Method for detecting residual solvent in istradefylline bulk drug

Abstract

The invention discloses a method for detecting a residual solvent in an istradefylline bulk drug, which comprises the following steps: taking the istradefylline bulk drug, preparing a test solution, injecting the test solution into a gas chromatograph, adopting a capillary column with 6% cyanopropylphenyl-94% methylsiloxane as a stationary phase, carrying out programmed temperature rise, setting the temperature of a sample inlet to be 195-205 DEG C, and detecting the residual solvent in the istradefylline bulk drug. The temperature of a flame ionization detector (FID) is 245-255 DEG C, the column temperature is 38-42 DEG C, the column pressure is 98-102 kPa, the split ratio is 10: 1, the sample size is 1 [mu] L, and the peak area is calculated according to an external standard method. According to the technical scheme, by adopting the chromatographic conditions, the separation degree between the solvents is larger than 1.5, operation is easy, specificity is good, sensitivity is high, and the residual solvents in the istradefylline raw material medicine can be effectively separated.

Description

Technical Field

[0001] This invention relates to a method for detecting residual solvents in itratheline raw materials, belonging to the field of pharmaceutical analysis technology. Background Technology

[0002] The chemical name of itratheline is 8-[( E [-2-(3,4-dimethoxyphenyl)vinyl]-1,3-diethyl-7-methylpurine-2,6-dione, with the following structural formula:

[0003]

[0004] Itradefylline is the first adenosine A2A receptor antagonist. It works by blocking receptors in the striatum and globus pallidus. Developed by Kyowa Hakko Co., Ltd. of Japan, it was approved for marketing in Japan in March 2013 for the treatment of Parkinson's disease decline by using levodopa-containing preparations.

[0005] The organic solvents used in the synthesis of itratheline raw materials include ethanol, dichloromethane, n-hexane, ethyl acetate, 1,4-dioxane, pyridine, toluene, N,N-dimethylformamide, etc. According to the ICH guidelines and the General Rules Appendix of the 2020 edition of the Chinese Pharmacopoeia (Part IV), residual solvents should be tested to ensure drug safety.

[0006] There are currently no literature reports on the determination of residual solvents in itratheline raw materials. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, the present invention provides a method for detecting residual solvents in itratheline raw materials, filling the gap in the existing technology for determining residual solvents in itratheline raw materials.

[0008] To achieve the above objectives, the present invention provides a method for detecting residual solvents in itratheline raw materials. The method comprises: using gas chromatography, taking itratheline raw materials, dissolving them in a solvent to prepare a test solution, and injecting the test solution into a gas chromatograph; using a capillary column with 6% cyanopropylphenyl-94% polydimethylsiloxane as the stationary phase, with programmed temperature rise, and setting the injection port temperature, flame ionization detector temperature, column temperature, column pressure, split ratio, and injection volume.

[0009] According to an embodiment of the present invention, the solvent is N-methylpyrrolidone, and the test solution is a solution containing 50 mg of itratheline raw material per 1 mL.

[0010] According to an embodiment of the present invention, the capillary column with 6% cyanopropylphenyl-94% polydimethylsiloxane as the stationary liquid is selected from DB-624 capillary columns with a specification of 60 m × 0.32 mm × 1.8 mm.

[0011] According to an embodiment of the present invention, the programmed temperature rise is as follows: the initial temperature is 40 °C, maintained for 8 min, the temperature is increased to 80 °C at a rate of 10 °C / min, maintained for 15 min, and then the temperature is increased to 220 °C at a rate of 40 °C / min, maintained for 15 min.

[0012] According to an embodiment of the present invention, the injection port temperature is selected from 195~205℃, the detector temperature is selected from 245~255℃, the column temperature is selected from 38~42℃, and the column pressure is selected from 98~102kPa.

[0013] Preferably, the injection port temperature is 200°C, the detector temperature is 250°C, the column temperature is 40°C, and the column pressure is 100 kPa.

[0014] According to an embodiment of the present invention, the split ratio is 10:1.

[0015] According to an embodiment of the present invention, the injection volume is 1 μL.

