Method for simultaneously determining pharmaceutical intermediate 1, 3, 5-trimethoxybenzene and related impurities

Abstract

The invention relates to a method for simultaneously determining a pharmaceutical intermediate 1, 3, 5-trimethoxybenzene and related impurities. The determination method comprises the following steps: adopting a gas chromatograph of Agilent Company, and matching a high-precision automatic sampler and a hydrogen flame ionization detector; the chromatographic column is a DB-1 series fused quartz capillary chromatographic column with high temperature resistance and a polyimide coating, the filler is dimethyl polysiloxane, and the specification is as follows: the length is 30m, the inner diameter is 0.53 mm, and the film thickness is 1.0 mu m; the test conditions are as follows: the column flow velocity is 2.0 ml / min, and the split ratio is 10: 1; the temperature of a sample inlet is 280 DEG C, and the temperature of a detector is 300 DEG C; the initial column temperature of a column oven is 130 DEG C, the temperature is increased to 210 DEG C at the speed of 5 DEG C / min and kept for 2 min, and then the temperature is increased to 300 DEG C at the speed of 15 DEG C / min and kept for 6 min; preparing a contrast solution and a sample solution; and performing sample injection detection. The method has the advantages that by adopting the analysis method, the impurity content accuracy is high, the separation effect is good, the accuracy is high, the detection result is stable, and the experimental result can be easily and quickly obtained, so that the impurity distribution is effectively and quickly controlled, and the product quality is improved.

Description

Technical Field

[0001] The present invention relates to the field of pharmaceutical and chemical analysis, and in particular to a method for simultaneously determining a pharmaceutical-grade intermediate 1,3,5-trimethoxybenzene and related impurities. Background Art

[0002] As a common chemical product, 1,3,5-trimethoxybenzene can be analyzed by high performance liquid chromatography or gas chromatography, but when used as a pharmaceutical intermediate, the content of each individual impurity must be strictly controlled, and the impurity requirement is no more than 0.1%, in order to improve the quality of pharmaceutical products and reduce adverse reactions. In the synthesis process of 1,3,5-trimethoxybenzene, its main raw materials and impurities will produce a variety of by-products and isomers. These substances have similar structures, similar properties and high index requirements, and the quantitative analysis of each substance is difficult.

[0003] The present invention adopts gas chromatography, cooperates with selected gas chromatography fillers for separation, and optimizes the column temperature rising program, so that the separation effect is better, the operation is simple, the method is high in accuracy and good in tolerance. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for simultaneously determining the pharmaceutical-grade intermediate 1,3,5-trimethoxybenzene and related impurities, which can solve the problem of difficulty in quantitative analysis of various by-products and isomers produced in the synthesis process of 1,3,5-trimethoxybenzene in the prior art.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows: the determination method simultaneously determines the content of multiple substances, and the measured related impurities are numbered Imp A ~ Imp H, which are aniline, 1,3-dimethoxybenzene, 1,2,3-trimethoxybenzene, 1-chloro-3,5-dimethoxybenzene, 1,2,4-trimethoxybenzene, 1-bromo-3,5-dimethoxybenzene, 1,3,5-tribromobenzene, 1-bromo-2,4,6-trimethoxybenzene and 2,4,6-tribromoaniline respectively; The determination method is gas chromatography, which includes the following steps: S1. Test conditions: Agilent gas chromatograph equipped with a high-precision automatic sample injector and hydrogen flame ionization detector; Inert gas was used as carrier gas, and the chromatographic column was a DB-1 series high temperature resistant, polyimide coated fused silica capillary column, the filler was dimethyl polysiloxane, and the specifications were 30m in length, 0.53mm in inner diameter, and 1.0μm in film thickness; The test conditions were a constant column flow rate of 2.0 ml / min, a split ratio of 10:1, an injection volume of 1 μL, a run time of 30 min, and a post-run time of 5 min; The injection port temperature was 280°C and the hydrogen flame ionization detector temperature was 300°C; The initial column temperature of the column oven was 130°C, which was increased to 210°C at 5°C / min and maintained for 2 min, then increased to 300°C at 15°C / min and maintained for 6 min; S2. Solution preparation: the dilution solution is ethyl acetate or dichloromethane; The impurity stock solution is prepared by taking 25 mg of each impurity reference substance, accurately weighing it, placing it in a 50 ml volumetric flask, dissolving it with a diluent, and then adjusting the volume, and shaking it well; weighing 2.5 g of 1,3,5-trimethoxybenzene, placing it in another 50 ml volumetric flask, accurately adding 5 ml of the above impurity stock solution, dissolving it with a diluent, and then adjusting the volume, and shaking it well to obtain the reference solution; The sample solution is 500 mg of 1,3,5-trimethoxybenzene sample, accurately weighed, placed in a 10 mL volumetric flask, dissolved and diluted to the scale with a diluent, and shaken well; S3. Inject samples for testing and calculate the content of each substance.

