Method for measuring content of nitrosamine impurity in venlafaxine hydrochloride sustained release tablet

Abstract

The invention relates to a method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets, which comprises the following steps: grinding venlafaxine hydrochloride sustained-release tablets into fine powder as a sample to be detected, and extracting with an extracting agent to obtain a test solution; and carrying out liquid chromatography-mass spectrometry detection on the test solution, and calculating according to the detection result to obtain the content of the nitrosamine impurity N-nitroso-demethyl-venlafaxine in the venlafaxine hydrochloride sustained release tablet. According to the method disclosed by the invention, the N-nitroso-demethyl-venlafaxine can be effectively extracted, and the nitrosamine impurity is quantitatively detected by adopting liquid chromatography-mass spectrometry detection, so that the problems that the nitrosamine impurity N-nitroso-demethyl-venlafaxine is low in content, difficult to detect and easy to interfere are successfully solved. The method is high in accuracy, precision and sensitivity and good in linearity, specificity and system adaptability.

Description

Technical Field

[0001] The invention relates to a method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets, and belongs to the technical field of drug analysis. Background Art

[0002] Venlafaxine hydrochloride sustained-release tablets are new antidepressants suitable for the treatment of various types of depression (including depression with anxiety) and generalized anxiety disorder, and can also be used to treat social anxiety and panic disorder. Venlafaxine hydrochloride is a phenylethylamine derivative and a serotonin and norepinephrine reuptake inhibitor. It exerts an antidepressant effect by inhibiting the reuptake of serotonin and norepinephrine and enhancing the central serotonergic and norepinephrine nerve functions.

[0003] The active ingredient of venlafaxine hydrochloride contains secondary or tertiary amine structures, which provide amino groups for the formation of nitrosamines, and are easily nitrosated with nitrites under specific conditions to form nitrosamine impurities. Nitrosamine impurities are potentially harmful to human health. Long-term exposure to nitrosamine impurities above the acceptable level may increase the risk of cancer. The maximum daily dose of venlafaxine hydrochloride sustained-release tablets is 225 mg / day. The FDA-published nitrosamine impurity N-nitroso-desmethyl-venlafaxine that may be contained in venlafaxine hydrochloride shall not exceed 26.5 ng / day (equivalent to 0.118 ppm). In view of the low content and high toxicity of the nitrosamine impurity, in order to ensure the safety of drug use, it is very necessary to develop an analytical method that is fast, easy to operate, has strong anti-interference ability, and can measure the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets.

[0004] After searching, it was found that the invention patent application with application number 201610240989.2 and application publication number CN105884630A disclosed a related substance of venlafaxine hydrochloride and its analysis and detection method, and the invention patent application with application number 202211323213.9 and application publication number CN115876911A disclosed a method for measuring related substances of venlafaxine hydrochloride tablets by liquid chromatography. The above technical schemes all use liquid chromatography to determine the impurities in venlafaxine hydrochloride tablets, but none of them pays attention to the low-content and highly toxic nitrosamine impurity N-nitroso-desmethyl-venlafaxine, and cannot meet the quantitative detection needs of the nitrosamine impurity. Summary of the invention

[0005] The main purpose of the present invention is to overcome the problems existing in the prior art and provide a method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets. The method adopts liquid chromatography-mass spectrometry to determine the content of nitrosamine impurity N-nitroso-desmethyl-venlafaxine, and has high accuracy, precision and sensitivity, and good linearity, specificity and system adaptability.

[0006] The technical solution of the present invention to solve the technical problem is as follows:

[0007] A method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets comprises the following steps:

[0008] The first step is to grind the venlafaxine hydrochloride sustained-release tablets into fine powder as a sample to be tested, and extract it with an extractant to obtain a test solution; wherein the extractant is one of methanol and acetonitrile or a combination thereof.

