A method for detecting multiple residual solvents in cabergoline active pharmaceutical ingredient

Abstract

This invention provides a method for detecting multiple residual solvents in cabergoline raw material, comprising: (1) gas chromatography analysis using a moderately polar polysiloxane capillary column; (2) weighing nine reference standards, dissolving them in dimethyl sulfoxide and mixing them to a final volume to obtain reference standard solutions; weighing a cabergoline sample, dissolving it in dimethyl sulfoxide and mixing it to a final volume to obtain a test solution; (3) performing gas chromatography analysis on the reference standard solution and the test solution respectively using step (1), recording the chromatograms, and calculating the content of each residual solvent in the test solution by peak area according to the external standard method. This invention can detect multiple residual solvents in cabergoline raw material simultaneously, detects a wide variety of residual solvents, has high detection efficiency, and saves manpower and resources.

Description

Technical Field

[0001] This invention relates to the field of analytical chemistry, and particularly to the field of residual solvent detection technology in cabergoline active pharmaceutical ingredient (API), specifically a method for detecting multiple residual solvents in cabergoline API. Background Technology

[0002] Cabergoline is a synthetic ergoline derivative and a long-acting dopamine receptor agonist with a high affinity for dopamine D2 receptors. Cabergoline inhibits prolactin secretion by acting on dopamine receptors in the pituitary gland. It also binds to dopamine D2 receptors in the striatum, mimicking the role of dopamine in motor control. Due to its free radical scavenging activity, cabergoline also possesses antioxidant and neuroprotective properties. Cabergoline is used to treat Parkinson's disease and hyperprolactinemia and pituitary adenomas with hyperprolactinemia. After oral administration, cabergoline is moderately bound to plasma proteins (approximately 50%) after absorption, with the remainder being metabolized in the liver through hydrolysis. Metabolites and approximately 4% of the unabsorbed drug are excreted in the urine. It is estimated that cabergoline has a half-life of approximately 60 hours. Its chemical name is 6-allyl-N-[3-(dimethylamino)propyl]-N-(ethylcarbamoyl)ergoline-8-carboxamide, and its structural formula is shown in Formula I below:

[0003]

[0004] I

[0005] Analysis of existing cabergoline synthesis processes revealed that cabergoline products may contain various organic solvents with potential safety hazards, including hydrocarbons (toluene, isobutylene), halogenated hydrocarbons (p-fluorotoluene), alcohols (methanol), ethers (methyl tert-butyl ether, tetrahydrofuran), esters (ethyl acetate), ketones (acetone), and amides (N,N-dimethylformamide). Since residual organic solvents not only offer no therapeutic benefit but may also harm human health, they should be removed as much as possible.

[0006] Currently, none of the published cabergoline patents cover analytical methods for cabergoline. While methods for detecting cabergoline content and related substances can be found in foreign pharmacopoeias such as USP-NF2023, EP11.0, and JP18, these methods do not cover the detection of residual solvents and therefore cannot meet the requirements for controlling residual solvents.

[0007] Therefore, it is desirable to provide a method for detecting multiple residual solvents in cabergoline raw material, which can detect multiple residual solvents in cabergoline raw material simultaneously, detect a wide variety of residual solvents, has high detection efficiency, and saves manpower and resources. Summary of the Invention

[0008] In order to overcome the shortcomings of the prior art, one object of the present invention is to provide a method for detecting multiple residual solvents in cabergoline raw material, which can detect multiple residual solvents in cabergoline raw material simultaneously, detects a wide variety of residual solvents, has high detection efficiency, saves manpower and material resources, and is suitable for large-scale promotion and application.

[0009] To achieve the above objectives, this invention provides a method for detecting multiple residual solvents in cabergoline raw material, characterized in that the multiple residual solvents include methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and isobutylene, and the method includes the following steps:

[0010] (1) Determine the gas chromatography analysis method:

[0011] Gas chromatography analysis was performed using a moderately polar polysiloxane capillary column;

[0012] (2) Preparation of reference solution and test solution:

[0013] Nine reference standards were weighed separately: methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide and isobutylene. They were dissolved in dimethyl sulfoxide and diluted to volume to prepare reference standard solutions.

[0014] Weigh out the cabergoline sample, dissolve it in dimethyl sulfoxide and mix thoroughly to obtain the test solution;

[0015] (3) Determination of residual solvent in cabergoline samples:

[0016] The reference solution and the test solution were subjected to gas chromatography analysis in step (1), the chromatograms were recorded, and the contents of each residual solvent in the test solution, namely methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide and isobutylene, were calculated by peak area according to the external standard method.

[0017] Preferably, in step (1), the medium-polarity polysiloxane capillary column is a capillary column with medium-polarity 6% cyanopropylphenyl-94% dimethyl polysiloxane as the stationary phase.

