Method for detecting impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidine-3-amine dihydrochloride

Abstract

The invention provides a method for detecting impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidine-3-amine dihydrochloride, which comprises the following steps: (1) mixing a reference substance with a blank solution to obtain a reference substance solution; (2) mixing a to-be-detected sample with a blank solution to obtain a test solution; and (3) respectively carrying out sample introduction on the test solution, the reference solution and the blank solution, and carrying out liquid chromatography-tandem mass spectrometry detection to obtain a detection result. The detection method provided by the invention can be used for simultaneously detecting four mutagenic impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidine-3-amine dihydrochloride, and is accurate, high in precision and good in repeatability.

Description

Technical Field

[0001] The invention belongs to the field of analytical chemistry, and specifically relates to a method for detecting impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride, and in particular to a method for detecting impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride with high accuracy. Background Art

[0002] (3R,4R)-1-Benzyl-N,4-dimethylpiperidin-3-amine dihydrochloride is also known as (3R,4R)-1-benzyl-N,4-dimethylpiperidin-3-amine dihydrochloride, cis-N-benzyl-3-methylamino-4-methylpiperidin dihydrochloride and cis-N-benzyl-3-methylamino-4-methylpiperidin dihydrochloride. It is a white solid powder and is an important chemical raw material that can be used to synthesize tofacitinib citrate. It is synthesized from 3-amino-4-methylpyridine through a series of reactions. N-[1,2,5,6-tetrahydro-4-methyl-1-(phenylmethyl)-3-pyridyl]acetamide, N-(4-methyl-3-pyridyl)acetamide and 3-acetamido-1-benzyl-4-methyl-pyridinium bromide are important intermediates in the reaction process and are all mutagenic impurities. Therefore, the content of these four impurities in (3R,4R)-1-benzyl-N,4-dimethylpiperidin-3-amine dihydrochloride needs to be strictly controlled.

[0003] At present, there is no literature reporting a method for detecting N-[1,2,5,6-tetrahydro-4-methyl-1-(phenylmethyl)-3-pyridinyl]acetamide, N-(4-methyl-3-pyridinyl)acetamide, 3-amino-4-methylpyridine and 3-acetamido-1-benzyl-4-methyl-pyridinium bromide in (3R,4R)-1-benzyl-N,4-dimethylpiperidin-3-amine dihydrochloride. Since the four impurities all need to be controlled below 40 ppm and the structures of the four impurities are similar, it is difficult to accurately detect them using ordinary liquid phases. Even if they can be detected, it takes a lot of time. Therefore, how to simultaneously detect the contents of N-[1,2,5,6-tetrahydro-4-methyl-1-(phenylmethyl)-3-pyridyl]acetamide, N-(4-methyl-3-pyridyl)acetamide, 3-amino-4-methylpyridine and 3-acetamido-1-benzyl-4-methyl-pyridinium bromide in (3R,4R)-1-benzyl-N,4-dimethylpiperidin-3-amine dihydrochloride is a technical problem that needs to be solved urgently. Summary of the invention

[0004] In view of the deficiencies of the prior art, the object of the present invention is to provide a method for detecting impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride, and in particular to provide a method for detecting impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride with high accuracy. The detection method provided by the present invention can simultaneously detect four mutagenic impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride, and the detection method is accurate, has high precision and good repeatability.

[0005] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0006] In one aspect, the present invention provides a method for detecting impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride, the detection method comprising the following steps:

[0007] (1) Mixing a reference substance with a blank solution to obtain a reference substance solution;

[0008] (2) Mixing the sample to be tested with the blank solution to obtain a test solution;

[0009] (3) The test solution, reference solution and blank solution are respectively injected for liquid chromatography tandem mass spectrometry detection to obtain the test results.

[0010] There is no order distinction between steps (1) and (2).

[0011] The impurities include any one or a combination of at least two of N-[1,2,5,6-tetrahydro-4-methyl-1-(phenylmethyl)-3-pyridinyl]acetamide, N-(4-methyl-3-pyridinyl)acetamide, 3-amino-4-methylpyridine or 3-acetamido-1-benzyl-4-methyl-pyridinium bromide.

[0012] The above method can effectively detect the mutagenic impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride, and the detection method is accurate, highly precise and reproducible.

