A method for determining 1,3-dichloro-2-propanol in iodixanol

Abstract

The application discloses a method for determining 1,3-dichloro-2-propanol in iodixanol, and relates to the technical field of drug analysis. The method adopts gas chromatography-mass spectrometry to detect the content of 1,3-dichloro-2-propanol in iodixanol, and can accurately determine the residual 1,3-dichloro-2-propanol in iodixanol by optimizing gas chromatography conditions and mass spectrometry conditions. The detection method has the characteristics of high sensitivity, good repeatability and accurate results.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical analysis technology, and more specifically, to a method for determining 1,3-dichloro-2-propanol in iodixanol. Background Technology

[0002] Iodixanol, a non-ionic isotonic dimer X-ray contrast agent, is widely used in contrast examinations of cardiovascular, cerebrovascular, and peripheral vascular systems. A source tracing assessment of the synthetic process of iodixanol active pharmaceutical ingredient (API) revealed that its key starting material, epichlorohydrin, is typically prepared from glycerol via a chlorination reaction to generate 1,3-dichloro-2-propanol, which is then cyclized. During this process, 1,3-dichloro-2-propanol can easily remain in epichlorohydrin and be carried into the API along with the raw materials, becoming a potential process impurity.

[0003]

[0004] Based on the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) Guideline M7(R2) issued in 2023, "Assessing and controlling DNA reactive (mutagenic) impurities in pharmaceuticals to limit potential carcinogenic risks," a structural risk assessment of 1,3-dichloro-2-propanol was conducted. The results showed that this compound possesses a genotoxic structure warning of haloalkanes, classifying it as a potential mutagenic impurity requiring key control, and posing a clear carcinogenic risk. Its residual amount in pharmaceuticals must be strictly controlled to ensure compliance with the acceptable intake limits specified in the guideline.

[0005] However, current methods for the specific detection of 1,3-dichloro-2-propanol impurities in iodixanol are scarce, and systematic quality control measures are inadequate. These methods fail to meet the requirements for low-level, high-sensitivity quality control of this impurity and are insufficient to support the compliance evaluation and process optimization of iodixanol raw materials. Therefore, there is an urgent need to develop a highly sensitive, repeatable, and accurate detection method for the residual detection and quantitative control of 1,3-dichloro-2-propanol in iodixanol, ensuring product quality and clinical medication safety.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a method for determining 1,3-dichloro-2-propanol in iodixanol. This method has the characteristics of high sensitivity, good repeatability and high accuracy, and is used to determine the content of 1,3-dichloro-2-propanol in iodixanol.

[0008] This invention is implemented as follows: This invention provides a method for determining 1,3-dichloro-2-propanol in iodixanol, comprising the following steps: diluting iodixanol in a solvent, shaking well, and preparing a test solution; detecting the test solution using gas chromatography-tandem mass spectrometry, and calculating the content of 1,3-dichloro-2-propanol in iodixanol using the external standard method; The solvent used is methanol; the gas chromatographic column uses polyethylene glycol as the stationary phase; the mass spectrometry detection mode is multiple reaction monitoring mode, with quantitative ion pairs at m / z 79.0→43.1 and qualitative ion pairs at m / z 81.0→43.1.

[0009] In an optional embodiment, the concentration of iodixanol in the test solution is 0.05-0.2 mg / ml.

[0010] In an optional embodiment, the chromatographic column is a TG-WAXMS or DB-WAX; the column dimensions are 30 m × 0.25 mm × 0.25 μm.

[0011] In an optional embodiment, the conditions for gas chromatography are as follows: the initial temperature of the gas chromatography is 55-70℃, maintained for 2.5-3.5 min, and then the temperature is increased to 190-210℃ at a rate of 15-20℃ / min, and maintained for 4.5-5.5 min.