[0016] According to an embodiment of the present invention, before preparing the test solution, the method further includes:

[0017] 1) Prepare a mixed solution containing 250 μg ethanol, 30 μg dichloromethane, 14.5 μg n-hexane, 250 μg ethyl acetate, 19 μg 1,4-dioxane, 10 μg pyridine, 44.5 μg toluene, and 44 μg N,N-dimethylformamide (DMF) per 1 mL as the system suitability solution;

[0018] 2) Take the system suitability solution, inject it into the gas chromatograph, and detect and record the chromatogram under the chromatographic conditions.

[0019] The beneficial effects of this invention are:

[0020] Compared with existing technologies, the detection method disclosed in this invention can effectively separate eight organic solvents in itratheline raw materials at the same time. The operation method is simple and fast, which improves the efficiency of itratheline drug quality detection. Attached Figure Description

[0021] Figure 1 Screening of 1-system suitability solutions for itratheline analysis methods;

[0022] Figure 2 Screening of 2-system suitability solutions for itratheline analysis methods;

[0023] Figure 3 Blank solvent for verifying the specificity of the itratheline analytical method;

[0024] Figure 4 Solution for validating the specificity and system suitability of the itratheline analytical method;

[0025] Figure 5 For the validation of the theophylline analytical method - sample determination - system suitability solution;

[0026] Figure 6 For the validation of the analytical method for itratheline - sample determination - test solution (batch number 158210401);

[0027] Figure 7 For the validation of the analytical method for itratheline - sample determination - test solution (batch number 158210402);

[0028] Figure 8 For the validation of the analytical method for itratheline - sample determination - test solution (batch number 158210403). Detailed Implementation

[0029] Instruments and reagents

[0030] Table 1 Instrument Information

[0031]

[0032] Table 2 Reagent Information

[0033]

[0034] Table 3 Sample Information

[0035]

[0036] Table 4. Determination of Solvent Residue in Itraphylline Raw Material

[0037]

[0038] Example 1: Specificity Test

[0039] Solvent: Initially, dimethyl sulfoxide was selected as the solvent, but it was found that blank dimethyl sulfoxide interfered with its peak elution, so the solvent was changed to N-methylpyrrolidone.

[0040] Take appropriate amounts of ethanol, dichloromethane, n-hexane, ethyl acetate, 1,4-dioxane, pyridine, toluene, and N,N-dimethylformamide in the same volumetric flask, and dilute with solvent to prepare a solution containing approximately 250 μg ethanol, 30 μg dichloromethane, 14.5 μg n-hexane, 250 μg ethyl acetate, 19 μg 1,4-dioxane, 10 μg pyridine, 44.5 μg toluene, and 44 μg N,N-dimethylformamide per ml. Shake well and use as the system suitability solution.

[0041] Separately, take appropriate amounts of ethanol, dichloromethane, n-hexane, ethyl acetate, 1,4-dioxane, pyridine, toluene, and N,N-dimethylformamide, and dilute them with solvents to prepare solutions of suitable concentrations, which will be used as positioning solutions for each solvent.

[0042] Under the chromatographic conditions described above, blank solution, system suitability solution, and each solvent localization solution were analyzed according to the method, and the chromatograms were recorded as follows: Figures 3-4 The results are shown in Table 5 below:

[0043] Table 5 Specificity Experiment Results

[0044]

[0045] Conclusion: Under the above chromatographic conditions, the resolution between each solvent and adjacent peaks was >1.5, and the theoretical plate number was >5000, indicating good method specificity.

[0046] Example 2: Linearity and Range

[0047] Take appropriate amounts of ethanol, dichloromethane, n-hexane, ethyl acetate, 1,4-dioxane, pyridine, toluene, and N,N-dimethylformamide, respectively, dissolve and dilute them in solvent (N-methylpyrrolidone) to prepare a mixed solution containing approximately 2.5 mg of ethanol, 0.3 mg of dichloromethane, 0.145 mg of n-hexane, 2.5 mg of ethyl acetate, 0.19 mg of 1,4-dioxane, 0.1 mg of pyridine, 0.445 mg of toluene, and 0.44 mg of N,N-dimethylformamide per ml. Shake well and use as the standard stock solution.