[0013] Preferably, the impurity is a combination of N-[1,2,5,6-tetrahydro-4-methyl-1-(phenylmethyl)-3-pyridinyl]acetamide, N-(4-methyl-3-pyridinyl)acetamide, 3-amino-4-methylpyridine and 3-acetamido-1-benzyl-4-methyl-pyridinium bromide.

[0014] The above method can detect four mutagenic impurities at the same time, effectively shortening the detection time and saving costs.

[0015] Preferably, the blank solution is an acetonitrile aqueous solution.

[0016] Preferably, the volume fraction of the acetonitrile aqueous solution is 40-60%, such as 40%, 45%, 50%, 55% or 60%, etc., but is not limited to the above-listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0017] Preferably, the mobile phase of the liquid chromatography comprises mobile phase A and mobile phase B, the mobile phase A is a formic acid aqueous solution, and the mobile phase B is acetonitrile;

[0018] Preferably, the volume fraction of the formic acid aqueous solution is 0.08-0.12%, such as 0.08%, 0.09%, 0.1%, 0.11% or 0.12%, but is not limited to the above-listed values. Other values ​​not listed within the above range are also applicable.

[0019] Preferably, the elution procedure of the liquid chromatography is gradient elution, and the specific process of the gradient elution is:

[0020] From 0 to 2 minutes, the volume fraction of mobile phase A is 100%, and the volume fraction of mobile phase B is 0;

[0021] From the 2nd to the 10th minute, the volume fraction of mobile phase A changes to 24% at a constant rate, and the volume fraction of mobile phase B changes to 76% at a constant rate;

[0022] At 10-10.1 min, the volume fraction of mobile phase A changes to 100% at a constant speed, and the volume fraction of mobile phase B changes to 0 at a constant speed;

[0023] From 10.1 to 14 min, the volume fraction of mobile phase A was 100%, and the volume fraction of mobile phase B was 0.

[0024] Preferably, the flow rate of the liquid chromatography is 0.28-0.32 mL / min.

[0025] Preferably, the column temperature of the liquid chromatography is 33-37°C.

[0026] Preferably, the injection volume of the liquid chromatography is 0.8-1.2 μL.

[0027] Among them, the flow rate can be 0.28mL / min, 0.29mL / min, 0.3mL / min, 0.31mL / min or 0.32mL / min, etc., the column temperature can be 33°C, 34°C, 35°C, 36°C or 37°C, etc., the injection volume can be 0.8μL, 0.9μL, 1μL, 1.1μL or 1.2μL, etc., but are not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable.

[0028] The above-mentioned specific liquid phase process and parameters can effectively improve the accuracy of detection.

[0029] On the other hand, the present invention also provides the use of the above detection method in the quality control of (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The invention provides a method for detecting impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride. The method can effectively detect four mutagenic impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride at the same time. The detection method is accurate, has high precision and good repeatability. The detection accuracy can be effectively improved by selecting specific liquid phase processes and parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is the specificity test result of the method in Example 1, wherein A is 3-amino-4-methylpyridine, B is N-(4-methyl-3-pyridyl)acetamide, C is N-[1,2,5,6-tetrahydro-4-methyl-1-(phenylmethyl)-3-pyridyl]acetamide, and D is 3-acetamido-1-benzyl-4-methyl-pyridinium bromide. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0034] In the following examples and tests, the following instruments were used:

[0035] Serial number Instrument Name model 1 Ultra-high performance liquid chromatography-tandem mass spectrometry Agilent 1290-G6470A 2 Electronic balance Mettler XSE205DU 3 Electronic balance Mettler XPR2

[0036] The reagents used are as follows

[0037] Reagent name level source Ultrapure water Ultrapure water Nanjing Medicine Stone Formic acid MS MACKLIN Methanol HPLC Honeywell Acetonitrile HPLC Honeywell

[0038] The reference substances and test substances used are as follows:

[0039]

[0040] Example 1

[0041] This embodiment provides a method for detecting impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride, and the specific steps are as follows:

[0042] (1) Preparation of reference substance solution: Accurately weigh 25 mg each of N-[1,2,5,6-tetrahydro-4-methyl-1-(phenylmethyl)-3-pyridinyl]acetamide, N-(4-methyl-3-pyridinyl)acetamide, 3-amino-4-methylpyridine and 3-acetamido-1-benzyl-4-methyl-pyridinium bromide, place in the same 25 mL volumetric flask, add 50% acetonitrile aqueous solution to make up to volume, shake well to obtain reference substance stock solution; accurately measure the reference substance stock solution and dilute it step by step to 4 ng / mL, shake well to obtain reference substance solution.

