Method for simultaneously detecting 10 impurities in candesi hydrothiadiazole tablets

Abstract

The invention belongs to the technical field of liquid phase detection, and particularly relates to a method for simultaneously detecting 10 impurities in candeshydrothiadiazole tablets. The method adopts liquid chromatography to simultaneously detect 10 impurities in the candesi hydrothiadiazole tablets, a ghost peak trapping column is connected to reduce baseline fluctuation, and the method specifically comprises the following steps: analyzing a candesi hydrothiadiazole solution by adopting a liquid chromatograph to obtain a chromatogram; and calculating the content of the to-be-detected component through the peak area of the chromatogram by an external standard method and a self-contrast method. Chromatographic conditions of the liquid chromatograph analysis comprise that a formic acid aqueous solution is used as a mobile phase A, acetonitrile is used as a mobile phase B, and gradient elution is carried out. The determination method disclosed by the invention is strong in specificity, high in sensitivity and good in selectivity, the content of 10 impurities can be detected by only using one set of analysis method, the analysis steps are simplified, the analysis time is greatly shortened, and the method can be used as an effective method for quality control of candehydrothiazide tablets.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid-phase detection. More specifically, it relates to a method for simultaneously detecting 10 impurities in candesartan cilexetil and hydrochlorothiazide tablets. Background Art

[0002] Candesartan cilexetil and hydrochlorothiazide tablets contain candesartan cilexetil and hydrochlorothiazide. Candesartan cilexetil belongs to the biphenyltetrazole class of highly selective angiotensin II receptor (AT1) antagonists (ARBs), and is a prodrug of candesartan. It can be rapidly hydrolyzed into the active metabolite candesartan in vivo, and exerts an antihypertensive effect by binding to the AT1 receptor of vascular smooth muscle and antagonizing the vasoconstrictive effect of AT1, reducing peripheral vascular resistance. Hydrochlorothiazide belongs to the thiazide diuretics. In addition to its diuretic effect, it also plays an important role in the treatment of hypertension. Its antihypertensive mechanism is not only to reduce blood volume, but also to reduce peripheral vascular resistance, and it is a commonly used component in antihypertensive compound preparations. The combination of ARBs and thiazide diuretics is one of the recommended combination antihypertensive regimens in hypertension guidelines of various countries. Relevant studies have also shown that the combination of candesartan cilexetil and hydrochlorothiazide has good efficacy for elderly patients with isolated systolic hypertension.

[0003] Candesartan cilexetil and hydrochlorothiazide tablets are included in multiple pharmacopoeias and standards, including USP2024, JP18, etc. By comparing these different quality standards, the relevant impurity information of candesartan cilexetil and hydrochlorothiazide tablets has been summarized. Among them, impurities I - III are the main impurities of hydrochlorothiazide, and impurities IV - X are the relevant impurities of candesartan cilexetil, as shown in the following table:

[0004]

[0005]

[0006] The current editions of JP18 and USP-NF both include the method for determining related substances in candesartan cilexetil and hydrochlorothiazide tablets (HPLC method). JP18 uses two different chromatographic condition systems for separate determination, and a total of 8 specified impurities are detected. The current edition of USP-NF (USP 2024) uses a mixed solution of acetonitrile, trifluoroacetic acid, and water with different volume ratios as mobile phases A and B, and detects for 70 minutes. The final detection method can separate candesartan cilexetil and hydrochlorothiazide from 7 specified impurities (the seven impurities detected in the USP correspond to impurities I, II, IV, V, VI, VIII, and X described in the present invention). Although its detection method can simultaneously detect more main impurities in candesartan cilexetil and hydrochlorothiazide tablets, the detection time is too long, the detected impurities are limited, not all the main impurities can be detected, and the mobile phase contains trifluoroacetic acid, which will remain on the surface of the reverse stationary phase, resulting in a decrease in the column life of the chromatographic column.

[0007] Due to the many differences in the high performance liquid chromatography (HPLC) method for detecting the two main components, candesartan cilexetil and hydrochlorothiazide, and the main impurities in candesartan cilexetil tablets, there are differences in the pretreatment steps, the selection of the chromatographic column, the composition of the mobile phase, the system suitability, and the selection of the detection wavelength, etc. when creating the detection method. This complexity not only makes the detection process cumbersome, but also prolongs the detection time. Therefore, there is an urgent need for a more efficient and accurate detection method and system to improve the detection efficiency and resolution. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the defects and deficiencies of the prior art and provide a method for simultaneously detecting 10 impurities in candesartan cilexetil tablets.

