Method for simultaneously detecting three nitrosamine impurities in desloratadine oral solution
Through ultra-high performance liquid chromatography-triple quadratic rod mass spectrometry, combined with the optimization of diluent and mobile phase systems, the accuracy and reliability of nitrosamine impurities detection in the oral solution of deloratadine in the prior art was solved, and efficient and accurate detection of three nitrosamine impurities was achieved.
Patent Information
- Application Number
- CN202510620444.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-14
- Publication Date
- 2025-06-10
AI Technical Summary
The prior art is difficult to accurately detect three nitrosamine impurities in deloratading oral solution, resulting in low recovery rates and poor detection accuracy and reliability.
Ultra-high performance liquid chromatography-triple quadratidine mass spectrometry was used to dilute the oral solution of deloratadine at a concentration of 2-3 μg/mL, use methanol aqueous solution as the diluent, and 0.1% formic acid water-acetonitrile as the mobile phase system was selected to perform gradient elution to achieve efficient detection of three nitrosamine impurities.
The rapid and accurate detection of three nitrosamine impurities in the oral solution of deloratadine was achieved, which improved the sensitivity and accuracy of the detection, reduced the analysis cost, and verified the accuracy and linearity of the method.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of drug detection, and particularly relates to a method for simultaneously detecting three nitrosamine impurities in loratadine oral solution. Background Art
[0003] Nitrosamine impurities may be introduced into the preparation through the raw material drug synthesis process (such as residual nitrosating agent), interaction of excipients, or improper storage conditions. As a second-generation antihistamine drug, loratadine oral solution has an increased risk of generating nitrosamine impurities due to its degradable components (such as syrup matrix) and complex production process. There may be three nitrosamine impurities: N-nitroso-loratadine, N-nitroso-desloratadine, and N-nitroso-11-fluoroloratadine.
[0004] Since nitrosamine substances have strong carcinogenicity, it is necessary to strictly control the content of nitrosamine impurities in loratadine oral solution.
[0005] In the current technology, there is only a detection method for N-nitroso-loratadine impurity in loratadine raw material drug. This method only detects N-nitroso-loratadine. Due to the more complex matrix of loratadine oral solution, which contains easily degradable components such as syrup matrix, it is found through experiments that the sample matrix has a greater interference on the detection. When using the existing detection method for detection, the recovery rate is low, and the accuracy and reliability of the detection are poor, making it difficult to directly detect. Summary of the Invention
[0006] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a method for simultaneously detecting three nitrosamine impurities in loratadine oral solution, which can quickly and accurately detect the three nitrosamine impurities in loratadine oral solution.
[0007] To achieve the above purpose, the present invention is realized through the following technical solutions: A method for simultaneously detecting three nitrosamine impurities in loratadine oral solution, comprising the following steps: Dissolve loratadine oral solution in a diluent to obtain a test solution, so that the concentration of loratadine in the test solution is 2 - 3 μg / mL. The diluent is an aqueous methanol solution, and in the aqueous methanol solution, the volume ratio of methanol to water is 1:0.8 - 1.2; Detect the test solution by ultra-high performance liquid chromatography-triple quadrupole mass spectrometry; The mobile phase A of the liquid chromatography is an aqueous formic acid solution with a volume percentage of 0.09 - 0.11%, and the mobile phase B is acetonitrile; The three nitrosamine impurities are N-nitroso-desloratadine, N-nitroso-iso-desloratadine, and N-nitroso-11-fluoro-desloratadine.
[0008]
[0009] Through experiments, it was found that the high-concentration desloratadine oral solution had severe matrix interference, resulting in a low recovery rate. After exploration, the concentration of desloratadine was set at 2.5 μg / mL, which could not only meet the sensitivity requirements but also the recovery rate met the requirements and satisfied the detection requirements.
[0010] When methanol aqueous solution was used as the diluent for the detection of the three nitrosamine impurities in desloratadine oral solution, problems such as solution turbidity, peak overlap, and weak signal response did not occur. It solved the solubility problem, reduced the matrix effect, and optimized the chromatographic conditions, thus achieving the efficient detection of the three nitrosamine impurities. Methanol has a strong dissolution ability and can be miscible with water in any proportion to form a methanol aqueous solution. When methanol and water are mixed at a volume ratio of 1:0.8 - 1.2, this mixed solvent system can effectively dissolve various components and nitrosamine impurities in desloratadine oral solution, making the test solution uniform and stable, and ensuring the accuracy and reliability of the detection results.