[0018] Preferably, in step (1), the gas chromatography analysis is performed under the following conditions:

[0019] Carrier gas: Nitrogen;

[0020] Injection: Direct injection;

[0021] Column temperature: The initial temperature is 50℃, maintained for 8 minutes, and then increased to 200℃ at a rate of 10℃ / min, and maintained for 12 minutes.

[0022] Inlet temperature: 150℃;

[0023] Detector: FID detector, detector temperature is 250℃;

[0024] Injection volume 1 μl;

[0025] Column flow rate: 0.8 mL / min ~ 1.2 mL / min;

[0026] Split ratio: 28:1~32:1.

[0027] More preferably, in step (1), the column flow rate is 1 mL / min.

[0028] More preferably, in step (1), the split ratio is 30:1.

[0029] Preferably, in step (2), the mass concentrations of methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and isobutylene in the reference solution are 300 μg / ml, 500 μg / ml, 500 μg / ml, 500 μg / ml, 72 μg / ml, 89 μg / ml, 150 μg / ml, 88 μg / ml, and 50 μg / ml, respectively.

[0030] Preferably, in step (2), the mass concentration of cabergoline in the test solution is 100 mg / mL.

[0031] The main beneficial effects of this invention are:

[0032] The method for detecting multiple residual solvents in cabergoline raw material of the present invention is used to detect multiple residual solvents, including methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide and isobutylene, comprising the following steps: (1) determining the gas chromatography analysis method: gas chromatography analysis is performed using a moderately polar polysiloxane capillary column; (2) preparing reference solution and test solution: weighing 9 reference standards methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide and isobutylene respectively. Dimethyl sulfoxide was used to dissolve and dilute the solution to prepare a reference solution; cabergoline sample was weighed, dissolved and diluted to prepare a test solution; (3) Determination of residual solvents in cabergoline sample: Gas chromatography analysis was performed on the reference solution and test solution in step (1), the chromatograms were recorded, and the content of each residual solvent in the test solution was calculated by peak area according to the external standard method. Therefore, it can detect multiple residual solvents in cabergoline raw material and can detect them simultaneously. It can detect a wide variety of residual solvents, has high detection efficiency, saves manpower and resources, and is suitable for large-scale promotion and application.

[0033] These and other objects, features and advantages of the present invention will be fully apparent from the following detailed description and drawings, and can be achieved by the means, devices and combinations thereof specifically pointed out in the summary of the invention. Attached Figure Description

[0034] Figure 1 This is a gas chromatogram of nine reference standards in a reference solution.

[0035] Figure 2 This is a linear relationship graph of methanol, where x is the concentration (mg / ml) and y is the peak area.

[0036] Figure 3 This is a linear relationship graph of acetone, where x is the concentration (mg / ml) and y is the peak area.

[0037] Figure 4 This is a linear relationship graph of tert-butyl methyl ether, where x is the concentration (mg / ml) and y is the peak area.

[0038] Figure 5 This is a linear relationship graph of ethyl acetate, where x is the concentration (mg / ml) and y is the peak area.

[0039] Figure 6 This is a linear relationship graph of tetrahydrofuran, where x is the concentration (mg / ml) and y is the peak area.

[0040] Figure 7 This is a linear relationship graph of toluene, where x is the concentration (mg / ml) and y is the peak area.

[0041] Figure 8 This is a linear relationship graph of p-fluorotoluene, where x is the concentration (mg / ml) and y is the peak area.

[0042] Figure 9 This is a linear relationship graph of N,N-dimethylformamide, where x is the concentration (mg / ml) and y is the peak area.

[0043] Figure 10 This is a linear relationship graph of isobutylene, where x is the concentration (mg / ml) and y is the peak area. Detailed Implementation

[0044] Cabergoline raw materials may contain various organic solvents with potential safety hazards. These residual organic solvents not only offer no therapeutic benefit but may also harm human health, and therefore should be removed as much as possible. However, there is currently no method for detecting residual solvents in cabergoline raw materials. After thorough and extensive research, a method for detecting multiple residual solvents in cabergoline raw materials is provided. This method can detect multiple residual solvents in cabergoline raw materials simultaneously, detects a wide variety of residual solvents, has high detection efficiency, and saves manpower and resources.

[0045] The method of the present invention for detecting multiple residual solvents in cabergoline active pharmaceutical ingredient is used to simultaneously detect methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and isobutylene, and includes the following steps:

[0046] (1) Determine the gas chromatography analysis method:

[0047] Gas chromatography analysis was performed using a moderately polar polysiloxane capillary column;

[0048] (2) Preparation of reference solution and test solution:

[0049] Nine reference standards were weighed separately: methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide and isobutylene. They were dissolved in dimethyl sulfoxide and diluted to volume to prepare reference standard solutions.