[0012] In an optional embodiment, the injection port temperature of the gas chromatography column is 280-300 ℃; the split ratio is (5-10):1; the carrier gas is high-purity helium; the column flow rate is 1.4-1.6 mL / min; and the injection volume is 0.8-1.2 μL.

[0013] In an optional embodiment, the mass spectrometer is a triple quadrupole tandem mass spectrometer, the ion source is an electron impact ion source with an ion source temperature of 220-240 ℃ and an electron energy of 65-75 eV, the collision gas is high-purity nitrogen, and the collision voltage is 4-6 V.

[0014] In an optional embodiment, the mass spectrometry detection conditions further include: a solvent delay time of 6-8 min; and a quadrupole comprising a first quadrupole and a second quadrupole, wherein the temperature of the first quadrupole is 145-155 ℃ and the temperature of the second quadrupole is 145-155 ℃.

[0015] In an optional embodiment, the determination method has a limit of quantitation of 12 ppb, a limit of detection of 4 ppb, a linear range of 1.2-10.9 ng / ml, and a linear correlation coefficient ≥99.9%.

[0016] In an optional embodiment, the determination method further includes the preparation of a reference solution: an appropriate amount of 1,3-dichloro-2-propanol reference standard is accurately weighed, dissolved in methanol, and quantitatively diluted; the content of the 1,3-dichloro-2-propanol reference standard is >99%.

[0017] In an optional embodiment, the concentration of the reference solution 1,3-dichloro-2-propanol is 3-12 ng / ml.

[0018] This invention offers the following advantages: It employs gas chromatography-mass spectrometry (GC-MS) to detect the content of 1,3-dichloro-2-propanol in iodixanol. By systematically optimizing GC conditions and mass spectrometry parameters, it can accurately and reliably determine trace amounts of 1,3-dichloro-2-propanol residues in iodixanol. This method boasts advantages such as high sensitivity, good repeatability, and accurate results, meeting the stringent control requirements for potentially mutagenic impurities in pharmaceuticals and providing an effective analytical tool for the quality control of iodixanol. Attached Figure Description To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a standard curve of 1,3-dichloro-2-propanol in this invention; Figure 2 This is a typical spectrum of methanol solvent in this invention; Figure 3 This is a typical chromatogram of the reference solution in this invention; Figure 4 This is a typical spectrum of the sample solution in this invention; Figure 5 This is a typical spectrum of the limit of quantitation in this invention; Figure 6 This is a typical spectrum of the detection limit in this invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0021] The following is a detailed description of a method for determining 1,3-dichloro-2-propanol in iodixanol provided by the present invention.

[0022] First, this invention provides a method for determining 1,3-dichloro-2-propanol in iodixanol, comprising the following steps: S1. Dilute iodixanol with solvent, shake well, and prepare the test solution.

[0023] In some preferred embodiments, methanol is used as the solvent, which does not interfere with the determination of 1,3-dichloro-2-propanol, and the iodixanol matrix in the test solution does not interfere with the determination of 1,3-dichloro-2-propanol.

[0024] Furthermore, the concentration of iodixanol in the test solution is 0.05-0.2 mg / ml, such as, but not limited to, 0.05 mg / ml, 0.1 mg / ml, 0.15 mg / ml or 0.2 mg / ml, preferably 0.1 mg / ml.

[0025] S2. Gas chromatography-tandem mass spectrometry (GC-MS) was used to detect the test solution, and the content of 1,3-dichloro-2-propanol in iodixanol was calculated by external standard method.

[0026] (1) Chromatographic conditions In some preferred embodiments, the gas chromatographic column uses polyethylene glycol (PEG-20M) as the stationary phase. The column may include, but is not limited to, TG-WAXMS or DB-WAX, and other columns with equivalent performance may also be used. The column dimensions are 30 m × 0.25 mm × 0.25 μm. Using this type of column can further improve the accuracy of 1,3-dichloro-2-propanol detection.

