Method for detecting residual solvent in ioversol

Abstract

The invention relates to a method for detecting a residual solvent in ioversol, headspace gas chromatography is adopted for determination, the residual solvent is selected from one or more of ethanol, acetic acid, N, N-dimethylacetamide, benzene and trichloromethane, and the conditions of the headspace gas chromatography are as follows: a chromatographic column is an ultrahigh inert gas chromatographic column; the filler is cyanopropyl-phenyl-polydimethylsiloxane, and the viscosity of the coating is 100-200mPa. S. The headspace equilibrium temperature is 90-110 DEG C, and the headspace equilibrium time is 20-40 minutes; the sampling mode is split sampling, and the split ratio is 1: 1. The method has the advantages of strong specificity, high sensitivity and wide linear range, and meets the requirements of drug quality control.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of pharmaceutical analysis, and particularly relates to a method for detecting residual solvents in ioversol. Background Art

[0002] Ioversol is a second-generation non-ionic iodinated contrast agent widely used in clinics. It has the advantages of low toxicity, high water solubility, low viscosity, low osmotic pressure, low incidence of adverse reactions, and relatively low price, and is widely used in medical imaging. Solvents such as ethanol, acetic acid, N,N-dimethylacetamide, benzene, and chloroform used in the production process may remain in the final product, affecting the product purity and safety. To ensure the drug quality, the control of residual solvents is particularly important. Traditional detection methods mostly use solvent extraction and other methods, which are complex in operation and low in efficiency. Therefore, there is an urgent need for a sensitive, accurate, and simple detection method to monitor the content of these residual solvents. Summary of the Invention

[0003] The present disclosure has established an efficient headspace gas chromatography method by optimizing the gas chromatography detection parameters, which can quickly and accurately detect multiple residual solvents in ioversol raw materials: ethanol, acetic acid, N,N-dimethylacetamide, benzene, and chloroform. This method has strong specificity, high sensitivity, and a wide linear range, meeting the requirements of drug quality control.

[0004] In a first aspect, the present disclosure provides a method for detecting residual solvents in ioversol, which is determined by headspace gas chromatography (HSGC), and the residual solvents are selected from one or more of ethanol, acetic acid, N,N-dimethylacetamide, benzene, and chloroform;

[0005] The conditions of the headspace gas chromatography are as follows:

[0006] The chromatographic column is an ultra-high inert gas chromatography column, and its packing is cyanopropyl-phenyl-polydimethylsiloxane;

[0007] The headspace equilibrium temperature is 90 - 110 °C (such as 90 °C, 95 °C, 100 °C, 105 °C, or 110 °C), and the headspace equilibrium time is 20 - 40 min (such as 20 min, 25 min, 30 min, 35 min, or 40 min);

[0008] The injection mode is split injection, and the split ratio is 1:1.

[0009] In some embodiments, in the first aspect, the residual solvents are ethanol, acetic acid, N,N-dimethylacetamide, benzene, and chloroform.

[0010] Second aspect, the present disclosure provides a detection method for determining at least two residual solvents in ioversol, which is determined by headspace gas chromatography. The residual solvents are selected from ethanol, acetic acid, N,N-dimethylacetamide, benzene, and chloroform. The conditions of the headspace gas chromatography are as follows:

[0011] The chromatographic column is an ultra-high inert gas chromatographic column, and its packing is cyanopropyl-phenyl-polydimethylsiloxane;

[0012] The headspace equilibrium temperature is 90-110 °C (such as 90 °C, 95 °C, 100 °C, 105 °C or 110 °C), and the headspace equilibrium time is 20-40 min (such as 20 min, 25 min, 30 min, 35 min or 40 min);

[0013] The injection mode is split injection, and the split ratio is 1:1.

[0014] In some embodiments, in the first aspect and / or the second aspect, the packing of the ultra-high inert gas chromatographic column is 6% cyanopropyl / phenyl and 94% polydimethylsiloxane.

[0015] In some embodiments, in the first aspect and / or the second aspect, the ultra-high inert gas chromatographic column is a DB624UI chromatographic column.

[0016] In some embodiments, in the first aspect and / or the second aspect, the specification of the chromatographic column of the headspace gas chromatography is 60 m × 0.32 mm × 1.8 μm.

[0017] In some embodiments, in the first aspect and / or the second aspect, the carrier gas used in the headspace gas chromatography is nitrogen or helium.

[0018] In some embodiments, in the first aspect and / or the second aspect, the carrier gas used in the headspace gas chromatography is nitrogen.

[0019] In some embodiments, in the first aspect and / or the second aspect, the flow rate of the carrier gas used in the headspace gas chromatography is 2-4 mL / min, such as 2 mL / min, 2.5 mL / min, 3 mL / min, 3.5 mL / min or 4 mL / min.

[0020] In some embodiments, in the first aspect and / or the second aspect, the flow rate of the carrier gas used in the headspace gas chromatography is 3 mL / min.

[0021] In some embodiments, in the first aspect and / or the second aspect, the column temperature of the headspace gas chromatography is a programmed temperature rise. The initial temperature is 36 - 44 °C (such as 36 °C, 37 °C, 38 °C, 39 °C, 40 °C, 41 °C, 42 °C, 43 °C or 44 °C), and it is heated at a rate of 15 - 25 °C / min (such as 15 °C / min, 16 °C / min, 17 °C / min, 18 °C / min, 19 °C / min, 20 °C / min, 21 °C / min, 22 °C / min, 23 °C / min, 24 °C / min or 25 °C / min) to 190 - 210 °C (such as 190 °C, 195 °C, 200 °C, 205 °C or 210 °C), and held for 5 - 15 min (such as 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min or 15 min).