[0006] Furthermore, the related impurities are numbered Imp A to Imp H, and have the following structures: .

[0007] Furthermore, in step S1, the carrier gas is helium.

[0008] The invention has the advantages that: the invention adopts gas chromatography to determine the content of 1,3,5-trimethoxybenzene and its isomers and related impurities, adopts an Agilent 8890 series gas chromatograph equipped with a hydrogen flame ionization (FID) detector and a high-precision automatic sample injector, adopts an Agilent DB-1 series chromatographic column, and involves the separation of no less than 10 related or structurally similar substances. By adopting the analytical method, the accuracy of the impurity content (calculated by the sample recovery rate) reaches more than 90.8%, has the characteristics of good separation effect, high accuracy, strong specificity, excellent precision, stable detection results, etc., can easily and quickly obtain experimental results, thereby effectively and quickly controlling the impurity distribution, improving product quality, reducing costs and increasing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is the test spectrum of the determination method in Example 1 of the present invention. DETAILED DESCRIPTION

[0010] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. The following embodiments can enable technicians in this field to understand the present invention more comprehensively, but the present invention is not limited to the scope of the embodiments.

[0011] A method for simultaneously determining a pharmaceutical-grade intermediate 1,3,5-trimethoxybenzene and related impurities, and simultaneously determining the contents of multiple substances. The related impurities measured are numbered Imp A to Imp H, which are aniline, 1,3-dimethoxybenzene, 1,2,3-trimethoxybenzene, 1-chloro-3,5-dimethoxybenzene, 1,2,4-trimethoxybenzene, 1-bromo-3,5-dimethoxybenzene, 1,3,5-tribromobenzene, 1-bromo-2,4,6-trimethoxybenzene and 2,4,6-tribromoaniline, and the related impurities are numbered Imp A to Imp H, and the structures are as follows: , The structure of 1,3,5-trimethoxybenzene is as follows: .

[0012] The determination method is gas chromatography, which includes the following steps: S1. Test conditions: Agilent gas chromatograph equipped with a high-precision automatic sample injector and hydrogen flame ionization detector; The inert gas was used as the carrier gas, the carrier gas was helium, the chromatographic column was a DB-1 series high temperature resistant, polyimide coated fused silica capillary chromatographic column, the filler was dimethyl polysiloxane, the specifications were 30m in length, 0.53mm in inner diameter, and 1.0μm in film thickness; The test conditions were a constant column flow rate of 2.0 ml / min, a split ratio of 10:1, an injection volume of 1 μL, a run time of 30 min, and a post-run time of 5 min; The injection port temperature was 280°C and the hydrogen flame ionization detector temperature was 300°C; The initial column temperature of the column oven was 130°C, which was increased to 210°C at 5°C / min and maintained for 2 min, then increased to 300°C at 15°C / min and maintained for 6 min; S2. Solution preparation: the dilution solution is ethyl acetate or dichloromethane; The impurity stock solution is to take 25 mg of each impurity reference substance, accurately weigh it, put it in a 50 ml volumetric flask, dissolve it with a diluent, make up to volume, and shake it well; weigh 2.5 g of 1,3,5-trimethoxybenzene and put it in another 50 ml volumetric flask, accurately add 5 ml of the above impurity stock solution, dissolve it with a diluent, make up to volume, and shake it well to obtain the control solution. The control solution is a solution with known impurities added. Its function is to locate the peak time of different impurities, check the separation effect of different impurities and the system applicability, and quantitatively calculate the content of impurities; The sample solution is 500 mg of 1,3,5-trimethoxybenzene sample, accurately weighed, placed in a 10 mL volumetric flask, dissolved and diluted to the scale with a diluent, and shaken well; S3, sample injection test, calculate the content of each substance, the test spectrum is as follows Figure 1 As shown, the separation effect is excellent. Figure 1 The peak before 4 minutes in the retention time is not shown. The possible solvent peaks before 4 minutes are methanol, ethanol, dichloromethane, and ethyl acetate, which can achieve baseline separation.

