Quality detection method for acetaminophen tablets

Abstract

The invention belongs to the technical field of pharmaceutical analysis, and relates to a quality detection method for acetaminophen tablets. The quality detection comprises simultaneous detection of active drug components, impurity components and bacteriostatic agent components; the active medicine component comprises acetaminophen; the impurity components comprise p-aminophenol and p-chlorophenylacetamide; and the bacteriostatic agent comprises the following components: methylparaben, ethylparaben and propylparaben. The detection time of the high performance liquid chromatography provided by the invention is only 22 minutes, which is far less than 1 hour in the prior art. The preparation method of the test solution has simple steps, does not need further dilution, and reduces the determination error. The mobile phase is methanol and pure water and does not contain buffer salt or acid, so that the loss of a chromatographic system is smaller.

Description

Technical Field

[0001] The invention belongs to the technical field of drug analysis, and relates to a method for detecting the quality of acetaminophen tablets, and in particular to a method for simultaneously determining the content of acetaminophen tablets and special impurities and antibacterial agents. Background Art

[0002] Acetaminophen tablets are an antipyretic and analgesic drug that is widely used in clinical practice, and this variety has been included in the national consistency evaluation varieties. There are many domestic manufacturers, and there are many types of excipients and processes. Accurately determining its content and controlling impurities are of key significance for drug quality control, ensuring the safety and effectiveness of clinical drug use, and passing the consistency evaluation.

[0003] The current version of the Pharmacopoeia of the People's Republic of China (2020 edition) Part II discloses that the content determination method of acetaminophen tablets is ultraviolet spectrophotometry. Since some excipients such as methylparaben, ethylparaben, and propylparaben have strong ultraviolet absorption, the specificity of the ultraviolet method for determining the content is not high; the impurity control of acetaminophen tablets in the current version of the Pharmacopoeia of the People's Republic of China (2020 edition) Part II only stipulates that para-aminophenol is checked, and another controlled special impurity in its raw material drug, para-chlorophenylacetamide, is not checked. The detection methods for para-aminophenol and para-chlorophenylacetamide under the raw material drug in the pharmacopoeia are two independent sets of liquid chromatography isogradient elution methods, which are time-consuming. At the same time, the antibacterial agents (methylparaben, ethylparaben, and propylparaben) are not easy to elute. When the pharmacopoeia method is used to detect acetaminophen tablets, it is impossible to effectively detect and separate para-aminophenol, para-chlorophenylacetamide, and antibacterial agents in acetaminophen tablets at the same time. In order to better detect the content of the main ingredients, special impurities and antibacterial agents in acetaminophen tablets and comprehensively improve the quality control level of acetaminophen tablets, it is of great significance to study a rapid, simple, highly specific and highly separated method for simultaneously determining the content of the main drug, special impurities and antibacterial agents in acetaminophen tablets. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for simultaneously detecting the main drug, special impurities and antibacterial agents in acetaminophen tablets in view of the deficiencies in the prior art. With the detection method provided by the present invention, a set of methods can simultaneously detect the main component acetaminophen, two special impurities (para-aminophenol and para-chlorophenylacetamide) and three antibacterial auxiliary materials (methylparaben, ethylparaben and propylparaben), which greatly shortens the analysis time and effectively improves the analysis efficiency, which is of great significance for comprehensively improving the quality control of acetaminophen tablets.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] The invention discloses a method for quality detection of acetaminophen tablets, wherein the quality detection comprises simultaneously detecting active drug components, impurity components and antibacterial agent components;

[0007] The active pharmaceutical ingredient includes acetaminophen;

[0008] The impurity components include p-aminophenol and p-chlorophenylacetamide;

[0009] The antibacterial agent ingredients include methylparaben, ethylparaben, and propylparaben;

[0010] The quality detection method comprises the following steps:

[0011] (1) Preparation of mixed reference solution

[0012] Take acetaminophen, p-aminophenol, p-chlorophenylacetamide, methylparaben, ethylparaben, and propylparaben standard products, dilute to volume with a methanol-water mixed solvent, and filter to obtain a mixed reference solution;

[0013] (2) Preparation of acetaminophen tablet sample solution

[0014] Take acetaminophen tablets, grind them into powder, weigh accurately, add methanol-water mixed solvent to make up to volume, filter, and obtain acetaminophen tablet sample solution;