[0009] The object of the present invention is to provide the application of the said method in the quality control of candesartan cilexetil tablets.

[0010] The above object of the present invention is achieved by the following technical solutions:

[0011] The present invention provides a method for simultaneously detecting 10 impurities in candesartan cilexetil tablets, and uses liquid chromatography to detect the candesartan cilexetil tablet solution;

[0012] The chromatographic conditions of the said liquid chromatography include: an aqueous formic acid solution with a volume concentration of 0.3 - 0.7% of mobile phase A, and acetonitrile of mobile phase B, and gradient elution is carried out;

[0013] The said gradient elution conditions are: 0 - 10 min, the volume fraction of mobile phase A is 90%, and the volume fraction of mobile phase B is 10%; 10 - 25 min, the volume fraction of mobile phase A changes from 90% to 25%, and the volume fraction of mobile phase B changes from 10% to 75%; 25 - 35 min, the volume fraction of mobile phase A is 25%, and the volume fraction of mobile phase B is 75%; 35 - 36 min, the volume fraction of mobile phase A changes from 25% to 10%, and the volume fraction of mobile phase B changes from 75% to 90%; 36 - 46 min, the volume fraction of mobile phase A is 10%, and the volume fraction of mobile phase B is 90%; 46 - 48 min, the volume fraction of mobile phase A changes from 10% to 90%, and the volume fraction of mobile phase B changes from 90% to 10%; 48 - 60 min, the volume fraction of mobile phase A is 90%, and the volume fraction of mobile phase B is 10%;

[0014] The said impurities include Impurity I - X, and the specific structures are as follows:

[0015]

[0016] The liquid chromatography detection method provided by the present invention can simultaneously detect 10 impurities in candesartan cilexetil tablets, and separate the impurities from candesartan cilexetil and hydrochlorothiazide in candesartan cilexetil tablets. Moreover, the contents of 10 impurities, candesartan cilexetil and hydrochlorothiazide can be calculated through the peak areas of the chromatograms by the external standard method and the self-control method.

[0017] The present invention uses a system with an aqueous solution of 0.3-0.7% formic acid and acetonitrile as the mobile phase, and performs gradient elution under the above-mentioned elution conditions, and can obtain chromatograms of characteristic peaks of impurities I-X. The characteristic peaks of impurities I-X have high peak purity, good peak resolution, short separation time, and do not contain other miscellaneous peaks. If other mobile phases or other gradient elution conditions are adopted, the relevant peaks of impurities I-X will be interfered, and the peak purity and peak resolution will become lower. That is, adopting the mobile phase and gradient elution conditions of the present invention can detect the contents of one to ten of impurities I-X. If other mobile phases or other gradient elution conditions are adopted, the number of peaks of the above-mentioned impurities I-X will decrease, and thus the simultaneous detection of the above 10 components cannot be completed.

[0018] Preferably, the chromatographic conditions of the liquid chromatography further include: the flow rate is 0.8-1.2 mL / min.

[0019] Preferably, the chromatographic conditions of the liquid chromatography further include: the column temperature is 20-40 °C.

[0020] Preferably, the detector includes at least one of an ultraviolet-visible light detector, a diode array detector or a mass spectrometry detector.

[0021] Preferably, the detection wavelength of the ultraviolet-visible light detector is 260-270 nm, and the detection wavelength of the diode array detector is 200-400 nm.

[0022] Preferably, the detection mode of the mass spectrometry detector is the multiple reaction ion monitoring mode.

[0023] Preferably, the chromatographic conditions of the liquid chromatography further include: a chromatographic column with octadecylsilyl-bonded silica gel as the stationary phase.

[0024] Preferably, the chromatographic column with octadecylsilyl-bonded silica gel as the stationary phase is selected from one of Waters SymmetryC18, ZORBAX Eclipse XDB-C18, phenomenex Luna C18, Capcell PAK ACR C18 column.

[0025] Preferably, the chromatographic column with octadecylsilyl-bonded silica gel as the stationary phase has a specification of 250×4.6 mm, 5 μm.