[0050] Weigh out the cabergoline sample, dissolve it in dimethyl sulfoxide and mix thoroughly to obtain the test solution;

[0051] (3) Determination of residual solvent in cabergoline samples:

[0052] The reference solution and the test solution were subjected to gas chromatography analysis in step (1), the chromatograms were recorded, and the contents of each residual solvent in the test solution, namely methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide and isobutylene, were calculated by peak area according to the external standard method.

[0053] In step (1), the medium polarity polysiloxane capillary column can be any suitable medium polarity polysiloxane capillary column. Preferably, in step (1), the medium polarity polysiloxane capillary column is a capillary column with medium polarity 6% cyanopropylphenyl-94% dimethyl polysiloxane as the stationary phase.

[0054] In step (1), the gas chromatography analysis can be performed under any suitable detection conditions. Preferably, in step (1), the gas chromatography analysis is performed under the following conditions:

[0055] Carrier gas: Nitrogen;

[0056] Injection: Direct injection;

[0057] Column temperature: The initial temperature is 50℃, maintained for 8 minutes, and then increased to 200℃ at a rate of 10℃ / min, and maintained for 12 minutes.

[0058] Inlet temperature: 150℃;

[0059] Detector: FID detector, detector temperature is 250℃;

[0060] Injection volume 1 μl;

[0061] Column flow rate: 0.8 mL / min ~ 1.2 mL / min;

[0062] Flow split ratio: 28:1~32:1;

[0063] In step (1), the column flow rate can be any suitable column flow rate, but more preferably, in step (1), the column flow rate is 1 mL / min.

[0064] In step (1), the split ratio can be any suitable split ratio, but preferably, in step (1), the split ratio is 30:1.

[0065] In step (2), the mass concentrations of methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and isobutylene in the reference solution can be determined as needed. Preferably, in step (2), the mass concentrations of methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and isobutylene in the reference solution are 300 μg / ml, 500 μg / ml, and 500 μg / ml, respectively. / ml, 500μg / ml, 500μg / ml, 72μg / ml, 89μg / ml, 150μg / ml, 88μg / ml and 50μg / ml, that is, each 1ml of the reference solution contains 300μg of methanol, 500μg of acetone, 500μg of tert-butyl methyl ether, 500μg of ethyl acetate, 72μg of tetrahydrofuran, 89μg of toluene, 150μg of p-fluorotoluene, 88μg of N,N-dimethylformamide and 50μg of isobutylene.

[0066] In step (2), the mass concentration of cabergoline in the test solution can be determined as needed. Preferably, in step (2), the mass concentration of cabergoline in the test solution is 100 mg / mL.

[0067] The present invention also conducted relevant methodological validation on the method for detecting multiple residual solvents in cabergoline active pharmaceutical ingredient of the present invention. The methodological validation included specificity, sensitivity, linearity and range, system precision, repeatability and recovery rate.

[0068] The specificity is verified by the following method:

[0069] Accurately measure the dimethyl sulfoxide solvent, reference solution and test solution, and perform the determination according to step (1). Record the chromatograms and investigate the retention time of different components in the dimethyl sulfoxide solvent, reference solution and test solution and the separation of adjacent components.

[0070] The sensitivity was verified using the following method:

[0071] Accurately weigh out nine reference standards: methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and isobutylene. Place them in volumetric flasks, dissolve and dilute with dimethyl sulfoxide, and then further dilute to prepare a series of solutions of different concentrations. Perform the determination according to step (1) and record the signal-to-noise ratio of the chromatogram. When the signal-to-noise ratio is 3, it is counted as the limit of detection; when the signal-to-noise ratio is 10, it is counted as the limit of quantitation.

[0072] The linearity and range are verified by the following method:

[0073] Nine reference standards, namely methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide and isobutylene, were weighed out and dissolved in dimethyl sulfoxide and diluted to volume to prepare a reference standard stock solution. The reference standard stock solution was diluted to obtain a series of standard curve solutions with concentration gradients. The determination was carried out according to step (1), and the chromatogram was recorded. The standard curve was plotted with the concentration of the reference standard as the abscissa and the corresponding peak area as the ordinate, and the linear equation was fitted.

[0074] The system precision was verified by the following method:

[0075] Inject the reference solution multiple times (e.g., 5 times) and calculate the RSD values ​​of the retention time and peak area of ​​different components in the reference solution.

[0076] Repeatability was verified using the following method:

[0077] Multiple samples (e.g., 6 samples) were tested using the test solution and the spiked test solution respectively, and the content was calculated by peak area according to the external standard method.

[0078] The recovery rate was verified by the following method:

[0079] Accurately add gradient amounts of reference standards to the test solution with known content of the analyte, prepare spiked test solutions at different concentration levels, and calculate their recovery rates.