[0009] The second step is to perform LC-MS detection on the test solution, and calculate based on the test results to obtain the content of the nitrosamine impurity N-nitroso-desmethyl-venlafaxine in the venlafaxine hydrochloride sustained-release tablets; wherein the detection conditions of the LC-MS detection include high performance liquid chromatography parameters; among the high performance liquid chromatography parameters, the chromatographic column uses a CS-C18 high performance liquid chromatography column, and the mobile phase consists of an aqueous solution of formic acid and an acetonitrile solution of formic acid.

[0010] The method can effectively extract the low-content nitrosamine impurity N-nitroso-desmethyl-venlafaxine in venlafaxine hydrochloride sustained-release tablets, and perform quantitative detection by liquid chromatography-mass spectrometry, thereby realizing the determination of the nitrosamine impurity content in venlafaxine hydrochloride sustained-release tablets, and has the advantages of high accuracy and high separation.

[0011] Preferably, in the first step, the extractant is a mixed solution of methanol and acetonitrile.

[0012] More preferably, in the extractant, the volume ratio of methanol to acetonitrile is 3 to 5:1.

[0013] By adopting the above preferred scheme, the extractant used in the first step can be further optimized, so that the nitrosamine impurity N-nitroso-desmethyl-venlafaxine can be extracted more effectively, and the interfering components can be reduced, thereby improving the detection accuracy.

[0014] Preferably, in the first step, during extraction, the solid-liquid ratio of the sample to be tested to the extractant is 25 mg: 0.8-1.5 mL in terms of venlafaxine.

[0015] Preferably, the specific process of the first step is:

[0016] Take a predetermined amount of venlafaxine hydrochloride sustained-release tablets, accurately weigh them, and grind them into fine powder as the sample to be tested; accurately weigh a predetermined amount of the sample to be tested, place it in a centrifuge tube, accurately measure a predetermined amount of extractant and add it to the centrifuge tube, shake and vortex to mix, then centrifuge to obtain the supernatant to obtain the test solution.

[0017] More preferably, in the specific process of the first step, the vortex time is at least 5 minutes, and the centrifugation condition is centrifugation at 15000-16000 rpm for at least 5 minutes.

[0018] By adopting the above preferred scheme, the specific technical details of the first step can be further optimized to achieve better extraction effect.

[0019] Preferably, in the second step, in the high performance liquid chromatography parameters, a high performance liquid chromatograph is used; the inner diameter of the chromatographic column is 4.6 mm, the length is more than 100 mm, and the particle size is 2.7 μm; the mobile phase is composed of an aqueous solution of 0.5±0.1% formic acid by volume: an acetonitrile solution of 0.5±0.1% formic acid by volume in a ratio of 55-65:35-45.

[0020] More preferably, in the HPLC parameters, the chromatographic column model is Agilent Poroshell 120CS-C18, 4.6×100 mm, 2.7 μm; the flow rate is 0.4-0.6 ml / min, the column temperature is 35° C.-45° C., and the injection volume is 10-30 μl.

[0021] By adopting the above preferred scheme, the high performance liquid chromatography parameters of the second step can be further optimized, the detection separation and accuracy can be further improved, and better detection effects can be achieved.

[0022] Preferably, in the second step, the detection conditions of the LC-MS detection also include mass spectrometry parameters; among the mass spectrometry parameters, a triple tandem quadrupole mass spectrometer is used; the ion source is an APCI ion source, the polarity is positive, the drying gas temperature is 300°C-350°C, the evaporation chamber temperature is 325°C-375°C, the drying gas flow rate is 4-6L / min, and the nebulizing gas pressure is 20-30psi.

[0023] More preferably, in the mass spectrometry parameters, the capillary voltage is 4000 V; the corona needle current is 4 μA; the monitoring mode adopts multiple reaction monitoring MRM, and the 275.2→215.2 channel is used for quantification; and the chromatogram type is TIC.

[0024] More preferably, among the mass spectrometry parameters, the mass spectrometry detection parameters include: time segmentation of 5-10 minutes, parent ion mass-to-charge ratio of 275.2, daughter ion mass-to-charge ratio of 215.2, dwell time of 500ms, fragmentation voltage of 80-120V, collision voltage of 5-7V, and acceleration voltage of 4-6V.