[0026] Preferably, the chromatographic conditions of the liquid chromatography further include: a chromatographic column with octadecylsilyl-bonded silica gel as the stationary phase and a chromatographic column for reducing the background interference of the mobile phase.

[0027] Preferably, the chromatographic column for reducing the background interference of the mobile phase includes, but is not limited to, the Welch Ghost-Buster ghost peak trapping column or the BIR background interference elimination column. More preferably, the specification of the chromatographic column for reducing the background interference of the mobile phase is 50×4.6 mm.

[0028] Preferably, the preparation method of the candesartan cilexetil tablets solution is: weighing candesartan cilexetil tablets and adding acetonitrile aqueous solution for dissolution. Using the method of the present invention can effectively simplify the sample pretreatment process, shorten the detection time, and has good specificity and precision.

[0029] Furthermore, the dissolution method is ultrasonic dissolution.

[0030] Preferably, the volume fraction of acetonitrile in the acetonitrile aqueous solution is 55-65%.

[0031] Furthermore, the present invention also protects the application of the method in the quality control of candesartan cilexetil tablets.

[0032] The present invention has the following beneficial effects:

[0033] The present invention provides a method for simultaneously detecting 10 impurities in candesartan cilexetil tablets. Using formic acid aqueous solution and acetonitrile as mobile phases A and B respectively, under a specific gradient elution process, 10 impurities in candesartan cilexetil tablets can be simultaneously detected in one chromatographic detection method; by comparing the peak emergence times of candesartan cilexetil, hydrochlorothiazide raw materials, excipients and the test solution chromatograms, and analyzing the sources of each impurity peak, it is found that candesartan can be used to locate and distinguish hydrochlorothiazide impurities from candesartan cilexetil impurities, and the related substance contents of hydrochlorothiazide and candesartan cilexetil are determined by the external standard method and the self-control method respectively. The detection method of the present invention is convenient to operate, has a short running time, strong specificity and high sensitivity, provides an effective detection method for monitoring the quality of candesartan cilexetil tablets, and further ensures the safety of the product. Description of the Drawings

[0034] Figure 1 It is the structure diagrams of 10 impurities.

[0035] Figure 2 It is the chromatogram of the system suitability solution.

[0036] Figure 3 It is the chromatogram of the test solution.

[0037] Figure 4 It is the chromatogram of the reference solution.

[0038] Figure 5 It is the chromatogram of the control solution.

[0039] Figure 6 It is the chromatogram of the sensitivity solution.

[0040] Figure 7 It is a schematic diagram showing the influence of the concentration of formic acid aqueous solution and column temperature on the resolution (R1) between the hydrochlorothiazide peak and the adjacent impurity peak.

[0041] Figure 8 It is a schematic diagram showing the influence of the concentration of formic acid aqueous solution and column temperature on the resolution (R2) between the candesartan cilexetil peak and the adjacent impurity peak.

[0042] Figure 9 It is a schematic diagram showing the optimization of the concentration of formic acid aqueous solution and column temperature at a flow rate of 1 mL / min.

[0043] Figure 10 It is a schematic diagram showing the influence of column temperature and flow rate on the resolution (R1) between the hydrochlorothiazide peak and the adjacent impurity peak.

[0044] Figure 11 It is a schematic diagram showing the influence of column temperature and flow rate on the resolution (R2) between the candesartan cilexetil peak and the adjacent impurity peak.

[0045] Figure 12 It is a schematic diagram showing the optimization of column temperature and flow rate when the concentration of formic acid aqueous solution is 0.5%.

[0046] Figure 13 It is a schematic diagram showing the influence of the concentration of formic acid aqueous solution and flow rate on the resolution (R1) between the hydrochlorothiazide peak and the adjacent impurity peak.

[0047] Figure 14 It is a schematic diagram showing the influence of the concentration of formic acid aqueous solution and flow rate on the resolution (R2) between the candesartan cilexetil peak and the adjacent impurity peak.

[0048] Figure 15 It is a schematic diagram showing the optimization of the concentration of formic acid aqueous solution and flow rate at a column temperature of 30°C.

[0049] Figure 16 It is the chromatogram of the system suitability solution under the chromatographic conditions of Comparative Example 1.

[0050] Figure 17 It is the chromatogram of the system suitability solution under the chromatographic conditions of Comparative Example 2.

