A method for detecting related substances in domperidone tablets

Abstract

The invention discloses a method for detecting related substances in domperidone tablets, and relates to the field of analytical chemistry. The detection method of the invention is as follows: the domperidone tablets are mixed with a diluent to obtain a test solution; the test solution is injected into a liquid chromatograph, loaded into a chromatographic column, and gradient eluted with mobile phase A and mobile phase B to separate domperidone from impurities in the test solution; mobile phase A and mobile phase B are respectively a mixture of 0.5% acetate buffer, methanol and acetonitrile, and the volume ratio of 0.5% acetate buffer, methanol and acetonitrile in mobile phase A is (59-61):35:(4-6); the volume ratio of 0.5% acetate buffer, methanol and acetonitrile in mobile phase B is (20-30):30:(40-50); a detector is used to test the separated domperidone and impurities to obtain a spectrum. The detection method of the invention realizes the effective separation of domperidone and various impurities, so that the separation between each spectrum peak is high, and the content of each impurity can be accurately detected.

Description

Technical Field

[0001] The invention relates to the field of analytical chemistry, and in particular to a method for detecting related substances in domperidone tablets. Background Art

[0002] The trade name of domperidone tablets is It is mainly used to treat indigestion, bloating, belching, nausea, vomiting and abdominal pain.

[0003] The main component of domperidone tablets is domperidone maleate, and the known impurities in domperidone tablets are impurity A, impurity B, impurity C, impurity D, impurity E and impurity F. In the past two years, studies have found impurity G [1-(3-chloropropyl)-1,3-dihydro-2H-benzimidazol-2-one)]. Impurity G is a genotoxic impurity with high toxicity. Impurity G is one of the synthetic raw materials and is difficult to remove in the production process. It should be controlled in the domperidone raw materials and finished products.

[0004] At present, there are few studies on the detection methods of related substances in domperidone tablets. In the prior art, a method for analyzing related substances in domperidone tablets using high performance liquid chromatography (HPLC) is used. The chromatographic conditions used in this method are as follows: chromatographic column: octadecylsilane bonded silica gel, mobile phase: methanol-0.5% ammonium acetate (60:40), diluent: mobile phase, elution mode: isocratic elution, column temperature: 30°C, wavelength: 285nm, injection volume: 20μL. The above prior art has the following disadvantages: it is difficult to detect all the impurities in the domperidone tablets by the above method, and the separation between the impurities is poor, and accurate quantification is not possible. Therefore, the above method currently only controls the total impurities in the domperidone tablets, and controls the total impurity content in the domperidone tablets to be ≤1.0%, and does not control each impurity separately, making it difficult to accurately reflect the situation of related substances in the domperidone tablets, and does not control impurity G. Summary of the invention

[0005] In view of the problems raised by the background technology, the purpose of the present invention is to propose a method for detecting related substances in domperidone tablets, which realizes the effective separation of domperidone and various impurities, makes the separation degree between various spectral peaks high, and can accurately detect the content of various impurities.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A method for detecting related substances in domperidone tablets comprises the following steps:

[0008] Step (1): mixing the domperidone tablets with the diluent, and filtering by ultrasonic filtering to obtain a test solution;

[0009] Step (2): injecting the test solution into a liquid chromatograph, loading it onto a chromatographic column, and performing gradient elution with mobile phase A and mobile phase B to separate domperidone from impurities in the test solution;

[0010] Mobile phase A and mobile phase B are both mixtures of 0.5% acetate buffer, methanol and acetonitrile, wherein the volume ratio of 0.5% acetate buffer, methanol and acetonitrile in mobile phase A is (59-61):35:(4-6); the volume ratio of 0.5% acetate buffer, methanol and acetonitrile in mobile phase B is (20-30):30:(40-50);

[0011] Step (3): using a detector to test the separated domperidone and impurities to obtain a spectrum.

[0012] Furthermore, in step (2), the procedure for gradient elution with mobile phase A and mobile phase B is as follows:

[0013] (a) From 0 to 10 min, mobile phase A decreased from 100% to 70%, and mobile phase B increased from 0% to 30%;

[0014] (b) 10 min to 26 min, maintaining mobile phase A at 70% and mobile phase B at 30%;

[0015] (c) From 26 to 45 min, mobile phase A decreased from 70% to 0%, and mobile phase B increased from 30% to 100%;

[0016] (d) 45 min to 50 min, mobile phase A increased from 0% to 100%, and mobile phase B decreased from 100% to 0%;

[0017] (e) 50 min to 60 min, maintaining mobile phase A at 100% and mobile phase B at 0%.

