Method for determining content of propylene glycol in phlegm-heat clearing injection
The gas chromatography detection of propylene glycol content in Tanreqing injection has solved the problem of no such determination in the prior art, and achieved rapid, simple and efficient detection effects, providing a basis for quality control and drug efficacy research.
Patent Information
- Application Number
- CN202311385925.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-24
- Publication Date
- 2025-04-25
AI Technical Summary
There is no method for determining the content of propylene glycol in Tanreqing Injection in the prior art.
The capillary column with polyethylene glycol as the stationary phase was used to detect the propylene glycol content in Tanreqing injection or its total solids by gas chromatography. The chromatographic conditions include the setting of program heating, inlet port and detector temperature.
It has achieved rapid, simple and efficient detection of the propylene glycol content in Tanreqing Injection, providing a theoretical basis for its quality control and in-depth research on the basis of drug efficacy substances.
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Figure CN119881115A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of medicines, and in particular to a method for determining the content of propylene glycol in Tanreqing injection. Background Art
[0002] Tanreqing Injection is made from five medicinal materials, including Scutellaria baicalensis, bear bile powder, goat horn, honeysuckle, and Forsythia, which are extracted and refined. It has the effects of clearing heat, detoxifying, and resolving phlegm. It is effective in treating upper respiratory tract infections, acute bronchitis, pneumonia, tuberculosis with lung infections, advanced lung cancer with lung infections, and severe asthma with infections.
[0003] There is no report on the method for determining the content of propylene glycol in Tanreqing injection in the prior art. Summary of the invention
[0004] Based on this, the present invention provides a method for determining the content of propylene glycol in Tanreqing injection or its total solids, the method comprising the following steps:
[0005] The test solution and the reference solution were tested, wherein the Tanreqing injection was composed of scutellaria baicalensis, bear bile powder, goat horn, honeysuckle, forsythia and propylene glycol, and the reference substance was propylene glycol.
[0006] The chromatographic conditions of the test are: using a capillary column with polyethylene glycol as the stationary phase, programmed temperature increase: initial temperature of 60-80°C, heating to 150-170°C at a rate of 10-30°C per minute, maintaining for 1-3 minutes, injection port temperature of 200-250°C, and detector temperature of 230-270°C;
[0007] According to the test results, the content information of propylene glycol in the Tanreqing injection is obtained.
[0008] Furthermore, the preparation method of the test solution includes: weighing an appropriate amount of Tanreqing injection, adding an ethanol solution with a volume percentage concentration of 10% to 100% to dilute it, and obtaining the test solution.
[0009] Furthermore, the preparation method of the reference solution includes: weighing an appropriate amount of propylene glycol; and adding an ethanol solution with a volume percentage concentration of 10% to 100% to prepare the reference solution with a propylene glycol concentration of 0.1 to 10 mg / ml.
[0010] Furthermore, the concentration of propylene glycol in the reference solution is about 1 mg / ml.
[0011] Furthermore, the volume ratio of the Tanreqing injection to the test sample solution is 1:100.
[0012] Furthermore, the volume percentage concentration of the ethanol solution is 100%.
[0013] Furthermore, the ethanol is an analytical grade reagent or a chromatographic grade reagent.
[0014] Furthermore, the ethanol is a chromatographically pure reagent.
[0015] Furthermore, the detection was performed using an Agilent 6890 gas chromatograph.
[0016] Furthermore, the capillary column is a polyethylene glycol 20000 (PEG-20M) capillary column.
[0017] Furthermore, the capillary column is a HP-INNOWAX capillary column.
[0018] Furthermore, the capillary column has a column length of 30 m, an inner diameter of 0.32 mm, and a membrane thickness of 0.25 μm.
[0019] Furthermore, the carrier gas used in the detection is nitrogen.
[0020] Furthermore, the flow rate of the carrier gas is 1 ml / min to 3 ml / min.
[0021] Further, the temperature is programmed to have an initial temperature of about 70° C., to be heated to about 160° C. at a rate of about 20° C. per minute, and then to be maintained for about 2 minutes.
[0022] Furthermore, the injection port temperature is 215-245°C, for example, about 230°C.
