A dipyridamole impurity localization solution and its preparation method and application

Abstract

The present invention relates to a dipyridamole impurity localization solution and a preparation method and application thereof. The localization solution is a mixed solution comprising dipyridamole impurity B, dipyridamole impurity D and dipyridamole, wherein the molar concentration ratio of the dipyridamole impurity B to the dipyridamole impurity D is 1:(2-10). The localization solution of the present invention can be used to simultaneously detect dipyridamole impurity B and dipyridamole impurity D, reducing the dependence on reference substances, and making up for the defect that the Food and Drug Inspection Institute has no dipyridamole impurity B and dipyridamole impurity D reference substances for sale. In addition, the preparation method of the present invention is simple, and the starting raw materials are easy to obtain. The present invention utilizes the concentration difference of dipyridamole impurity B and dipyridamole impurity D in the localization solution, and utilizes the peak area size in liquid chromatography to locate dipyridamole impurity B and dipyridamole impurity D.

Description

Technical Field

[0001] The invention belongs to the technical field of drug analysis, and in particular relates to a dipyridamole impurity localization solution and a preparation method and application thereof. Background Art

[0002] Dipyridamole (chemical structure shown in Formula 1) mainly uses its antiplatelet aggregation effect to prevent thrombosis. It is used in combination with aspirin for secondary prevention of transient ischemic attack (TIA) and ischemic stroke and treatment of coronary heart disease; it is used in combination with warfarin to prevent thrombosis after valve replacement surgery.

[0003] The intravenous injection can be used as a diagnostic reagent for myocardial ischemia (dipyridamole test) by utilizing its vasodilatory effect, as an auxiliary examination method for coronary heart disease, and to determine the extent of myocardial ischemia.

[0004]

[0005] The main synthetic route of dipyridamole is as follows: the tetrachloride (2,4,6,8-tetrachloropyrimido[5,4-d]pyrimidine) is condensed with piperidine to form the dichloride (2,6-dichloro-4,8-di(piperidin-1-yl)pyrimido[5,4-d]pyrimidine), and the dichloride is condensed with diethanolamine to form dipyridamole.

[0006]

[0007] Seven impurities appeared in the above-mentioned synthesis route of dipyridamole, and the control methods of dipyridamole impurities are included in the Chinese Pharmacopoeia (hereinafter referred to as ChP2020), the European Pharmacopoeia (hereinafter referred to as EP10.4), and the United States Pharmacopoeia (hereinafter referred to as USP-NF2021). ChP2020, EP10.4, and USP-NF2021 all use liquid chromatography to determine the content of impurities. Information such as the location method of impurities, limit requirements, and the method of obtaining reference substances is shown in Table 1.

[0008] Table 1 Overview of dipyridamole-related impurities

[0009]

[0010] As shown in Table 1, EP10.4 and USP-NF2021 control the limits of known impurities B and D, but the purchase cycle of impurity reference substances of the United States Pharmacopoeia is long and the price is high, which makes it difficult to purchase; the purchase cycle of impurity reference substances of the European Pharmacopoeia is long, and they contain more impurities. Each peak can only be identified under the detection method of the European Pharmacopoeia, which is not conducive to the development and application of new methods. ChP2020 did not control it. The reasons are: 1. The China Food and Drug Inspection Institute does not have reference substances for related impurities; 2. There is no corresponding location method for impurities B and impurities D.

[0011] In summary, it is necessary to provide a positioning solution containing dipyridamole impurity B and dipyridamole impurity D. Summary of the invention

[0012] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, the present invention provides a dipyridamole impurity localization solution.

[0013] The invention also provides a method for preparing a dipyridamole impurity localization solution.

[0014] The present invention also provides a method for positioning and detecting dipyridamole impurity B and dipyridamole impurity D.

[0015] The first aspect of the present invention provides a dipyridamole impurity localization solution, comprising the following steps:

[0016] The positioning solution is obtained by reacting dipyridamole with diethanolamine under alkaline catalyst conditions; the positioning solution is a mixed solution including dipyridamole impurity B, dipyridamole impurity D and dipyridamole, and the molar concentration ratio of the dipyridamole impurity B to the dipyridamole impurity D is 1:(2-10).