[0022] In some embodiments, in the first aspect and / or the second aspect, the column temperature of the headspace gas chromatography is a programmed temperature rise. The initial temperature is 40 °C, and it is heated at a rate of 20 °C / min to 200 °C and held for 10 min.

[0023] In some embodiments, in the first aspect and / or the second aspect, the headspace equilibrium temperature of the headspace gas chromatography is 100 °C, and the headspace equilibrium time is 30 min.

[0024] In some embodiments, in the first aspect and / or the second aspect, the inlet temperature of the headspace gas chromatography is 210 - 240 °C, such as 210 °C, 215 °C, 220 °C, 225 °C, 230 °C, 235 °C or 240 °C.

[0025] In some embodiments, in the first aspect and / or the second aspect, the inlet temperature of the headspace gas chromatography is 220 - 235 °C.

[0026] In some embodiments, in the first aspect and / or the second aspect, the inlet temperature of the headspace gas chromatography is 220 °C.

[0027] In some embodiments, in the first aspect and / or the second aspect, the detector of the headspace gas chromatography is a flame ionization detector (FID).

[0028] In some embodiments, in the first aspect and / or the second aspect, the temperature of the detector of the headspace gas chromatography is 240 - 260 °C, such as 240 °C, 245 °C, 250 °C, 255 °C or 260 °C.

[0029] In some embodiments, in the first aspect and / or the second aspect, the temperature of the detector of the headspace gas chromatography is 250 °C.

[0030] In some embodiments, in the first aspect and / or the second aspect, the injection volume of the headspace gas chromatography is 0.1 to 3 μL, such as 0.5 μL, 1 μL, 1.5 μL, 2 μL, 2.5 μL, or 3 μL.

[0031] In some embodiments, in the first aspect and / or the second aspect, the injection volume of the headspace gas chromatography is 1 μL.

[0032] In some embodiments, in the first aspect and / or the second aspect, the running time of the headspace gas chromatography is 45 to 60 min, such as 45 min, 46 min, 47 min, 48 min, 49 min, 50 min, 51 min, 52 min, 53 min, 54 min, 55 min, 56 min, 57 min, 58 min, 59 min, or 60 min.

[0033] In some embodiments, in the first aspect and / or the second aspect, the running time of the headspace gas chromatography is 52 min.

[0034] In some embodiments, in the first aspect and / or the second aspect, the detection method includes the following steps:

[0035] (1) Prepare a reference solution containing the aforementioned residual solvents;

[0036] (2) Prepare a test solution of iopamidol;

[0037] (3) Detect the reference solution and the test solution respectively by headspace gas chromatography.

[0038] In some embodiments, in step (1), the method for preparing the reference solution containing residual solvents includes: mixing a diluent and the residual solvents to obtain a reference stock solution, and then diluting the reference stock solution 5 to 200 times (such as 5 times, 10 times, 15 times, 20 times, 25 times, 30 times, 35 times, 40 times, 45 times, 50 times, 55 times, 60 times, 65 times, 70 times, 75 times, 80 times, 85 times, 90 times, 95 times, 100 times, 150 times, or 200 times) with the diluent to obtain a reference solution, and the diluent is water (such as purified water).

[0039] In some embodiments, in step (2), the method for preparing the test solution of iopamidol includes: mixing iopamidol and a diluent to obtain a test solution, and the diluent is water (such as purified water).

[0040] In some embodiments, in step (2), the test sample solution contains residual solvents, and the residual solvents are selected from one or more of ethanol, acetic acid, N,N-dimethylacetamide, benzene, and chloroform.

[0041] In some embodiments, in step (2), the test sample solution contains the aforementioned residual solvents, and the preparation method of the test sample solution of iopamidol includes: mixing iopamidol and the reference substance solution in step (1) to obtain the test sample solution.

[0042] In some embodiments, in step (2), the diluent used in the preparation process of the test sample solution is water, such as purified water.

[0043] In some embodiments, in the first aspect and / or the second aspect, the resolution of one or more peaks of ethanol, chloroform, acetic acid, benzene, and N,N-dimethylacetamide measured by the detection method is greater than 1.5, such as greater than 2 or greater than 2.5.

[0044] In some embodiments, in the first aspect and / or the second aspect, the RSD of the peak area of one or more peaks of ethanol, chloroform, acetic acid, benzene, and N,N-dimethylacetamide measured by the detection method is less than or equal to 10%, such as less than or equal to 9.5%, less than or equal to 9%, less than or equal to 8.5%, less than or equal to 8%, less than or equal to 7.5%, less than or equal to 7%, less than or equal to 6.5%, or less than or equal to 6%.

[0045] In some embodiments, in the first aspect and / or the second aspect, the S / N of one or more peaks of ethanol, chloroform, acetic acid, benzene, and N,N-dimethylacetamide measured by the detection method is greater than 3.

[0046] In some embodiments, in the first aspect and / or the second aspect, the S / N of one or more peaks of ethanol, chloroform, acetic acid, benzene, and N,N-dimethylacetamide measured by the detection method is greater than 10.

[0047] In some embodiments, in the first aspect and / or the second aspect, the RSD of the retention time of one or more peaks of ethanol, chloroform, acetic acid, benzene, and N,N-dimethylacetamide measured by the detection method is less than or equal to 2.0%, such as less than or equal to 1.5%, less than or equal to 1.0%, or less than or equal to 0.5%.