[0023] Furthermore, the detector temperature is 235-265°C, for example, about 250°C.
[0024] Furthermore, the injection volume used in the detection is 0.5-5 μl, for example, about 1 μl.
[0025] Furthermore, the number of theoretical plates calculated based on the polyethylene glycol peak is not less than 30,000.
[0026] Furthermore, the information is calculated according to the external standard method based on the corresponding peak areas in the recorded chromatogram of the test solution and the chromatogram of the reference solution.
[0027] Furthermore, according to the external standard method and calculation based on the peak area, the propylene glycol content in each 1 ml of the Tanreqing injection is 93-114 mg.
[0028] Furthermore, the content of propylene glycol in the total solid of the Tanreqing injection was measured by heating at 105° C. for 3 hours after evaporation, and each 1 ml contained 6 to 10 mg of propylene glycol.
[0029] Furthermore, the content of propylene glycol in the total solid of the Tanreqing injection was measured by drying at 105° C. for 12 hours, and each 1 ml contained 2 to 3 mg of propylene glycol.
[0030] Furthermore, the standard curve of propylene glycol is y=332.6x-1.966, r 2 =0.999.
[0031] According to another aspect of the present invention, there is provided a use of the above method in quality detection and / or quality evaluation and / or quality control of Tanreqing injection or its total solids.
[0032] Beneficial effects of the present invention:
[0033] The method of the invention is simple, efficient and rapid, and provides a theoretical basis for the quality control of Tanreqing injection or its total solids and the in-depth study of the material basis of the drug efficacy by detecting the content of propylene glycol. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without exceeding the scope of protection required by the present invention.
[0035] Figure 1 The figure is a schematic diagram of the propylene glycol content determination result of the present invention, wherein A is the chromatogram of the propylene glycol reference solution, B is the chromatogram of the test solution, and C is the chromatogram of the blank solvent (ethanol). DETAILED DESCRIPTION
[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.
[0037] Unless otherwise indicated, all technical and scientific terms and abbreviations used herein have the meanings commonly understood by those of ordinary skill in the field of the invention or the field in which the terms are used. Although any methods, conditions, substances or materials similar to or equivalent to those disclosed herein may be used in the practice of the present invention, preferred methods, conditions, substances or materials are described herein.
[0038] The present invention is intended to encompass all alternatives, variations and equivalents that may be included in the present invention as defined by the claims. Those skilled in the art will recognize many methods and materials similar or equivalent to those described herein that can be used in the practice of the present invention. The present invention is in no way limited to the methods and materials described.
[0039] As used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.
[0040] In the present invention, the term "comprising" is synonymous with "including". As used herein, the terms "comprising", "including", "having", "containing" or any other variation thereof are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus comprising the listed elements is not necessarily limited to only those elements, but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.
[0041] As described in the background technology section, there is no report on the method for determining the propylene glycol content in Tanreqing injection in the prior art. In order to solve the above problem, the present invention provides a method for determining the propylene glycol content in Tanreqing injection or its total solids, the method comprising the following steps:
[0042] The test solution and the reference solution were tested, wherein the Tanreqing injection was composed of scutellaria baicalensis, bear bile powder, goat horn, honeysuckle, forsythia and propylene glycol, and the reference substance was propylene glycol.
[0043] The chromatographic conditions of the test are: using a capillary column with polyethylene glycol as the stationary phase, programmed temperature increase: initial temperature of 60-80°C, heating to 150-170°C at a rate of 10-30°C per minute, maintaining for 1-3 minutes, injection port temperature of 200-250°C, and detector temperature of 230-270°C;
[0044] According to the test results, the content information of propylene glycol in the Tanreqing injection is obtained.
[0045] In the present invention, when temperature, rate, time, concentration, injection volume, equivalent, concentration, or other values or parameters are expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any upper range limit or preferred value with any lower range limit or preferred value, regardless of whether the range is disclosed separately. For example, when the range "10-30" is disclosed, the described range should be interpreted as including the range "10-30", "10-29", "10-28", "10-27", "10-26", "10-25", "10-24", "10-23", "10-22", "10-21", "10-20", "10-19", "10-18", "10-17", "10-16", "10-15", "10-14", "10-13", "10-12", "10-11", etc. When a numerical range is described herein, unless otherwise indicated, that range is intended to include the endpoints and all integers and fractions within that range.