[0018] Furthermore, in step (1), the diluent is a mixture of 0.5% ammonium acetate buffer, methanol and acetonitrile, and in the diluent, the volume ratio of the 0.5% ammonium acetate buffer, the methanol and the acetonitrile is 60:35:5.

[0019] Further, in the mobile phase A, the volume ratio of the 0.5% acetate buffer, the methanol and the acetonitrile is 60:35:5;

[0020] In the mobile phase B, the volume ratio of the 0.5% acetate buffer, the methanol and the acetonitrile is 25:30:45.

[0021] Furthermore, in step (2), the column temperature of the chromatographic column is 25-35° C., the column length is 200-300 mm, the column inner diameter is 4.6 mm, and the filler particle size of the chromatographic column is 5 μm.

[0022] Furthermore, in step (2), the total flow rate of the mobile phase A and the mobile phase B is 0.8 to 1.2 mL / min.

[0023] Furthermore, in step (2), the injection volume of the test solution is 10 to 30 μL.

[0024] Furthermore, in step (3), the detection wavelength of the detector is 283-287 nm.

[0025] Furthermore, in the step (1), the preparation method of the test solution is as follows: 20 domperidone tablets are ground into fine powder, the sample powder is placed in a 50 mL volumetric flask, a diluent is added, ultrasonically shaken for 20 minutes, then diluted to the scale with the diluent, filtered, 3 mL of the front filtrate is discarded, and the subsequent filtrate is taken to obtain the test solution.

[0026] Furthermore, the method for detecting related substances in domperidone tablets is used in the preparation of domperidone tablets.

[0027] The above technical solution has the following beneficial effects: the detection method of the technical solution realizes the effective separation of domperidone and various impurities by changing the type of mobile phase and the mobile phase elution gradient, so that the separation between each spectrum peak is high, and the content of each impurity can be accurately detected. Moreover, domperidone and each impurity have a good linear relationship and high test accuracy. At the same time, the present invention can accurately detect the genotoxic impurity G, greatly reducing the laboratory workload. The detection method of the present invention can greatly improve the control of the impurity content in the production process of domperidone tablets. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The spectrum obtained by testing the separation solution using the analytical method of the prior art;

[0029] Figure 2 The spectrum obtained by testing each impurity AF of domperidone according to the analytical method of the prior art;

[0030] Figure 3 The spectrum obtained by testing domperidone and impurity AF using the detection method of Example 1;

[0031] Figure 4 This is a spectrum obtained by testing the test solution and impurity G using the detection method of Example 1;

[0032] Figure 5This is a spectrum obtained by testing mixed impurities using the detection method of Example 1;

[0033] Figure 6 This is a blank spectrum obtained by testing using the detection method of Example 1 but using a diluent of 0.5% ammonium acetate-methanol = 40:60;

[0034] Figure 7 The spectrum obtained by testing using the diluent of the present invention (0.5% ammonium acetate buffer (pH=5.0): methanol: acetonitrile=60:35:5);

[0035] Figure 8 This is the spectrum obtained after testing the blank solution using the detection method of Example 1. DETAILED DESCRIPTION

[0036] The following is combined with Figure 1-8 And specific implementation methods further illustrate the technical solution of the present invention.

[0037] A method for detecting related substances in domperidone tablets comprises the following steps:

[0038] Step (1): mixing the domperidone tablets with the diluent, and filtering by ultrasonic filtering to obtain a test solution;

[0039] Step (2): injecting the test solution into a liquid chromatograph, loading it onto a chromatographic column, and performing gradient elution with mobile phase A and mobile phase B to separate domperidone from impurities in the test solution;

[0040] Mobile phase A and mobile phase B are both mixtures of 0.5% acetate buffer, methanol and acetonitrile, wherein the volume ratio of 0.5% acetate buffer, methanol and acetonitrile in mobile phase A is (59-61):35:(4-6); the volume ratio of 0.5% acetate buffer, methanol and acetonitrile in mobile phase B is (20-30):30:(40-50);

[0041] Step (3): using a detector to test the separated domperidone and impurities to obtain a spectrum.