[0025] By adopting the above preferred scheme, the mass spectrometry parameters of the second step can be further optimized, the detection separation and accuracy can be further improved, and better detection effects can be achieved.

[0026] Preferably, the specific process of the second step is:

[0027] First, N-nitroso-desmethyl-venlafaxine reference substance was used, methanol was used as solvent, and reference substance solutions of preset series concentrations were prepared, and LC-MS detection was performed respectively. According to the test results, a standard curve of concentration-peak area for N-nitroso-desmethyl-venlafaxine was established; then, the test solution was tested by LC-MS, and the content of nitrosamine impurity N-nitroso-desmethyl-venlafaxine in venlafaxine hydrochloride sustained-release tablets was obtained by calculation based on the test results combined with the standard curve.

[0028] More preferably, in the specific process of the second step, the preset series concentrations are in the concentration range of 0.1 to 10 ng / ml, and the number of preset series concentrations is at least 5; the quantitative limit is first determined based on the test results of the reference solution of the preset series concentrations, and then a standard curve is established with the concentration of the quantitative limit as the lower limit.

[0029] By adopting the above preferred scheme, the specific technical details of the second step can be further optimized to achieve better detection results.

[0030] Compared with the prior art, the present invention uses a specific extractant to extract venlafaxine hydrochloride sustained-release tablets, can effectively extract N-nitroso-desmethyl-venlafaxine, and uses liquid chromatography-mass spectrometry to quantitatively detect the nitrosamine impurity, thereby successfully overcoming the problems of low content, difficulty in detection, and easy interference of the nitrosamine impurity N-nitroso-desmethyl-venlafaxine. The method of the present invention has high accuracy, precision, and sensitivity, and good linearity, specificity, and system adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is the chromatogram of the reference substance solution in Example 1 of the present invention.

[0032] Figure 2 It is the chromatogram of the blank solvent in Example 1 of the present invention.

[0033] Figure 3 It is the chromatogram of the blank auxiliary material in Example 1 of the present invention.

[0034] Figure 4 It is the chromatogram of the test solution in Example 1 of the present invention.

[0035] Figure 5 It is the chromatogram of the test solution in Comparative Example 1 of the present invention.

[0036] Figure 6 It is the chromatogram of the test solution in Comparative Example 2 of the present invention.

[0037] Figure 7 It is the chromatogram of the test solution in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0038] The technical solutions specifically implemented in the present invention are as follows:

[0039] A method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets comprises the following steps:

[0040] The first step is to grind the venlafaxine hydrochloride sustained-release tablets into fine powder as a sample to be tested, and extract them with an extractant to obtain a test solution.

[0041] Among them, the extractant is one of methanol, acetonitrile or a combination thereof; the extractant is preferably a mixed solution of methanol and acetonitrile, wherein the volume ratio of methanol to acetonitrile is preferably 3 to 5:1, for example 3:1, 3.5:1, 4:1, 4.5:1 or 5:1, but is not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable.

[0042] During extraction, the solid-liquid ratio of the sample to be tested and the extractant calculated as venlafaxine is 25 mg:0.8-1.5 mL, for example, 25:0.8 mg / mL, 25:0.9 mg / mL, 25:1 mg / mL, 25:1.1 mg / mL, 25:1.2 mg / mL, 25:1.3 mg / mL, 25:1.4 mg / mL or 25:1.5 mg / mL, but is not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable.

[0043] Specifically, the specific process of the first step is:

[0044] Take a predetermined amount of venlafaxine hydrochloride sustained-release tablets, weigh them accurately, grind them into fine powder, and use them as the sample to be tested; weigh a predetermined amount of the sample to be tested accurately, put it into a centrifuge tube, accurately measure a predetermined amount of extractant and add it to the centrifuge tube, shake and vortex to mix, then centrifuge to take the supernatant, and obtain the test solution. The vortex time is at least 5 minutes, and the centrifugation condition is centrifugation at 15000-16000 rpm for at least 5 minutes.