[0048] The detection method for residual solvents in ioversol provided by the present disclosure adopts headspace gas chromatography and can simultaneously detect the contents of ethanol, acetic acid, N,N-dimethylacetamide, benzene and chloroform. This method is convenient, efficient and accurate, and meets the guiding principles of method validation in the Chinese Pharmacopoeia in terms of system suitability, limit of quantification, linear relationship, precision, accuracy and solution stability, and can be used for the quality control of ioversol bulk drugs.

[0049] Term Definition

[0050] To make the present disclosure easier to understand, certain technical and scientific terms are specifically defined below. Unless otherwise clearly defined herein, all other technical and scientific terms used herein have the meanings commonly understood by those of ordinary skill in the art to which the present disclosure pertains.

[0051] Unless the context clearly requires otherwise, throughout the specification and claims, the words: "comprising", "having", "including", etc. shall be understood to have an inclusive meaning, rather than an exclusive or exhaustive meaning; that is, the meaning of "including but not limited to".

[0052] There are certain errors in the numerical values in the present disclosure. Generally speaking, plus or minus 10% belongs to the reasonable error range. Of course, the context in which the numerical value is used needs to be considered. For example, for the particle size of the active ingredient, the error after measurement of this numerical value does not exceed plus or minus 10%, and can be plus or minus 9%, plus or minus 8%, plus or minus 7%, plus or minus 6%, plus or minus 5%, plus or minus 4%, plus or minus 3%, plus or minus 2% or plus or minus 1%, preferably plus or minus 5%.

[0053] "One or more" in the present disclosure means one, two or more than two.

[0054] "One or more items" in the present disclosure means one item, two items or more than two items.

[0055] "One or more" in the present disclosure means one, two or more than two. Description of the Drawings

[0056] Figure 1 It is the gas chromatogram of the blank solution.

[0057] Figure 2 It is the gas chromatogram of the system suitability solution.

[0058] Figure 3 It is the gas chromatogram of the test solution.

[0059] Figure 4 It is the gas chromatogram of the spiked test solution 1 (ethanol, acetic acid, N,N-dimethylacetamide, benzene).

[0060] Figure 5It is the gas chromatogram of the labeled test sample 2 solution (chloroform).

[0061] Figure 6 It is the gas chromatogram of the reference solution 1 (ethanol, acetic acid, N,N-dimethylacetamide, benzene).

[0062] Figure 7 It is the gas chromatogram of the reference solution 2 (chloroform).

[0063] Figure 8 It is the linear regression graph of ethanol.

[0064] Figure 9 It is the linear regression graph of acetic acid.

[0065] Figure 10 It is the linear regression graph of N,N-dimethylacetamide.

[0066] Figure 11 It is the linear regression graph of benzene.

[0067] Figure 12 It is the linear regression graph of chloroform. Detailed implementation manners

[0068] The following further describes the present disclosure in combination with embodiments, but these embodiments do not limit the scope of the present disclosure.

[0069] Embodiment 1:

[0070] 1. Instruments and reagents

[0071] Shimadzu GC-2014HS10, purified water (Wahaha), ethanol (HPLC grade, MackLin, 99.8%), glacial acetic acid (GC grade, MackLin, 99.8%), N,N-dimethylacetamide (HPLC grade, MackLin, 99.8%), chloroform (analytical grade, Sinopharm Chemical Reagent Co., Ltd., 99%), benzene (analytical grade, Sinopharm Chemical Reagent Co., Ltd.)

[0072] 2. Preparation of solutions

[0073] Blank solution (diluent): Purified water

[0074] Preparation of reference stock solution: Weigh accurately about 260 mg of ethanol reference substance, about 260 mg of acetic acid reference substance, about 58 mg of N,N-dimethylacetamide reference substance, about 20 mg of benzene reference substance, and about 32 mg of chloroform reference substance. Transfer them separately into 100 mL volumetric flasks, dissolve with diluent and dilute to the mark, and mix well to obtain a reference stock solution with an ethanol concentration of about 2600.0000 μg / mL, a reference stock solution with an acetic acid concentration of about 2600.0000 μg / mL, a reference stock solution with an N,N-dimethylacetamide concentration of about 580.0000 μg / mL, a reference stock solution with a benzene concentration of about 200.0000 μg / mL, and a reference stock solution with a chloroform concentration of about 320.0000 μg / mL;

[0075] Preparation of reference solution 1: Pipette accurately 5 mL of ethanol reference stock solution, 5 mL of acetic acid reference stock solution, 5 mL of N,N-dimethylacetamide reference stock solution, and 0.5 mL of benzene reference stock solution into a 50 mL brown volumetric flask, dilute to the mark with diluent, and shake well. Pipette accurately 2.0 mL of the above solution into a 20 mL headspace vial, seal it to obtain a reference solution 1 with an ethanol concentration of about 260.0000 μg / mL, an acetic acid concentration of about 260.0000 μg / mL, an N,N-dimethylacetamide concentration of about 58.0000 μg / mL, and a benzene concentration of about 2.0000 μg / mL.

[0076] Preparation of reference solution 2: Pipette accurately 1 mL of chloroform reference stock solution into a 100 mL brown volumetric flask, dilute to the mark with diluent, and shake well. Pipette accurately 2.0 mL of the above solution into a 20 mL headspace vial, seal it to obtain a reference solution 2 with a chloroform concentration of about 3.2000 μg / mL.