[0048] Transfer 0.15 mL, 0.3 mL, 0.5 mL, 0.7 mL, and 1.0 mL of the standard stock solution to 5 mL volumetric flasks, respectively, and dilute with N-methylpyrrolidone to prepare solutions of 30%, 60%, 100%, 140%, and 200%, respectively. Shake well to obtain linear solutions of each gradient concentration.

[0049] Accurately measure 1 μl of the linear solution and inject it into the gas chromatograph, then record the chromatogram. Perform linear regression on the peak area A using the solvent concentration ρ, and the results are shown in Table 6 below:

[0050] Table 6 Results of Linear Experiments

[0051]

[0052] Conclusion: The linear relationship of each solvent is good between 30% and 200% of its corresponding limit concentration, with r greater than 0.998 and y-intercept deviation less than 25% of the 100% response value.

[0053] Example 3: Limit of Quantitation and Limit of Detection

[0054] Reference stock solution: Same as "Standard stock solution" under the linearity and range section;

[0055] Take an appropriate amount of the standard stock solution and dilute it stepwise at a signal-to-noise ratio of approximately 3:1 to prepare a detection limit solution; dilute it stepwise at a signal-to-noise ratio of approximately 10:1 to prepare a quantitation limit solution. Accurately measure 1 μl of each solution and inject it into the chromatograph sequentially. Inject the quantitation limit solution into the chromatograph six times consecutively and record the chromatograms. The results are shown in Tables 7 and 8 below.

[0056] Table 7 Results of Limit of Quantitation and Limit of Detection

[0057]

[0058] Table 8 Precision results of limit of quantitation injection

[0059]

[0060] Conclusion: Under these chromatographic conditions, the limits of quantitation and detection for each solvent are lower than the limit concentration of this product, and the RSD of the limit of quantitation peak area is less than 20% (n=6), indicating that the above method can effectively detect the residues of each solvent.

[0061] Example 4 Accuracy

[0062] Reference stock solution: Same as "Standard stock solution" under the linearity and range section;

[0063] Reference solution: Measure 1 ml of the standard stock solution into a 10 ml volumetric flask, dilute to the mark with solvent (N-methylpyrrolidone), and shake well to obtain the reference solution;

[0064] Spiked test solution: Take about 100 mg of this product and place it in a 2 ml volumetric flask. Add 0.16 ml (80% concentration), 0.2 ml (100% concentration), and 0.24 ml (120% concentration) of standard stock solution respectively. Dissolve and dilute to the mark with solvent (N-methylpyrrolidone), shake well, and use as the spiked test solution (prepare 3 parallel portions of each concentration solution).

[0065] Inject 1 μl each of the reference solution and the spiked test solution into the gas chromatograph. Record the chromatograms, calculate the amount of each solvent by peak area using the external standard method, and calculate the recovery rate. The results are shown in Table 9 below:

[0066] Table 9 Results of Recovery Test

[0067]

[0068] Conclusion: The recoveries of each solvent were 90%–110% at various concentration gradients within the range of 80%–120%, with RSDs all <10%, indicating good accuracy of the method.

[0069] Example 5 Sample Injection Precision

[0070] Six consecutive injections were performed using a 100% limit concentration solution under the "Linearity and Range" section. Chromatograms were recorded, and the peak area and retention time RSD were calculated. The results are shown in Table 10 below.

[0071] Table 10 Results of Injection Precision Test

[0072]

[0073] Conclusion: When the same solution was injected six times consecutively, the peak area RSD of the analyte was always <10.0%, and the retention time RSD was always <1.0%. The injection precision was good.

[0074] Example 6 Solution Stability

[0075] Test solution: Take an appropriate amount of this product, dissolve and dilute it with solvent (N-methylpyrrolidone) to prepare a solution containing about 50 mg per 1 ml, which is used as the test solution;

[0076] Reference solution: Take the 100% limit concentration solution under the "Linearity and Range" section as the reference solution;

[0077] The above solution was left at room temperature, and 1 μl was precisely measured and injected into the gas chromatograph at 0, 2, 4, 6, 8, 10, 12, and 24 hours, respectively. The chromatograms were recorded to examine the stability of the solution at room temperature. The experimental results are shown in Tables 11 and 12 below.