[0017] One of the technical solutions of the present invention regarding the dipyridamole impurity localization solution has at least the following beneficial effects:

[0018] The positioning solution of the present invention can be used to simultaneously detect dipyridamole impurity B and dipyridamole impurity D, reducing the dependence on reference substances, and making up for the defect that China Food and Drug Inspection Institutes has no reference substances for sale of dipyridamole impurity B and dipyridamole impurity D. In addition, the preparation method of the present invention is simple, and the starting materials are easy to obtain. The present invention limits the molar concentration ratio of dipyridamole impurity B and dipyridamole impurity D to 1: (2 to 10). By utilizing the difference in the molar concentration of dipyridamole impurity B and dipyridamole impurity D in the positioning solution, the peak area size is used to locate dipyridamole impurity B and dipyridamole impurity D in liquid chromatography, and they can be distinguished without limiting specific chromatographic conditions.

[0019] According to some embodiments of the present invention, the mixed solution is diluted with a solvent to a concentration of 6 μg / mL to 2 mg / mL of dipyridamole.

[0020] According to some embodiments of the present invention, the solvent is an organic solvent or an aqueous solution containing an organic solvent.

[0021] According to some embodiments of the invention, the organic solvent comprises at least one of methanol, ethanol or acetonitrile.

[0022] According to some embodiments of the present invention, the CAS number of dipyridamole is 58-32-2.

[0023] According to some embodiments of the present invention, the CAS number of the dipyridamole impurity B is 16908-47-7.

[0024] According to some embodiments of the present invention, the CAS number of the dipyridamole impurity D is 1176886-12-6.

[0025] A second aspect of the present invention provides a method for preparing a dipyridamole impurity localization solution, comprising the following steps:

[0026] The positioning solution is obtained by reacting dipyridamole with diethanolamine under the condition of alkaline catalyst; the positioning solution comprises dipyridamole impurity B, dipyridamole impurity D and a mixed solution of dipyridamole; and the reaction temperature is 80-220°C.

[0027] According to some embodiments of the present invention, the molar ratio of dipyridamole to diethanolamine is 1:(3.9-7.7).

[0028] According to some embodiments of the invention, the alkaline catalyst includes at least one of sodium hydroxide, sodium carbonate, sodium tert-butoxide or potassium tert-butoxide.

[0029] According to some embodiments of the present invention, the reaction temperature is 145°C to 155°C.

[0030] According to some embodiments of the present invention, the reaction time is 1.5 h to 2.5 h.

[0031] According to some embodiments of the present invention, the alkaline catalyst is 20 mol% to 30 mol% of the amount of dipyridamole.

[0032] The third aspect of the present invention provides a method for localizing and detecting dipyridamole impurity B and dipyridamole impurity D, comprising the following steps:

[0033] Test solution: Dissolve dipyridamole API in an organic solvent;

[0034] Positioning solution: Take the positioning solution described above;

[0035] The HPLC conditions included the following parameters:

[0036] Chromatographic column: octadecylsilane bonded silica gel; specifications: 4.0mm×100mm, 5μm;

[0037] The mobile phase is selected from a mixed solution of potassium dihydrogen phosphate solution and methanol, a mixed solution of ammonium formate or acetonitrile;

[0038] Detection wavelength: 295nm; column temperature: 45℃;

[0039] The positioning solution and the test solution are subjected to liquid chromatography analysis respectively according to the liquid chromatography conditions, and the test solution is positioned and detected by the positioning solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is the chromatogram of the reference solution;

[0041] Figure 2 is a chromatogram of the positioning solution of Example 1 of the present invention;

[0042] Figure 3 is the chromatogram of the test solution;

[0043] Figure 4 is the blank solution chromatogram;