[0011] The production process of desloratadine oral solution is complex and contains easily degradable components, while the syrup matrix usually contains various sugars and macromolecular substances, which may be affected by various factors during the dissolution process. If the diluent is selected improperly, resulting in incomplete dissolution of some components, it will cause the detection result to be low and unable to truly reflect the content of nitrosamine impurities in the sample.
[0012] The reasons for using formic acid water as mobile phase A and acetonitrile as mobile phase B are as follows: The 0.1% formic acid water - acetonitrile solution selected in the present invention as the mobile phase system solved the problems of poor resolution, weak mass spectrometry signal, poor peak shape, and high system pressure when used for the detection of the three nitrosamine impurities in desloratadine oral solution, and could meet the detection requirements. Specifically as follows: ① Improve the separation effect. The structures of the three nitrosamine impurities in desloratadine oral solution are different, and a higher separation degree is required. Gradient elution with the mobile phase composed of formic acid water and acetonitrile can effectively separate the impurities at different times according to the different interactions between the impurities and the stationary phase, facilitating effective detection; ②Improve the peak shape. Formic acid can adjust the pH value of the mobile phase, inhibit the dissociation of certain components in the sample, reduce tailing, make the chromatographic peaks sharper and more symmetrical, and improve the sensitivity and accuracy of detection. For substances such as nitrosamine impurities whose existence forms may change under different pH conditions, formic acid-water can optimize their retention and peak shape in the chromatographic column. In the experimental results of the examples, when 0.1% formic acid-water was used as mobile phase A, the peak shapes of each impurity were good, which was conducive to quantitative analysis.
[0013] ③Suitable for mass spectrometry detection. Acetonitrile has the characteristics of low ultraviolet absorption and good volatility, and can effectively reduce background interference in mass spectrometry detection, improving the sensitivity and signal-to-noise ratio of detection. When detected in the positive ion mode by an electrospray ionization source (ESI), acetonitrile as mobile phase B can be fully mixed with the sample, promoting sample ionization, and is more suitable for the detection requirements of triple quadrupole mass spectrometry (UPLC-MS / MS), thus achieving high-sensitivity detection of nitrosamine impurities.
[0014] ④Improve the ionization efficiency in the positive ion mode.
[0015] When the formic acid concentration in the mobile phase is too high, it affects the chromatographic separation effect; formic acid at too high a concentration has certain corrosiveness and will damage the chromatographic column; it interferes with mass spectrometry detection, affects the ionization efficiency, causes unstable mass spectrometry signals, and reduces the detection sensitivity.
[0016] In some embodiments, mobile phase A is an aqueous solution of formic acid with a volume percentage of 0.1%.
[0017] In some embodiments, in the methanol aqueous solution, the volume ratio of methanol to water is 1:1.
[0018] In some embodiments, in the chromatographic column used in ultra-high performance liquid chromatography, octadecylsilyl-bonded silica gel is used as the filler.
[0019] In some embodiments, the concentration of desloratadine in the test solution is 2.6 - 2.7 μg / mL.
[0020] In some embodiments, the gradient elution program of mobile phase A and mobile phase B is as follows: 0 - 8 min, mobile phase A decreases from 90% to 20%, and mobile phase B increases from 10% to 80%; 8 - 8.1 min, mobile phase A increases from 20% to 90%, and mobile phase B decreases from 80% to 10%; 8.1 - 10 min, mobile phase A is 90%, and mobile phase B is 10%.
[0021] In some embodiments, in liquid chromatography, the flow rate of the mobile phase is 0.35 - 0.45 mL / min; the column temperature is 25 - 35 °C.
[0022] Preferably, in high performance liquid chromatography, the flow rate of the mobile phase is 0.4 mL / min; the column temperature is 30 °C.
[0023] In some embodiments, the chromatographic column is Hypersil GOLD, 100 mm×2.1 mm, 1.9 μm.
[0024] In some embodiments, the mass spectrometry conditions are as follows: the ion source is an electrospray ionization source, the scanning mode is the positive ion mode, and the detection mode is multiple reaction monitoring (MRM).