[0045] The second step is to perform liquid chromatography-mass spectrometry detection on the test solution, and calculate based on the test results to obtain the content of the nitrosamine impurity N-nitroso-desmethyl-venlafaxine in the venlafaxine hydrochloride sustained-release tablets.

[0046] Among them, the LC-MS detection conditions include high-performance liquid chromatography parameters. In the high-performance liquid chromatography parameters, a high-performance liquid chromatograph is used; the chromatographic column uses a CS-C18 high-performance liquid chromatography column, whose inner diameter is 4.6mm, length is more than 100mm, and particle size is 2.7μm (for example: the chromatographic column model is Agilent Poroshell120CS-C18, 4.6×100mm, 2.7μm); the mobile phase is composed of an aqueous solution of 0.5±0.1% formic acid by volume: an acetonitrile solution of 0.5±0.1% formic acid by volume in a ratio of 55 to 65:35 to 45. In addition, in the high-performance liquid chromatography parameters, the flow rate is 0.4 to 0.6ml / min, the column temperature is 35℃ to 45℃, and the injection volume is 10 to 30μl.

[0047] The LC-MS detection conditions also include mass spectrometry parameters. In the mass spectrometry parameters, a triple tandem quadrupole mass spectrometer is used; the ion source is an APCI ion source, the polarity is positive, the drying gas temperature is 300℃-350℃, the evaporation chamber temperature is 325℃-375℃, the drying gas flow rate is 4-6L / min, and the nebulizer gas pressure is 20-30psi. The capillary voltage is 4000V; the corona needle current is 4μA; the monitoring mode uses multiple reaction monitoring MRM, and the 275.2→215.2 channel is used for quantification; the chromatogram type is TIC.

[0048] In addition, among the mass spectrometry parameters, the mass spectrometry detection parameters include: time segmentation of 5-10 minutes, parent ion mass-to-charge ratio of 275.2, product ion mass-to-charge ratio of 215.2, dwell time of 500ms, fragmentation voltage of 80-120V, collision voltage of 5-7V, and acceleration voltage of 4-6V.

[0049] Specifically, the specific process of the second step is:

[0050] First, N-nitroso-desmethyl-venlafaxine reference substance is used, methanol is used as solvent, and reference substance solutions of preset series concentrations are prepared, and LC-MS detection is performed respectively, and a standard curve of concentration-peak area for N-nitroso-desmethyl-venlafaxine is established according to the test results; then the test solution is subjected to LC-MS detection, and the content of nitrosamine impurity N-nitroso-desmethyl-venlafaxine in venlafaxine hydrochloride sustained-release tablets is obtained by calculation based on the test results combined with the standard curve. Among them, the preset series concentration is in the concentration range of 0.1 to 10 ng / ml, and the number of preset series concentrations is at least 5; the quantitative limit is first determined according to the test results of the reference substance solution of the preset series concentration, and then the standard curve is established with the concentration of the quantitative limit as the lower limit.

[0051] The present invention is further described in detail below with reference to the accompanying drawings and in conjunction with the examples. However, the present invention is not limited to the examples given. The experimental operations involved in the following content, if no specific experimental conditions are indicated, are carried out under conventional conditions or under the conditions recommended by the manufacturer. The experimental materials and reagents involved in the following content are all commercially available unless otherwise specified.

[0052] Example 1

[0053] This example conducts a methodological investigation on the technical solution specifically implemented in the present invention as described above, and determines the content of the nitrosamine impurity N-nitroso-desmethyl-venlafaxine in venlafaxine hydrochloride sustained-release tablets (specification: 75 mg).

[0054] The specific contents of this embodiment are as follows.