[0042] It is worth noting that the technical solution can completely separate the known impurities (impurity A, impurity B, impurity C, impurity D, impurity E, impurity F and impurity G) in the domperidone tablets by changing the mobile phase and using gradient elution, and can accurately detect the content of each impurity. At the same time, since the genotoxic impurity G in the domperidone tablets is not controlled in the prior art, and there is no corresponding method for control, the detection method of the technical solution can accurately detect the content of the genotoxic impurity G in the domperidone tablets at the same time, increase the control of the genotoxic impurity G in the domperidone tablets, so as to better ensure the safety of the user's medication, and use the same analysis method as other impurity detection, and the method is simple, which can greatly reduce the workload.

[0043] Specifically, since there are many known impurities in domperidone tablets, the mobile phase used in the prior art is methanol-0.5% ammonium acetate (60:40) and an isocratic elution method, and the impurities cannot be well separated (e.g. Figure 1 and Figure 2 ), therefore, it is difficult to detect all the impurities, it is impossible to accurately quantify them, it is difficult to control the impurities, and it is impossible to accurately reflect the situation of related substances in the product. The mobile phase A used in this technical solution is: 0.5% acetate buffer: methanol: acetonitrile = 60:35:5 (volume ratio); the mobile phase B is: 0.5% acetate buffer: methanol: acetonitrile = 25:30:45, and the mobile phase A and mobile phase B are used for gradient elution. By changing the mobile phase and using gradient elution, the known impurities in the domperidone tablets (impurity A, impurity B, impurity C, impurity D, impurity E, impurity F and impurity G) can be completely separated, and the content of each impurity (such as Figure 3 , Figure 4 and Figure 5 As shown), each impurity can be controlled to accurately reflect the situation of related substances in the product. At the same time, the detection method in this technical solution has high sensitivity, low detection limit, wide linear range and high accuracy.

[0044] Specifically, the liquid chromatograph used in the present technical solution is a Waters high performance liquid chromatograph or other types of chromatographs.

[0045] Specifically, the 0.5% acetate buffer in the technical solution is a 0.5% ammonium acetate buffer. The preparation method of the 0.5% ammonium acetate buffer is as follows: weigh 5 g of ammonium acetate, dissolve it with an appropriate amount of water and dilute it to 1000 mL to obtain a 0.5% acetate buffer.

[0046] To further illustrate, in step (2), the procedure for gradient elution using mobile phase A and mobile phase B is as follows:

[0047] (a) From 0 to 10 min, mobile phase A decreased from 100% to 70%, and mobile phase B increased from 0% to 30%;

[0048] (b) 10 min to 26 min, maintaining mobile phase A at 70% and mobile phase B at 30%;

[0049] (c) From 26 to 45 min, mobile phase A decreased from 70% to 0%, and mobile phase B increased from 30% to 100%;

[0050] (d) 45 min to 50 min, mobile phase A increased from 0% to 100%, and mobile phase B decreased from 100% to 0%;

[0051] (e) 50 min to 60 min, maintaining mobile phase A at 100% and mobile phase B at 0%.

[0052] It is worth noting that the present technical solution controls the gradient elution procedure and optimizes the mobile phase gradient elution ratio, which can further improve the separation between domperidone and various impurities and reduce the tailing factor. Specifically, the gradient elution procedure of the present technical solution is:

[0053] (a) From 0 to 10 min, mobile phase A decreased from 100% to 70%, and mobile phase B increased from 0% to 30%;

[0054] (b) From 10 min to 26 min, the mobile phase A was maintained at 70% and the mobile phase B was maintained at 30%;

[0055] (c) From 26 min to 45 min, mobile phase A decreased from 70% to 0%, and mobile phase B increased from 30% to 100%;

[0056] (d) From 45 min to 50 min, mobile phase A increased from 0% to 100%, and mobile phase B decreased from 100% to 0%;

[0057] (e) From 50 min to 60 min, mobile phase A was maintained at 100% and mobile phase B was maintained at 0%.

[0058] Specifically, the increase / decrease in the above program is a linear increase / decrease or a gradient increase / decrease; specifically, a linear decrease refers to a uniform linear decrease, such as in program (a), the first mobile phase is uniformly decreased at a rate of 3% / min. A gradient decrease refers to maintaining a constant value in a certain period of time, and decreasing to another constant value in the next period of time.

[0059] Preferably, the increment / decrement in the above procedure is a linear increment / decrement.

[0060] Further description, in step (1), the diluent is a mixture of 0.5% ammonium acetate buffer, methanol and acetonitrile, and in the diluent, the volume ratio of the 0.5% ammonium acetate buffer, the methanol and the acetonitrile is 60:35:5.