[0080] To provide a clearer understanding of the technical content of this invention, the following embodiments are provided for detailed description. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Unless otherwise stated, the instruments, pharmaceuticals, reagents, etc., used in the following embodiments can all be obtained through conventional commercial means.

[0081] Unless otherwise stated, the term "camergoline" as used in this invention refers to the compound with CAS number 81409-90-7 and chemical name 6-allyl-N-[3-(dimethylamino)propyl]-N-(ethylcarbamoyl)ergoline-8-carboxamide.

[0082] Unless otherwise stated, the term "residual solvent" as used in this invention refers to a substance that plays a role in dissolving materials during the production of active pharmaceutical ingredients, excipients and / or formulations, but is not completely removed after production is completed. It is usually a volatile or semi-volatile organic compound.

[0083] Unless otherwise stated, the term "methanol" as used in this invention refers to a compound with CAS number 67-56-1, represented as CH3OH, CH4O, or MeOH.

[0084] Unless otherwise stated, the term "acetone" as used in this invention refers to a compound with CAS number 67-64-1, represented as CH3COCH3, C3H6O, or ACE.

[0085] Unless otherwise stated, the term "methyl tert-butyl ether" as used in this invention refers to the compound with CAS number 1634-04-4, represented as (CH3)3COCH3, t-C4H9OCH3, or t-BuOMe.

[0086] Unless otherwise stated, the term "ethyl acetate" as used in this invention refers to the compound with CAS number 141-78-6, represented as CH3CO2CH2CH3, AcOEt, or EA.

[0087] Unless otherwise stated, the term "tetrahydrofuran" as used in this invention refers to a compound with CAS number 109-99-9, represented as CH2CH2OCH2CH2 or THF.

[0088] Unless otherwise stated, the term "toluene" (or "methylbenzene") as used in this invention refers to a compound with CAS number 108-88-3, represented as C6H5CH3, PhCH3, PhMe, or Tol.

[0089] Unless otherwise stated, the term "p-fluorotoluene" as used in this invention refers to the compound with CAS number 352-32-9, represented as C7H7F, 1-fluoro-4-methylbenzene, 4-methylfluorobenzene, or 4-fluorotoluene.

[0090] Unless otherwise stated, the term "N,N-dimethylformamide" as used in this invention refers to the compound with CAS number 68-12-2, represented as C3H7NO, DMF.

[0091] Unless otherwise stated, the term "isobutylene" as used in this invention refers to the compound with CAS number 115-11-7, represented as C4H8 or 2-methylpropene.

[0092] Unless otherwise stated, the term "polysiloxane" as used herein refers to a class of polymers with repeating Si-O bonds as the main chain and groups attached to the Si atoms as side chains. Typically, the groups attached to the Si atoms are methyl, fluoroalkyl, cyanoalkyl, vinyl, phenyl, etc. Based on the type and proportion of the connecting groups, polysiloxanes can be broadly classified into non-polar (e.g., 100% dimethyl polysiloxane), weakly polar (e.g., 5% diphenyl dimethyl polysiloxane (e.g., SPB-5 type), 5% diphenyl 1% vinyl dimethyl polysiloxane), and moderately polar (e.g., 50% diphenyl dimethyl polysiloxane, 14% cyanopropylphenyl dimethyl polysiloxane, 6% cyanopropylphenyl 94% dimethyl polysiloxane), etc.

[0093] Instruments and reagents used in the examples:

[0094] Gas chromatograph: GC-2010Pro gas chromatograph, manufactured by Shimadzu Corporation of Japan.

[0095] Chromatographic column: A capillary column with moderate polarity 6% cyanopropylphenyl-94% dimethylpolysiloxane as the stationary phase, DB-624 type capillary column (0.32mm×60m, 1.8μm or similar polarity).

[0096] Drug: Cabergoline (22HW5010-I-231016B1, 22HW5010-I-231101B1, 22HW5010-I-240522B1), Nanjing Huawi Pharmaceutical Technology Group Co., Ltd.

[0097] Solvent: Dimethyl sulfoxide (DMSO), GC-HS grade, manufactured by Salau Reagents, Spain.

[0098] Reference standard:

[0099] Methanol, HPLC grade, Shanghai Lingfeng Chemical Reagent Co., Ltd.

[0100] Acetone, AR grade, Yonghua Chemical Co., Ltd.;

[0101] tert-Butyl methyl ether, HPLC grade, Shanghai Titan Technology Co., Ltd.;

[0102] Ethyl acetate, HPLC grade, Shanghai Maclean Biotechnology Co., Ltd.

[0103] Tetrahydrofuran, HPLC grade, Shanghai Titan Technology Co., Ltd.;

[0104] Toluene, HPLC grade, Yonghua Chemical Co., Ltd.