[0051] Figure 18 It is the chromatogram of the system suitability solution under the chromatographic conditions of Comparative Example 3. Specific implementation manners

[0052] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific embodiments. However, the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the technical field.

[0053] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0054] Example 1

[0055] 1. Sample preparation:

[0056] (1) The preparation method of 0.5% formic acid aqueous solution is as follows: Take 5 mL of formic acid, dissolve it in 600 - 800 mL of water, and dilute it with water to 1000 mL.

[0057] (2) The preparation method of the test solution is as follows: Take an appropriate amount of the fine powder of candesartan cilexetil tablets, add an appropriate amount of 60% acetonitrile aqueous solution, sonicate to dissolve it, cool it, dilute it with 60% acetonitrile aqueous solution. Finally, each 1 mL of the test solution contains approximately 0.4 mg of candesartan cilexetil and 0.3 mg of hydrochlorothiazide. Shake well, filter, and take the filtrate.

[0058] (3) The preparation method of the reference solution is as follows: Take appropriate amounts of the reference substances of 4 - amino - 6 - chloro - 1,3 - benzenedisulfonamide (Impurity I) and chlorothiazide (6 - chloro - 2H - 1,2,4 - benzothiadiazine - 7 - sulfonamide - 1,1 - dioxide, Impurity II), accurately weigh them, dissolve them with 60% acetonitrile aqueous solution and quantitatively dilute. Finally, each 1 mL of the reference solution contains approximately 3.2 μg of Impurity I and 1.6 μg of Impurity II.

[0059] (4) The preparation method of the control solution is as follows: Accurately measure an appropriate amount of the test solution, quantitatively dilute it with 60% acetonitrile aqueous solution. Finally, each 1 mL of the control solution contains approximately 2 μg of candesartan cilexetil and 1.6 μg of hydrochlorothiazide.

[0060] (5) The preparation method of the hydrochlorothiazide system suitability stock solution is as follows: Take appropriate amounts of Impurity I, Impurity II, and Impurity III respectively, dissolve and dilute them with 60% acetonitrile aqueous solution. Finally, each 1 mL of the hydrochlorothiazide system suitability stock solution contains approximately 80 μg of Impurity I, Impurity II, and Impurity III.

[0061] (6) The preparation method of the candesartan cilexetil system suitability stock solution is as follows: Take appropriate amounts of Impurities IV - X and place them in a 50 - mL volumetric flask, dissolve and dilute them with 60% acetonitrile aqueous solution to prepare a solution containing 80 μg of Impurities IV - X per 1 mL.

[0062] (7) The preparation method of the system suitability solution is as follows: Take about 16 mg of hydrochlorothiazide reference substance and about 20 mg of candesartan cilexetil reference substance, place them in a 50 mL volumetric flask, dissolve with an appropriate amount of 60% acetonitrile aqueous solution, add 2 mL each of the hydrochlorothiazide system suitability stock solution and the candesartan cilexetil system suitability stock solution, and dilute to 50 mL with 60% acetonitrile aqueous solution, then shake well.

[0063] (8) The preparation method of the sensitivity solution is as follows: Accurately measure an appropriate amount of the control solution, quantitatively dilute it with 60% acetonitrile aqueous solution. Finally, each 1 mL of the sensitivity solution contains about 0.2 μg of candesartan cilexetil and 0.16 μg of hydrochlorothiazide.

[0064] 2. Detection conditions:

[0065] Chromatographic conditions: Use 0.5% formic acid aqueous solution as mobile phase A and acetonitrile as mobile phase B for gradient elution. Chromatographic column: Waters Symmetry C18 (250×4.6 mm, 5 μm). Connect a Welch Ghost-Buster ghost peak trapping column (50×4.6 mm) before the injector. The detector is a diode array detector and a mass spectrometry detector. Among them, the detection wavelength of the diode array detector is 265 nm, the flow rate is 1 mL / min, the column temperature is 30 °C, and the injection volume is 10 μL.

[0066] Gradient elution conditions: 0 - 10 min, the volume fraction of mobile phase A is 90%, and the volume fraction of mobile phase B is 10%; 10 - 25 min, the volume fraction of mobile phase A changes from 90% to 25%, and the volume fraction of mobile phase B changes from 10% to 75%, and keep it until 35 minutes; 35 - 36 min, the volume fraction of mobile phase A changes from 25% to 10%, and the volume fraction of mobile phase B changes from 75% to 90%, and keep it until 46 minutes; 46 - 48 min, the volume fraction of mobile phase A changes from 10% to 90%, and the volume fraction of mobile phase B changes from 90% to 10%, and keep it until 60 minutes.