[0077] Test solution: Weigh accurately 2.0 g of iofendylate raw material, pipette accurately 2.0 mL of purified water, transfer them into a 20 mL headspace vial, seal it to obtain a test solution with iofendylate concentration of about 1000 mg / mL.

[0078] Preparation of spiked test solution 1: Weigh accurately about 2.0 g of iofendylate raw material, transfer it into a 20 mL headspace vial, pipette accurately 2.0 mL of reference solution 1, seal it to obtain a spiked test solution 1 with an ethanol concentration of about 260.0000 μg / mL, an acetic acid concentration of about 260.0000 μg / mL, an N,N-dimethylacetamide concentration of about 58.0000 μg / mL, a benzene concentration of about 2.0000 μg / mL, and an iofendylate concentration of about 1000 mg / mL.

[0079] Preparation of spiked test solution 2: Weigh approximately 2.0 g of iopamidol raw material accurately, place it in a 20 mL headspace vial, accurately transfer 2.0 mL of reference solution 2, seal it to obtain spiked test solution 2 with a chloroform concentration of approximately 3.2000 μg / mL and an iopamidol concentration of approximately 1000 mg / mL.

[0080] Preparation of system suitability solution: Accurately transfer 5 mL of ethanol reference stock solution, 5 mL of acetic acid reference stock solution, 5 mL of N,N-dimethylacetamide reference stock solution, 0.5 mL of benzene reference stock solution, and 0.5 mL of chloroform reference stock solution into a 50 mL brown volumetric flask, dilute to the mark with diluent, shake well. Accurately measure 2.0 mL of the above solution, place it in a 20 mL headspace vial, seal it to obtain a system suitability solution with an ethanol concentration of approximately 260.0000 μg / mL, an acetic acid concentration of approximately 260.0000 μg / mL, an N,N-dimethylacetamide concentration of approximately 58.0000 μg / mL, a benzene concentration of approximately 2.0000 μg / mL, and a chloroform concentration of approximately 3.2000 μg / mL.

[0081] 2. The chromatographic conditions for gas chromatography are as follows:

[0082] Chromatographic column: DB624UI, 60 m × 0.32 mm × 1.8 μm; Detector: FID; Flow rate: 3 mL / min; Split ratio: 1:1; Injection volume: 1 μL; Run time: 52 min; Column temperature: Programmed temperature rise (40°C; rise to 200°C at a rate of 20°C / min and hold for 10 min); Injection port temperature: 220°C; Detector temperature: 250°C; Equilibrium temperature: 100°C; Equilibrium time: 30 min; Transfer line temperature: 110°C.

[0083] The gas chromatogram of the blank solution is as shown in Figure 1 , indicating that the blank solution does not interfere with the determination of ethanol, acetic acid, N,N-dimethylacetamide, benzene, and chloroform. The gas chromatogram of the system suitability solution is as shown in Figure 2 . Among them, the resolution of ethanol (retention time 5.819 min), acetic acid (retention time 7.817 min), N,N-dimethylacetamide (retention time 11.914 min), benzene (retention time 8.099 min), chloroform (retention time 7.595 min) (retention time 5.819 min) from the surrounding peaks (the other peaks closest to this residual solvent peak) is greater than 1.5. The gas chromatogram of the test solution is as shown in Figure 3 . Among them, the resolution of ethanol from the surrounding peaks is 2.929, which is greater than 1.5. The gas chromatograms of spiked test sample 1 and spiked test sample 2 are as shown in Figure 4 and Figure 5As shown, the separations of the peaks of ethanol, chloroform, acetic acid, benzene and N,N-dimethylacetamide from the surrounding peaks (other peaks closest to the residual solvent peak) are 2.916, 10.560, 14.607, 3.704 and 46.322, respectively, all greater than 1.5. The specificity of this method is good.

[0084] Comparative Example 1:

[0085] Different chromatographic columns DB-WAX UI, CP-Volamine and DB-624UI were selected for analysis, and the reference solution 1 prepared in Example 1 was tested by gas chromatography. Except for the different chromatographic column models, the specific conditions of gas chromatography were the same as those in Example 1. The separation degree of each solvent peak was recorded.

[0086] The results show that when the chromatographic column is DB-WAX UI, the resolution of the residual solvent ethanol peak is only 1.0, and the chromatographic peak has a tailing phenomenon. When the chromatographic column is CP-Volamine, the resolution of the residual solvent ethanol peak is 1.1. According to the relevant standards for drug quality, it is clearly required that the resolution of the residual solvent peak of the drug must be greater than 1.5. Obviously, the current resolution cannot meet the requirements of this standard. When the chromatographic column is DB-624UI, the resolution of the residual solvent ethanol peak is 2.916. It meets the requirements.

[0087] Comparative Example 2:

[0088] The reference solution 1 prepared in Example 1 was tested by gas chromatography. The specific conditions of gas chromatography were the same as those in Example 1 except that the headspace equilibrium temperature was different.

[0089] The results show that when the headspace equilibrium temperature is set to 60°C, the chromatographic peak area of ​​N,N-dimethylacetamide is about 1000. Under this temperature condition, the detection signal is relatively weak, and it is difficult to accurately capture the slight changes in the content of N,N-dimethylacetamide, resulting in limitations in the sensitivity and accuracy of the detection. When the headspace equilibrium temperature is increased to 100°C, the experimental results are different, and the chromatographic peak area of ​​N,N-dimethylacetamide increases to about 2200, which is a significant increase compared to 60°C. This change intuitively reflects the significant improvement in detection sensitivity, which can more accurately determine the content of N,N-dimethylacetamide.