[0043] (2) Preparation of test solution: Accurately weigh 5 mg of the sample to be tested (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride, put it into a 50 mL volumetric flask, add 50% acetonitrile aqueous solution to make up to volume, shake well, and obtain the test solution.

[0044] (3) The test solution, the reference solution and the 50% acetonitrile aqueous solution were respectively subjected to liquid chromatography tandem mass spectrometry detection, and the detection results were calculated.

[0045] The parameters of liquid chromatography-tandem mass spectrometry were as follows:

[0046]

[0047]

[0048] Comparative Example 1

[0049] This comparative example provides a method for detecting impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride, which is consistent with Example 1 except that the gradient elution procedure is as follows.

[0050] Elution conditions:

[0051]

[0052] Comparative Example 2

[0053] This comparative example provides a method for detecting impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride, which is consistent with Example 1 except that formic acid is replaced by an equal amount of ammonia water.

[0054] Effect verification:

[0055] The method provided in Example 1 was verified, and the investigation items and methods (the detection method is the same as in Example 1) are as follows:

[0056] 1. System Applicability

[0057] Solution preparation:

[0058] 1) Blank solution / diluent

[0059] 50% acetonitrile water

[0060] 2) Reference solution

[0061] Reference substance stock solution 1-1 (1 mg / mL): Take 25 mg of Imp-tof-40, Imp-tof-61, Imp-tof-62, and mgImp-tof-63 reference substances respectively, accurately weigh them, place them in a 25 mL volumetric flask, add an appropriate amount of diluent, ultrasonically dissolve and dilute to the scale, shake well, and use them as reference substance stock solution 1-1;

[0062] Reference substance stock solution 2-1 (1 mg / mL): Take 25 mg of each of Imp-tof-40, Imp-tof-61, Imp-tof-62, and Imp-tof-63 reference substances, accurately weigh them, place them in a 25 mL volumetric flask, add an appropriate amount of diluent, ultrasonically dissolve and dilute to the scale, shake well, and use them as reference substance stock solution 2-1;

[0063] Reference substance stock solution 1-2 (10ug / mL): Accurately measure 0.1mL of reference substance stock solution 1-1, place in a 10mL volumetric flask, add diluent to dilute to the scale, shake well, and use as reference substance stock solution 1-2;

[0064] Reference substance stock solution 2-2 (10ug / mL): Accurately measure 0.1mL of reference substance stock solution 2-1, place in a 10mL volumetric flask, add diluent to dilute to the scale, shake well, and use as reference substance stock solution 2-2;

[0065] Reference substance stock solution 1-3 (0.2ug / mL): Accurately measure 0.5mL of reference substance stock solution 1-2, place in a 25mL volumetric flask, add diluent to dilute to the scale, shake well, and use as reference substance stock solution 1-3;

[0066] Reference substance stock solution 2-3 (0.2ug / mL): Accurately measure 0.5mL of reference substance stock solution 2-2, place in a 25mL volumetric flask, add diluent to dilute to the mark, shake well, and use as reference substance stock solution 2-3;

[0067] Reference substance solution 1 (4 ng / mL): Accurately measure 1.0 mL of reference substance stock solution 1-3, place in a 50 mL volumetric flask, add diluent to dilute to the mark, shake well, and use this as reference substance solution 1, marked as STD1;

[0068] Reference solution 2 (4 ng / mL): Accurately measure 1.0 mL of reference stock solution 2-3, place in a 50 mL volumetric flask, add diluent to dilute to the mark, shake well, and use this as reference solution 2, marked as STD2;

[0069] 3) Sensitivity solution

[0070] Accurately measure 0.2 mL of reference stock solution 1-3, place in a 50 mL volumetric flask, add diluent to dilute to the mark, shake well, and mark as SS.

[0071] Inspection content: Take 1 injection or more of blank solution, 1 injection of sensitivity solution, 5 injections of reference solution 1, and 2 injections of reference solution 2. Inspect the signal-to-noise ratio of the sensitivity solution, the RSD of the STD1 peak area and retention time of the 5 injections, the recovery rate of STD2, the recovery rate of the return injection and the RSD of the STD1 peak area in the entire sequence.