[0015] (3) High performance liquid chromatography analysis and result calculation

[0016] The mixed reference substance solution obtained in step (1) and the acetaminophen tablet sample solution obtained in step (2) are respectively injected into a high performance liquid chromatograph, and the chromatogram is recorded. The chromatogram is quantified by the peak area according to the external standard method to calculate the content of the corresponding substance;

[0017] Among them, high performance liquid chromatography was used for determination, and the specific high performance liquid chromatography conditions were as follows:

[0018] Chromatographic column: Octadecylsilane bonded silica gel as filler, specification (150mm~250mm)×4.6mm, 5μm;

[0019] Mobile phase A: methanol;

[0020] Mobile phase B: water;

[0021] Injection volume: 15-25 μL;

[0022] Flow rate: 0.9mL / min~1.1mL / min;

[0023] Detection wavelength: 245nm;

[0024] Column temperature: 25℃~35℃;

[0025] Gradient elution;

[0026] The gradient elution program is as follows:

[0027]

[0028]

[0029] In some embodiments, preferably, in the methanol-water mixed solvent, the volume ratio of methanol to water is 30:70.

[0030] In some embodiments, preferably, the chromatographic column has a specification of 150 mm×4.6 mm and 5 μm.

[0031] In some embodiments, preferably, the injection volume is 20 μL.

[0032] In some embodiments, preferably, the flow rate is 1.0 mL / min.

[0033] In some embodiments, preferably, the column temperature is 30°C.

[0034] The application of the above-mentioned quality detection method in the simultaneous separation of acetaminophen and para-aminophenol, para-chlorophenylacetamide, methylparaben, ethylparaben and propylparaben in acetaminophen tablets is also within the protection scope of the present invention.

[0035] The application of the above-mentioned quality detection method in simultaneously determining the content of acetaminophen and para-aminophenol, the content of p-chlorophenylacetamide, the content of methylparaben, the content of ethylparaben, and the content of propylparaben in acetaminophen tablets is also within the protection scope of the present invention.

[0036] The application of the above-mentioned quality detection method in the simultaneous separation of acetaminophen and para-aminophenol, p-chlorophenylacetamide, methylparaben, ethylparaben, and propylparaben in acetaminophen tablets, and the simultaneous determination of the content of acetaminophen and the content of para-aminophenol, the content of p-chlorophenylacetamide, the content of methylparaben, the content of ethylparaben, and the content of propylparaben in acetaminophen tablets is also within the protection scope of the present invention.

[0037] Beneficial effects:

[0038] (1) The high performance liquid chromatography method provided by the present invention has a higher separation efficiency than the ultraviolet visible spectrophotometry method specified in the existing standards, can effectively eliminate the interference of auxiliary materials with ultraviolet absorption, and has strong specificity.

[0039] (2) The present invention can simultaneously determine two special impurities with genotoxicity (p-aminophenol and p-chlorophenylacetamide) and three antibacterial agents with ultraviolet absorption and strong chromatographic retention (methylparaben, ethylparaben, and propylparaben), thereby making up for the defects of the existing standard that acetaminophen tablets only detect p-aminophenol but do not control p-chlorophenylacetamide and that the antibacterial agents cannot be eluted to interfere with the determination.

[0040] (3) The detection time of the high performance liquid chromatography method provided by the present invention is only 22 minutes, which is much shorter than 1 hour in the prior art.

[0041] (4) The method for preparing the test solution of the present invention is simple and convenient, and no further dilution is required, thereby reducing the measurement error.

[0042] (5) The mobile phase of the present invention is methanol and pure water, does not contain buffer salts or acids, and causes less loss to the chromatographic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0044] Figure 1 This is a representative liquid chromatogram of the sample determined using the Chinese Pharmacopoeia (2020 edition) acetaminophen tablets inspection method for para-aminophenol.

[0045] Figure 2 This is a representative liquid chromatogram of the antibacterial agents in the sample determined using the Chinese Pharmacopoeia (2020 edition) acetaminophen tablets inspection method for para-aminophenol.

[0046] Figure 3 Representative liquid chromatograms for locating six substances using the method for testing p-chlorophenylacetamide in acetaminophen in the Chinese Pharmacopoeia (2020 edition).

[0047] Figure 4 This is a representative liquid chromatogram of the localization of p-chlorophenylacetamide using the USP2024 acetaminophen tablets related substance test method.