[0090] Comparative Example 3:

[0091] The reference solution 1 prepared in Example 1 was tested by gas chromatography. Except for the different split ratio, the specific conditions of gas chromatography were the same as those in Example 1.

[0092] The results showed that when the split ratio of chloroform was 1:2, the peak area response was approximately 2,000, while when the split ratio changed to 1:1, the peak area response could reach 4,000. This indicates that the split ratio has a significant impact on the peak area response of chloroform. A smaller split ratio (i.e., 1:1) can result in a higher peak area response for chloroform, possibly because a smaller split ratio allows a relatively larger total amount to enter the detector, thus generating a stronger signal.

[0093] Example 2: System Suitability

[0094] System Suitability: The reference solution 1 with an ethanol concentration of approximately 260.0000 μg / mL, an acetic acid concentration of approximately 260.0000 μg / mL, an N,N-dimethylacetamide concentration of approximately 58.0000 μg / mL, and a benzene concentration of approximately 2.0000 μg / mL, and the reference solution 2 with a chloroform concentration of approximately 3.2000 μg / mL prepared in Example 1 were detected by gas chromatography. The specific gas chromatography conditions were the same as those in Example 1, and the RSD of the peak areas of ethanol, acetic acid, N,N-dimethylacetamide, benzene, and chloroform in the solution were recorded.

[0095] The results are as Figure 6 、 7 shown. For the reference solution 1, the RSD of the peak area of ethanol was 1.6%, the RSD of the peak area of acetic acid was 1.7%, the RSD of the peak area of N,N-dimethylacetamide was 3.9%, and the RSD of the peak area of benzene was 5.5%. For the reference solution 2, the RSD of the peak area of chloroform was 3.9%, all of which were less than 10%. This indicates that the system suitability of the present disclosure complies with the regulations.

[0096] Example 3: Limit of Quantitation

[0097] Limit of Quantitation: The reference solution 1 with an ethanol concentration of approximately 260.0000 μg / mL, an acetic acid concentration of approximately 260.0000 μg / mL, an N,N-dimethylacetamide concentration of approximately 58.0000 μg / mL, and a benzene concentration of approximately 2.0000 μg / mL, and the reference solution 2 with a chloroform concentration of approximately 3.2000 μg / mL prepared in Example 1 were quantitatively diluted step by step with a diluent, and then detected by gas chromatography. The specific gas chromatography conditions were the same as those in Example 1. The limit of quantitation was obtained according to a signal-to-noise ratio of not less than 10:1, and the results are shown in Table 1.

[0098] Table 1

[0099]

[0100]

[0101] As can be seen from Table 1, in the quantitative limit solution, the S / N of the chromatographic peaks of ethanol, acetic acid, N,N-dimethylacetamide, benzene and chloroform are all greater than 10; the RSD of the retention times of ethanol, acetic acid, N,N-dimethylacetamide, benzene and chloroform are all ≤2.0%; the RSD of the peak areas of ethanol, acetic acid, N,N-dimethylacetamide, benzene and chloroform are all ≤10%. It shows that the quantitative limit of the present disclosure meets the requirements.

[0102] Example 4: Detection Limit

[0103] The reference solution 1 with an ethanol concentration of about 260.0000 μg / mL, an acetic acid concentration of about 260.0000 μg / mL, an N,N-dimethylacetamide concentration of about 58.0000 μg / mL and a benzene concentration of about 2.0000 μg / mL and the reference solution 2 with a chloroform concentration of about 3.2000 μg / mL prepared in Example 1 were diluted to an appropriate concentration as the detection limit solution, and detected by gas chromatography. The conditions of the gas chromatography were the same as those in Example 1. The detection limit was obtained according to a signal-to-noise ratio of not less than 3, and the results are shown in Table 2.

[0104] Table 2

[0105]

[0106]

[0107] As can be seen from Table 2, in the detection limit solution, the S / N of the chromatographic peaks of ethanol, acetic acid, N,N-dimethylacetamide, benzene and chloroform are all greater than 3. It shows that the detection limit of the present disclosure meets the requirements.

[0108] Example 5: Linear Relationship

[0109] According to Example 1, reference solution 1 and reference solution 2 were prepared. According to Table 3, an appropriate amount of the reference stock solutions of ethanol, acetic acid, N,N-dimethylacetamide, benzene and chloroform was accurately pipetted and placed in a suitable brown volumetric flask, diluted to the mark with the diluent, and shaken well. 2.0 mL of the above solution was accurately measured and placed in a 20 mL headspace vial, sealed to prepare linear solution 1.

[0110] Table 3

[0111]

[0112] According to Table 4, an appropriate amount of the reference stock solution of chloroform was accurately pipetted and placed in a suitable brown volumetric flask, diluted to the mark with the diluent, and shaken well. 2.0 mL of the above solution was accurately measured and placed in a 20 mL headspace vial, sealed to prepare linear solution 4.