[0055] (1) Preparation of mobile phase

[0056] Mobile phase A is a 0.5% formic acid aqueous solution. The specific preparation process is: accurately measure 5 ml of anhydrous formic acid, dilute it with 1000 ml of water, shake it well, and filter it through a 0.45 μm pore size water membrane for use.

[0057] Mobile phase B is 0.5% formic acid in acetonitrile solution. The specific preparation process is: accurately measure 5 ml of anhydrous formic acid, dilute with 1000 ml of acetonitrile, shake well, filter through a 0.45 μm pore size organic membrane and set aside.

[0058] Mobile phase: Take mobile phase A and mobile phase B in a predetermined ratio, mix well to obtain mobile phase, and set aside.

[0059] (2) Preparation of test solution

[0060] Take 5 tablets of venlafaxine hydrochloride sustained-release tablets (specification: 75 mg), weigh them, and grind them into fine powder; accurately weigh an appropriate amount of fine powder (approximately equivalent to 250 mg of venlafaxine), place it in a centrifuge tube, accurately measure 10 ml of methanol-acetonitrile (4:1, v / v) into the above centrifuge tube, immediately shake manually and vortex for 5 minutes; then centrifuge at 15000 rpm for 5 minutes, and take the supernatant as the test solution for sample injection analysis.

[0061] (3) Preparation of reference solution

[0062] Weigh about 1.5 mg of N-nitroso-desmethyl-venlafaxine reference substance, place it in a 50 ml volumetric flask, dilute to the mark with methanol, and shake well; accurately measure 1 ml of the above solution, place it in a 100 ml volumetric flask, dilute to the mark with methanol, and shake well; accurately measure 1 ml of the above solution, place it in a 100 ml volumetric flask, dilute to the mark with methanol, and shake well.

[0063] (4) LC-MS detection conditions

[0064] i) HPLC parameters

[0065] Using high performance liquid chromatography;

[0066] Column: Agilent Poroshell 120CS-C18, 4.6×100 mm, 2.7 μm;

[0067] Flow rate: 0.5 ml / min;

[0068] Column temperature: 40°C;

[0069] Injection volume: 20 μl;

[0070] Running time: 20 minutes;

[0071] Mobile phase: mobile phase A: mobile phase B = 60:40, v / v;

[0072] ii) Mass spectrometry MSD parameters

[0073] A triple tandem quadrupole mass spectrometer was used, model Agilent G6475AQQQ-MSD;

[0074] Ion source: APCI;

[0075] Polarity: positive;

[0076] Drying gas temperature: 325℃;

[0077] Evaporation chamber temperature: 350℃;

[0078] Dry gas flow: 5L / min;

[0079] Atomizing gas pressure: 25psi;

[0080] Capillary voltage: 4000V;

[0081] Corona needle current: 4μA;

[0082] Monitoring mode: multiple reaction monitoring (MRM), 275.2→215.2 channel for quantification;

[0083] Chromatogram type: TIC.

[0084] The mass spectrometry detection parameters are shown in Table 1.

[0085] Table 1. Mass spectrometry parameters for N-nitroso-desmethyl-venlafaxine

[0086]

[0087] (5) Methodological investigation

[0088] A methodological investigation was conducted on the detection method using the above-mentioned LC-MS detection conditions, and the specific contents are as follows.

[0089] i) Injection reproducibility:

[0090] The reference solution was injected 6 times continuously. In the result graph, the peak areas of the chromatographic peaks of N-nitroso-desmethyl-venlafaxine were 2651, 2539, 2580, 2550, 2520, and 2523, respectively. The %RSD was calculated to be 1.9, which was less than 20.0, indicating that the above detection method had good precision.

[0091] ii) Exclusivity:

[0092] Inject the reference solution, blank solvent (i.e. methanol), and blank excipients separately. Figure 1 As shown in the chromatogram of the reference solution, the retention time of N-nitroso-desmethyl-venlafaxine is 6.749 minutes, and the retention time of the blank solvent ( Figure 2 ) and blank excipients ( Figure 3 ) at this retention time without interference. This result shows that the above detection method has good specificity.