[0027] In some preferred embodiments, the injection port temperature of the gas chromatographic column is 280-300 ℃; the split ratio is (5-10):1; the carrier gas is high-purity helium; the column flow rate is 1.4-1.6 mL / min; and the injection volume is 0.8-1.2 μL. By optimizing various parameters of gas chromatography, this invention helps to improve the separation effect, enhance sensitivity, and further improve the accuracy of detection.

[0028] As an example, the injection port temperature is, for example but not limited to, 280 °C, 285 °C, 290 °C, 295 °C, or 300 °C, preferably 280 °C; the split ratio is, for example but not limited to, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1, preferably 10:1; the column flow rate is, for example but not limited to, 1.4 mL / min, 1.45 mL / min, 1.5 mL / min, 1.55 mL / min, or 1.6 mL / min, preferably 1.5 mL / min; the injection volume is, for example but not limited to, 0.8 μL, 0.9 μL, 1.0 μL, 1.1 μL, or 1.2 μL, preferably 1.0 μL.

[0029] In some preferred embodiments, the chromatographic conditions further include: controlling the initial temperature at 55-70 °C, maintaining it for 2.5-3.5 min, increasing the temperature to 190-210 °C at a rate of 15-20 °C / min, and maintaining it for 4.5-5.5 min.

[0030] For example, the initial temperature is, for example but not limited to, 55 ℃, 60 ℃, 65 ℃ or 70 ℃; the heating rate is, for example but not limited to, 15 ℃ / min, 16 ℃ / min, 17 ℃ / min, 18 ℃ / min, 19 ℃ / min or 20 ℃ / min; and the temperature after heating is 190 ℃, 195 ℃, 200 ℃, 205 ℃ or 210 ℃.

[0031] (2) Mass spectrometry conditions In some preferred embodiments, the mass spectrometer is a triple quadrupole tandem mass spectrometer, the ion source is an electron impact ion source, the ion source temperature is 220-240 °C, for example, but not limited to, 220 °C, 225 °C, 230 °C or 240 °C, etc.; the electron energy is 65-75 eV, for example, but not limited to, 65 eV, 67 eV, 69 eV, 71 eV, 73 eV or 75 eV, etc.; the collision gas is high-purity nitrogen gas, and the collision voltage is 4-6 V, for example, but not limited to, 4 V, 5 V or 6 V, etc.

[0032] Furthermore, the detection mode of the mass spectrometer is multiple reaction monitoring (MRM), with quantitative ion pairs at m / z 79.0→43.1 and qualitative ion pairs at m / z 81.0→43.1.

[0033] The mass spectrometry detection conditions also include: a solvent delay time of 6-8 min, such as, but not limited to, 6 min, 6.5 min, 7 min, 7.5 min, or 8 min; and a quadrupole including a first quadrupole (MS1) and a second quadrupole (MS2), with the first quadrupole temperature at 145-155 ℃ and the second quadrupole temperature at 145-155 ℃. The temperatures of the first and second quadrupoles can be the same or different, and can be independently 145 ℃, 150 ℃, or 155 ℃, etc.

[0034] It should be noted that the inventors achieved the goal of accurately detecting 1,3-dichloro-2-propanol in iodixanol by optimizing chromatographic and mass spectrometric conditions. The above chromatographic and mass spectrometric conditions are a whole scheme, and the parameters are an organic whole that works together.

[0035] In some preferred embodiments, the determination method has a limit of quantitation of 12 ppb, a limit of detection of 4 ppb, a linear range of 1.2-10.9 ng / ml, and a linear correlation coefficient ≥99.9%.

[0036] In some preferred embodiments, the determination method further includes the preparation of a reference solution: an appropriate amount of 1,3-dichloro-2-propanol reference standard is accurately weighed, dissolved in methanol, and quantitatively diluted; the content of the 1,3-dichloro-2-propanol reference standard is >99%, wherein the concentration of 1,3-dichloro-2-propanol in the reference solution is 3-12 ng / ml.