[0113] Table 4

[0114]

[0115]

[0116] Detection was carried out by gas chromatography, and the conditions of gas chromatography were the same as those in Example 1. With the concentration of each component as the X-axis and the response as the Y-axis, a linear curve was plotted, and the correlation coefficient R, slope, and linear equation were calculated. The results are shown in Table 5, and the linear graph is shown in Figures 8 - 12 。

[0117] Table 5

[0118]

[0119]

[0120] As can be seen from Table 5, for ethanol in the range of 78.9300 μg / mL to 526.2000 μg / mL (equivalent to 30% to 200% of the limit concentration), the linear equation is y = 5904.6x - 39338, the correlation coefficient is 0.999, ≥ 0.990, and the linearity is good. For acetic acid in the range of 78.9600 μg / mL to 526.4000 μg / mL (equivalent to 30% to 200% of the limit concentration), the linear equation is y = 90.904x - 6632.7, the correlation coefficient is 0.9985, ≥ 0.990, and the linearity is good. For N,N-dimethylacetamide in the range of 17.4600 μg / mL to 116.4000 μg / mL (equivalent to 30% to 200% of the limit concentration), the linear equation is y = 39.2x - 327.51, the correlation coefficient is 0.9992, and the linearity is good. For benzene in the range of 0.6990 μg / mL to 4.6600 μg / mL (equivalent to 30% to 200% of the limit concentration), the linear equation is y = 39.2x - 327.51, the correlation coefficient is 0.9992, ≥ 0.990, and the linearity is good. For chloroform in the range of 0.9660 μg / mL to 6.4400 μg / mL (equivalent to 30% to 200% of the limit concentration), the linear equation is y = 1810.5x - 131.3, the correlation coefficient is 0.9903, ≥ 0.990, and the linearity is good.

[0121] Example 6: Repeatability

[0122] Six portions of reference solution 1, reference solution 2, spiked test solution 1, and spiked test solution 2 were prepared in parallel with reference to Example 1, and detection was carried out by gas chromatography. The specific conditions of gas chromatography were the same as those in Example 1, and the results are shown in Table 6.

[0123] Table 6

[0124]

[0125]

[0126] As can be seen from Table 6, the RSD of the ethanol peak area is 3.9%, the RSD of the acetic acid peak area is 6.1%, the RSD of the N,N-dimethylacetamide peak area is 8.3%, the RSD of the benzene peak area is 8.2%, and the RSD of the chloroform peak area is 9.1%, all ≤ 10%, indicating good repeatability of the present disclosure.

[0127] Example 7: Intermediate precision

[0128] Six reference solution 1, reference solution 2, repeatability solution 1, repeatability solution 2, intermediate precision solution 1 and intermediate precision solution 2 were prepared in parallel with reference to Example 1. The preparation of repeatability solution 1 and intermediate precision solution 1 was the same as that of the spiked test sample solution 1 in Example 1, and the preparation of repeatability solution 2 and intermediate precision solution 2 was the same as that of the spiked test sample solution 2 in Example 1. Gas chromatography was used for detection, and the specific conditions of gas chromatography were the same as those in Example 1. The results are shown in Table 7.

[0129] Table 7

[0130]

[0131]

[0132]

[0133] As can be seen from Table 7, for intermediate precision, the RSD of the ethanol peak area is 2.6%, the RSD of the acetic acid peak area is 2.6%, the RSD of the N,N-dimethylacetamide peak area is 8.0%, the RSD of the benzene peak area is 9.5%, and the RSD of the chloroform peak area is 9.4%, all ≤ 10%. For the results of 12 samples including 6 repeatability solutions, the RSD of the ethanol peak area is 3.2%, the RSD of the acetic acid peak area is 5.1%, the RSD of the N,N-dimethylacetamide peak area is 8.3%, the RSD of the benzene peak area is 8.9%, and the RSD of the chloroform peak area is 8.9%, all ≤ 10%. This indicates good intermediate precision of the detection method of the present disclosure.

[0134] Example 8: Accuracy

[0135] The accuracy tests of starting ethanol, acetic acid, and N,N-dimethylacetamide are expressed as recovery rate (%).

[0136] Reference solution 3: Accurately pipette 10 mL of ethanol reference stock solution, 10 mL of acetic acid reference stock solution, 10 mL of N,N-dimethylacetamide reference stock solution, and 1 mL of benzene reference stock solution into a 50 mL brown volumetric flask, dilute to the mark with diluent, and mix well. (Ethanol concentration: 520.0000 μg / mL, 0.0520%; Acetic acid concentration: 520.0000 μg / mL, 0.0520%; N,N-dimethylacetamide concentration: 116.0000 μg / mL, 0.0116%; Benzene concentration: 4.0000 μg / mL, 0.0004%)

[0137] Reference solution 4: Accurately pipette 1 mL of chloroform reference stock solution into a 50 mL brown volumetric flask, dilute to the mark with diluent, and mix well. (Chloroform concentration: 6.4000 μg / mL, 0.0006%)

[0138] Test solution 1 for 50% recovery: Take about 2.0 g of iopamidol raw material, accurately weigh it, place it in a 20 mL headspace vial, accurately pipette 0.5 mL of reference solution 3 and 1.5 mL of purified water, and seal. Prepare three replicates in parallel. (Ethanol concentration: 130.0000 μg / mL, 0.0130%; Acetic acid concentration: 130.0000 μg / mL, 0.0130%; N,N-dimethylacetamide concentration: 29.0000 μg / mL, 0.0029%; Benzene concentration: 1.0000 μg / mL, 0.0001%)

[0139] Test solution 1 for 100% recovery: Take about 2.0 g of iopamidol raw material, accurately weigh it, place it in a 20 mL headspace vial, accurately pipette 1.0 mL of reference solution 3 and 1.0 mL of purified water, and seal. Prepare three replicates in parallel. (Ethanol concentration: 260.0000 μg / mL, 0.0260%; Acetic acid concentration: 260.0000 μg / mL, 0.0260%; N,N-dimethylacetamide concentration: 58.0000 μg / mL, 0.0058%; Benzene concentration: 2.0000 μg / mL, 0.0002%)