[0061] It is worth noting that during the detection process, if the diluent is a mixture of methanol and 0.5% ammonium acetate (the volume ratio of methanol and 0.5% ammonium acetate is 60:40), the gradient elution method is used and it is found that the diluent interferes with the detection of related substances, affecting the integration of related substances and the calculation of results (such as Figure 6 As shown), the diluent of the present technical solution, that is, the diluent is 0.5% ammonium acetate buffer (pH = 5.0): methanol: acetonitrile = 60:35:5, and the diluent has no interference with the detection of related substances during detection (such as Figure 7 Therefore, in step (1), the diluent in the technical solution and the domperidone tablets are mixed to prepare the test solution, which is more conducive to the detection of various impurities in the sample and reduces the interference of various impurities.

[0062] Specifically, the preparation method of 0.5% ammonium acetate buffer solution with pH=5.0 in the technical solution is as follows: weigh 5 g of ammonium acetate, dissolve and dilute to 1000 mL with an appropriate amount of water, and adjust the pH to 5.0±0.1 with glacial acetic acid.

[0063] Further description, in the mobile phase A, the volume ratio of the 0.5% acetate buffer, the methanol and the acetonitrile is 60:35:5;

[0064] In the mobile phase B, the volume ratio of the 0.5% acetate buffer, the methanol and the acetonitrile is 25:30:45.

[0065] Further explanation, in step (2), the column temperature of the chromatographic column is 25-35° C., the column length is 200-300 mm, the column inner diameter is 4.6 mm, and the filler particle size of the chromatographic column is 5 μm.

[0066] Specifically, the chromatographic column of the present technical solution is a C18 chromatographic column, which is a chromatographic column filled with octadecyl bonded silica gel. This type of chromatographic column has a good separation effect for domperidone and impurities in domperidone and can reduce peak tailing.

[0067] Preferably, the C18 chromatographic column in the technical solution is Waters XBridge ShieLd RPC18 (250*4.6, 5μm). The chromatographic column in the technical solution can also be any other chromatographic column with equivalent performance to the above C18 chromatographic column.

[0068] Preferably, during the test, the column temperature of the chromatographic column is 28-32° C. The separation and detection effect is better within this temperature range, and the separation degree of each component is ≥1.5.

[0069] More preferably, the column temperature of the chromatographic column is 30° C. At this temperature, the separation effect of each spectral peak is good and tailing can be effectively reduced.

[0070] The column length is 250 mm, the column inner diameter is 4.6 mm, and the filler particle size of the chromatographic column is 5 μm.

[0071] Further description, in step (2), the total flow rate of the mobile phase A and the mobile phase B is 0.8 to 1.2 mL / min.

[0072] Preferably, the total flow rate of the mobile phase A and the mobile phase B is 0.9-1.1 mL / min, and within this flow rate range, the separation degree of each component is ≥1.5.

[0073] More preferably, the total flow rate of the mobile phase A and the mobile phase B is 1.0 mL / min.

[0074] Further explanation: in step (2), the injection volume of the test solution is 10 to 30 μL.

[0075] Preferably, the injection volume of the test solution is 20 μL.

[0076] Further explanation: in step (3), the detection wavelength of the detector is 283-287 nm.

[0077] Specifically, the detector is an ultraviolet detector with a detection wavelength of 283-287 nm.

[0078] Preferably, the detection wavelength of the detector is 285 nm, at which wavelength each impurity and domperidone have a good response.

[0079] Further explanation, in the step (1), the preparation method of the test solution is as follows: 20 domperidone tablets are ground into fine powder, the sample powder is placed in a 50 mL volumetric flask, a diluent is added, ultrasonically and shaken for 20 minutes, then diluted to the scale with the diluent, filtered, 3 mL of the front filtrate is discarded, and the subsequent filtrate is taken to obtain the test solution.

[0080] Specifically, the preparation method of the test solution in this technical solution is as follows: take 20 tablets of the product, accurately weigh them, grind them into fine powder with a mortar, accurately weigh the sample powder (equivalent to 25 mg of the main component) into a 50 mL volumetric flask, add an appropriate amount of diluent, ultrasonically shake for 20 minutes, dilute to the scale with the diluent, filter with an RC 0.45 μm filter membrane, discard 3 mL of the front filtrate and take the subsequent filtrate. (Contains about 0.5 mg / mL of domperidone).

[0081] As a further explanation, the method for detecting related substances in domperidone tablets is applied in the preparation of domperidone tablets.