[0037] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0038] The reagents used in the embodiments and comparative examples of this invention are as follows: Iodixanol, purchased from Jiangxi Brothers Pharmaceutical Co., Ltd., batch numbers A04-240201, A04-240202 and A04-240203; 1,3-dichloro-2-propanol sample, purchased from Shanghai Maclean Biochemical Technology Co., Ltd., batch number C17690447; methanol, purchased from SIGMA-ALDRICH, batch number 34860-4L-R, with a purity greater than 99.9%.

[0039] Example 1 This embodiment provides a method for determining 1,3-dichloro-2-propanol in iodixanol, which includes the following steps: 1. GC-MS detection conditions: Chromatographic conditions: Column: TG-WAXms (30 m × 0.25 mm × 0.25 μm, serial number: 1650984); Column temperature: initial temperature 60 ℃, hold for 3 min, then increase to 200 ℃ at a rate of 20 ℃ / min, hold for 5 min; Injector temperature: 280 ℃; Flow rate: 1.5 ml / min; Split ratio: 10:1.

[0040] Mass spectrometry conditions: EI source temperature: 230 ℃; electron energy: 70 eV; solvent delay: 7 min; step size: 0.1 amu; collision gas: high-purity nitrogen; MS1 temperature: 150 ℃; MS2 temperature: 150 ℃; mass spectrometry monitoring mode: multiple reaction monitoring (MRM) mode, quantitative ion pair: 79.0→43.1, collision voltage: 5V; qualitative ion pair: 81.0→43.1, collision voltage: 5V.

[0041] 2. Solution preparation Test solution: Accurately weigh 5.0067 g of this product, place it in a 50 ml volumetric flask, add 40 ml of methanol, sonicate to dissolve, cool, dilute to the mark with methanol, and shake well.

[0042] Reference solution: Accurately weigh 0.2458 g of 1,3-dichloro-2-propanol and place it in a 100 ml volumetric flask. Dissolve and dilute to the mark with methanol, shake well, accurately measure 1 ml and place it in a 100 ml volumetric flask, then dilute to the mark with methanol. Accurately measure 1 ml and place it in a 100 ml volumetric flask, then dilute to the mark with methanol. Accurately measure 10 ml and place it in a 100 ml volumetric flask, then dilute to the mark with methanol. Accurately measure 5 ml and place it in a 20 ml volumetric flask, then dilute to the mark with methanol.

[0043] System suitability: After injecting the reference solution 6 times consecutively, the relative standard deviation of the peak area of ​​the quantitative ion pair of 1,3-dichloro-2-propanol (mz 79.0→43.1) should not exceed 10%.

[0044] The reference solution was injected six times consecutively. The peak areas of the quantitative ion pair of 1,3-dichloro-2-propanol (79.0→43.1) were 3413, 3351, 3215, 3308, 3304, and 3106, respectively. The relative standard deviation (RSD) of the peak area was 3.3%, which met the requirements.

[0045] 3. Establishment and validation of the method for determining 1,3-dichloro-2-propanol in iodixanol.

[0046] (1) Exclusivity Take 1 μl of blank reagent: methanol solution; Take 1 μl of the test solution: iodixanol solution; inject separately and record the chromatogram.

[0047] Solvent spectra as follows Figure 2 As shown, the solvent does not interfere with the determination of 1,3-dichloro-2-propanol, and the iodixanol matrix in the test solution does not interfere with the determination of 1,3-dichloro-2-propanol, indicating that the proposed method has good specificity.

[0048] (2) Linearity and range Preparation of the reference stock solution: Accurately weigh 0.2458 g of 1,3-dichloro-2-propanol and place it in a 100 ml volumetric flask. Dissolve and dilute to the mark with methanol, and shake well. Accurately measure 1 ml of this solution and place it in a 100 ml volumetric flask. Dilute to the mark with methanol, and shake well. Accurately measure 1 ml of this solution and place it in a 100 ml volumetric flask. Dilute to the mark with methanol, and shake well. This is the reference stock solution ①. Accurately measure 10 ml of reference stock solution ① and place it in a 100 ml volumetric flask. Dilute to the mark with methanol, and shake well. This is the reference stock solution ②.