[0140] Test solution 1 for 150% recovery: Take about 2.0 g of iopamidol raw material, accurately weigh it, place it in a 20 mL headspace vial, accurately pipette 1.5 mL of reference solution 3 and 0.5 mL of purified water, and seal. Prepare three replicates in parallel. (Ethanol concentration: 390.0000 μg / mL, 0.0390%; Acetic acid concentration: 390.0000 μg / mL, 0.0390%; N,N-dimethylacetamide concentration: 87.0000 μg / mL, 0.0087%; Benzene concentration: 3.0000 μg / mL, 0.0003%)

[0141] Test sample solution 2 with 50% recovery rate: Take about 2.0 g of ioversol raw material, weigh accurately, place it in a 20 mL headspace vial, accurately pipette 0.5 mL of reference solution 4 and 1.5 mL of purified water, and seal. Prepare three portions in parallel. (Concentration of chloroform: 1.6000 μg / mL, 0.0002%)

[0142] Test sample solution 2 with 100% recovery rate: Take about 2.0 g of ioversol raw material, weigh accurately, place it in a 20 mL headspace vial, accurately pipette 1.0 mL of reference solution 4 and 1.0 mL of purified water, and seal. Prepare three portions in parallel. (Concentration of chloroform: 3.2000 μg / mL, 0.0003%)

[0143] Test sample solution 2 with 150% recovery rate: Take about 2.0 g of ioversol raw material, weigh accurately, place it in a 20 mL headspace vial, accurately pipette 1.5 mL of reference solution 4 and 0.5 mL of purified water, and seal. Prepare three portions in parallel. (Concentration of chloroform: 4.8000 μg / mL, 0.0005%).

[0144] Detection was carried out by gas chromatography. The specific conditions of gas chromatography were the same as those in Example 1, and the results are shown in Table 8 below.

[0145] Table 8

[0146]

[0147]

[0148] As can be seen from Table 8, the recovery rate of ethanol was in the range of 104.54% - 119.46%, the RSD was 4.4%, ≤10%, meeting the requirements; the recovery rate of acetic acid was in the range of 95.02% - 108.74%, the RSD was 4.8%, ≤10%, meeting the requirements; the recovery rate of N,N-dimethylacetamide was in the range of 95.09% - 108.3%, the RSD was 5.1%, ≤10%, meeting the requirements; the recovery rate of benzene was in the range of 96.73% - 113.67%, the RSD was 5.9%, ≤10%, meeting the requirements; the recovery rate of chloroform was in the range of 92.05% - 117.74%, the RSD was 8.9%, ≤10%, meeting the requirements. It shows that the accuracy of the detection method disclosed in this application is good.

[0149] Example 9: Solution stability

[0150] Stability of ethanol, acetic acid, N,N-dimethylacetamide, benzene and chloroform solutions: Take Stability Solution 1, Stability Solution 2, Reference Solution 1 and Reference Solution 2 and measure them after standing at room temperature for different times. Stability Solution 1 and Stability Solution 2 are prepared in the same way as the spiked test sample solutions 1 and 2 in Example 1. Calculate the RSD of the chromatographic peak areas of ethanol, acetic acid, N,N-dimethylacetamide, benzene and chloroform solutions. Detection is carried out by gas chromatography. The specific conditions of gas chromatography are the same as those in Example 1. The results are shown in Table 9.

[0151] Table 9

[0152]

[0153]

[0154] As can be seen from Table 9, the RSD of the ethanol peak area is 3.0%, the RSD of the acetic acid peak area is 6.2%, the RSD of the N,N-dimethylacetamide peak area is 7.9%, the RSD of the benzene peak area is 10.0%, and the RSD of the chloroform peak area is 7.9%, all ≤ 10%. It shows that the solution stability of the detection method disclosed in this application is good.

[0155] Example 10: Durability

[0156] Prepare spiked test sample solution 1 and spiked test sample solution 2 according to Example 1. Detection is carried out by gas chromatography. The normal conditions refer to the gas chromatography conditions in Example 1. Condition 1: The initial column temperature is 38 °C, and the rest are the same as the normal conditions; Condition 2: The initial column temperature is 42 °C, and the rest are the same as the normal conditions; Condition 3: The detector temperature is 245 °C, and the rest are the same as the normal conditions; Condition 4: The detector temperature is 255 °C, and the rest are the same as the normal conditions; Condition 5: The inlet temperature is 225 °C, and the rest are the same as the normal conditions; Condition 6: The inlet temperature is 235 °C, and the rest are the same as the normal conditions. The results are shown in Table 10.

[0157] Table 10

[0158]

[0159]

[0160]

[0161] As can be seen from Table 10, the RSD of ethanol content measured at different column temperatures was 5.0%, the RSD of acetic acid content was 9.5%, the RSD of N,N-dimethylacetamide content was 5.9%, the RSD of benzene content was 2.8%, and the RSD of chloroform content was 6.7%, all ≤ 10%; the RSD of ethanol content measured at different detector temperatures was 2.7%, the RSD of acetic acid content was 7.0%, the RSD of N,N-dimethylacetamide content was 6.9%, the RSD of benzene content was 7.3%, and the RSD of chloroform content was 9.6, all ≤ 10%; the RSD of ethanol content measured at different injection port temperatures was 2.1%, the RSD of acetic acid content was 9.1%, the RSD of N,N-dimethylacetamide content was 7.6%, the RSD of benzene content was 6.9%, and the RSD of chloroform content was 5.1%, all ≤ 10%. It shows that the solution durability of the detection method of the present disclosure is good.