[0082] The detection method of the technical solution realizes the effective separation of domperidone and impurities by changing the type of mobile phase and the mobile phase elution gradient, so that the separation between each spectrum peak is high, and each impurity content can be accurately detected. Moreover, domperidone and each impurity have a good linear relationship and high test accuracy. At the same time, the present invention can accurately detect the genotoxic impurity G, greatly reducing the laboratory workload. The detection method of the present invention can greatly improve the control of the impurity content in the production process of domperidone tablets.

[0083] Specifically, impurity A is 5-chloro-1-(piperidin-4-yl)-1H-benzoxazol[d]imidazol-2(3H)-one, with the molecular formula C 12 H 14 ClN3O, molecular weight is 251.71, structural formula is as follows:

[0084]

[0085] Impurity B is 4-(5-chloro-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl)-1-formylpiperidine, with the molecular formula C 13 H 14 ClN3O, molecular weight is 279.72, structural formula is as follows:

[0086]

[0087] Impurity C is cis-4-(5-chloro-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl)-1-[3-(2-oxo-2,3-dihydro-1H-benzimidazol-1-yl)propyl]piperidine-1-oxide, with the molecular formula C 22 H 24 ClN5O3, molecular weight is 441.92, structural formula is as follows:

[0088]

[0089] Impurity D is 5-chloro-3-[3-(2-oxo-2,3-dihydro-1H-benzimidazol-1-yl)piperidin-4-yl]-1,3-dihydro-2H-benzimidazol-2-one, with the molecular formula C 32 H 34 ClN7O3, molecular weight is 600.12, structural formula is as follows:

[0090]

[0091] Impurity E is 1-[3-[4-5-chloro-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl)piperidin-1-yl]propyl]-3-[3-(2-oxo-2,3-dihydro-1H-benzimidazol-1-yl)piperidin-1-yl]propyl]-1,3-dihydro-2H-benzimidazol-2-one, with the molecular formula C 32 H 34 ClN7O3, molecular weight is 600.12, structural formula is as follows:

[0092]

[0093] Impurity F is 1,3-di[3-[4-(5-chloro-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl)piperidin-1-yl]propyl]-1,3-dihydro-2H-benzimidazol-2-one, with the molecular formula C 37 H 42 Cl2N8O3, molecular weight is 717.70, structural formula is as follows:

[0094]

[0095] Impurity G is (1-(3-chloropropyl)-1,3-dihydro-2H-benzimidazol-2-one, with the molecular formula C 10 H 11 ClN2O, molecular weight is 210.66, structural formula is as follows:

[0096]

[0097] The present technical solution is further described below in conjunction with embodiments.

[0098] Example 1

[0099] 1. Instruments and parameters

[0100] Liquid chromatograph: Waters high performance liquid chromatograph or other models

[0101] Chromatographic column: Waters XBridge ShieLd RPC18250*4.6, 5μm.

[0102] Liquid phase parameters:

[0103] Detection wavelength: 285nm;

[0104] Flow rate: 1.0 mL / min;

[0105] Column temperature: 30°C;

[0106] Injection volume: 20 μL;

[0107] Running time: 60min;

[0108] 2. Solution preparation

[0109] 0.5% ammonium acetate buffer: weigh 5 g of ammonium acetate, dissolve it in appropriate amount of water and dilute to 1000 mL;

[0110] Mobile phase A: 0.5% ammonium acetate buffer: methanol: acetonitrile = 60:35:5, filtered, sonicated;

[0111] Mobile phase B: 0.5% ammonium acetate buffer: methanol: acetonitrile = 25:30:45. Filter, sonicate;

[0112] pH = 5.0 0.5% ammonium acetate buffer: weigh 5 g of ammonium acetate, dissolve it with appropriate amount of water and dilute it to 1000 mL, and adjust the pH to 5.0 ± 0.1 with glacial acetic acid;

[0113] Dilution solution: pH = 5.0 0.5% ammonium acetate buffer: methanol: acetonitrile = 60:35:5, mix well.

