity E (Z)-2-(5-fluoro-2-methyl-1-(4-(methylsulfinyl)benzyl)-1H-inden-3-yl)acetate Degradation impurities Oxidative degradation products of active pharmaceutical ingredients Example

[0017] Test method: Determined by high performance liquid chromatography (General Chapter 0512, Part IV, 2020 Edition of the Chinese Pharmacopoeia). (1) Reagent solutions and reference standards Acetonitrile (HPLC grade) Formic acid (AR grade) Water (purified water) Impurity A Reference Standard Impurity B Reference Standard Impurity C Reference Standard Impurity D Reference Standard Impurity E Reference Standard Sulinic acid reference standard (2) Instruments and equipment High Performance Liquid Chromatography Balance (3) Preparation of test solution and control solution Solvents: Acetonitrile-water (50:50) solution, acetonitrile-water (80:20) solution Blank excipient: Accurately weigh 150 mg of blank excipient, place it in a 50 ml volumetric flask, add 100 ml of 80% acetonitrile, sonicate for 20 min to dissolve, and dilute to the mark with 80% acetonitrile, shake well, filter, discard 3 ml, accurately measure 2.5 ml of the filtrate, place it in a 20 ml volumetric flask, dilute to the mark with 50% acetonitrile, and shake well.

[0018] Test solution: Take 5 test tablets, place them in a 250ml volumetric flask, add 100ml of 80% acetonitrile, sonicate for 20min to dissolve, dilute to the mark with 80% acetonitrile, shake well, filter, discard 3ml, accurately measure 2.5ml of the filtrate, place it in a 20ml volumetric flask, dilute to the mark with 50% acetonitrile, and shake well.

[0019] Control solution: Accurately measure 1 ml of the test solution and place it in a 200 ml volumetric flask. Dilute to the mark with 50% acetonitrile and shake well.

[0020] (4) System suitability solution Take appropriate amounts of impurity A, impurity B, impurity C, impurity D, impurity E and sulindac reference standard, accurately weigh them, dissolve them in solvent and quantitatively dilute them to prepare a mixed solution containing approximately 2.5 μg of each impurity and 0.5 mg of sulindac per 1 ml.

[0021] Accurately measure blank solution (i.e. solvent), blank excipient, system suitability solution, test solution, and control solution, and inject them into the liquid chromatograph, recording the chromatograms.

[0022] Example 1 (1) Optimization of chromatographic conditions Take the test solution of the active pharmaceutical ingredient and optimize the mobile phase ratio based on the gradient elution method for related substances in sulindac raw material USP.

[0023] chromatographic column Column: GL InerSustain C18 4.6×150mm, 5μm Column temperature: 40℃ Mobile phase A: 0.1% formic acid aqueous solution Mobile phase B: 0.1% formic acid acetonitrile solution Flow rate: 0.8 ml / min Detection wavelength: 330nm Injection volume: 20 μl Test solution: 0.5 mg / ml The elution conditions are as follows: Elution gradient condition 1: Time (min) A% B% 0 70 30 5 70 30 25 65 35 40 30 70 50 30 70 52 70 30 60 70 30 Elution gradient condition 2: Time (min) A% B% 0 70 30 5 70 30 25 65 35 50 30 70 55 30 70 57 70 30 65 70 30 Under elution condition 1, the resolution between the main peak of the sample and subsequent impurity peaks was greater than 1.5, and the resolution between impurity A and its preceding impurity peak was also greater than 1.5. However, the resolution of the three unknown impurity peaks between impurities D and C did not meet the requirements and further optimization is needed. Under elution condition 2, the three unknown impurity peaks between impurities D and C in the test solution were basically separated, and no impurity peaks interfered with the detection of known impurities. Figure 2 This is an HPLC chromatogram of the specificity experiment in Example 2 of the present invention.

[0024] Example 2 Specificity Experiment Blank solvent (diluent): 50% acetonitrile, 80% acetonitrile.

[0025] Sulindac positioning solution: Take an appropriate amount of sulindac reference standard, accurately weigh it, add diluent to dissolve it and quantitatively dilute it to prepare a solution containing approximately 0.5 mg of ketotifen per 1 ml.

[0026] Impurity A reference solution: Take an appropriate amount of each impurity reference standard, accurately weigh it, add diluent to dissolve it and quantitatively dilute it to prepare a solution containing approximately 25 μg of impurity A per 1 ml.

[0027] Impurity B reference solution: Take an appropriate amount of each impurity reference standard, accurately weigh it, add diluent to dissolve it and quantitatively dilute it to prepare a solution containing approximately 25 μg of impurity B per 1 ml.

[0028] Impurity C reference solution: Take an appropriate amount of each impurity reference standard, accurately weigh it, add diluent to dissolve it and quantitatively dilute it to prepare a solution containing approximately 25 μg of impurity C per 1 ml.