[0025] Preferably, the triple quadrupole mass spectrometry detection parameters are as follows: the IS voltage is 5500 V; the curtain gas (CUR) is 35 psi; the nebulizer gas (GAS1) is 50 psi; the auxiliary gas (GAS2) is 50 psi; the ion source temperature is 550 °C; the collision gas is 8; For N-nitroso-desloratadine, Q1 is 340.2 Da, Q3 is 281.2 Da, the declustering potential (DP) is 100 V, and the collision energy (CE) is 30 V.
[0026] For N-nitroso-desloratadine-d5, Q1 is 340.2 Da, Q3 is 267.1 Da, the declustering potential (DP) is 80 V, and the collision energy (CE) is 26 V.
[0027] For N-nitroso-11-fluoro-desloratadine, Q1 is 360.2 Da, Q3 is 340.2 Da, the declustering potential (DP) is 105 V, and the collision energy (CE) is 18 V.
[0028] The beneficial effects obtained by one or more of the above embodiments of the present invention are as follows: The present invention can simultaneously analyze and detect three nitrosamine impurities in desloratadine oral solution by using ultra-high performance liquid chromatography-mass spectrometry technology, providing a strong guarantee for effectively controlling the quality of drugs and ensuring the safety of drugs.
[0029] When using the ultra-high performance liquid chromatography tandem mass spectrometry technology of the present invention to detect three nitrosamine impurities in desloratadine oral solution, it has high selectivity, good method specificity, the quantitative limits are all as low as less than 10% of the limit, the detection limits are as low as 3% of the limit, and the detection can be completed in only 10 minutes. The method has high sensitivity, can quickly and accurately detect the contents of the three nitrosamine impurities in the sample, and effectively reduces the analysis cost.
[0030] The present invention also verifies the accuracy of the nitrosamine impurities in the range of 50% to 150% of the limit concentration (0.008%). The recoveries of the three nitrosamine impurities are between 80% and 120%, and the accuracy is good; it also verifies the linearity of the three nitrosamine impurities in the range of the quantitative limit to 200%. For the three nitrosamine impurities in the above range, r>0.990, and the linearity is good. Description of the Drawings
[0031] The accompanying drawings of the specification, which form a part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.
[0032] Figure 1 It is the chromatogram of the N-nitroso-desloratadine blank solution in Example 1 of the present invention; Figure 2 It is the chromatogram of the N-nitroso-desloratadine impurity reference solution in Example 1 of the present invention; Figure 3 It is the chromatogram of N-nitroso-desloratadine in the test solution in Example 1 of the present invention; Figure 4 It is the chromatogram of N-nitroso-desloratadine in the 100% spiked solution in Example 1 of the present invention; Figure 5 It is the chromatogram of the N-nitroso-desloratadine blank solution in Example 1 of the present invention; Figure 6 It is the chromatogram of the N-nitroso-desloratadine impurity reference solution in Example 1 of the present invention; Figure 7 It is the chromatogram of N-nitroso-desloratadine in the test solution in Example 1 of the present invention; Figure 8 It is the chromatogram of N-nitroso-desloratadine in the 100% spiked solution in Example 1 of the present invention; Figure 9 It is the chromatogram of the N-nitroso-11-fluoro-desloratadine blank solution in Example 1 of the present invention; Figure 10 It is the chromatogram of the N-nitroso-11-fluoro-desloratadine impurity reference solution in Example 1 of the present invention; Figure 11 It is the chromatogram of N-nitroso-11-fluoro-desloratadine in the test solution in Example 1 of the present invention; Figure 12 It is the chromatogram of N-nitroso-11-fluoro-desloratadine in the 100% spiked solution in Example 1 of the present invention. Detailed Description of the Invention
[0033] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.
[0034] It should be noted that the content of nitrosamine impurities in the desloratadine oral solution can be calculated by the external standard method, and the calculation formula is as follows: Nitrosamine impurity (%) = ; Where: A U -- Peak area of nitrosamine impurity in the test solution; A S -- Peak area of nitrosamine impurity in the reference solution; C S -- Concentration of nitrosamine impurity in the reference solution, ng / mL; C U -- Concentration of the test solution calculated based on the labeled amount, ng / mL.
[0035] The present invention will be further described below in conjunction with embodiments.