[0114] The method for detecting related substances in the domperidone tablets of this embodiment comprises the following steps:

[0115] Step (1): Take 20 domperidone tablets, accurately weigh them, grind them into fine powder with a mortar, accurately weigh the sample powder (equivalent to 25 mg of the main component) and place it in a 50 mL volumetric flask, add an appropriate amount of diluent (0.5% ammonium acetate buffer (pH = 5.0): methanol: acetonitrile = 60:35:5), ultrasonically shake for 20 minutes, then dilute to scale with the diluent, filter with a 0.45 μm filter membrane, discard 3 mL of the front filtrate and take the subsequent filtrate to obtain a test solution (containing approximately 0.5 mg / mL of domperidone); accurately transfer 1.0 mL of the test solution to a 100 mL volumetric flask, dilute to scale with the diluent, shake well, and obtain a reference solution (containing approximately 5 μg / mL of domperidone);

[0116] Step (2): injecting the test solution into a liquid chromatograph, loading it onto a C18 chromatographic column, and performing gradient elution with mobile phase A and mobile phase B to separate domperidone from impurities in the test solution;

[0117] Mobile phase A and mobile phase B are both mixtures of 0.5% acetate buffer, methanol and acetonitrile, wherein the volume ratio of 0.5% acetate buffer, methanol and acetonitrile in mobile phase A is 60:35:5; the volume ratio of 0.5% acetate buffer, methanol and acetonitrile in mobile phase B is 25:30:45;

[0118] The gradient elution procedure was as follows:

[0119] (a) From 0 to 10 min, mobile phase A decreased from 100% to 70%, and mobile phase B increased from 0% to 30%;

[0120] (b) 10 min to 26 min, maintaining mobile phase A at 70% and mobile phase B at 30%;

[0121] (c) From 26 to 45 min, mobile phase A decreased from 70% to 0%, and mobile phase B increased from 30% to 100%;

[0122] (d) 45 min to 50 min, mobile phase A increased from 0% to 100%, and mobile phase B decreased from 100% to 0%;

[0123] (e) 50 min to 60 min, maintaining mobile phase A at 100% and mobile phase B at 0%;

[0124] Step (3): using a detector (ultraviolet detector) to test the separated domperidone and impurities to obtain a spectrum.

[0125] Specifically, as follows Figure 3 As shown, the spectra obtained by testing the separated domperidone and impurities in this embodiment are as follows. Figure 3 It can be seen that the domperidone tablets and the known impurities (impurity A, impurity B, impurity C, impurity D, impurity E, impurity F, impurity G) in this embodiment can be completely separated, and the content of each impurity can be accurately detected.

[0126] Effect Example 1

[0127] Solution preparation:

[0128] Mixed impurity reference solution: Precisely prepare an appropriate amount of each impurity reference substance, place it in a 100 ml volumetric flask, add diluent to dilute to the scale, shake well, and further dilute to form an impurity reference solution (containing approximately 25 μg / ml of domperidone impurities A, B, C, D, E, and F, and approximately 10 μg / ml of domperidone impurity G).

[0129] Impurity test solution: Accurately weigh about 250 mg of the sample, place it in a 50 ml volumetric flask, dissolve it with the impurity control solution and dilute it to the scale, shake well, and obtain.

[0130] Test solution: Take 20 tablets of this product, accurately weigh them, grind them into fine powder with a mortar, accurately weigh the sample powder (equivalent to 25 mg of the main ingredient) into a 50 mL volumetric flask, add an appropriate amount of diluent, ultrasonically shake for 20 minutes, then dilute to the scale with the diluent, filter with an RC 0.45 μm filter membrane, discard the previous filtrate 3 mL and take the subsequent filtrate, which is the test solution (containing approximately 0.5 mg / mL of domperidone).

[0131] Reference solution: Accurately pipette 1.0 mL of the test solution into a 100 mL volumetric flask, dilute to the mark with diluent, and shake well to obtain the reference solution (containing approximately 5 μg / mL of domperidone).

[0132] 1. System adaptability

[0133] The impurity-spiked test solution and the diluent were injected into a high performance liquid chromatograph and chromatographic analysis was performed according to the method of Example 1. The analysis results are shown in Table 1 below.

[0134] Table 1 System adaptability analysis results

[0135]

[0136]

[0137] From the analysis results in Table 1, it can be seen that the system suitability meets the requirements. Mobile phase A, mobile phase B, and diluent have no interference with the main peak and the retention window of each known impurity; the RRT of impurity A is 0.25, the RRT of impurity B is 0.45, the RRT of impurity C is 0.49, the RRT of impurity G is 0.60, the RRT of impurity D is 1.56, the RRT of impurity E is 1.58, and the RRT of impurity F is 1.79; the purity threshold of the main peak and impurities A\B\C\G\D\E\F in the test solution is greater than the purity angle; the separation degree of domperidone impurities A\B\C\G\D\E\F and adjacent impurities is greater than 1.5, and the separation degree of domperidone main peak and adjacent impurities is greater than 1.5, and the result meets the acceptance standard.