[0093] iii) Linearity, limit of quantitation and limit of detection:

[0094] Take an appropriate amount of N-nitroso-desmethyl-venlafaxine reference substance, accurately weigh it, dissolve and dilute it with methanol to obtain the following series of reference substance solutions: 0.44769ng / ml, 1.4923ng / ml, 2.9846ng / ml, 4.4769ng / ml, 5.9692ng / ml, inject them respectively, and the corresponding peak areas are 361, 1208, 2631, 4123, 5649 respectively; thus, the linear equation is obtained: Y=964X-169 (X is concentration, Y is peak area), R 2 =0.999.

[0095] It can be seen that N-nitroso-desmethyl-venlafaxine has a significant linear relationship with the peak response value in the range of 0.45-5.9 ng / ml (0.018-0.24 ppm, note: calculated based on the test solution concentration of 25 mg / ml, the same below), and the quantification limit is 0.45 ng / ml (0.018 ppm).

[0096] The lowest concentration of the reference solution was diluted with methanol and tested. The results showed that the detection limit was 0.18 ng / ml (0.0072 ppm).

[0097] iv) Recovery rate:

[0098] The recovery test was conducted by adding three levels of N-nitroso-desmethyl-venlafaxine (20%, 100%, 200%) to the test sample. Specifically, a certain amount of N-nitroso-desmethyl-venlafaxine was added to the blank excipient of venlafaxine hydrochloride sustained-release tablets, and then three levels of test solution were prepared in three portions according to the preparation method described above, and the content was determined respectively. The measured value was compared with the theoretical value to calculate the recovery rate. The results show (Table 2) that the average recovery rates of N-nitroso-desmethyl-venlafaxine at the three levels were 94.1%, 97.9%, and 96.9% (limit: 80.0%-120.0%), and the %RSD were 1.3, 1.1, and 1.8 (limit: no more than 20.0). The results show that the above detection method has good accuracy.

[0099] Table 2, recovery rate data of this embodiment

[0100]

[0101] v) Repeatability:

[0102] Six sample solutions containing 100% N-nitroso-desmethyl-venlafaxine were prepared for determination. The recoveries of N-nitroso-desmethyl-venlafaxine were 98.9%, 96.7%, 98.0%, 97.7%, 97.8%, and 100.9%, respectively, and the %RSD was 1.5 (limit: not more than 20.0). The results show that the above detection method has good precision.

[0103] (6) Test sample testing

[0104] Take the test solution and inject it into the test method using the above LC-MS test conditions. The results are as follows: Figure 4 As shown, the result of the calculation is: the amount of N-nitroso-desmethyl-venlafaxine in the test solution is 0.74 ng / ml (0.03 ppm), which is much lower than 0.118 ppm (i.e., the limit standard issued by the FDA mentioned in the background technology).

[0105] Example 2

[0106] This example is basically the same as Example 1, except that the test solution of this example is prepared as follows:

[0107] Take 5 tablets of venlafaxine hydrochloride sustained-release tablets (specification: 75 mg), weigh them, and grind them into fine powder. Accurately weigh an appropriate amount of fine powder (equivalent to approximately 250 mg of venlafaxine), place it in a centrifuge tube, accurately measure 10 ml of methanol into the above centrifuge tube, immediately shake manually and vortex for 5 minutes. Centrifuge at 15000 rpm for 5 minutes, and take the supernatant for sampling and analysis.

[0108] Example 3

[0109] This example is basically the same as Example 1, except that the test solution of this example is prepared as follows:

[0110] Take 5 tablets of Venlafaxine Hydrochloride Sustained Release Tablets (Specification: 75 mg), weigh them, and grind them into fine powder. Accurately weigh an appropriate amount of fine powder (equivalent to approximately 250 mg of Venlafaxine), place it in a centrifuge tube, accurately measure 10 ml of acetonitrile into the above centrifuge tube, immediately shake manually and vortex for 5 minutes. Centrifuge at 15000 rpm for 5 minutes, and take the supernatant for sampling and analysis.