[0072] 2. Exclusivity

[0073] Solution preparation:

[0074] 1) Blank solution

[0075] Reference "System Suitability" Blank Solution

[0076] 2) Reference solution

[0077] Reference "System Suitability" Reference Solution 1

[0078] 3) Sample solution

[0079] Reference "Accuracy and Repeatability" Test Solution 1

[0080] 4) 100% spiked test solution

[0081] Reference "Accuracy and Repeatability" 100% spiked test solution 1

[0082] Inspection content: Take 1 injection of blank solution, 1 injection of reference solution, 1 injection of test solution, 1 injection of 100% spiked test solution, and inspect the specificity

[0083] 3. Linear

[0084] Use the reference substance stock solutions 1-3 under "System Suitability" to prepare a series of linear solutions, including 20% ​​linear solution, 50% linear solution, 100% linear solution, 150% linear solution and 200% linear solution. The specific preparation process is as follows:

[0085] Linear solution preparation

[0086]

[0087] Investigation content:

[0088] Take one injection each of L-20, L-50, L-100, L-100, L-150, and L-200 solutions, and examine the linear correlation coefficient r, response factor RSD, the ratio of the absolute value of the intercept b to the Y response when X is 100%, the residual sum of squares, and the ratio to the limit concentration. Report the linear equation relative to the test solution concentration.

[0089] 4. Limit of Detection and Limit of Quantitation

[0090] Solution preparation

[0091] 1) Detection limit solution

[0092] Take 5.0mL of the quantitative limit solution and place it in a 10mL volumetric flask, dilute it to the scale with diluent, and shake well.

[0093] 2) Quantitative limit solution

[0094] Refer to sensitivity solutions under “System Suitability”.

[0095] Inspection content: Take one injection of the detection limit solution to inspect the signal-to-noise ratio of the detection limit solution, and inject 6 injections of the quantification limit solution to inspect the peak area RSD and signal-to-noise ratio of the quantification limit solution.

[0096] 5. Accuracy and Repeatability

[0097] Solution preparation:

[0098] 1) Test solution

[0099] Test solution 1: Take 5.328 mg of the test sample, accurately weigh it, place it in a 50 mL volumetric flask, add diluent to dissolve and dilute to the scale, shake well, and mark it as SPL-1.

[0100] Test solution 2: Take 5.573 mg of the test sample, accurately weigh it, place it in a 50 mL volumetric flask, add diluent to dissolve and dilute to the scale, shake well, and mark it as SPL-2.

[0101] 2) Spiked test solution

[0102] Take about 5 mg of PBIN20121437 test sample, weigh accurately, place in a 50 mL volumetric flask, add appropriate amount of diluent to dissolve, then add reference substance stock solution 1-3 under "System Suitability", dissolve with diluent and dilute to the scale, shake well (see the table below).

[0103] Preparation table of spiked test solution

[0104]

[0105] Investigation content: Take 2 portions of test solution and inject 1 injection each, 3 portions of 20% spiked test solution and inject 1 injection each, 3 portions of 50% spiked test solution and inject 1 injection each, 6 portions of 100% spiked test solution and inject 1 injection each, 3 portions of 200% spiked test solution, and investigate the recovery rate of the 4 levels of spiked test solution and the RSD of the recovery rate.

[0106] 6. Intermediate Precision

[0107] Solution preparation:

[0108] 1) Blank / Diluent

[0109] 50% acetonitrile

[0110] 2) Mobile phase A

[0111] Take 1.0mL formic acid into 1000mL ultrapure water and mix well.

[0112] 3) Mobile phase B

[0113] Methanol

[0114] 4) Reference solution

[0115] Reference substance stock solution 1-1 (1 mg / mL): Take approximately 25 mg of each of Imp-tof-40, Imp-tof-61, Imp-tof-62, and Imp-tof-63 reference substances, accurately weigh them, place them in a 25 mL volumetric flask, add an appropriate amount of diluent, ultrasonically dissolve and dilute to the scale, shake well, and use them as reference substance stock solution 1-1;

[0116] Reference substance stock solution 2-1 (1 mg / mL): Take approximately 25 mg of each of Imp-tof-40, Imp-tof-61, Imp-tof-62, and Imp-tof-63 reference substances, accurately weigh them, place them in a 25 mL volumetric flask, add an appropriate amount of diluent, ultrasonically dissolve and dilute to the scale, shake well, and use this as reference substance stock solution 2-1;

[0117] Reference substance stock solution 1-2 (10ug / mL): Accurately measure 0.1mL of reference substance stock solution 1-1, place in a 10mL volumetric flask, add diluent to dilute to the scale, shake well, and use as reference substance stock solution 1-2;