[0138] Specifically, the above solution was also tested using the analytical method of the prior art, and the test results are shown in Table 2 and Figure 2 As shown in Table 2 and Figure 2 It can be seen that when the related substances in domperidone tablets are detected by the analytical method of the prior art, all impurities cannot be detected and the separation between the impurities is poor.

[0139] Table 2 Analysis results of tests using existing technology

[0140]

[0141] 2. Linear range investigation

[0142] The mixed impurity control solution was diluted to prepare the following solutions: the linear study concentration range of domperidone impurities A, B, C, D, E, and F was 0.1 μg / ml to 50 μg / ml (equivalent to 0.4% to 200% of the reference solution; equivalent to 0.001% to 0.5% of the sample concentration); the linear study concentration range of domperidone impurity G was 0.1 μg / ml to 50 μg / ml (equivalent to 10% to 500% of the reference solution; equivalent to 0.001% to 0.5% of the sample concentration), and chromatographic analysis was performed according to the method of Example 1. The results are shown in Table 3 below. It can be seen from Table 3 that domperidone and each impurity have a good linear relationship within a certain concentration range.

[0143] Table 3 Linear range investigation results

[0144]

[0145]

[0146] 3. Investigation of limit of quantification

[0147] The mixed impurity control solution was diluted to prepare the following solution: The linear study concentration range of domperidone impurities A, B, C, D, E, F, and G was 0.1 μg / ml. Chromatographic analysis was performed according to the method of Example 1. The results are shown in Table 4 below. It can be seen from Table 4 that the quantitative limits of domperidone and each impurity using the method of the present technical solution are very low.

[0148] Table 4 Quantitation limit investigation results

[0149]

[0150] 4. Detection limit investigation

[0151] The domperidone and mixed impurity control solutions below the limit of quantitation were rediluted, and the concentration of each solution was about 0.3ug / ml.

[0152] Chromatographic analysis was performed according to the method of Example 1. The results are shown in Table 5 below. It can be seen from Table 5 that the detection limits of domperidone and each impurity using the method of the present technical solution are very low.

[0153] Table 5 Detection limit investigation results

[0154]

[0155] 5. Accuracy test

[0156] Prepare the test solution with quantitative limit impurities: accurately weigh about 250 mg of the sample, place it in a 50 ml volumetric flask, dissolve and dilute to the scale with the quantitative limit impurity control solution, shake well, and obtain.

[0157] Take the impurity test solution and the quantitative limit impurity test solution, inject them into the high performance liquid chromatograph, and perform chromatographic analysis according to the detection method of Example 1. The results are shown in Table 6. It can be seen from Table 6 that the recovery rates of domperidone and each impurity meet the requirements, and the method can accurately detect the content of each impurity.

[0158] Table 6 Accuracy test results

[0159]

[0160]

[0161] 6. Precision inspection

[0162] The precision of the detection method of Example 1 was examined by conducting a repeatability experiment on 6 sample solutions. The results showed that the RSD% of each impurity and the total impurities in the 6 sample solutions in the repeatability experiment were between 1-3, respectively, and the RSD% of each impurity and the total impurities in the 6 sample solutions in the intermediate precision experiment were between 1-2, respectively. In the 12 sample solutions with repeatability, the RSD% of each impurity and the total impurities were between 1-3, respectively. It can be seen that the measurement result RSD≤5%, indicating that the intermediate precision is good.

[0163] 7. Solution stability study

[0164] The reference solution and the test solution were placed at room temperature (25°C) and 5°C, and tested according to the test method of Example 1, and the results were compared with the results on day 0.

[0165]

[0166] It shows that the reference solution and the test solution are very stable when placed at room temperature (25°C) and 5°C for 3 days and 1 day respectively.

[0167] 8. Durability inspection

[0168] According to the adjustment range allowed by this method, the factors such as the mobile phase ratio, flow rate, column temperature, ultraviolet detection wavelength, injection volume, etc. are adjusted respectively, and other conditions are detected according to the detection method of Example 1.

[0169] The separation degree between each known impurity of domperidone and the adjacent peak is greater than 1.0, the separation degree between the main peak and the adjacent peak is greater than 1.0, and the number of impurities detected is consistent with that before the change. The ratio of the result of each impurity <1.0% to the result before the change is within the most stringent requirement of 110%, and those greater than 1.0% are between 95-105%, which meets the requirements.