[0049] Accurately measure 1 ml, 3 ml, 5 ml, 7 ml, and 9 ml of the reference stock solution ② and place them in 20 ml volumetric flasks respectively. Dilute to the mark with methanol and shake well to obtain reference solutions ① to ⑤.

[0050] Accurately measure 1 μl of each of the reference solutions ① to ⑤, inject them separately, and determine them under the chromatographic and mass spectrometric conditions described above. Record the chromatograms, with concentration (ng / ml) on the x-axis and peak area (A) on the y-axis. Plot a linear regression equation. The linear regression equation for 1,3-dichloro-2-propanol is y = 521.856986x + 84.119510, with a correlation coefficient of 0.9994. See Table 1. Figure 1 The results showed that 1,3-dichloro-2-propanol exhibited good linearity in the range of 1.2167-10.9504 ng / ml.

[0051] Table 1. Results of Standard Curve Measurement

[0052] (3) Precision Reference solution: Take the above reference solution ③.

[0053] Repeatability test solution: Accurately weigh 5.0067g, 5.0070g, 5.0143g, 5.0201g, 5.0200g, and 5.0214g of this product and place them in 50ml volumetric flasks respectively. Add 40ml of methanol, sonicate to dissolve, cool, dilute to the mark with methanol, and shake well.

[0054] Accurately measure 1 μl each of the reference solution and the repeatability test solution, and determine them according to the above chromatographic and mass spectrometric conditions, respectively. Record the chromatograms. The results are shown in Tables 2 and 3. Figure 3 .

[0055] Table 2 Calculation results of f-values ​​for reference solutions

[0056] Table 3 Repeatability Test Results

[0057] According to the repeatability test results, 1,3-dichloro-2-propanol was not detected in any of the six iodixanol test solutions with different weights, indicating that the method has good repeatability in sample detection, and the residual level of this impurity in the tested batches of iodixanol is below the detection limit. Meanwhile, the relative standard deviation (RSD) of the response factor for the reference solution was 3.1%, indicating that the instrument and method have good precision in the determination process and the results are reliable.

[0058] Intermediate precision: Intermediate precision reference solution stock solution ①: Accurately weigh 0.2460 g of 1,3-dichloro-2-propanol, place it in a 100 ml volumetric flask, dissolve and dilute to the mark with methanol, and shake well. Accurately measure 1 ml and place it in a 100 ml volumetric flask, dilute to the mark with methanol, and shake well. Accurately measure 1 ml and place it in a 100 ml volumetric flask, dilute to the mark with methanol, and shake well. Accurately measure 25 ml and place it in a 100 ml volumetric flask, dilute to the mark with methanol, and shake well.

[0059] Intermediate precision reference solution: Accurately measure 5 ml of intermediate precision reference solution stock solution ①, place it in a 50 ml volumetric flask, dilute to the mark with methanol, and shake well.

[0060] Intermediate precision spiked test solutions: Accurately weigh 5.0238 g, 5.0255 g, 5.0182 g, 5.0218 g, 5.0292 g, and 5.0179 g of this product, and place them separately in 50 ml volumetric flasks. Accurately add 5 ml of intermediate precision reference solution stock solution ①, 5 ml of each solution, 5 ml of each solution, 5 ml of each solution, 5 ml of each solution, and 35 ml of methanol. Sonicate to dissolve, cool, dilute to the mark with methanol, and shake well. These are the intermediate precision spiked test solutions ① to ⑥.