[0105] p-Fluorotoluene, HPLC grade, Shanghai Maclean Biotechnology Co., Ltd.

[0106] N,N-Dimethylformamide, HPLC grade, Shanghai Titan Technology Co., Ltd.;

[0107] Isobutylene, HPLC grade, Anaiji Chemical Reagent.

[0108] Example 1: Solution Preparation

[0109] 1. Preparation of reference solution:

[0110] Nine reference standards—methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and isobutylene—were accurately weighed and placed in volumetric flasks. Dimethyl sulfoxide was added to dissolve and dilute to volume, preparing a mixed solution containing 300 μg methanol, 500 μg acetone, 500 μg tert-butyl methyl ether, 500 μg ethyl acetate, 72 μg tetrahydrofuran, 89 μg toluene, 150 μg p-fluorotoluene, 88 μg N,N-dimethylformamide, and 50 μg isobutylene per 1 mL. This solution was used as the reference solution.

[0111] 2. Preparation of the test solution:

[0112] Accurately weigh cabergoline and place it in a volumetric flask. Dissolve it in dimethyl sulfoxide and dilute to volume to prepare a 100 mg / mL solution, which will serve as the test solution.

[0113] Example 2: Determination of Gas Chromatography Analysis Conditions

[0114] A moderately polar polysiloxane capillary column was selected for gas chromatography to determine a reference solution containing nine reference standards (Example 1). This reference solution simulates the nine residual solvents contained in cabergoline. The optimal chromatographic conditions are shown in Table 1. Using these conditions to determine the residual solvents in cabergoline, the corresponding gas chromatograms showed good peak shapes, reasonable retention times, and relatively ideal resolution between peaks. Specific details are as follows: Figure 1 As shown.

[0115] Table 1. Chromatographic conditions for detecting multiple residual solvents in cabergoline.

[0116]

[0117] Example 3 Methodological Validation

[0118] 3.1 Exclusivity:

[0119] Accurately measure 1 μl each of blank solvent (DMSO), reference solution (Example 1), and test solution (Example 1), and determine them according to the chromatographic conditions of Example 2. Record the chromatograms of each solution, examine the retention time (min) of different components in each solution and the separation of adjacent components. The results are shown in Table 2.

[0120] Table 2 Specificity Results

[0121]

[0122] The results in Table 2 show that: (1) DMSO, used as a solvent, was well separated from the nine analytes (methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and isobutylene), and the solvent did not interfere with the detection; (2) All nine analytes were effectively separated, with a resolution greater than 1.5 and a theoretical plate number greater than 5000. The peak elution order of the reference solution was isobutylene, methanol, acetone, methyl tert-butyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and DMSO, with DMSO being the last peak; (3) The test sample did not interfere with the detection (the residual solvent that may exist in the cabergoline sample has been determined by the synthesis process, and therefore does not contain other residual solvents that can produce gas chromatographic peaks), indicating that the detection method of the present invention has good specificity.

[0123] 3.2 Sensitivity:

[0124] Nine reference standards (i.e., methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and isobutylene) were weighed separately, dissolved and diluted with DMSO to prepare mixed solutions containing 0.12 mg of methanol, 0.20 mg of acetone, 0.20 mg of tert-butyl methyl ether, 0.20 mg of ethyl acetate, 0.029 mg of tetrahydrofuran, 0.036 mg of toluene, 0.060 mg of p-fluorotoluene, 0.035 mg of N,N-dimethylformamide, and 0.020 mg of isobutylene per 1 ml. These solutions were then prepared into solutions of different concentrations through stepwise dilution. Chromatographic measurements were performed according to the conditions described in Example 2, and the signal-to-noise ratio (S / N) of the chromatograms were recorded. When the signal-to-noise ratio is 3, the concentration (μg / ml) at this time is calculated, which is the limit of detection; when the signal-to-noise ratio is 10, the concentration (μg / ml) at this time is calculated, which is the limit of quantitation. The same method is used to dilute 6 samples and the repeatability is examined. The results are shown in Tables 3-1, 3-2 and 3-3.

[0125] Table 3-1 Limit of Detection (LOD), Limit of Quantification (LOQ), and Repeatability Results of LOQ (Part 1)

[0126]

[0127] Table 3-2 Limit of Detection (LOD), Limit of Quantification (LOQ), and Repeatability Results of LOQ (Part II)

[0128]

[0129] Table 3-3 Limits of Detection and Limits of Quantification, and Repeatability Results of Limit of Quantification (Part III)

[0130]

[0131] The results in Tables 3-1, 3-2 and 3-3 show that the peak area RSD values ​​of the six solutions measured at the limit of quantitation were all less than 20%, and the percentage of the limit of quantitation and limit of detection of each solvent relative to the concentration of the test solution was less than 40% of its limit, indicating that the detection method of the present invention has good sensitivity.