[0046] In a preferred embodiment, the method for preparing the test solution comprises: weighing an appropriate amount of Tanreqing injection, adding an ethanol solution with a volume percentage concentration of 10% to 100% to dilute it, and obtaining the test solution.
[0047] In a preferred embodiment, the preparation method of the reference solution comprises: weighing an appropriate amount of propylene glycol; and adding an ethanol solution with a volume percentage concentration of 10% to 100% to prepare the reference solution containing propylene glycol at a concentration of 0.1 to 10 mg / ml.
[0048] In a preferred embodiment, the concentration of propylene glycol in the control solution is about 1 mg / ml.
[0049] In the present invention, "about" refers to a value within the range of ±5% of a specific value. For example, "about 1" includes ±5% of 1, or from 0.95 to 1.05.
[0050] In a preferred embodiment, the volume ratio of the Tanreqing injection to the test sample solution is 1:100.
[0051] In a preferred embodiment, the volume percentage concentration of the ethanol solution is 100%.
[0052] In a preferred embodiment, the ethanol is an analytical grade reagent or a chromatographic grade reagent.
[0053] In a preferred embodiment, the ethanol is a chromatographic grade reagent.
[0054] In a preferred embodiment, the detection is performed using an Agilent 6890 gas chromatograph.
[0055] In a preferred embodiment, the capillary column is a polyethylene glycol 20000 (PEG-20M) capillary column.
[0056] In order to obtain a more excellent propylene glycol chromatographic peak elution time and peak shape, in a preferred embodiment, the capillary column is a HP-INNOWAX capillary column.
[0057] In a preferred embodiment, the capillary column has a column length of 30 m, an inner diameter of 0.32 mm, and a membrane thickness of 0.25 μm.
[0058] In a preferred embodiment, the carrier gas used in the detection is nitrogen.
[0059] In a preferred embodiment, the flow rate of the carrier gas is 1 ml / min to 3 ml / min.
[0060] In order to obtain a more excellent propylene glycol chromatographic peak elution time and peak shape, in a preferred embodiment, the temperature is programmed to have an initial temperature of about 70°C, and to be heated to about 160°C at a rate of about 20°C per minute and then maintained for about 2 minutes.
[0061] In the present invention, "about" refers to a value within a range of ±5% of a specific value. For example, "about 70" includes ±5% of 70, or from 66.5 to 73.5; "about 20" includes ±5% of 20, or from 19 to 21; "about 160" includes ±5% of 160, or from 152 to 168; "about 2" includes ±5% of 2, or from 1.9 to 2.1.
[0062] In a preferred embodiment, the injection port temperature is 215-245°C, such as about 230°C.
[0063] In a preferred embodiment, the detector temperature is 235-265°C, such as about 250°C.
[0064] In a preferred embodiment, the injection volume used in the detection is 0.5-5 μl, such as about 1 μl.
[0065] In the present invention, "about" refers to a value within a range of ±5% of a specific value. For example, "about 230" includes ±5% of 230, or from 218.5 to 241.5; "about 250" includes ±5% of 250, or from 237.5 to 262.5; "about 1" includes ±5% of 1, or from 0.95 to 1.05.
[0066] In a preferred embodiment, the number of theoretical plates calculated based on the polyethylene glycol peak is not less than 30,000.
[0067] In a preferred embodiment, the information is calculated according to the external standard method based on the corresponding peak areas in the recorded chromatogram of the test solution and the chromatogram of the reference solution.
[0068] In a preferred embodiment, according to the external standard method and calculated by peak area, the propylene glycol content in each 1 ml of the Tanreqing injection is 93-114 mg.
[0069] In a preferred embodiment, the content of propylene glycol in the total solid of the Tanreqing injection is determined by heating at 105° C. for 3 hours after evaporation, and each 1 ml contains 6 to 10 mg of propylene glycol.