[0048] Figure 5 This is a representative liquid chromatography chromatogram of the location of ethylparaben using the USP2024 acetaminophen tablets related substance test method.

[0049] Figure 6 The liquid phase representative chromatogram of the blank solvent in Example 1 is shown in FIG.

[0050] Figure 7 This is a representative chromatogram of the liquid phase of the test solution (manufacturer A) in Example 1.

[0051] Figure 8The liquid phase representative chromatogram of the mixed reference solution in Example 1.

[0052] Fig. 9 This is a representative chromatogram of the liquid phase of the mixed positioning solution specificity test in Example 2.

[0053] Fig.10 It is a representative UV scan of the acetaminophen reference solution in Example 2.

[0054] Fig.11 This is a representative UV scan of the sample solution of acetaminophen tablets (manufacturer A) in Example 2.

[0055] Fig.12 This is a representative UV scan of the sample solution of acetaminophen tablets (Manufacturer B) in Example 2.

[0056] Fig.13 This is a representative UV scan of the sample solution of acetaminophen tablets (Manufacturer C) in Example 2.

[0057] Fig.14 This is a representative UV scan of the p-aminophenol reference solution in Example 2.

[0058] Fig.15 It is a representative UV scan of the p-chlorophenylacetamide reference substance solution in Example 2.

[0059] Fig.16 It is a representative UV scan of the methylparaben reference solution in Example 2.

[0060] Fig.17 It is a representative UV scan of the ethylparaben reference solution in Example 2.

[0061] Fig.18 It is a representative UV scan of the propylparaben reference solution in Example 2.

[0062] Fig.19 This is a representative liquid chromatogram of the mixed positioning solution in Example 2 (column temperature: 25°C).

[0063] Fig. 20 This is a representative liquid chromatogram of the mixed positioning solution in Example 2 (column temperature: 30°C).

[0064] Fig.21 This is a representative liquid chromatogram of the mixed positioning solution in Example 2 (column temperature: 35°C).

[0065] Fig. 22 This is a representative liquid chromatogram of the mixed positioning solution in Example 2 (flow rate: 0.9 mL / min).

[0066] Fig.23 This is a representative liquid chromatogram of the mixed positioning solution in Example 2 (flow rate: 1.0 mL / min).

[0067] Fig.24 This is a representative liquid chromatogram of the mixed positioning solution in Example 2 (flow rate: 1.1 mL / min). DETAILED DESCRIPTION

[0068] The present invention can be better understood according to the following examples. However, it is easy for those skilled in the art to understand that the contents described in the examples are only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims.

[0069] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0070] 1. Reagents and Materials

[0071] Acetaminophen (Source: Tanmo Quality Inspection Standard Material Center, batch number: 23120437, purity: 99.9%);

[0072] p-Aminophenol (Source: China Food and Drug Inspection Institute, Batch No.: 100802-202306, Purity: 98.2%);

[0073] p-Chlorophenylacetamide (Source: China Food and Drug Inspection Institute, Batch No.: 100850-202304, Purity: 100.0%);

[0074] Methylparaben (Source: China Food and Drug Inspection Institute, Batch No.: 100278-202307, Purity: 100%);

[0075] Ethyl paraben (Source: China Food and Drug Inspection Institute, Batch No.: 100847-202105, Purity: 100.0%);

[0076] Propylparaben (Source: China Food and Drug Inspection Institute, Batch No.: 100444-202306, Purity: 99.9%);

[0077] Acetaminophen tablets-Manufacturer A (Source: Di'ao Group Chengdu Pharmaceutical Co., Ltd., batch number: 230301, specification: 0.5g / tablet);

[0078] Acetaminophen tablets-Manufacturer B (Source: Shanxi Fenhe Pharmaceutical Co., Ltd., batch number: 241002, specification: 0.3g / tablet);

[0079] Acetaminophen tablets - Manufacturer C (Source: Northeast Pharmaceutical Group Shenyang No. 1 Pharmaceutical Co., Ltd., batch number: 1230508, specification: 0.3g / tablet).

[0080] 2. Main instruments

[0081] LC220 high performance liquid chromatograph, Shanghai Yidian Co., Ltd.