[0061] Accurately measure 1 μl each of the intermediate precision reference solution and the intermediate precision spiked test solution, and determine them according to the above chromatographic and mass spectrometric conditions, and record the chromatograms. Inject the intermediate precision reference solution and intermediate precision spiked test solution ① six times consecutively, and the precision results are shown in Table 4. Intermediate precision spiked test solutions ① to ⑥ were used as repeatability tests, and the results are shown in Table 5.

[0062] Table 4 Results of intermediate precision test

[0063] Table 5 Results of repeatability tests on spiked samples

[0064] According to the intermediate precision test results, the average peak area of ​​the six spiked test solutions was 3812.2, with a relative standard deviation (RSD) of 2.3%; the average peak area of ​​the six consecutive injections of the reference solution was 4107.5, with an RSD of 3.0%. Both RSDs were less than 5%, indicating that the method has good intermediate precision for determining 1,3-dichloro-2-propanol in iodixanol under different dates and operating conditions, and the method is reproducible.

[0065] (4) Accuracy Reference stock solution ③: Accurately measure 25 ml of the above reference stock solution ①, place it in a 100 ml volumetric flask, dilute to the mark with methanol, and shake well.

[0066] Reference solution: Take the above reference solution ③.

[0067] Recovery test solutions: Accurately weigh 5.0280g, 5.0344g, 5.0086g, 5.0197g, 5.0320g, 5.0250g, 5.0276g, 5.0140g, and 5.0194g of this product, and place them in separate 50ml volumetric flasks. Accurately add 3ml, 3ml, 3ml, 5ml, 5ml, 5ml, 7ml, 7ml, and 7ml of the reference stock solution ③, add 35ml of methanol, sonicate to dissolve, cool, dilute to the mark with methanol, and shake well. These are the recovery test solutions ① to ⑨. Accurately measure 1 μl each of the reference solution and the recovery test solution, and determine them under the chromatographic and mass spectrometric conditions described above. Record the chromatograms. The results are detailed in Table 6.

[0068] Table 6 Results of 1,3-Dichloro-2-propanol Recovery Test

[0069] According to the accuracy test results, the recoveries of 1,3-dichloro-2-propanol at three different spiking levels ranged from 95.02% to 105.34%, with an average recovery of 99.91% and a relative standard deviation (RSD) of 4.0% (n=9). The results indicate that this method has good accuracy and can reliably determine the residual amount of 1,3-dichloro-2-propanol in iodixanol.

[0070] (5) Durability (A) Initial temperature change in column temperature Setting 1: Initial temperature 60 ℃, held for 3 min, then increased to 200 ℃ at 20 ℃ / min, held for 5 min; Setting 2: Initial temperature 55 ℃, held for 3 min, with the same subsequent temperature increase program; Setting 3: Initial temperature 70 ℃, held for 3 min, with the same subsequent temperature increase program. Six injections were performed consecutively on each of the above reference solution ③ and the above recovery test solution ④ under the above three conditions. The relative standard deviation (RSD) of the peak area of ​​the quantitative ion pair of 1,3-dichloro-2-propanol (m / z 79.0→43.1) in the two samples was examined. The results are shown in Tables 7 and 8.

[0071] Table 7. Durability test results at an initial temperature of 55℃

[0072] Table 8. Durability test results at an initial temperature of 70℃

[0073] The results show that, at an initial temperature of 55℃, the peak area RSD for reference solution ③ after 6 consecutive injections was 1.8%, and the RSD for recovery test solution ④ was not listed (calculated value approximately 1.1%). At an initial temperature of 70℃, the RSD for reference solution ③ was 0.9%, and the RSD for recovery test solution ④ was 1.1%. Both RSDs under the adjusted conditions were less than 10%, indicating that within a range of ±5℃ from the initial temperature, this method exhibits good robustness to column temperature changes, and the system suitability meets the requirements.