[0044] Figure 5 It is a DAD (Diode Array Detector) spectrum of the reference solution at a wavelength of 200nm to 400nm; the left figure is the DAD spectrum of dipyridamole impurity B; the right figure is the DAD spectrum of dipyridamole impurity D;

[0045] Figure 6 1 is a DAD spectrum diagram of the positioning solution of Example 1 of the present invention at a wavelength of 200nm to 400nm; the left figure is a DAD spectrum diagram of dipyridamole impurity B; the right figure is a DAD spectrum diagram of dipyridamole impurity D;

[0046] Figure 7 is a chromatogram of the impurity B reference solution in Experimental Example 2 of the present invention;

[0047] Figure 8 is a chromatogram of the impurity D reference solution in Experimental Example 2 of the present invention;

[0048] Fig. 9 is the chromatogram of the positioning solution in Experimental Example 2 of the present invention;

[0049] Fig.10is the chromatogram of the test solution in Experimental Example 2 of the present invention;

[0050] Fig.11 is the blank solution chromatogram in Experimental Example 2 of the present invention;

[0051] Fig.12 It is the DAD spectra of the impurity B and impurity D reference solution in Experimental Example 2 of the present invention at a wavelength of 200nm to 400nm; the left figure is the DAD spectra of dipyridamole impurity B; the right figure is the DAD spectra of dipyridamole impurity D;

[0052] Fig.13 It is a DAD spectrum diagram of the positioning solution in Experimental Example 2 of the present invention at a wavelength of 200nm to 400nm; the left figure is a DAD spectrum diagram of dipyridamole impurity B; the right figure is a DAD spectrum diagram of dipyridamole impurity D;

[0053] Fig.14 is the mass spectrum of the impurity B reference solution in Experimental Example 3 of the present invention;

[0054] Fig.15 is the mass spectrum of the solution for localization of impurity B in Experimental Example 3 of the present invention;

[0055] Fig.16 is the mass spectrum of the impurity B test solution in Experimental Example 3 of the present invention;

[0056] Fig.17 is the mass spectrum of the impurity D reference solution in Experimental Example 3 of the present invention;

[0057] Fig.18 is the mass spectrum of the solution for localization of impurity D in Experimental Example 3 of the present invention;

[0058] Fig.19 It is the mass spectrum of the impurity D test solution in Experimental Example 3 of the present invention. DETAILED DESCRIPTION

[0059] The technical solutions in the embodiments of the present invention will be described clearly and completely below, but the implementation manner of the present invention is not limited thereto.

[0060] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0061] The raw materials used in the following examples and comparative examples are as follows:

[0062] Dipyridamole (API) was sourced from Yabao Pharmaceutical Group Co., Ltd., diethanolamine (analytical grade) was purchased from Tianjin Fuyu Fine Chemical Co., Ltd., sodium hydroxide (analytical grade) was purchased from Guangzhou Chemical Reagent Factory, and potassium tert-butoxide (analytical grade) was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0063] Example 1

[0064] This embodiment provides a dipyridamole impurity localization solution, wherein the content ratio of the three components of dipyridamole impurity B, dipyridamole impurity D and dipyridamole is about 0.8:3:96, and the preparation method thereof is as follows:

[0065] Take 0.3g of diethanolamine, 0.25g of dipyridamole and 25μL of 5mol / L sodium hydroxide solution, put them in a 100mL round-bottom flask, and place them in a magnetic heating stirrer at 150℃ for a short heating to make the diethanolamine in the round-bottom flask change from thick to thin, take out the round-bottom flask and gently rotate it to make the dipyridamole soak in the diethanolamine, gently put a rotor in the round-bottom flask, install a spherical condenser, and place it in a magnetic heating stirrer for reflux heating. The speed of the magnetic rotor is 300 revolutions per minute. After 2 hours, take out the round-bottom flask and cool it to room temperature in a water bath with a stopper. Add 5mL of methanol, dissolve it by ultrasound, shake it well, filter it, and take the filtrate as the stock solution of the positioning solution.