[0132] 3.3 Linearity and Range:

[0133] Nine reference standards (i.e., methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and isobutylene) were weighed separately and diluted with DMSO to prepare a mixed solution containing 3 mg of methanol, 5 mg of acetone, 5 mg of tert-butyl methyl ether, 5 mg of ethyl acetate, 0.72 mg of tetrahydrofuran, 0.89 mg of toluene, 1.5 mg of p-fluorotoluene, 0.88 mg of N,N-dimethylformamide, and 0.5 mg of isobutylene per ml, which was used as the reference standard stock solution. Accurately measure 1 ml, 1 ml, 1 ml, 3 ml, and 2 ml of the reference standard stock solution, and place them in volumetric flasks of 25 ml, 20 ml, 10 ml, 20 ml, and 10 ml, respectively. Dilute to the mark with dimethyl sulfoxide and shake well, resulting in dilutions of 25 times, 20 times, 10 times, 20 / 3 times, and 5 times, respectively, as linear solutions of various concentration gradients (40%, 50%, 100%, 150%, and 200%). For each reference standard, measure the limit of quantitation (LOQ) solution and the above five linear solutions, and determine them according to the chromatographic conditions in Example 2. Record the chromatograms, and plot a standard curve with concentration (mg / ml) on the x-axis and the corresponding peak area on the y-axis. Fit the linear equation (correlation coefficient ≥ 0.998). The results are shown in Table 4.

[0134] Table 4 Linearity Results

[0135]

[0136] Table 4 shows that: for methanol in the concentration range of 0.0048~0.6026 mg / mL, the linear equation is y = 336299.2573x - 1728.6906, with a correlation coefficient r = 0.9996; for acetone in the concentration range of 0.0008~1.0115 mg / mL, the linear equation is y = 2786740.1103x - 30180.4941, with a correlation coefficient r = 0.9997; for methyl tert-butyl ether in the concentration range of 0.0002~0.9995 mg / mL, the linear equation is y = 13153537.0953x + 14958.2252, with a correlation coefficient r = 0.9998; for ethyl acetate in the concentration range of 0. Within the concentration range of 0.0008–1.0015 mg / mL, the linear equation was y = 1952848.5715x - 23741.2567, with a correlation coefficient r = 0.9995; for tetrahydrofuran within the concentration range of 0.0006–0.1551 mg / mL, the linear equation was y = 3195694.9257x - 5555.9723, with a correlation coefficient r = 0.9995; for toluene within the concentration range of 0.0007–0.1797 mg / mL, the linear equation was y = 2423405.5209x - 5147.1012. The correlation coefficients were as follows: 1. For p-fluorotoluene, the linear equation was y = 1370674.6909x - 4933.3623 within the concentration range of 0.0012–0.3036 mg / mL, with a correlation coefficient r = 0.9994; 2. For N,N-dimethylformamide, the linear equation was y = 34050.8457x - 123.5755 within the concentration range of 0.0378–0.1891 mg / mL, with a correlation coefficient r = 0.9996; 3. For isobutylene, the linear equation was y = 29642183.6705x - 25768.7949 within the concentration range of 0.0001–0.1012 mg / mL, with a correlation coefficient r = 0.9996. All these results met the validation requirements, and the linear relationships of various residual solvents were good within the above concentration ranges.

[0137] 3.4 System Precision:

[0138] The reference solution in section 3.1 was injected five times consecutively (the retention time RSD% of each component in the reference solution was ≤1.0%, and the peak area RSD was ≤10%). The results are shown in Table 5.

[0139] Table 5 System precision results (retention time RT / min and peak area A)

[0140]

[0141] As shown in Table 5, the retention time RSD (n=5) and peak area RSD (n=5) of the nine residual solvents in the reference solution are all less than 1.0%, which meets the verification requirements, indicating that the detection method of the present invention has good system accuracy.

[0142] 3.5 Repeatability:

[0143] Accurately weigh the test sample (22HW5010-I-231016B1), dissolve it in DMSO, and quantitatively dilute it to prepare a solution containing 100 mg per ml, which is the test sample solution. Separately, accurately weigh 1 g of the same test sample, place it in a 10 ml volumetric flask, add 1.0 ml of the reference stock solution from section 3.3, dissolve it in DMSO, and dilute it to the mark to prepare the spiked test sample solution.

[0144] Six parallel portions of the test solution and the spiked test solution were prepared and tested according to the chromatographic conditions in Example 2. The test results were calculated by peak area using the external standard method (content ≤0.1%, RSD≤30%; content 0.1~0.2%, RSD<20%; content 0.2~0.5%, RSD≤10%). The results are shown in Table 6.