[0170] Through the above examples, it can be verified that the detection method of the technical solution has good specificity, the blank solution and known impurities have no interference with the detection, the baseline separation can be achieved between each impurity peak and between the impurity peak and the main peak, and the purity threshold of the main peak and the known impurities in the test solution meets the requirements; domperidone and each impurity have a good linear relationship within a certain concentration range, and the repeatability results show that the detection method has good precision, and the recovery rates of domperidone and each impurity meet the requirements. The method can accurately detect the content of each impurity; the durability test shows that the number of impurities detected when the detection conditions change is consistent with that before the change, and the ratio of the results of each impurity <1.0% to the results before the change of conditions is within the strictest requirement of 110%, and those greater than 1.0% are between 95-105%. The mixed reference solution and the test solution are both stable within 3 days and 1 day, respectively. Therefore, the detection method of the technical solution is suitable for the detection of domperidone tablets.

[0171] The technical principle of the present invention is described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific implementations of the present invention without paying creative labor, and these methods will fall within the scope of protection of the present invention.

Claims

1. A method for detecting related substances in domperidone tablets, characterized in that: The following steps are involved: Step (1): mixing the domperidone tablets with the diluent, and filtering by ultrasonic filtering to obtain a test solution; Step (2): injecting the test solution into a liquid chromatograph and loading it onto a chromatographic column, wherein the column temperature of the chromatographic column is 25 to 35° C., the column length is 200 to 300 mm, the column inner diameter is 4.6 mm, and the filler particle size of the chromatographic column is 5 μm; and gradient elution is performed using mobile phase A and mobile phase B to separate domperidone from impurities in the test solution, and the total flow rate of the mobile phase A and the mobile phase B is 0.8 to 1.2 mL / min; Mobile phase A and mobile phase B are both mixtures of 0.5% acetate buffer, methanol and acetonitrile, wherein the volume ratio of 0.5% acetate buffer, methanol and acetonitrile in mobile phase A is (59-61):35:(4-6); the volume ratio of 0.5% acetate buffer, methanol and acetonitrile in mobile phase B is (20-30):30:(40-50); Correspondingly, the procedure for gradient elution with mobile phase A and mobile phase B is: (a) From 0 to 10 min, mobile phase A decreased from 100% to 70%, and mobile phase B increased from 0% to 30%; (b) 10 min to 26 min, maintaining mobile phase A at 70% and mobile phase B at 30%; (c) From 26 to 45 min, mobile phase A decreased from 70% to 0%, and mobile phase B increased from 30% to 100%; (d) 45 min to 50 min, mobile phase A increased from 0% to 100%, and mobile phase B decreased from 100% to 0%; (e) 50 min to 60 min, maintaining mobile phase A at 100% and mobile phase B at 0%; Step (3): using a detector to test the separated domperidone and impurities to obtain a spectrum.

2. The method for detecting related substances in domperidone tablets according to claim 1, characterized in that: In step (1), the diluent is a mixture of 0.5% ammonium acetate buffer, methanol and acetonitrile, and in the diluent, the volume ratio of the 0.5% ammonium acetate buffer, the methanol and the acetonitrile is 60:35:

5.

3. The method for detecting related substances in domperidone tablets according to claim 1, characterized in that: In the mobile phase A, the volume ratio of the 0.5% acetate buffer, the methanol and the acetonitrile is 60:35:5; In the mobile phase B, the volume ratio of the 0.5% acetate buffer, the methanol and the acetonitrile is 25:30:

45.

4. The method for detecting related substances in domperidone tablets according to claim 1, characterized in that: In step (2), the injection volume of the test solution is 10 to 30 μL.

5. The method for detecting related substances in domperidone tablets according to claim 1, characterized in that: In step (3), the detection wavelength of the detector is 283-287 nm.

6. The method for detecting related substances in domperidone tablets according to claim 1, characterized in that: In the step (1), the preparation method of the test solution is as follows: 20 domperidone tablets are ground into fine powder, the sample powder is placed in a 50 mL volumetric flask, a diluent is added, ultrasonically shaken for 20 minutes, then diluted to the scale with the diluent, filtered, 3 mL of the front filtrate is discarded, and the subsequent filtrate is taken to obtain the test solution.

7. The method for detecting related substances in domperidone tablets according to claim 1, characterized in that: The method for detecting related substances in domperidone tablets is applied in the preparation of domperidone tablets.

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