[0066] Example 2

[0067] This embodiment provides a dipyridamole impurity localization solution, wherein the content ratio of the three components of dipyridamole impurity B, dipyridamole impurity D and dipyridamole is about 0.3:2:97.5, and the preparation method thereof is the same as that of Example 1, the only difference being that in this embodiment, 50 μL of 10% potassium tert-butoxide tert-butanol solution is used to replace the sodium hydroxide in Example 1.

[0068] Experimental Example 1

[0069] The positioning solution stock solution prepared by Example 1 of the present invention is tested, wherein there is a significant difference in the concentration of dipyridamole impurity B and dipyridamole impurity D. When using high-efficiency chromatography to detect, suitable chromatographic conditions and positioning solutions of suitable concentration are selected. In theory, the chromatogram will show 1 small and 1 large 2 clearly distinguishable impurity peaks, the smaller peak area is dipyridamole impurity B, and the larger peak area is dipyridamole impurity D, from which the retention time of these 2 impurity peaks can be determined. According to this characteristic, when using liquid chromatography to detect impurity B or impurity D of dipyridamole bulk drugs and related preparations, the positioning solution prepared by the present invention can be used to replace the relevant reference substance.

[0070] When measuring the sample, the peak positions of the two impurities in the test solution can be determined based on the retention time of the dipyridamole impurity peak B and the dipyridamole impurity peak D in the positioning solution. The two impurities in the sample can be quantified by combining the self-control method, thereby achieving the purpose of accurately locating impurities without using reference substances.

[0071] The specific implementation methods are as follows:

[0072] Test solution: Take 10 mg of dipyridamole, accurately weigh it, put it in a 5 mL volumetric flask, add an appropriate amount of methanol, dissolve it and dilute it to the scale, shake it well, filter it, and take the filtrate to obtain the solution.

[0073] Location solution: Prepare the dipyridamole impurity location solution stock solution according to Example 1 of the present invention, accurately measure 1 mL of the stock solution and place it in a 25 mL volumetric flask, dilute to the mark with methanol, shake well, filter, and take the filtrate to obtain the solution.

[0074] Reference solution: Take 1 bottle of EP10.4 mixed peak identification reference (2 mg per bottle), add 1 mL of methanol, shake well, and obtain.

[0075] Blank solution: Take about 0.3g of diethanolamine, weigh it accurately, put it in a 5mL volumetric flask, add 25μL of 5mol / L sodium hydroxide solution, dilute to the scale with methanol, shake well, accurately measure 1mL and put it in a 25mL volumetric flask, dilute to the scale with methanol, shake well, filter, and take the filtrate to obtain.

[0076] Chromatographic conditions: octadecylsilane bonded silica gel was used as filler (brand: Shimadzu; model: InertSustainAQ-C18; specification: 4.0 mm×100 mm, 5 μm); 0.1% potassium dihydrogen phosphate solution (pH value was adjusted to 7.0 with 0.5 mol / L sodium hydroxide solution) was used as mobile phase A, and methanol was used as mobile phase B; gradient elution was performed according to Table 2; column temperature was 45°C; flow rate was 1.2 mL per minute; UV detection wavelength was 295 nm; wavelength range of DAD scanning was 200 nm to 400 nm; injection volume was 5 μL.

[0077] Table 2 Elution program

[0078]

[0079] Determination method: Take 5 μL of reference solution, positioning solution, test solution and blank solution, inject into liquid chromatograph (brand: Agilent; model: 1290 Infinity II), and record the chromatogram and spectrum.

[0080] Chromatogram of reference solution Figure 1 ; Positioning solution chromatogram see Figure 2 ; Chromatogram of test solution is shown in Figure 3 ; Blank solution chromatogram see Figure 4 ; The DAD spectra of impurities B and D in the reference solution are shown in Figure 5 ; The DAD spectra of impurities B and D in the positioning solution are shown in Figure 6 .