[0111] The detection methods of Examples 1 to 3 were tested for recovery rate comparison. A certain amount of N-nitroso-desmethyl-venlafaxine was added to the blank excipient of venlafaxine hydrochloride sustained-release tablets. Three test solutions with concentrations of 20%, 100% and 200% were prepared according to the corresponding test solution preparation method. The contents were measured respectively, and the measured values ​​were compared with the theoretical values ​​to calculate the recovery rate. The results are shown in Table 3 below.

[0112] Table 3. Comparative data of recovery rate

[0113]

[0114] From the above data, it can be seen that the recoveries of the three levels of N-nitroso-desmethyl-venlafaxine in Examples 1 to 3 are all between 80.0-120.0%, and the %RSD does not exceed 20.0, among which, the recoveries of the three levels of Example 1 are all between 90.0-110.0%, and the %RSD does not exceed 3.0, which is significantly better than that of Examples 2 and 3. The above results show that the detection methods of Examples 1 to 3 are all good in accuracy.

[0115] Comparative Example 1

[0116] This comparative example is basically the same as Example 1, except that the chromatographic column used in the high performance liquid chromatography (HPLC) parameters of this comparative example is Agilent Poroshell 120EC-C18, 4.6×100 mm, 2.7 μm.

[0117] Take the test solution and inject it into the test method using the LC-MS test conditions of this comparative example. The results are as follows: Figure 5 As shown, the peak shape of the chromatographic peak of N-nitroso-desmethyl-venlafaxine is obviously poor.

[0118] Comparative Example 2

[0119] This comparative example is basically the same as Example 1, except that the mobile phase of this comparative example is prepared as follows:

[0120] Mobile phase A is a 0.5% formic acid aqueous solution (same as in Example 1); mobile phase B is acetonitrile. The mobile phase is prepared by mixing mobile phase A and mobile phase B at a ratio of 60:40, v / v, i.e., the mobile phase is: 0.5% formic acid aqueous solution: acetonitrile = 60:40, v / v.

[0121] Take the test solution and inject it into the test method using the LC-MS test conditions of this comparative example. The results are as follows: Figure 6 As shown, the peak shape of the chromatographic peak of N-nitroso-desmethyl-venlafaxine is obviously poor.

[0122] Comparative Example 3

[0123] This comparative example is basically the same as Example 1, except that, in the mass spectrometry detection parameters of this comparative example, the collision voltage is 4V and the acceleration voltage is 3V.

[0124] Take the test solution and inject it into the test method using the LC-MS test conditions of this comparative example. The results are as follows: Figure 7 As shown, the peak response of the chromatographic peak of N-nitroso-desmethyl-venlafaxine is obviously smaller.

[0125] The applicant declares that the present invention illustrates the technical solution of the present invention through the above-mentioned embodiments, 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.

[0126] 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.

[0127] 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 determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets, characterized in that: The following steps are involved: The first step is to grind the venlafaxine hydrochloride sustained-release tablets into fine powder as a sample to be tested, and extract it with an extractant to obtain a test solution; wherein the extractant is one of methanol and acetonitrile or a combination thereof; The second step is to perform LC-MS detection on the test solution, and calculate according to the test results to obtain the content of nitrosamine impurity N-nitroso-desmethyl-venlafaxine in venlafaxine hydrochloride sustained-release tablets; wherein the detection conditions of the LC-MS detection include high performance liquid chromatography parameters; in the high performance liquid chromatography parameters, the chromatographic column adopts a CS-C18 high performance liquid chromatography column, and the mobile phase consists of an aqueous solution of formic acid and an acetonitrile solution of formic acid.

2. The method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets according to claim 1, characterized in that: In the first step, the extractant is a mixed solution of methanol and acetonitrile.

3. The method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets according to claim 2, characterized in that: In the extractant, the volume ratio of methanol to acetonitrile is 3 to 5:

1.