[0118] Reference substance stock solution 2-2 (10ug / mL): Accurately measure 0.1mL of reference substance stock solution 2-1, place in a 10mL volumetric flask, add diluent to dilute to the scale, shake well, and use as reference substance stock solution 2-2;

[0119] Reference substance stock solution 1-3 (0.2ug / mL): Accurately measure 0.5mL of reference substance stock solution 1-2, place in a 25mL volumetric flask, add diluent to dilute to the scale, shake well, and use as reference substance stock solution 1-3;

[0120] Reference substance stock solution 2-3 (0.2ug / mL): Accurately measure 0.5mL of reference substance stock solution 2-2, place in a 25mL volumetric flask, add diluent to dilute to the mark, shake well, and use as reference substance stock solution 2-3;

[0121] Reference substance solution 1 (4 ng / mL): Accurately measure 1.0 mL of reference substance stock solution 1-3, place in a 50 mL volumetric flask, add diluent to dilute to the mark, shake well, and use this as reference substance solution 1, marked as STD1;

[0122] Reference solution 2 (4 ng / mL): Accurately measure 1.0 mL of reference stock solution 2-3, place in a 50 mL volumetric flask, add diluent to dilute to the mark, shake well, and use this as reference solution 2, marked as STD2;

[0123] 5) Sensitivity solution

[0124] Accurately measure 0.2 mL of reference stock solution 1-3, place in a 50 mL volumetric flask, add diluent to dilute to the mark, shake well, and mark as SS.

[0125] 6) Test solution

[0126] Test solution 1: Take about 5 mg of the test sample, accurately weigh it, place it in a 50 mL volumetric flask, add diluent to dissolve and dilute to the scale, shake well, and mark it as SPL-1.

[0127] Test solution 2: Take about 5 mg of the test sample, weigh it accurately, put it in a 50 mL volumetric flask, add diluent to dissolve and dilute to the scale, shake well, and mark it as SPL-2.

[0128] 7) 100% spiked test solution

[0129] Take about 5 mg of PBIN20121437 test sample, weigh accurately, place in a 50 mL volumetric flask, add appropriate amount of diluent to dissolve, then add reference substance stock solution 1-3, dissolve with diluent and dilute to the scale, shake well (see the table below).

[0130] Intermediate precision 100% spiked test solution preparation table

[0131]

[0132]

[0133] Inspection content: Take 1 injection or more of blank solution, 1 injection of sensitivity solution, 5 injections of reference solution 1, 2 injections of reference solution 2, 1 injection of each of 2 test solution, 1 injection of each of 6 100% spiked test solution, check that the blank solution has no interference, check the peak area and retention time RSD of 5 injections of STD1 solution, check the recovery rate of STD2, and the recovery rate and recovery rate RSD of 6 100% spiked test solution.

[0134] 7. Solution stability

[0135] Solution preparation

[0136] 1) Reference solution

[0137] Reference "Intermediate Precision" Reference Solution 1

[0138] 2) Spiked test solution

[0139] Reference "Intermediate precision" 100% spiked test solution first (Spike-100%-1)

[0140] Investigation content: The reference solution and 100% spiked test solution were stored at room temperature, and the ratio of the peak areas of N-[1,2,5,6-tetrahydro-4-methyl-1-(phenylmethyl)-3-pyridinyl]acetamide, N-(4-methyl-3-pyridinyl)acetamide, 3-amino-4-methylpyridine and 3-acetamido-1-benzyl-4-methyl-pyridinium bromide in the solutions at different times to the peak areas in the 0h solution was investigated.

[0141] 8. Durability

[0142] Solution preparation:

[0143] 1) Blank solution

[0144] Reference "System Suitability" Blank Solution

[0145] 2) Sensitivity solution

[0146] Reference "System Suitability" Sensitivity Solution

[0147] 3) Reference solution 1

[0148] Reference "System Suitability" Reference Solution 1

[0149] 4) Reference solution 2

[0150] Reference "System Suitability" Reference Solution 2

[0151] 5) Test solution

[0152] Reference "Accuracy and Repeatability" Test Solution 1

[0153] 6) 100% spiked test solution

[0154] Reference "Accuracy and Repeatability" 100% spiked test solution 1 (Spike-100%-1)

[0155] Reference "Accuracy and Repeatability" 100% spiked test solution 2 (Spike-100%-2)

[0156] Examination content: Under each durability condition, inject 1 or more blank solution, 1 sensitivity solution, 1 reference solution 1, 1 reference solution 2, 1 test solution, and 1 injection of each of 2 100% spiked test solutions to examine the signal-to-noise ratio of the sensitivity solution, the peak area and retention time RSD of 5 STD1 solutions, the recovery of STD2 solution, and the recovery of 2 100% spiked test solutions.