[0036] Example 1: Specificity Solution preparation: Diluent (blank solution): Measure 500 mL of methanol and 500 mL of water, and mix well.
[0037] Nitrosamine impurity reference solution: Weigh an appropriate amount of N-nitroso-desloratadine, N-nitroso-desloratadine isomer, and N-nitroso-11-fluorodesloratadine impurity reference substances, dissolve them in the diluent, and quantitatively dilute to prepare a solution with a concentration of 0.2 ng / mL.
[0038] Test solution: Take an appropriate amount of desloratadine oral solution, dissolve it in the diluent, and quantitatively dilute to prepare a solution containing about 2.5 μg of desloratadine per 1 mL.
[0039] System suitability solution: Take an appropriate amount of desloratadine oral solution, add an appropriate amount of three nitrosamine impurities, and dilute with the diluent to prepare a mixed solution containing about 2.5 μg of desloratadine and 0.2 ng of each nitrosamine impurity per 1 mL.
[0040] Chromatographic and mass spectrometric conditions: Chromatographic column: Hypersil GOLD, 100 mm × 2.1 mm, 1.9 μm; Mobile phase: Mobile phase A is 0.1% formic acid aqueous solution; Mobile phase B is acetonitrile; Elution mode: Gradient elution program, as shown in Table 1; Table 1
[0041] Flow rate 0.4 mL / min; Column temperature is 30 °C; Injection volume is 10 μL; Injection temperature is 4 °C; Ion source: ESI source, positive ion scan; Scanning mode: MRM acquisition mode; IS voltage: 5500 V (+); Curtain gas CUR is 35 psi; nebulizer GAS1 is 50 psi; auxiliary gas GAS2 is 50 psi; ion source temperature is 550 °C; collision gas: 8.
[0042] The mass spectrometry parameters are shown in Table 2: Table 2
[0043] Experimental conclusion: Precisely measure the above solution, inject it into an ultra-high performance liquid chromatography-mass spectrometry instrument, record the chromatogram, and the results are shown in Table 3. The chromatogram of N-nitroso-desloratadine in the blank solution is shown in Figure 1 , the N-nitroso-desloratadine impurity reference solution is shown in Figure 2 , the N-nitroso-desloratadine in the test solution is shown in Figure 3 , the N-nitroso-desloratadine in the 100% spiked test solution is shown in Figure 4 ; the chromatogram of N-nitroso-desloratadine in the blank solution is shown in Figure 5 , the N-nitroso-desloratadine impurity reference solution is shown in Figure 6 , the N-nitroso-desloratadine in the test solution is shown in Figure 7 , the N-nitroso-desloratadine in the 100% spiked test solution is shown in Figure 8 ; the chromatogram of N-nitroso-11-fluorodesloratadine in the blank solution is shown in Figure 9 , the N-nitroso-11-fluorodesloratadine impurity reference solution is shown in Figure 10 , the N-nitroso-11-fluorodesloratadine in the test solution is shown in Figure 11 , the N-nitroso-11-fluorodesloratadine in the 100% spiked test solution is shown in Figure 12 .
[0044] Table 3 Specificity results
[0045] Conclusion: The blank solvent and the test solution do not interfere with the detection of N-nitroso-salbutamol impurities, and the specificity of the present invention is good.
[0046] Example 2: Linearity and range experiment Solution preparation Precisely weigh an appropriate amount of the nitrosamine impurity reference substance, and prepare a series of linear investigation solutions with concentrations ranging from the limit of quantification (see Example 3, about 7% of the limit) to about 200%.
[0047] The chromatographic and mass spectrometric conditions were the same as those in Example 1.
[0048] Conclusion: Precisely measure the above solution, inject it into an ultra-high performance liquid chromatography-mass spectrometry instrument, record the chromatogram, and the results are shown in Table 4. Using the concentration as the abscissa and the peak area as the ordinate, a linear regression equation was made.
[0049] Table 4 Linear experiment results of N-nitroso-salbutamol impurities
[0050] Conclusion: Within the measurement range (equivalent to 7% - 200% of the limit), the linear relationships of each nitrosamine impurity were good, meeting the requirements of methodology.
[0051] Example 3: Quantitation limit and detection limit Solution preparation Take the linear solution in Example 2 and dilute it step by step. The concentration when the signal-to-noise ratio S / N ≈ 3 was used as the detection limit, and the concentration when S / N ≈ 10 was used as the quantitation limit.