4. The method for determining the nitrosamine impurity content in venlafaxine hydrochloride sustained-release tablets according to claim 1, characterized in that, in the first step, during extraction, the solid-liquid ratio of the sample to be tested based on venlafaxine to the extractant is 25 mg:0.8-1.5 mL.

5. The method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets according to claim 1, characterized in that: The specific process of the first step is: Take a predetermined amount of venlafaxine hydrochloride sustained-release tablets, accurately weigh them, and grind them into fine powder as the sample to be tested; accurately weigh a predetermined amount of the sample to be tested, place it in a centrifuge tube, accurately measure a predetermined amount of extractant and add it to the centrifuge tube, shake and vortex to mix, then centrifuge to obtain the supernatant to obtain the test solution.

6. The method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets according to claim 5, characterized in that: In the specific process of the first step, the vortexing time is at least 5 minutes, and the centrifugation condition is centrifugation at 15000-16000 rpm for at least 5 minutes.

7. The method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets according to any one of claims 1 to 6, characterized in that: In the second step, among the high performance liquid chromatography parameters, a high performance liquid chromatograph is used; the inner diameter of the chromatographic column is 4.6 mm, the length is more than 100 mm, and the particle size is 2.7 μm; the mobile phase is composed of an aqueous solution of 0.5±0.1% formic acid by volume: an acetonitrile solution of 0.5±0.1% formic acid by volume in a ratio of 55-65:35-45.

8. The method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets according to claim 7, characterized in that Among the high performance liquid chromatography parameters, the column model is Agilent Poroshell120CS-C18, 4.6×100 mm, 2.7 μm; the flow rate is 0.4-0.6 ml / min, the column temperature is 35° C.-45° C., and the injection volume is 10-30 μl.

9. The method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets according to claim 7, characterized in that: In the second step, the detection conditions of the LC-MS detection also include mass spectrometry parameters; among the mass spectrometry parameters, a triple tandem quadrupole mass spectrometer is used; the ion source is an APCI ion source, the polarity is positive, the drying gas temperature is 300°C-350°C, the evaporation chamber temperature is 325°C-375°C, the drying gas flow rate is 4-6L / min, and the nebulizing gas pressure is 20-30psi.

10. The method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets according to claim 9, characterized in that Among the mass spectrometry parameters, the capillary voltage was 4000 V; the corona needle current was 4 μA; the monitoring mode adopted multiple reaction monitoring (MRM), and the 275.2→215.2 channel was used for quantification; and the chromatogram type was TIC.

11. The method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets according to claim 9, characterized in that: Among the mass spectrometry parameters, the mass spectrometry detection parameters include: time segmentation of 5-10 minutes, parent ion mass-to-charge ratio of 275.2, product ion mass-to-charge ratio of 215.2, dwell time of 500ms, fragmentation voltage of 80-120V, collision voltage of 5-7V, and acceleration voltage of 4-6V.

12. The method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets according to any one of claims 1 to 6, characterized in that: The specific process of the second step is: First, N-nitroso-desmethyl-venlafaxine reference substance was used, methanol was used as solvent, and reference substance solutions of preset series concentrations were prepared, and LC-MS detection was performed respectively. According to the test results, a standard curve of concentration-peak area for N-nitroso-desmethyl-venlafaxine was established; then, the test solution was tested by LC-MS, and the content of nitrosamine impurity N-nitroso-desmethyl-venlafaxine in venlafaxine hydrochloride sustained-release tablets was obtained by calculation based on the test results combined with the standard curve.

13. The method for determining the content of nitrosamine impurities in venlafaxine hydrochloride sustained-release tablets according to claim 12, characterized in that: In the specific process of the second step, the preset series concentrations are in the concentration range of 0.1 to 10 ng / ml, and the number of the preset series concentrations is at least 5; the quantitative limit is first determined based on the test results of the reference solution of the preset series concentrations, and then a standard curve is established with the concentration of the quantitative limit as the lower limit.

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