[0070] In a preferred embodiment, the content of propylene glycol in the total solid of the Tanreqing injection is determined by drying at 105° C. for 12 hours, and each 1 ml contains 2 to 3 mg of propylene glycol.
[0071] In a preferred embodiment, the standard curve of propylene glycol is y=332.6x-1.966, r 2 =0.999.
[0072] According to another aspect of the present invention, there is provided a use of the above method in quality detection and / or quality evaluation and / or quality control of Tanreqing injection or its total solids.
[0073] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples without specifying specific conditions are usually carried out according to conventional conditions or conditions recommended by the manufacturer.
[0074] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein can be applied to the methods of the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only.
[0075] The above features mentioned in the present invention or the features mentioned in the embodiments can be combined in any way. All the features disclosed in this patent specification can be used in combination with any combination form, and each feature disclosed in the specification can be replaced by any alternative feature that can provide the same, equal or similar purpose. Therefore, unless otherwise specified, the disclosed features are only general examples of equal or similar features.
[0076] Example
[0077] Determination of propylene glycol content in Tanreqing injection
[0078] 1. Instruments and test drugs
[0079] Agilent 6890 gas chromatograph, propylene glycol (provided by the National Institute for the Control of Pharmaceutical and Biological Products, batch number 19001-201704, 99.7%), Tanreqing injection (provided by Shanghai Kaibao Pharmaceutical Co., Ltd.), and ethanol was chromatographically pure (MERCK).
[0080] 2. Chromatographic conditions and system suitability test
[0081] 2.1 Chromatographic column
[0082] Compared with SUPELCO Fused Silica Capillary Column 60m×0.32mm×1.8μm and DG-624 (30m×0.32mm, 1.8μm), the chromatographic column: HP-INNOWAX 30m×0.32mm 0.25μm produces a better propylene glycol peak in terms of elution time and peak shape.
[0083] 2.2 Column temperature investigation
[0084] Exploration condition 1: The starting temperature was 80°C, maintained for 1 min, increased to 160°C at 20°C / min, maintained for 2 min, increased to 220°C at 15°C / min, maintained for 5 min. As a result, the propylene glycol chromatographic peak had tailing.
[0085] Exploration condition 2: The initial column temperature was 120°C, maintained for 1 min, then increased to 200°C at 10°C / min and maintained for 1 min. As a result, the propylene glycol chromatographic peak had tailing.
[0086] Exploration condition 3: initial temperature 80°C, maintained for 2 min, increased to 250°C at a rate of 10°C / min, maintained for 10 min, the result was that the propylene glycol chromatographic peak had tailing.
[0087] Exploration condition 4: initial temperature 100°C, hold for 10 min, increase to 180°C at a rate of 60°C / min, hold for 5 min, increase to 220°C at a rate of 60°C / min, hold for 5 min, the result is that the propylene glycol chromatographic peak has tailing.
[0088] Exploration condition 5: The initial temperature was 80°C, maintained for 10 min, then raised to 200°C at a rate of 70°C / min and maintained for 7 min. As a result, the propylene glycol chromatographic peak had tailing.
[0089] Exploration condition 6: The starting temperature is 70℃, then it is directly increased to 160℃ at 20℃ / min, maintained for 2min, then increased to 220℃ at 15℃ / min, maintained for 5min. The chromatographic peak time and peak shape of propylene glycol are good, such as Figure 1 shown.
[0090] 3. Solvent exploration
[0091] First, water, which has the best solubility in propylene glycol, was used as the solvent. It was found that the main peak had a tailing phenomenon. As the number of injections increased, the tailing became more and more serious, which was related to the water residue in the gas phase column. Ethanol was used as the solvent, and the tailing of the main peak was improved. When analytical pure reagents were used, it was found that there was an interference peak at the main peak position. After using chromatographic pure reagents, there was no interference at the main peak position.
[0092] 4. Investigation of linear relationship
[0093] Accurately weigh 994.08 mg of propylene glycol reference substance, place it in a 100 ml volumetric flask, add ethanol to the scale, mix well to obtain a standard stock solution with a concentration of 9.9109776 mg / ml, and then dilute it with ethanol to form a series of standard mixed reference solutions ①②③④⑤⑥.