[0078] Table 11 Results of the stability test of the test sample solution

[0079]

[0080] Table 12 Results of stability test of reference solution

[0081]

[0082] Conclusion: The test solution showed good stability under natural conditions for 24 hours, with RSD < 10% (n=8); the reference solution also showed good stability under natural conditions for 24 hours, with RSD < 10% (n=8).

[0083] Example 7 Durability

[0084] Reference solution: Take the 100% limit concentration solution under the "Linearity and Range" section as the reference solution;

[0085] Spiked test solution: The same as the 100% accuracy solution under the "Accuracy" section is used as the spiked test solution;

[0086] The chromatographic conditions for detecting this product were appropriately varied, including detector temperature (250℃±5℃), injection port temperature (200℃±5℃), column temperature (40℃±2℃), column pressure (100kPa±2kPa), and different batches of chromatographic columns (DB-624 capillary columns). The evaluation indicators included system suitability, peak elution time of impurity peaks in the solution, theoretical plate number, resolution, and recovery rate of the spiked sample. The test results are shown in Table 13 below:

[0087] Table 13 Durability Results

[0088]

[0089] Note: Column 1 and Column 2 represent columns of the same model but from different batches.

[0090] Conclusion: When there are slight changes in the initial column temperature, injection port temperature, detector temperature, and column pressure in the chromatographic conditions, or when different batches of chromatographic columns are used, the resolution of each solvent is not less than 1.5, the theoretical plate number is not less than 5000, the recovery rate of the test sample is within the qualified range, and there is almost no impact on the detection of each residual solvent.

[0091] Example 8 Sample Determination

[0092] Test solution: Take an appropriate amount of the raw material of this product, accurately weigh it, put it into a 50 ml volumetric flask, add N-methylpyrrolidone to dissolve and dilute to the mark, and prepare a solution containing about 50 mg per 1 mL as the test solution;

[0093] Reference solution: Take the 100% limit concentration solution under the "Linearity and Range" section as the reference solution;

[0094] The stationary phase consisted of 6% cyanopropylphenyl-94% methylsiloxane (or a similar polarity). The initial temperature was 40°C, maintained for 8 minutes, then increased to 80°C at a rate of 10°C per minute, maintained for 15 minutes, and then increased to 220°C at a rate of 40°C per minute, maintained for 15 minutes. The detector was a flame ionization detector (FID) with a detector temperature of 250°C. The injection port temperature was 200°C, and the injection volume was 1 μl.

[0095] The system suitability requirements stipulate that in the chromatogram of the reference solution, ethanol, dichloromethane, n-hexane, ethyl acetate, 1,4-dioxane, pyridine, toluene, and N,N-dimethylformamide should elute in sequence, and the resolution between each component peak should meet the requirements.

[0096] For the assay, accurately measure the reference solution and the test solution, inject them separately into the gas chromatograph, and record the chromatograms.

[0097] The limits are calculated based on peak area using the external standard method. This product contains no more than 0.5% ethanol, no more than 0.5% ethyl acetate, no more than 0.038% 1,4-dioxane, no more than 0.029% n-hexane, no more than 0.02% pyridine, no more than 0.089% toluene, no more than 0.088% N,N-dimethylformamide, and no more than 0.06% dichloromethane.

[0098] Three batches of this product were taken to test for solvent residues in the active pharmaceutical ingredient. The chromatograms are shown in the figure below. Figures 5-8 The test results are shown in Table 14 below:

[0099] Table 14 Solvent Residue Detection Results

[0100]

[0101] Example 9: Conditional Filtering 1

[0102] A CP-Volamine column (30m × 0.32mm, 5.0μm) was used. The initial temperature was 60℃, maintained for 10 minutes, and then increased to 240℃ at a rate of 30℃ per minute, maintained for 25 minutes. A flame ionization detector (FID) was used with a detector temperature of 260℃; the injection port temperature was 200℃; the column pressure was 30 kPa; the split ratio was 30:1; and the injection volume was 1 μl.