[0052] The chromatographic and mass spectrometric conditions were the same as those in Example 1.
[0053] Conclusion: Precisely measure the above solution, inject it into an ultra-high performance liquid chromatography-mass spectrometry instrument, record the chromatogram, and the results are shown in Table 5.
[0054] Table 5 Test results of quantitation limit and detection limit
[0055] Conclusion: The quantitation limits of the three nitrosamine impurities were lower than 10% of the impurity limit of this product, and the detection limits were lower than 3% of the impurity limit of this product. The detection limit and quantitation limit of the present invention both met the requirements for quantitative detection of the three nitrosamine impurities in the test sample, and the method had high sensitivity.
[0056] Example 4: Accuracy experiment Accuracy was investigated through a recovery test, and the research covered the limit concentration range of 50% - 150%.
[0057] Solution preparation Nitrosamine impurity stock solution (100 μg / mL): Take appropriate amounts of N-nitroso-desloratadine, N-nitroso-desloratadine isomer, and N-nitroso-11-fluoro-desloratadine reference substances, accurately weigh them, dissolve and dilute with 30% methanol to make a 100 μg / mL solution.
[0058] Nitrosamine impurity stock solution (0.5 μg / mL): Accurately measure 0.5 mL of the above nitrosamine impurity stock solution (100 μg / mL), place it in a 100 mL volumetric flask, dilute it to the mark with 50% methanol, and shake well.
[0059] Nitrosamine impurity stock solution (10 ng / mL): Accurately measure 1 mL of the above nitrosamine impurity stock solution (0.5 μg / mL), place it in a 50 mL volumetric flask, dilute it to the mark with 50% methanol, and shake well.
[0060] Reference solution: Accurately measure 1 mL of the nitrosamine impurity stock solution (10 ng / mL), place it in a 50 mL volumetric flask, dilute it to the mark with 50% methanol, and shake well.
[0061] Accuracy solution: Accurately measure 0.25 mL of each loratadine oral solution, transfer them to 50 mL volumetric flasks respectively. Accurately measure 0.5 mL, 1.0 mL, and 1.5 mL of the nitrosamine impurity stock solution (10 ng / mL) respectively, dissolve and dilute them to the mark with the diluent, and shake well. Prepare 3 parallel samples for each spiked concentration level.
[0062] The chromatographic and mass spectrometric conditions are the same as those in Example 1.
[0063] Conclusion: Accurately measure the above solutions, inject them into an ultra-high performance liquid chromatography-mass spectrometry instrument, record the chromatogram, and calculate by the external standard method based on the peak area. The accuracy results are shown in Tables 6 to 8.
[0064] Table 6 Accuracy test results of N-nitroso-loratadine
[0065] Table 7 Accuracy test results of N-nitroso-desloratadine
[0066] Table 8 Accuracy test results of N-nitroso-11-fluoro-loratadine
[0067] Conclusion: At the 50%, 100%, and 150% accuracy solutions, the recoveries of the three nitrosamine impurities are all between 80% and 120%, and the RSD values are all less than 10%. The test results show that the accuracy of the present invention is good.
[0068] Example 5: Precision experiment Solution preparation Precisely measure 0.25 mL of desloratadine oral solution, transfer it into a 50 mL volumetric flask, add 1.0 mL of N-nitrosamine impurity stock solution (10 ng / mL), dissolve with diluent and dilute to the mark, shake well, and prepare 6 portions in parallel.
[0069] Control solution: The same as in Example 4.
[0070] Chromatographic and mass spectrometric conditions: The same as in Example 1.
[0071] Conclusion: Precisely measure the above solution, inject it into an ultra-high performance liquid chromatography-mass spectrometry instrument, record the chromatogram, calculate the impurity content, and the precision results are shown in Table 9.
[0072] Table 9 Precision test results
[0073] Conclusion: For the detection results of 6 repeatability sample solutions prepared in parallel, the RSD values of the three nitrosamine impurities are less than 10%, proving that the repeatability of the present invention is good.
[0074] Example 6: Solution stability experiment Solution preparation Take the test solution and reference solution in Example 1, place them at room temperature, and inject for detection at different time points.
[0075] Chromatographic and mass spectrometric conditions: The same as in Example 1.