[0094] Accurately pipette 1 μl of the above-mentioned reference solution, inject it into the liquid chromatograph, and record the peak area. With concentration (μg) as the horizontal axis and peak area as the vertical axis, draw a standard curve and perform regression analysis. The results show that within the range of 0.0991098 to 4.95549 μg of propylene glycol, the injection volume has a good linear relationship with the peak area, and the linear equation is y=332.6x-1.966, r2=0.999, as shown in Table 1.
[0095] Table 1 Investigation of the linear relationship of propylene glycol
[0096] Reference Concentration of reference substance (μg) Peak area 1 0.0991098 30.55076 2 0.495549 166.29846 3 0.991098 335.22131 4 1.98220 631.50348 5 2.97329 1004.28479 6 4.95549 1644.62402
[0097] 5. Parallel test of reference solution
[0098] Accurately pipette propylene glycol reference solution (0.991098 mg / ml), inject 6 times continuously, record the peak area, and the results are shown in Table 2.
[0099] Table 2 Parallel test of reference solution
[0100]
[0101] 6. Stability test of test solution
[0102] Take a sample (batch number: 1711220) and prepare the test solution according to the proposed method. The sample was injected and analyzed at 0 hour, 1 hour, 3 hours, 6 hours, 12 hours, 18 hours and 24 hours. The results showed that the test solution was basically stable within 0 to 24 hours, as shown in Table 3.
[0103] Table 3 Stability test of test solution
[0104]
[0105] 7. Precision test (repeatability and accuracy test)
[0106] Take 0.05ml, 0.5ml and 0.7ml of this product (batch number: 1711220, measured content is 96.08mg / ml) in 6 copies, add 0.5ml, 5ml and 8ml of standard stock solution (9.9109776mg / ml) into a 100ml volumetric flask, dilute to the scale with ethanol, determine the content according to the proposed method, calculate the recovery rate, and the results are shown in Table 4.
[0107] Table 4 Accuracy test of propylene glycol
[0108]
[0109]
[0110] The results showed that the proposed method had good repeatability and high accuracy.
[0111] 8. Sample determination
[0112] According to the proposed method, 33 batches of samples were tested and the results are shown in Table 5.
[0113] Table 5 Sample determination
[0114]
[0115] 9. Content limit
[0116] When this product is added to the finished product, the amount of propylene glycol added is 100ml / 1000ml. According to its density (1.0381g / ml), the theoretical amount added is 103.81mg / ml. The average content of propylene glycol in 33 batches is 97.0mg / ml, which is close to the theoretical limit. Taking into account the test results of the samples and the actual production situation, the content limit is temporarily formulated based on the theoretical addition amount ±10% as follows: 93-114mg of propylene glycol per 1ml. After accumulating the test results of multiple batches of samples, a reasonable content limit will be formulated.
[0117] All 33 batches of samples met the requirements.
[0118] Example 2 Determination of Propylene Glycol Content in Total Solids of Tanreqing Injection
[0119] Through the study of the material components of Tanreqing injection, the total solids in Tanreqing injection were determined in order to calculate the percentage of the identified components in the total solids.
[0120] Since 10% (100 mg / ml) propylene glycol is added in the production process of this product, and the boiling point of propylene glycol is 180-190°C, according to the operating method of "evaporating to dryness and heating at 105°C for 3 hours" in the national drug standard, the total solid is dissolved in water and the propylene glycol content is determined by gas chromatography. The results show that each ml contains 6-10 mg propylene glycol.
[0121] The total solid content (almost constant weight) was determined by drying at 105°C for 12 hours. The propylene glycol content was determined after the total solid was dissolved in water. As shown in Table 6, the propylene glycol content per 1 ml was about 2 to 3 mg.
[0122] Table 6 Determination results of propylene glycol content in the total solids of Tanreqing injection
[0123] Tanreqing injection batch number Propylene glycol content (mg / ml) 091029 2.43 091106 2.27 091111 2.76 091118 2.50 091125 1.89 091205 2.12 091212 2.14 091222 2.25 091228 2.71 100107 2.45 100114 2.83 100124 3.26 100202 2.44 100216 2.00
[0124] The embodiments of the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, changes or deformations made by those skilled in the art based on the ideas of the present invention, the specific implementation methods and application scope of the present invention, all belong to the scope of protection of the present invention. In summary, the content of this specification should not be understood as limiting the present invention.