[0067] Mass spectrometry conditions: Use HESI ion source, spray voltage 4.0 kV, ion transfer tube temperature 380 °C, dryer temperature 450 °C, sheath gas pressure 48 arb, auxiliary gas pressure 30 arb, and adopt Full MS / dd-MS 2 mode scanning, the full mass spectrometry scanning range is m / z 100 - 1000, and the collision energy is 15 - 30 eV.

[0068] 3. Experimental method:

[0069] Separate aliquots of the system suitability solution, test solution, control solution, reference solution, and sensitivity solution were injected into the liquid chromatograph, and gradient elution was performed under the above chromatographic detection conditions. The chromatogram was recorded to confirm the chromatographic peaks corresponding to impurities I to X. And the mass-to-charge ratios of the molecular ions and fragment ions in the chromatogram were identified by mass spectrometry. The monitored parent ions in the monitored ion pairs are shown in Table 1 below, and the fragment ions include but are not limited to those described in the table below.

[0070] Table 1 Mass Spectrometry Parent Ions and Fragment Ions of 10 Impurities

[0071]

[0072] 4. Experimental Results:

[0073] Figure 2 The chromatogram of the system suitability solution is shown. It can be seen from the figure that under the detection conditions described in the present invention, hydrochlorothiazide, candesartan cilexetil, and impurities I to X can be completely separated, and the resolution between adjacent peaks is greater than 2.0, meeting the acceptable standard for liquid phase separation.

[0074] Figure 3 The chromatogram of the test solution is shown. It can be seen from the figure that the contents of impurities I, II, III, VI, VII, and X are relatively high. The contents of impurities I and II were calculated by the external standard method, and the formula is as follows:

[0075]

[0076] In the formula, C R is the concentration of the reference solution, A X is the peak area of the impurity in the test solution; A R is the peak area of the main peak in the reference solution; C X is the concentration of the test solution.

[0077] The content of impurity I is 0.3% and the content of impurity II is 0.1%;

[0078] The contents of other impurities were calculated by the self-control method, and the formula is as follows:

[0079]

[0080] In the formula, C R ’ is the concentration of the control solution, A X is the peak area of the impurity in the test solution; A R ’ is the peak area of the main peak in the control solution; C X is the concentration of the test solution.

[0081] The contents of other impurities were calculated by the self - comparison method. The content of impurity Ⅲ was 0.1%, the content of impurity Ⅵ was 0.2%, the content of impurity Ⅶ was 0.1%, the content of impurity Ⅹ was 0.1%, the content of other maximum impurities was 0.1%, and the total impurity content was 1.0%. Impurity peaks with peak areas smaller than those of the corresponding chromatographic peaks in the sensitivity solution were ignored.

[0082] Figure 4 It was the chromatogram of the reference solution. The contents of impurity Ⅰ and impurity Ⅱ were calculated by the external standard method based on the peak area.

[0083] Figure 5 It was the chromatogram of the control solution. The contents of impurities Ⅲ - Ⅹ were calculated by the self - comparison method based on the peak area.

[0084] Figure 6 It was the chromatogram of the sensitivity solution. It could be seen from the figure that the signal - to - noise ratios of the hydrochlorothiazide peak and the candesartan cilexetil peak were 145 and 95 respectively, both greater than 10, meeting the quantitative requirements.

[0085] Example 2

[0086] Detection conditions:

[0087] The difference from Example 1 was that the concentration of formic acid aqueous solution (0.3 - 0.7%) and the column temperature (20 - 40°C) were changed, and the effects of different concentrations of formic acid aqueous solution and column temperature on the chromatogram were investigated. The remaining detection conditions were exactly the same as those in Example 1.