[0157] The results are as follows:

[0158]

[0159]

[0160]

[0161]

[0162]

[0163] The above results fully demonstrate that the method provided by the present invention can simultaneously detect four mutagenic impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride, and the detection method is accurate and has good specificity (specificity results are shown in Figure 1 As shown, the horizontal axis is time, A is 3-amino-4-methylpyridine, B is N-(4-methyl-3-pyridyl)acetamide, C is N-[1,2,5,6-tetrahydro-4-methyl-1-(phenylmethyl)-3-pyridyl]acetamide, and D is 3-acetamido-1-benzyl-4-methyl-pyridinium bromide), with high precision, good repeatability, good stability and high durability.

[0164] Then the above method was used to test the accuracy of the method in Comparative Example 1-2, and the results were as follows:

[0165] Comparative Example 1:

[0166]

[0167] Comparative Example 2:

[0168]

[0169] It can be found that the present invention effectively improves the accuracy of detection by adopting a specific elution procedure.

[0170] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the detection method of impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride of the present invention, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0171] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0172] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A method for detecting impurities in (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloric acid, characterized in that: The detection method comprises the following steps: (1) Mixing a reference substance with a blank solution to obtain a reference substance solution; (2) Mixing the sample to be tested with the blank solution to obtain a test solution; (3) injecting the test solution, the reference solution and the blank solution respectively for liquid chromatography tandem mass spectrometry detection to obtain the test results; Steps (1) and (2) are not sequential; The impurities include any one or a combination of at least two of N-[1,2,5,6-tetrahydro-4-methyl-1-(phenylmethyl)-3-pyridinyl]acetamide, N-(4-methyl-3-pyridinyl)acetamide, 3-amino-4-methylpyridine or 3-acetamido-1-benzyl-4-methyl-pyridinium bromide.

2. The detection method according to claim 1, characterized in that: The impurity is a combination of N-[1,2,5,6-tetrahydro-4-methyl-1-(phenylmethyl)-3-pyridinyl]acetamide, N-(4-methyl-3-pyridinyl)acetamide, 3-amino-4-methylpyridine and 3-acetamido-1-benzyl-4-methyl-pyridinium bromide.

3. The detection method according to claim 1 or 2, characterized in that: The blank solution is an acetonitrile aqueous solution.

4. The detection method according to claim 3, characterized in that: The volume fraction of the acetonitrile aqueous solution is 40-60%.

5. The detection method according to any one of claims 1 to 4, characterized in that: The mobile phase of the liquid chromatography comprises mobile phase A and mobile phase B, wherein the mobile phase A is a formic acid aqueous solution and the mobile phase B is acetonitrile; Preferably, the volume fraction of the formic acid aqueous solution is 0.08-0.12%.

6. The detection method according to claim 5, characterized in that: The elution procedure of the liquid chromatography is gradient elution, and the specific process of the gradient elution is: From 0 to 2 minutes, the volume fraction of mobile phase A is 100%, and the volume fraction of mobile phase B is 0; From the 2nd to the 10th minute, the volume fraction of mobile phase A changes to 24% at a constant rate, and the volume fraction of mobile phase B changes to 76% at a constant rate; At 10-10.1 min, the volume fraction of mobile phase A changes to 100% at a constant speed, and the volume fraction of mobile phase B changes to 0 at a constant speed; From 10.1 to 14 min, the volume fraction of mobile phase A was 100%, and the volume fraction of mobile phase B was 0.

7. The detection method according to any one of claims 1 to 6, characterized in that: The flow rate of the liquid chromatography is 0.28-0.32 mL / min.

8. The detection method according to any one of claims 1 to 7, characterized in that: The column temperature of the liquid chromatography is 33-37°C.

9. The detection method according to any one of claims 1 to 8, characterized in that: The injection volume of the liquid chromatography is 0.8-1.2 μL.

10. Use of the detection method according to any one of claims 1 to 9 in the quality control of (3R, 4R)-1-benzyl-N, 4-dimethylpiperidin-3-amine dihydrochloride.

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