[0013] Accuracy test: The accuracy of the method was tested by adding different concentrations of impurities to the sample. The concentrations tested were 0.05%, 0.10% and 0.15% of the sample concentration, and each concentration was repeated 6 times. The recovery rate was greater than 90.8%, and the relative standard deviation was ≤3.9%. The accuracy was calculated by measured value / true value × 100%.

[0014] Tolerance test: The tolerance of the test method was tested by changing parameters such as column flow rate, column temperature, split ratio, etc. Only one parameter was changed in each test, and the parameter change range was ±5%. The results were compared with the results when the parameters were not changed. The deviation of the retention time of 1,3,5-trimethoxybenzene and its impurities was no more than 5.3%, and the separation degree was no less than 1.5, which met the tolerance requirements of the method.

[0015] Comparative Example 1: A gas chromatography column of a different model with similar specifications to those in Example 1 was prepared and tested under the same conditions. The chromatography column was DB-1 30m×0.53mm×1.5μm (Part No. 125-1032).

[0016] Comparative Example 2: A gas chromatography column of a different model with similar specifications to those in Example 1 was prepared and tested under the same conditions. The chromatography column was DB-1 30m×0.32mm×1.0μm (Part No. 125-1033). The test results of Comparative Examples 1 and 2: the separation degree between the impurity Imp F and the main component in the chromatographic column of part number 125-1032 is less than 1.5; the tailing factor of the impurity Imp I in the chromatographic column of part number 125-1033 does not meet expectations; while the impurities in the chromatographic column of Example 1 are well separated, and the separation effect of Example 1 is significantly better than that of Comparative Examples 1 and 2.

[0017] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for simultaneously determining pharmaceutical-grade intermediate 1,3,5-trimethoxybenzene and related impurities, characterized in that: This determination method determines the contents of multiple substances simultaneously. The related impurities measured are numbered Imp A ~ Imp H, which are aniline, 1,3-dimethoxybenzene, 1,2,3-trimethoxybenzene, 1-chloro-3,5-dimethoxybenzene, 1,2,4-trimethoxybenzene, 1-bromo-3,5-dimethoxybenzene, 1,3,5-tribromobenzene, 1-bromo-2,4,6-trimethoxybenzene and 2,4,6-tribromoaniline respectively; The determination method is gas chromatography, which includes the following steps: S1. Test conditions: Agilent gas chromatograph equipped with a high-precision automatic sample injector and hydrogen flame ionization detector; Inert gas was used as carrier gas, and the chromatographic column was a DB-1 series high temperature resistant, polyimide coated fused silica capillary column, the filler was dimethyl polysiloxane, and the specifications were 30m in length, 0.53mm in inner diameter, and 1.0μm in film thickness; The test conditions were a constant column flow rate of 2.0 ml / min, a split ratio of 10:1, an injection volume of 1 μL, a run time of 30 min, and a post-run time of 5 min; The injection port temperature was 280°C and the hydrogen flame ionization detector temperature was 300°C; The initial column temperature of the column oven was 130°C, which was increased to 210°C at 5°C / min and maintained for 2 min, then increased to 300°C at 15°C / min and maintained for 6 min; S2. Solution preparation: the dilution solution is ethyl acetate or dichloromethane; The impurity stock solution is prepared by taking 25 mg of each impurity reference substance, accurately weighing it, placing it in a 50 ml volumetric flask, dissolving it with a diluent, and then adjusting the volume, and shaking it well; weighing 2.5 g of 1,3,5-trimethoxybenzene, placing it in another 50 ml volumetric flask, accurately adding 5 ml of the above impurity stock solution, dissolving it with a diluent, and then adjusting the volume, and shaking it well to obtain the reference solution; The sample solution is 500 mg of 1,3,5-trimethoxybenzene sample, accurately weighed, placed in a 10 mL volumetric flask, dissolved and diluted to the scale with a diluent, and shaken well; S3. Inject samples for testing and calculate the content of each substance.

2. A method for simultaneously determining a pharmaceutical-grade intermediate 1,3,5-trimethoxybenzene and related impurities according to claim 1, characterized in that: The related impurities are numbered Imp A ~ Imp H, and the structures are as follows: 。 3. A method for simultaneously determining a pharmaceutical-grade intermediate 1,3,5-trimethoxybenzene and related impurities according to claim 1, characterized in that: In the step S1, the carrier gas is helium.

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