[0088] The system suitability solution described in Example 1 was taken and subjected to liquid chromatography detection under the above - mentioned detection conditions. The results showed that within the range of the concentration of formic acid aqueous solution (0.3 - 0.7%) and the column temperature (20 - 40°C), the separation effects between the hydrochlorothiazide peak and adjacent impurity peaks and between the candesartan cilexetil peak and adjacent impurity peaks all met the requirements. When the concentration of formic acid aqueous solution was 0.5% and the column temperature was 30°C, the separation effect was the best (see Figures 7 - 8 ). Using the Derringer equation, a global optimal model was established with the comprehensive indexes of the resolution (R1) between the hydrochlorothiazide peak and adjacent impurity peaks, the resolution (R2) between the candesartan cilexetil peak and adjacent impurity peaks, and the retention time of the last chromatographic peak. The response surface of the global optimal function showed (see Figure 9 ) that the effect was the best when the concentration of formic acid aqueous solution was 0.5%, the column temperature was 30°C, and the flow rate was 1 mL / min.

[0089] Example 3

[0090] Detection conditions:

[0091] It is different from Example 1 in that the column temperature (20 - 40 °C) and the flow rate (0.8 - 1.2 mL / min) are changed to investigate the effects of different column temperatures and flow rates on the chromatogram, and the remaining detection conditions are exactly the same as those in Example 1.

[0092] Take the system suitability solution described in Example 1 and perform liquid phase detection according to the above detection conditions. The results show that within the range of column temperature (20 - 40 °C) and flow rate (0.8 - 1.2 mL / min), the separation effects of the hydrochlorothiazide peak and the adjacent impurity peaks and the candesartan cilexetil peak and the adjacent impurity peaks all meet the requirements. When the column temperature is 30 °C and the flow rate is 1.0 mL / min, the separation effect is the best (see Figures 10 - 11 ). Using the Derringer equation, a global optimal model is established with the comprehensive indexes of the resolution (R1) of the hydrochlorothiazide peak and the adjacent impurity peaks, the resolution (R2) of the candesartan cilexetil peak and the adjacent impurity peaks, and the retention time of the last chromatographic peak. The response surface of the global optimal function shows (see Figure 12 ) that the effect is the best when the concentration of the formic acid aqueous solution is 0.5%, the column temperature is 30 °C, and the flow rate is 1 mL / min.

[0093] Example 4

[0094] Detection conditions:

[0095] It is different from Example 1 in that the concentration of the formic acid aqueous solution (0.3 - 0.7%) and the flow rate (0.8 - 1.2 mL / min) are changed to investigate the effects of the concentration of the formic acid aqueous solution and the flow rate on the chromatogram, and the remaining detection conditions are exactly the same as those in Example 1.

[0096] Take the system suitability solution described in Example 1 and perform liquid phase detection according to the above detection conditions. The results show that within the range of the concentration of the formic acid aqueous solution (0.3 - 0.7%) and the flow rate (0.8 - 1.2 mL / min), the separation effects of the hydrochlorothiazide peak and the adjacent impurity peaks and the candesartan cilexetil peak and the adjacent impurity peaks all meet the requirements. When the concentration of the formic acid aqueous solution is 0.5% and the flow rate is 1.0 mL / min, the separation effect is the best (see Figures 13 - 14 ). Using the Derringer equation, a global optimal model is established with the comprehensive indexes of the resolution (R1) of the hydrochlorothiazide peak and the adjacent impurity peaks, the resolution (R2) of the candesartan cilexetil peak and the adjacent impurity peaks, and the retention time of the last chromatographic peak. The response surface of the global optimal function shows (see Figure 15 ) that the effect is the best when the concentration of the formic acid aqueous solution is 0.5%, the column temperature is 30 °C, and the flow rate is 1 mL / min.

[0097] Comparative Example 1

[0098] Detection conditions:

[0099] The difference from Example 1 is that mobile phase A is an aqueous solution of 0.5% acetic acid, and the remaining detection conditions are exactly the same as those in Example 1.

[0100] Take the system suitability solution described in Example 1 and perform liquid phase detection according to the above detection conditions. The results are as Figure 16 shown. It can be seen from the figure that when mobile phase A is changed from an aqueous formic acid solution to an aqueous acetic acid solution, impurity I and impurity II cannot be separated.

[0101] Comparative Example 2

[0102] Detection conditions:

[0103] The difference from Example 1 is that mobile phase B is a tetrahydrofuran-methanol solution (volume ratio of methanol to tetrahydrofuran is 10:1), and the remaining detection conditions are exactly the same as those in Example 1.