[0081] The main component peak and some impurity peaks will appear in the chromatogram of the test solution. Since the positioning solution and the test solution are made of the same batch of dipyridamole raw materials, theoretically, these peaks will also appear in the chromatogram of the positioning solution. The chromatogram of the positioning solution will have two additional very obvious chromatographic peaks than the chromatogram of the test solution. These two peaks are dipyridamole impurity B and dipyridamole impurity D. Combined with the obvious difference in the concentrations of these two impurities in the positioning solution, it can be judged that the one with a smaller peak area is dipyridamole impurity B, and the one with a larger peak area is dipyridamole impurity D.

[0082] contrast Figure 1 to Figure 4 After deducting the chromatographic peaks identical to those of the test solution and the blank solution, the chromatographic peaks of the positioning solution are basically consistent with the phenomenon discussed above. There are two obvious impurity peaks in the remaining chromatographic peaks, and their retention times are consistent with the retention times of the dipyridamole impurity B peak and the dipyridamole impurity D peak in the chromatographic peaks of the reference solution. The DAD spectra of the positioning solution and the reference solution (see Figure 5-6 ) are also consistent. It can be seen that the positioning solution can accurately locate the dipyridamole impurity B and the dipyridamole impurity D.

[0083] According to the present invention, a total of 6 stock solutions of the location solution of dipyridamole impurity B and dipyridamole impurity D are prepared, each stock solution is diluted according to the above location solution preparation method, determined according to the above determination method, and calculated according to the area normalization method. After testing, the peak area of ​​dipyridamole impurity B in the 6 location solutions accounts for 0.5% to 1.0% of the total peak area, and the peak area of ​​dipyridamole impurity D accounts for 2% to 5% of the total peak area; and the peak areas of dipyridamole impurity B and dipyridamole impurity D in the 6 location solutions are greater than the peak areas of the corresponding impurities in the reference solution, and the specificity is good.

[0084] It can be seen from the above experimental examples that the dipyridamole impurity B and dipyridamole impurity D in the positioning solution will show two impurity peaks, one small and one large, under the chromatographic conditions of EP10.4. Therefore, the size of the peak area can be used to make a clear distinction. If the dipyridamole impurity B and dipyridamole impurity D are distinguished according to the order of peak appearance, the one with a shorter retention time is the dipyridamole impurity B, and the one with a longer retention time is the dipyridamole impurity D. In the future work of detecting dipyridamole impurity B and dipyridamole impurity D, the reference substance can be omitted, and the positioning solution can be directly used for positioning, which can reduce the dependence on the reference substance. The content determination of impurities in the sample can be quantitatively determined by referring to the self-control method of EP10.4.

[0085] Experimental Example 2

[0086] The determination method of Experimental Example 2 is the same as that of Experimental Example 1, except that:

[0087] Reference solution: Take appropriate amount of dipyridamole impurity B and impurity D reference substances, weigh accurately, and dilute with methanol to make solutions containing approximately 0.5 μg of each per 1 mL.

[0088] The chromatographic conditions are different. Octadecylsilane bonded silica gel is used as filler (brand: model: XB-C18; specification: 2.1mm×150mm, 1.7μm); 10mmol / L ammonium formate solution (pH adjusted to 5.0 with formic acid) as mobile phase A, acetonitrile as mobile phase B; gradient elution according to Table 3; column temperature 45°C; flow rate 0.3mL per minute; UV detection wavelength 295nm; DAD scanning wavelength range 200nm~400nm; injection volume 2μL.

[0089] Table 3 Elution program

[0090]

[0091] Determination method: Take 2 μL of reference solution, positioning solution, test solution and blank solution, inject into liquid chromatograph (brand: Agilent; model: 1290 Infinity II), and record the chromatogram and spectrum.

[0092] Chromatogram of reference solution Figure 7 and Figure 8 ; Positioning solution chromatogram see Fig. 9 ; Chromatogram of test solution is shown in Fig.10 ; Blank solution chromatogram see Fig.11 ; The DAD spectra of impurities B and D in the reference solution are shown in Fig.12 ; The DAD spectra of impurities B and D in the positioning solution are shown in Fig.13 .