Claims
1. A method for determining the content of propylene glycol in Tanreqing injection or its total solids, characterized in that: The method comprises the following steps: The test solution and the reference solution were tested, wherein the Tanreqing injection was composed of scutellaria baicalensis, bear bile powder, goat horn, honeysuckle, forsythia and propylene glycol, and the reference substance was propylene glycol. The chromatographic conditions of the detection are: using a capillary column with polyethylene glycol as the stationary phase, programmed temperature increase: the initial temperature is 60-80°C, the temperature is increased to 150-170°C at a rate of 10-30°C per minute, and maintained for 1-3 minutes, the injection port temperature is 200-250°C, and the detector temperature is 230-270°C; According to the test results, the content information of propylene glycol in the Tanreqing injection is obtained.
2. The method according to claim 1, characterized in that The preparation method of the test solution comprises: weighing an appropriate amount of Tanreqing injection, adding an ethanol solution with a volume percentage concentration of 10% to 100% to dilute it, and obtaining the test solution.
3. The method according to claim 1, characterized in that The preparation method of the reference solution comprises: weighing an appropriate amount of propylene glycol; and adding an ethanol solution with a volume percentage concentration of 10% to 100% to prepare the reference solution containing propylene glycol at a concentration of 0.1 to 10 mg / ml; Preferably, the concentration of propylene glycol in the reference solution is about 1 mg / ml; Preferably, the volume ratio of the Tanreqing injection to the test solution is 1:100; Preferably, the volume percentage concentration of the ethanol solution is 100%; Preferably, the ethanol is an analytical grade reagent or a chromatographic grade reagent; More preferably, the ethanol is a chromatographic grade reagent.
4. The method according to claim 1, characterized in that The detection was performed using an Agilent 6890 gas chromatograph; Preferably, the capillary column is a polyethylene glycol 20000 (PEG-20M) capillary column; Preferably, the capillary column is a HP-INNOWAX capillary column.
5. The method according to claim 1, characterized in that The capillary column has a column length of 30 m, an inner diameter of 0.32 mm, and a film thickness of 0.25 μm.
6. The method according to claim 1, characterized in that The carrier gas used in the detection is nitrogen; Preferably, the flow rate of the carrier gas is 1 ml / min to 3 ml / min; Preferably, the programmed temperature increase is an initial temperature of about 70°C, which is increased to about 160°C at a rate of about 20°C per minute and then maintained for about 2 minutes; Preferably, the injection port temperature is 215-245°C, for example about 230°C; Preferably, the detector temperature is 235-265°C, for example about 250°C; Preferably, the injection volume used in the detection is 0.5-5 μl, such as about 1 μl.
7. The method according to claim 1, characterized in that The number of theoretical plates calculated based on the polyethylene glycol peak is not less than 30,000.
8. The method according to claim 1, characterized in that The information is calculated according to the corresponding peak areas in the recorded chromatogram of the test solution and the chromatogram of the reference solution, using the external standard method to calculate the content of propylene glycol in the Tanreqing injection; Preferably, according to the external standard method and calculated by peak area, in the Tanreqing injection, each 1 ml contains 93 to 114 mg of propylene glycol; Preferably, the content of propylene glycol in the total solid of the Tanreqing injection is determined by heating at 105°C for 3 hours after evaporation, and each 1 ml contains 6 to 10 mg of propylene glycol; Preferably, the content of propylene glycol in the total solid of the Tanreqing injection is determined by drying at 105° C. for 12 hours, and each 1 ml contains 2 to 3 mg of propylene glycol.
9. The method according to claim 1, characterized in that: The standard curve of propylene glycol is y=332.6x-1.966, r 2 =0.
999.
10. Use of the method according to any one of claims 1 to 9 in quality detection and / or quality evaluation and / or quality control of Tanreqing injection or its total solids.