[0076] Conclusion: Precisely measure the above solution, inject it into an ultra-high performance liquid chromatography-mass spectrometry instrument, record the chromatogram, and the solution stability results are shown in Table 10.
[0077] Table 10 Solution stability test results
[0078] Conclusion: When the test solution and reference solution are placed at room temperature for 16 hours, the peak areas of the three nitrosamine impurities do not change significantly, indicating that the test solution and reference solution are stable within 16 hours.
[0079] Based on the above experimental results, using the detection method of the present invention to detect the three nitrosamine impurities in desloratadine oral solution, the blank solvent and the main component do not interfere with the detection of each nitrosamine impurity. The method has strong specificity, high sensitivity, and accurate quantification. It is of great significance for the quality control of desloratadine oral solution and its preparations to ensure drug safety.
[0080] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A method for simultaneously detecting three nitrosamine impurities in desloratadine oral solution, characterized in that: The steps include: Dissolve the desloratadine oral solution in a diluent to obtain a test solution, so that the concentration of desloratadine in the test solution is 2-3 μg / mL, and the diluent is a methanol-water solution, in which the volume ratio of methanol to water is 1:0.8-1.2; The test solution was detected by ultra-performance liquid chromatography-triple quadrupole mass spectrometry; The mobile phase A of the liquid chromatography was a 0.09-0.11% by volume formic acid aqueous solution, and the mobile phase B was acetonitrile; The three nitrosamine impurities are N-nitroso-desloratadine, N-nitroso-isodesloratadine and N-nitroso-11-fluorodesloratadine.
2. The method for simultaneously detecting three nitrosamine impurities in desloratadine oral solution according to claim 1, characterized in that: The mobile phase A was a 0.1% by volume formic acid solution.
3. The method for simultaneously detecting three nitrosamine impurities in desloratadine oral solution according to claim 1, characterized in that: In the methanol-water solution, the volume ratio of methanol to water is 1:
1.
4. The method for simultaneously detecting three nitrosamine impurities in desloratadine oral solution according to claim 1, characterized in that: The chromatographic column used in ultra-high performance liquid chromatography uses octadecylsilane bonded silica gel as the filler.
5. The method for simultaneously detecting three nitrosamine impurities in desloratadine oral solution according to claim 1, characterized in that: The concentration of desloratadine in the test solution was 2.6-2.7 μg / mL.
6. The method for simultaneously detecting three nitrosamine impurities in desloratadine oral solution according to claim 1, characterized in that: The gradient elution program of mobile phase A and mobile phase B is: 0-8min, mobile phase A decreased from 90% to 20%, and mobile phase B increased from 10% to 80%; 8-8.1min, mobile phase A increased from 20% to 90%, and mobile phase B decreased from 80% to 10%; 8.1~10 min, mobile phase A 90%, mobile phase B 10%.
7. The method for simultaneously detecting three nitrosamine impurities in desloratadine oral solution according to claim 1, characterized in that: In liquid chromatography, the flow rate of the mobile phase is 0.35~0.45 mL / min; the column temperature is 25~35℃.
8. The method for simultaneously detecting three nitrosamine impurities in desloratadine oral solution according to claim 7, characterized in that: In liquid chromatography, the flow rate of the mobile phase was 0.4 mL / min and the column temperature was 30 °C.
9. The method for simultaneously detecting three nitrosamine impurities in desloratadine oral solution according to claim 1, characterized in that: The chromatographic column is Hypersil GOLD, 100 mm×2.1 mm, 1.9 μm.
10. The method for simultaneously detecting three nitrosamine impurities in desloratadine oral solution according to claim 1, characterized in that: The triple quadrupole mass spectrometer detection parameters were: IS voltage 5500 V; curtain gas CUR 35 psi; nebulizer GAS1 50 psi; auxiliary gas GAS2 50 psi; ion source temperature 550°C; collision gas: 8; N-nitroso-desloratadine, Q1 is 340.2 Da, Q3 is 281.2 Da, DP is 100 V, CE is 30 V; N-nitroso-isodesloratadine, Q1 is 340.2 Da, Q3 is 267.1 Da, DP is 80 V, CE is 26 V; N-nitroso-11-fluorodesloratadine, Q1 is 360.2 Da, Q3 is 340.2 Da, DP is 105 V, and CE is 18 V.