[0145] Table 6 Repeatability Results

[0146]

[0147] The results in Table 6 show that the average content of p-fluorotoluene detected in the test solution was 0.04%, with an RSD value (n=6) of 4.7%, which is less than 30%. Other solvents were not detected. In the spiked test solution, the contents of methanol, acetone, methyl tert-butyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and isobutylene were 0.31%, 0.50%, 0.51%, 0.50%, 0.074%, 0.087%, 0.19%, 0.085%, and 0.05%, respectively, with RSD values ​​(n=6) of 2.7%, 1.1%, 1.7%, 1.3%, 5.2%, 8.6%, 8.5%, 6.9%, and 8.8%, respectively. All of these met the validation requirements, indicating that the detection method of the present invention has good repeatability.

[0148] 3.6 Recovery rate:

[0149] Using the test sample from section 3.5, precise amounts of reference standards (i.e., methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and isobutylene) were added to prepare recovery solutions at different concentration levels. Specifically, 2 g of the test sample was accurately weighed and placed in a 20 ml volumetric flask. 1.0 ml, 2.0 ml, and 3.0 ml of the reference standard stock solution from section 3.3 were added, and the solution was dissolved and diluted to the mark with DMSO to prepare three aliquots of spiked test sample solutions at three concentration levels: 50%, 100%, and 150%. The solutions were analyzed under the chromatographic conditions described in Example 2, and the chromatograms were recorded. The recovery rates were calculated (recovery rates were in the range of 90–108%, RSD ≤ 10%). The results are shown in Tables 7-1, 7-2, and 7-3.

[0150] Table 7-1 Recovery Rate Results (I)

[0151]

[0152] Table 7-2 Recovery Rate Results (II)

[0153]

[0154] Table 7-3 Recovery Rate Results (Part 3)

[0155]

[0156] The results in Tables 7-1, 7-2, and 7-3 show that the average recoveries of the nine solvents in the spiked test solution were 99.1%, 98.6%, 98.4%, 98.1%, 97.6%, 95.0%, 92.9%, 93.3%, and 92.2%, respectively, all within the range of 90% to 108%. The RSD values ​​(n=9) were 1.1%, 0.8%, 0.7%, 0.9%, 1.2%, 1.2%, 0.9%, 1.1%, and 1.0%, respectively, all less than 10%. The recovery rates of the detection method of this invention meet the requirements, indicating that the detection method of this invention has good accuracy.

[0157] The above verification test results show that the specificity, sensitivity, linearity and range, system accuracy, repeatability, and recovery rate of the detection method of the present invention are all good.

[0158] Example 4: Determination of Residual Solvents in Cabergoline Pharmaceuticals

[0159] 4.1 Measurement method:

[0160] Three batches of cabergoline (batch numbers: 22HW5010-I-231016B1, 22HW5010-I-231101B1, 22HW5010-I-240522B1) were accurately weighed, dissolved in DMSO, and diluted to prepare a solution containing 100 mg per ml, which was used as the test solution. A reference solution was prepared according to the method described in Example 1. The reference solution and the test solution were analyzed under the chromatographic conditions described in Example 2, and the chromatograms were recorded. The content of each residual solvent in the test solution was calculated by peak area using the external standard method.

[0161] 4.2 Testing Standards:

[0162] The content limits for residual solvents are as follows: by weight percentage (wt%), methanol shall not exceed 0.3%, acetone shall not exceed 0.5%, tert-butyl methyl ether shall not exceed 0.5%, ethyl acetate shall not exceed 0.5%, tetrahydrofuran shall not exceed 0.072%, toluene shall not exceed 0.089%, p-fluorotoluene shall not exceed 0.15%, N,N-dimethylformamide shall not exceed 0.088%, and isobutylene shall not exceed 0.05%. These content limits are based on the Residual Solvent Determination Method in General Chapter 0861 of the Chinese Pharmacopoeia (2020 Edition), and ICH M7(R2) (Assessing and controlling DNA reactive (mutagenic) impurities in drugs to limit potential carcinogenic risks) and Q3A(R2) (Impurities in new active pharmaceutical ingredients).

[0163] 4.3 Test Results

[0164] Please see Table 8 for the test results.

[0165] Table 8 Sample Test Results

[0166]

[0167] The results in Table 8 show that: the cabergoline 22HW5010-I-231016B1 batch had a p-fluorotoluene content of 0.08%, while the rest were undetectable; the cabergoline 22HW5010-I-231101B1 batch had a p-fluorotoluene content of 0.06%, while the rest were undetectable; and the cabergoline 22HW5010-I-240522B1 batch had a p-fluorotoluene content of 0.04%, while the rest were undetectable. This indicates that the detection method of the present invention can efficiently, effectively, and accurately detect the content of various residual solvents, and the method is highly feasible and suitable for widespread use.