[0029] Impurity D reference solution: Take an appropriate amount of each impurity reference standard, accurately weigh it, add diluent to dissolve it and quantitatively dilute it to prepare a solution containing approximately 25 μg of impurity D per 1 ml.

[0030] Impurity E reference solution: Take an appropriate amount of each impurity reference standard, accurately weigh it, add diluent to dissolve it and quantitatively dilute it to prepare a solution containing approximately 25 μg of impurity E per 1 ml.

[0031] System suitability solution: Take appropriate amounts of impurity A, impurity B, impurity C, impurity D, impurity E and sulindac reference standard, accurately weigh them, dissolve them in solvent and quantitatively dilute them to prepare a mixed solution containing approximately 2.5 μg of each impurity and 0.5 mg of sulindac per 1 ml.

[0032] Blank excipient solution: Accurately weigh 150 mg of blank excipient, place it in a 50 ml volumetric flask, add 100 ml of 80% acetonitrile, sonicate for 20 min to dissolve, and dilute to the mark with 80% acetonitrile, shake well, filter, discard 3 ml, accurately measure 2.5 ml of the filtrate, place it in a 20 ml volumetric flask, dilute to the mark with 50% acetonitrile, and shake well.

[0033] Test solution: Take 5 tablets of the test sample, place them in a 250ml volumetric flask, add 100ml of 80% acetonitrile, sonicate for 20min to dissolve, then dilute to the mark with 80% acetonitrile, shake well, filter, discard 3ml, accurately measure 2.5ml of the filtrate, place it in a 20ml volumetric flask, dilute to the mark with 50% acetonitrile, and shake well. Control solution: Accurately measure 1 ml of the test solution and place it in a 200 ml volumetric flask. Dilute to the mark with 50% acetonitrile and shake well.

[0034] Take blank solvent, blank excipient solution, test solution, sulindac, system suitability solution, impurity A, impurity B, impurity C, impurity D, impurity E reference solution and reference solution and determine according to the method, and record the chromatogram.

[0035] List the blank solvent, blank excipient solution, test solution, sulindac, system suitability solution, impurity A, impurity B, impurity C, impurity D, and impurity E in that order, and attach... Figure 1 The HPLC chromatogram of sulindac test solution (elution condition 2).

[0036] Results of specificity test: Blank solution, blank excipient, and sulindac showed no interference in the detection of any impurities in the solution. In the chromatogram of the system suitability solution, except for the solvent peak, sulindac, impurity A, impurity B, impurity D, impurity E, and impurity C were eluted sequentially, and the resolution between impurity A and sulindac was 6.6 > 1.5.

[0037] Example 3: Limit of Quantitation and Limit of Detection Experiment The signal-to-noise ratio (SNR) was used to determine the limits of detection (LOD) and quantitation (LOQ). The reference stock solution was diluted until the SNR of sulindac and impurities A, B, C, D, and E was approximately 3–10; the concentration of these impurities was then designated as the LOD for that impurity. The LOD of sulindac and impurities A, B, C, D, and E was determined until the SNR was approximately 10–30; the LOD for these impurities was then designated as the LOQ for that impurity. Simultaneously, a mixed solution of the reference standard at the LOQ concentration was prepared, and six parallel determinations were performed to examine the peak area and retention time. The results are shown in the table below.

[0038] As shown in the table above, the limits of quantitation and detection of known impurities are both lower than 0.05% of the concentration of the test sample solution, which meets the requirements.

Claims

1. A method for separating sulindac and its impurities, characterized in that, The method includes using a high-performance liquid chromatograph to determine sulindac impurities in the test sample.

2. The separation method according to claim 1, characterized in that, The mobile phase A of the high-performance liquid chromatography is water-formic acid, and the mobile phase B is acetonitrile-formic acid.

3. The separation method according to claim 1, wherein the volume ratio of water to formic acid in mobile phase A is 100:1, and the volume ratio of acetonitrile to formic acid in mobile phase B is 100:

1.

4. The separation method according to claim 1, characterized in that, The detection wavelength of the high-performance liquid chromatograph is 330 nm.

5. The separation method according to claim 1, characterized in that, The impurities include: impurity A, impurity B, impurity C, impurity D, and impurity E.

6. The separation method according to claim 1, characterized in that, The elution conditions for the high-performance liquid chromatograph are as follows: Time (min) A% B% 0 70 30 5 70 30 25 65 35 50 30 70 55 30 70 57 70 30 65 70 30。 7. The separation method according to claim 1, characterized in that, The column temperature of the high-performance liquid chromatograph is 40℃.

8. The separation method according to claim 1, characterized in that, The injection volume of the high-performance liquid chromatograph is 20 μl.

9. The separation method according to claim 1, characterized in that, The gradient elution time of the high performance liquid chromatograph is 65 min.

10. The use of the method according to any one of claims 1 to 9 in the preparation of sulindac active pharmaceutical ingredient.

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