[0093] contrast Figure 7 to Figure 11 After deducting the chromatographic peaks identical to those of the test solution and the blank solution from the chromatogram of the positioning solution, the phenomenon is basically consistent with the above-mentioned phenomenon. There are two obvious impurity peaks in the remaining chromatographic peaks, and their retention times are consistent with the retention times of the impurity B peak and the impurity D peak in the chromatogram of the reference solution. The DAD spectra of the positioning solution and the reference solution (see Figure 12-13 ) are also consistent. It can be seen that the positioning solution can accurately locate impurities B and impurity D under different chromatographic conditions.

[0094] Experimental Example 3

[0095] The positioning solution prepared by the present invention can also be used in a mass spectrometer to qualitatively analyze whether there are impurities in the sample. Using an ultra-high performance liquid chromatography tandem high-resolution mass spectrometer, the specific steps are as follows:

[0096] Test solution: Take appropriate amount of crude impurity B and impurity D, weigh accurately, dissolve and dilute with methanol to make solutions containing about 200 ng of each per 1 mL, filter and take the filtrate as the impurity B test solution and impurity D test solution, respectively.

[0097] Location solution: Prepare the location solution stock solutions of impurity B and impurity D according to Example 1 of the present invention. Accurately measure 0.1 mL of the stock solution and place it in a 200 mL volumetric flask, dilute it to the mark with methanol, shake well, filter, and take the filtrate as the impurity B location solution; accurately measure 5 mL of the impurity B location solution and place it in a 20 mL volumetric flask, dilute it to the mark with methanol, shake well, filter, and take the filtrate as the impurity D location solution.

[0098] Reference solution: Take appropriate amount of impurity B and impurity D reference substances respectively, weigh accurately, dissolve and dilute with methanol to make solutions containing about 100 ng of each per 1 mL, filter and take the filtrate to obtain.

[0099] Chromatographic conditions: Use octadecylsilane bonded silica gel as filler (brand: model: XB-C18; specification: 2.1mm×150mm, 1.7μm); 10mmol / L ammonium formate solution (adjust pH to 5.0 with formic acid) as mobile phase A, acetonitrile as mobile phase B; gradient elution according to Table 4; column temperature 45℃; flow rate 0.3mL per minute; detection wavelength 295nm; injection volume 2μL.

[0100] Table 4 Elution program

[0101]

[0102] Mass spectrometry conditions: A quadrupole-electrostatic field orbital trap high-resolution mass spectrometer (brand: Thermo Fisher; model: QExactive) was used for determination. An electrospray ion source (ESI) was used in positive ion scanning mode. The ion source parameters are shown in Table 5.

[0103] Table 5 Ion source parameters

[0104]

[0105] The monitoring mode was full scan. The acquisition time of each component in the mass spectrometer is shown in Table 6.

[0106] Table 6 Collection time of each component

[0107]

[0108] Determination method: Take 2 μL of reference solution, positioning solution and test solution respectively, inject them into ultra-performance liquid chromatography-tandem high-resolution mass spectrometry, and record the mass spectrum.

[0109] The mass spectrum of impurity B reference solution is shown in Fig.14 The mass spectrum of impurity B is shown in Fig.15 The mass spectrum of the impurity B test solution is shown in Fig.16 .

[0110] [M+H] of the molecular ion peak of impurity B + The precise molecular weight of impurity B is 525.3144. Theoretically, the molecular ion peak [M+H] of impurity B measured in the positioning solution and the reference solution is + Compared with 525.3144, it should be consistent, and the retention time of the peak should also be consistent.

[0111] contrast Figure 14-15 , the [M+H] of the molecular ion peak of impurity B measured in the positioning solution and the reference solution + Compared with 525.3144, they are consistent, and the retention time of the impurity B peak of the two is consistent. It can be seen that the positioning solution can effectively locate and identify impurity B.

[0112] Similarly, if impurity B is present in the test solution, it should elute at the same retention time as the positioning solution, and the [M+H] + Also consistent.