[0168] Therefore, this invention establishes a method for simultaneously detecting nine residual solvents in cabergoline by: 1) determining a gas chromatography analysis method; 2) preparing reference solutions and test solutions; and 3) determining residual solvents in the sample. These nine residual solvents are methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide, and isobutylene. The method of this invention can effectively and accurately detect these nine residual solvents simultaneously in cabergoline. It has a wide range of applications, high detection efficiency, strong specificity, and accurate and reliable detection results, meeting the requirements for residual solvent detection and suitable for routine detection of residual solvents in cabergoline raw materials.

[0169] Compared with the prior art, the method for simultaneous detection of multiple residual solvents in cabergoline of the present invention has the following advantages:

[0170] 1) The method of the present invention can effectively and accurately detect nine common residual solvents in cabergoline at the same time. It can detect a wide variety of residual solvents and has a wide range of applications. At the same time, it avoids the cumbersome process of separate detection by multiple methods, improves detection efficiency, and saves manpower and resources.

[0171] 2) The method of the present invention uses gas chromatography, and selects dimethyl sulfoxide (DMSO) as the best solvent for dissolving cabergoline by means of column fractionation scheme, and selects a medium polarity polysiloxane capillary column, thereby achieving a better separation effect;

[0172] 3) This invention successfully establishes a method for detecting residual solvents in cabergoline using GC (gas chromatography). This method can not only be used for the detection of residual solvents, but can also be applied to other detection projects, providing support for the development of other projects.

[0173] In summary, the method for detecting multiple residual solvents in cabergoline raw material of the present invention can detect multiple residual solvents in cabergoline raw material simultaneously, detects a wide variety of residual solvents, has high detection efficiency, saves manpower and resources, and is suitable for large-scale promotion and application.

[0174] Therefore, it is evident that the objective of this invention has been fully and effectively achieved. The function and structural principles of this invention have been demonstrated and explained in the embodiments. Any modifications can be made to the implementation methods without departing from these principles. Therefore, this invention includes all modified embodiments based on the spirit and scope of the claims.

Claims

1. A method for detecting a plurality of residual solvents in carminaliine drug substance, characterized in that, The plurality of residual solvents include methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide and isobutene, and the method comprises the following steps: (1) determining a gas chromatography analysis method: A medium-polarity polysiloxane capillary chromatographic column is used for gas chromatography analysis; (2) preparing a control solution and a test solution: 9 control samples of methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide and isobutene are weighed respectively, dissolved with dimethyl sulfoxide and diluted to a constant volume, and mixed uniformly to serve as the control solution; A carminaline sample is weighed, dissolved with dimethyl sulfoxide and diluted to a constant volume, and mixed uniformly to serve as the test solution; (3) determining residual solvents in the carminaline sample: The control solution and the test solution are respectively subjected to gas chromatography analysis according to step (1), and chromatograms are recorded; the contents of each residual solvent, i.e. methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide and isobutene, in the test solution are calculated according to the external standard method and peak area; In step (1), the gas chromatography analysis is performed under the following conditions: Carrier gas: nitrogen; Injection: direct injection; Column temperature: the initial temperature is 50°C, maintained for 8 min, then increased to 200°C at a rate of 10°C / min, and maintained for 12 min; Injection port: the injection port temperature is 150°C; Detector: FID detector, detector temperature is 250°C; Injection volume: 1 μl; Column flow rate: 0.8 mL / min~1.2 mL / min; Split ratio: 28:1~32:

1.

2. The method of claim 1, wherein the plurality of residual solvents in carminaliine drug substance are detected. In step (1), the medium-polarity polysiloxane capillary chromatographic column is a capillary column with medium-polarity 6% cyano propyl phenyl-94% dimethyl polysiloxane as the stationary liquid.

3. The method for detecting multiple residual solvents in cabergoline raw material as described in claim 1, characterized in that, In step (1), the column flow rate is 1 mL / min.

4. The method for detecting multiple residual solvents in cabergoline raw material as described in claim 1, characterized in that, In step (1), the split ratio is 30:

1.

5. The method for detecting multiple residual solvents in cabergoline raw material as described in claim 1, characterized in that, In step (2), the mass concentrations of methanol, acetone, tert-butyl methyl ether, ethyl acetate, tetrahydrofuran, toluene, p-fluorotoluene, N,N-dimethylformamide and isobutene in the control solution are 300 μg / ml, 500 μg / ml, 500 μg / ml, 500 μg / ml, 72 μg / ml, 89 μg / ml, 150 μg / ml, 88 μg / ml and 50 μg / ml respectively.

6. The method for detecting multiple residual solvents in cabergoline raw material as described in claim 1, characterized in that, In step (2), the mass concentration of carminaline in the test solution is 100 mg / mL.

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