[0104] Take the system suitability solution described in Example 1 and perform liquid phase detection according to the above detection conditions. The results are as Figure 17 shown. It can be seen from the figure that when mobile phase B is changed from acetonitrile to a tetrahydrofuran-methanol solution, candesartan cilexetil and impurity VIII cannot be separated.

[0105] Comparative Example 3

[0106] Detection conditions:

[0107] The difference from Example 1 is that the gradient elution conditions are different, and the remaining detection conditions are exactly the same as those in Example 1.

[0108] The gradient elution conditions of this comparative example are as follows: 0 - 2 min, the volume fraction of mobile phase A is 90%, and the volume fraction of mobile phase B is 10%; 2 - 40 min, the volume fraction of mobile phase A changes from 90% to 10%, and the volume fraction of mobile phase B changes from 10% to 90%; 40 - 50 min, the volume fraction of mobile phase A is 10%, and the volume fraction of mobile phase B is 90%; 50 - 51 min, the volume fraction of mobile phase A changes from 10% to 90%, and the volume fraction of mobile phase B changes from 90% to 10%; 51 - 60 min, the volume fraction of mobile phase A is 90%, and the volume fraction of mobile phase B is 10%.

[0109] Take the system suitability solution described in Example 1 and perform liquid phase detection according to the above detection conditions. The results are as Figure 18 shown. It can be seen from the figure that by changing the elution gradient, impurity I and impurity II cannot be separated, and impurity IV and impurity V cannot be separated.

[0110] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for simultaneously detecting 10 impurities in candecyrrhizal tablets, characterized in that: The candeothiocarb tablet solution was tested by liquid chromatography, and the chromatographic conditions included: Mobile phase A: 0.3-0.7% formic acid aqueous solution, mobile phase B: acetonitrile, gradient elution; The gradient elution conditions are as follows: from 0 to 10 min, the volume fraction of mobile phase A is 90%, and the volume fraction of mobile phase B is 10%; from 10 to 25 min, the volume fraction of mobile phase A changes from 90% to 25%, and the volume fraction of mobile phase B changes from 10% to 75%; from 25 to 35 min, the volume fraction of mobile phase A is 25%, and the volume fraction of mobile phase B is 75%; from 35 to 36 min, the volume fraction of mobile phase A changes from 25% to 10%, and the volume fraction of mobile phase B changes from 75% to 90%; from 36 to 46 min, the volume fraction of mobile phase A is 10%, and the volume fraction of mobile phase B is 90%; from 46 to 48 min, the volume fraction of mobile phase A changes from 10% to 90%, and the volume fraction of mobile phase B changes from 90% to 10%; from 48 to 60 min, the volume fraction of mobile phase A is 90%, and the volume fraction of mobile phase B is 10%; The impurities include impurities I to X, and the specific structure is as follows:

2. The method according to claim 1, characterized in that: The chromatographic conditions also include: a flow rate of 0.8 to 1.2 mL / min.

3. The method according to claim 1, characterized in that: The chromatographic conditions also include: a column temperature of 20 to 40°C.

4. The method according to claim 1, characterized in that: The detector of the liquid chromatography comprises at least one of an ultraviolet visible light detector, a diode array detector or a mass spectrometer detector.

5. The method according to claim 4, characterized in that: The detection wavelength of the ultraviolet visible light detector is 260-270 nm, and the detection wavelength of the diode array detector is 200-400 nm.

6. The method according to claim 1, characterized in that: The chromatographic conditions also include: a chromatographic column using octadecylsilane bonded silica gel as a stationary phase.

7. The method according to claim 6, characterized in that: The chromatographic column with octadecylsilane bonded silica gel as the stationary phase is selected from one of Waters Symmetry C18, ZORBAX Eclipse XDB-C18, phenomenex Luna C18, and Capcell PAKACR C18 columns.

8. The method according to claim 1, characterized in that: The chromatographic conditions also include: a chromatographic column using octadecylsilane bonded silica gel as a stationary phase and a chromatographic column that reduces background interference of a mobile phase.

9. The method according to claim 1, characterized in that: The preparation method of the candeserthiazole tablet solution is as follows: weigh the candeserthiazole tablets, and add acetonitrile aqueous solution to dissolve them.

10. Use of the method according to any one of claims 1 to 9 in quality monitoring of candesertioide tablets.

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