[0113] contrast Figure 15-16 , which is consistent with the above inference. The molecular ion peaks [M+H] + The retention time is consistent with that of the sample. Therefore, it can provide evidence for the presence of impurity B in the sample.

[0114] The mass spectrum of impurity D reference solution is shown in Fig.17 The mass spectrum of impurity D is shown in Fig.18 The mass spectrum of the impurity D test solution is shown in Fig.19 .

[0115] The identification method of impurity D is the same as that of impurity B. The [M+H] + The exact molecular weight is 461.2983.

[0116] contrast Figure 17-18 , the [M+H] of the molecular ion peak of impurity D measured in the positioning solution and the reference solution + Compared with 461.2983, they are consistent, and the retention time of the impurity D peak of the two is consistent. It can be seen that the positioning solution can effectively locate and identify impurity D.

[0117] contrast Figure 18-19, locate the [M+H] of the molecular ion peak in the mass spectrum of the solution and the mass spectrum of the test solution + The retention time is consistent with that of the sample. Therefore, it can provide evidence for the presence of impurity D in the sample.

[0118] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A dipyridamole impurity localization solution, characterized in that: The positioning solution is a mixed solution comprising dipyridamole impurity B, dipyridamole impurity D and dipyridamole, wherein the molar concentration ratio of the dipyridamole impurity B to the dipyridamole impurity D is 1:(2-10); The dipyridamole impurity localization solution is prepared by a method comprising the following steps: The positioning solution is obtained by reacting dipyridamole with diethanolamine under alkaline catalyst conditions; the positioning solution includes dipyridamole impurity B, dipyridamole impurity D and a mixed solution of dipyridamole; the reaction temperature is 145°C to 155°C; and the reaction time is 1.5h to 2.5h.

2. The dipyridamole impurity localization solution according to claim 1, characterized in that: The mixed solution is diluted with a solvent to a concentration of 6 μg / mL to 2 mg / mL based on the concentration of dipyridamole.

3. The dipyridamole impurity localization solution according to claim 2, characterized in that: The solvent is an organic solvent or an aqueous solution containing an organic solvent.

4. The dipyridamole impurity localization solution according to claim 3, characterized in that: The organic solvent includes at least one of methanol, ethanol or acetonitrile.

5. The method for preparing the dipyridamole impurity localization solution according to any one of claims 1 to 4, characterized in that: The steps include: The positioning solution is obtained by reacting dipyridamole with diethanolamine under the condition of alkaline catalyst; the positioning solution comprises dipyridamole impurity B, dipyridamole impurity D and a mixed solution of dipyridamole; and the reaction temperature is 145°C to 155°C.

6. The method for preparing the dipyridamole impurity localization solution according to claim 5, characterized in that: The molar ratio of dipyridamole to diethanolamine is 1:(3.9-7.7).

7. The method for preparing the dipyridamole impurity localization solution according to claim 5, characterized in that: The alkaline catalyst includes at least one of sodium hydroxide, sodium carbonate, sodium tert-butoxide or potassium tert-butoxide.

8. The method for preparing the dipyridamole impurity localization solution according to claim 5, characterized in that: The alkaline catalyst is 20 mol% to 30 mol% of the amount of dipyridamole.

9. A method for localizing and detecting dipyridamole impurity B and dipyridamole impurity D, characterized in that: The steps include: Test solution: Dissolve dipyridamole API in an organic solvent; Positioning solution: the positioning solution according to any one of claims 1 to 4; The HPLC conditions included the following parameters: Chromatographic column: octadecylsilane bonded silica gel; The mobile phase is selected from a mixed solution of potassium dihydrogen phosphate and methanol, a mixed solution of ammonium formate or acetonitrile; Detection wavelength: 295nm; column temperature: 45℃; The positioning solution and the test solution are subjected to liquid chromatography analysis respectively according to the liquid chromatography conditions, and the test solution is positioned and detected by the positioning solution.

Images