[0074] (B) Column velocity variation Column flow rate was set to 1.5 ml / min for setting 1, 1.4 ml / min for setting 2, and 1.6 ml / min for setting 3. Six injections were performed consecutively on each of the above three samples, using the reference solution ③ and the recovery test solution ④. The relative standard deviation (RSD) of the peak area of ​​the 1,3-dichloro-2-propanol quantitative ion pair (m / z 79.0→43.1) in the two samples was examined. The results are shown in Tables 9 and 10.

[0075] Table 9. Results of the durability test at a column flow rate of 1.4 ml / min

[0076] Table 10. Results of the durability test at a column flow rate of 1.6 ml / min

[0077] Based on the above experimental results, at a column flow rate of 1.4 ml / min, the peak area RSD for reference solution ③ after 6 consecutive injections was 1.2%, and the RSD for recovery test solution ④ was 1.6%; at a column flow rate of 1.6 ml / min, the RSD for reference solution ③ was 0.6%, and the RSD for recovery test solution ④ was 1.8%. The RSDs under both conditions are well less than 10%, indicating that within a column flow rate range of ±0.1 ml / min, this method has good robustness, and the system suitability meets the requirements.

[0078] (C) Stability of the tested solution Take the above reference solution ③ and recovery test solution ④, and after standing at room temperature for 0, 4, 8, 12 and 18 hours respectively, accurately measure 1 μl of each, and determine them according to the above chromatographic and mass spectrometric conditions. Record the chromatograms. The results are shown in Table 11: 1,3-dichloro-2-propanol in reference solution ③ and recovery solution ④ is relatively stable within 18 hours.

[0079] Table 11 Stability Test Results

[0080] (6) Limit of quantitation and limit of detection Limit of quantitation solution: Take the above reference solution ① (1.2167 ng / ml).

[0081] Detection limit solution: Accurately measure 3 ml of the reference solution ①, place it in a 10 ml volumetric flask, dilute to the mark with methanol, and shake well (0.3650 ng / ml).

[0082] Accurately measure 1 μl each of the limit of quantitation solution and the limit of detection solution, and determine them respectively under the chromatographic and mass spectrometric conditions described above. Record the chromatograms, as shown below. Figure 5 and Figure 6 As shown. The signal-to-noise ratio (SNR) of the 1,3-dichloro-2-propanol peak in the limit of quantitation solution is 10.7. The SNR of the 1,3-dichloro-2-propanol peak in the limit of detection solution is 3.8.

[0083] Limit of quantitation = 0.0000012% (12 ppb) Detection limit = 0.0000004% (4 ppb) (7) Sample testing Three batches of iodixanol raw material samples were tested according to the method, and the results are shown in Table 12 and 12. Figure 4 .

[0084] Table 12 Sample Test Results

[0085] In summary, after systematic methodological validation, the GC-MS method established in this study for determining the residue of 1,3-dichloro-2-propanol in iodixanol showed good performance in all indicators. Specificity studies showed that neither the blank solvent nor the sample matrix interfered with the detection of the target impurity; the relative standard deviations (RSDs) for system suitability, instrument repeatability, and method repeatability were 3.3%, 3.3%, and 4.0%, respectively, with an intermediate precision RSD of 2.3%, all significantly better than the requirement of no more than 10%. The linear range covered ±50% of the limit concentration (1.2–10.9 ng / ml), with a correlation coefficient R² of 0.9994, indicating good linearity. In the accuracy test, the recovery rate ranged from 95.02% to 105.34%, with an average recovery rate of 99.91%, meeting the acceptance criteria of 80%–120%. The limits of quantitation and detection were 12 ppb and 4 ppb, respectively, indicating high sensitivity. In the robustness test, the RSDs under different conditions were all less than 5%. Therefore, the method proposed in this invention has good specificity, high sensitivity, good precision and accuracy, and is durable and reliable. It can be used for the quality control of the residual amount of genotoxic impurity 1,3-dichloro-2-propanol in iodixanol.