[0103] The system suitability solution from Example 8 was used as the test sample, and the chromatogram was recorded. The results showed that the resolution did not meet the requirements under these conditions. Figure 1 .

[0104] By selecting other column types based on solvent properties and screening for appropriate conditions, ideal separation results can be obtained.

[0105] Example 10 Conditional Filtering 2

[0106] A DB-624 capillary column (60m × 0.32mm × 1.8mm) was used. The initial temperature was 40℃, maintained for 8 minutes, then increased to 100℃ at a rate of 10℃ per minute, maintained for 8 minutes; finally, the temperature was increased to 220℃ at a rate of 30℃ per minute, maintained for 15 minutes. A flame ionization detector (FID) was used, with a detector temperature of 250℃; the injection port temperature was 200℃; the column pressure was 100 kPa; the split ratio was 15:1; and the injection volume was 1 μl.

[0107] The system suitability solution from Example 8 was used as the test sample, and the chromatogram was recorded. The results showed that under these conditions, the separation between pyridine and toluene was poor. Figure 2 .

[0108] By changing the heating program and the splitting ratio, ideal separation results can be obtained.

[0109] The above description is only a part or preferred embodiment of the present invention. Neither the text nor the drawings should limit the scope of protection of the present invention. All equivalent structural transformations made using the content of the present invention specification and drawings under the overall concept of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present invention.

Claims

1. A method for detecting residual solvent in itratheline raw material, characterized in that, The method is as follows: gas chromatography is used to prepare a test solution by dissolving isotretinoin raw material in a solvent, and injecting the test solution into the gas chromatograph; a capillary column with 6% cyanopropylphenyl-94% polydimethylsiloxane as stationary liquid is used, and the temperature is programmed, with the injection port temperature, flame ionization detector temperature, column temperature, column pressure, split ratio and injection volume set.

2. The method for detecting residual solvent in itratheline raw material according to claim 1, characterized in that, The solvent is N-methylpyrrolidone, and the test solution is a solution containing 50 mg of itratheline raw material per 1 mL.

3. The method for detecting residual solvent in itratheline raw material according to claim 1, characterized in that, The capillary column is selected from DB-624 capillary columns, with specifications of 60 m × 0.32 mm × 1.8 mm.

4. The method for detecting residual solvent in itratheline raw material according to claim 1, characterized in that, The temperature program is as follows: the initial temperature is 40 ℃, maintained for 8 min, then increased to 80 ℃ at a rate of 10 ℃ / min, maintained for 15 min, and then increased to 220 ℃ at a rate of 40 ℃ / min, maintained for 15 min.

5. The method for detecting residual solvent in itratheline raw material according to claim 1, characterized in that, The injection port temperature is selected from 195~205℃, the detector temperature is selected from 245~255℃, the column temperature is selected from 38~42℃, and the column pressure is selected from 98~102kPa.

6. The method for detecting residual solvent in itratheline raw material according to claim 5, characterized in that, The injection port temperature is 200℃, the detector temperature is 250℃, the column temperature is 40℃, and the column pressure is 100kPa.

7. The method for detecting residual solvent in itratheline raw material according to claim 1, characterized in that, The aforementioned split ratio is 10:

1.

8. The method for detecting residual solvent in itratheline raw material according to claim 1, characterized in that, The injection volume is 1 μL.

9. The method for detecting residual solvent in itratheline raw material according to claim 1, characterized in that, Before preparing the test solution, the following steps are also included: 1) Prepare a mixed solution containing 250 μg ethanol, 30 μg dichloromethane, 14.5 μg n-hexane, 250 μg ethyl acetate, 19 μg 1,4-dioxane, 10 μg pyridine, 44.5 μg toluene, and 44 μg N,N-dimethylformamide (DMF) per 1 mL as the system suitability solution; 2) Take the system suitability solution, inject it into the gas chromatograph, and detect and record the chromatogram under the chromatographic conditions.

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