[0162] Example 11: Sample Determination

[0163] According to the detection method of residual solvents ethanol, acetic acid, N,N-dimethylacetamide, benzene and chloroform in iopamidol raw material drug described in Example 1, two parallel solutions of a batch of samples were injected for analysis, and the contents of residual solvents ethanol, acetic acid, N,N-dimethylacetamide, benzene and chloroform in iopamidol raw material drug were detected by the detection method. Gas chromatography was used for detection, and the specific conditions of gas chromatography were the same as those in Example 1. The results are shown in Table 11.

[0164] Table 11

[0165]

[0166] As can be seen from Table 11, ethanol was detected in both of the two parallel iopamidol raw material drugs in a batch, while acetic acid, N,N-dimethylacetamide, benzene and chloroform were not detected.

Claims

1. A method for detecting residual solvents in ioversol, wherein the residual solvents are determined by headspace gas chromatography, wherein the residual solvents are selected from one or more of ethanol, acetic acid, N,N-dimethylacetamide, benzene and chloroform; The conditions of the headspace gas chromatography are: The chromatographic column is an ultra-high inert gas chromatographic column, and its filler is cyanopropyl-phenyl-polydimethylsiloxane; The headspace equilibrium temperature is 90-110°C, and the headspace equilibrium time is 20-40 minutes; The injection mode was split injection with a split ratio of 1:

1.

2. A detection method for determining at least two residual solvents in ioversol, which is determined by headspace gas chromatography, wherein the residual solvent is selected from ethanol, acetic acid, N,N-dimethylacetamide, benzene and chloroform, and the conditions of the headspace gas chromatography are: The chromatographic column is an ultra-high inert gas chromatographic column, and its filler is cyanopropyl-phenyl-polydimethylsiloxane; The headspace equilibrium temperature is 90-110°C, and the headspace equilibrium time is 20-40 minutes; The injection mode was split injection with a split ratio of 1:

1.

3. The detection method according to claim 1 or 2, wherein the filler of the ultra-high inert gas chromatography column is 6% cyanopropyl / phenyl and 94% polydimethylsiloxane; preferably, the ultra-high inert gas chromatography column is a DB624UI chromatography column.

4. The detection method according to any one of claims 1 to 3, wherein the carrier gas is nitrogen or helium, preferably nitrogen; And / or, the flow rate of the carrier gas is 2-4 mL / min, preferably 3 mL / min.

5. The detection method according to any one of claims 1-4, wherein the column temperature of the headspace gas chromatography is programmed, with an initial temperature of 36-44°C, which is increased to 190-210°C at a rate of 15-25°C / min and maintained for 5-15 min; preferably, the initial temperature is 40°C, which is increased to 200°C at a rate of 20°C / min and maintained for 10 min.

6. The detection method according to any one of claims 1 to 5, wherein the headspace equilibrium temperature of the headspace gas chromatography is 100°C and the headspace equilibrium time is 30 min.

7. The detection method according to any one of claims 1 to 6, wherein the injection port temperature of the headspace gas chromatography is 210 to 240°C, preferably 220°C; And / or, the detector of the headspace gas chromatography is a hydrogen flame ionization detector; And / or, the temperature of the detector of the headspace gas chromatography is 240-260°C, preferably 250°C.

8. The detection method according to any one of claims 1 to 7, wherein the injection mode of the headspace gas chromatography is split injection, and the split ratio is 0.2 to 5:1, preferably 1:1; And / or, the injection volume of the headspace gas chromatography is 0.1 to 3 μL, preferably 1 μL; And / or, the running time of the headspace gas chromatography is 45 to 60 min, preferably 52 min.

9. The detection method according to any one of claims 1 to 8, wherein the detection method comprises the following steps: (1) preparing a reference solution containing the residual solvent according to claim 1 or 2; (2) preparing a test solution of iodine; (3) Use headspace gas chromatography to detect the reference solution and the test solution respectively.

10. The detection method according to claim 9, wherein in step (1), the preparation method of the reference solution containing residual solvent comprises: The diluent and the residual solvent are mixed to obtain a reference substance stock solution, and the reference substance stock solution is diluted 5 to 200 times with the diluent to obtain a reference substance solution, wherein the diluent is water; And / or, in step (2), the test solution contains the residual solvent according to claim 1, and the preparation method of the test solution of ioversol comprises: mixing ioversol with the reference solution in step (1) to obtain the test solution.

11. The detection method according to any one of claims 1 to 10, wherein the detection method satisfies one or more of the following: (1) The separation degree of one or more peaks of ethanol, chloroform, acetic acid, benzene and N,N-dimethylacetamide measured by the detection method is greater than 1.5; (2) The RSD of the peak area of ​​one or more peaks of ethanol, chloroform, acetic acid, benzene and N,N-dimethylacetamide measured by the detection method is less than or equal to 10%; (3) The S / N ratio of one or more peaks of ethanol, chloroform, acetic acid, benzene and N,N-dimethylacetamide measured by the detection method is greater than 3; (4) The S / N ratio of one or more peaks of ethanol, chloroform, acetic acid, benzene and N,N-dimethylacetamide measured by the detection method is greater than 10; (5) The retention time RSD of one or more peaks of ethanol, chloroform, acetic acid, benzene and N,N-dimethylacetamide measured by the detection method is less than or equal to 2.0%.

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