[0086] Comparative Example 1 This comparative example provides a detection method, the detection steps of which are the same as those in Example 1, except that N,N-dimethylformamide and dimethyl sulfoxide are used instead of methanol as solvents to detect the mass spectrometric response of 1,3-dichloro-2-propanol.

[0087] The results showed that DMF and DMSO had good solubility for iodixanol, but due to their high boiling points, they were prone to remaining in the column during detection, leading to a continuous and rapid decrease in the mass spectrometric response of 1,3-dichloro-2-propanol and poor stability. In contrast, methanol provided good response stability. Therefore, neither DMF nor DMSO is suitable, and only methanol can be used as a suitable solvent for this method.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining 1,3-dichloro-2-propanol in iodixanol, characterized in that, Includes the following steps: Iodixanol was diluted with solvent, shaken well, and prepared into a test solution; the test solution was detected by gas chromatography-tandem mass spectrometry, and the content of 1,3-dichloro-2-propanol in iodixanol was calculated by external standard method. The solvent used is methanol; the gas chromatographic column uses polyethylene glycol as the stationary phase; the mass spectrometry detection mode is multiple reaction monitoring mode, with quantitative ion pairs at m / z 79.0→43.1 and qualitative ion pairs at m / z 81.0→43.

1.

2. The method for determining 1,3-dichloro-2-propanol in iodixanol according to claim 1, characterized in that, The concentration of iodixanol in the test solution is 0.05-0.2 mg / ml.

3. The method for determining 1,3-dichloro-2-propanol in iodixanol according to claim 1, characterized in that, The chromatographic column is either TG-WAXMS or DB-WAX; the column dimensions are 30 m × 0.25 mm × 0.25 μm.

4. The method for determining 1,3-dichloro-2-propanol in iodixanol according to claim 1, characterized in that, The conditions for gas chromatography are as follows: the initial temperature of the gas chromatography is 55-70 ℃, maintained for 2.5-3.5 min, and then increased to 190-210 ℃ at a rate of 15-20 ℃ / min, and maintained for 4.5-5.5 min.

5. The method for determining 1,3-dichloro-2-propanol in iodixanol according to claim 4, characterized in that, The gas chromatographic column has an injection port temperature of 280-300 ℃; a split ratio of (5-10):1; a carrier gas of high purity helium; a column flow rate of 1.4-1.6 mL / min; and an injection volume of 0.8-1.2 μL.

6. The method for determining 1,3-dichloro-2-propanol in iodixanol according to claim 1, characterized in that, The mass spectrometer used is a triple quadrupole tandem mass spectrometer. The ion source is an electron impact ion source with a temperature of 220-240℃ and an electron energy of 65-75 eV. The collision gas is high-purity nitrogen with a collision voltage of 4-6 V.

7. The method for determining 1,3-dichloro-2-propanol in iodixanol according to claim 1, characterized in that, The mass spectrometry detection conditions also include: a solvent delay time of 6-8 min; and a quadrupole comprising a first quadrupole and a second quadrupole, wherein the temperature of the first quadrupole is 145-155 ℃ and the temperature of the second quadrupole is 145-155 ℃.

8. The method for determining 1,3-dichloro-2-propanol in iodixanol according to claim 1, characterized in that, The determination method has a limit of quantitation of 12 ppb, a limit of detection of 4 ppb, a linear range of 1.2-10.9 ng / ml, and a linear correlation coefficient ≥99.9%.

9. The method for determining 1,3-dichloro-2-propanol in iodixanol according to claim 1, characterized in that, The determination method further includes the preparation of a reference solution: take an appropriate amount of 1,3-dichloro-2-propanol reference standard, accurately weigh it, dissolve it in methanol and dilute it quantitatively; the content of the 1,3-dichloro-2-propanol reference standard is >99%.

10. The method for determining 1,3-dichloro-2-propanol in iodixanol according to claim 9, characterized in that, The concentration of the reference solution 1,3-dichloro-2-propanol is 3-12 ng / ml.

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