[0082] 3. Structural information of various impurities in acetaminophen tablets

[0083] Table 2 Structural information of various impurities in acetaminophen tablets

[0084]

[0085] Embodiment 1:

[0086] (1) Preparation of test solution

[0087] Take 20 acetaminophen tablets (manufacturer A) under the weight difference item, grind them into powder, accurately weigh an appropriate amount (equivalent to approximately 20 mg acetaminophen), add methanol-water mixed solvent (methanol and water volume ratio is 30:70) to make a solution containing approximately 0.2 mg acetaminophen per 1 mL, filter with a 0.45 μm microporous filter membrane, and take the filtrate to obtain the test solution.

[0088] (2) Preparation of mixed reference solution

[0089] Take appropriate amount of acetaminophen, p-aminophenol, p-chlorophenylacetamide, methylparaben, ethylparaben, and propylparaben reference substances, weigh accurately, add methanol-water mixed solvent (methanol and water volume ratio is 30:70) to dissolve and make a solution containing approximately 0.2 mg acetaminophen, 0.0002 mg p-aminophenol, 0.0002 mg p-chlorophenylacetamide, 0.0004 mg methylparaben, 0.00008 mg ethylparaben, and 0.00006 mg propylparaben per 1 mL, filter with a 0.45 μm microporous filter membrane to obtain a mixed reference substance solution.

[0090] (3) HPLC conditions

[0091] The HPLC conditions were as follows:

[0092] Chromatographic column: octadecylsilane bonded silica gel as filler (150 mm × 4.6 mm, 5 μm);

[0093] Mobile phase A: methanol;

[0094] Mobile phase B: water;

[0095] Injection volume: 20 μL;

[0096] Flow rate: 1.0 mL / min;

[0097] Detection wavelength: 245nm;

[0098] Column temperature: 30°C;

[0099] Gradient elution;

[0100] The gradient elution program is as follows:

[0101] Table 3 Gradient elution program

[0102]

[0103]

[0104] (4) Accurately measure 20 μL of blank solvent (methanol-water mixed solvent, the volume ratio of methanol to water is 30:70), the above test solution and the above mixed reference solution, respectively, and inject them into high performance liquid chromatography for analysis and detection, and record the chromatogram.

[0105] Representative chromatograms of blank solvents are shown in Figure 6 The representative chromatogram of the liquid phase of the test solution is shown in Figure 7 The representative liquid chromatogram of the mixed reference solution is shown in Figure 8 shown.

[0106] Example 2: Methodological Validation

[0107] 1. Specificity test

[0108] (1) Preparation of mixed positioning solution

[0109] Accurately weigh each substance, and use a methanol-water mixed solvent (methanol and water volume ratio of 30:70) to prepare a solution containing acetaminophen, 2 special impurities (para-aminophenol and p-chlorophenylacetamide) and 3 antibacterial agents (methylparaben, ethylparaben, and propylparaben) (each 1 mL contains approximately 0.20 mg of acetaminophen, 0.64 mg of p-aminophenol, 0.13 mg of p-chlorophenylacetamide, 0.04 mg of methylparaben, 0.06 mg of ethylparaben, and 0.04 mg of propylparaben), and filter with a 0.45 μm microporous filter membrane to obtain a mixed positioning solution.

[0110] (2) Inject the mixed positioning solution into a high performance liquid chromatograph for analysis and detection. The high performance liquid chromatography conditions are the same as those of "the high performance liquid chromatography conditions of step (3) in Example 1" and record the chromatogram.

[0111] The specific representative chromatogram of the mixed positioning solution is shown in Fig. 9 , the specific separation parameter results are shown in the following table:

[0112] Table 4 Separation parameters of acetaminophen, special impurities and antibacterial agents

[0113] Peak sequence name Retention time (min) Relative principal component retention time Separation from the front peak 01 p-Aminophenol 2.1903 0.69 0.00 02 Acetaminophen 3.1903 1.00 5.4299 03 Methylparaben 9.3778 2.94 33.1720 04 p-Chlorophenylacetamide 12.8611 4.03 12.9982 05 Ethylparaben 13.7528 4.31 2.6045 06 Propylparaben 15.9944 5.01 9.9939

[0114] The results showed that acetaminophen could be well separated from two special impurities (p-aminophenol and p-chlorophenylacetamide) and three antibacterial agents (methylparaben, ethylparaben and propylparaben), and the separation degrees were all greater than 2.

[0115] 2. Selection of mobile phase

[0116] In the prior art, phosphate or other substances (such as acid) are added to the aqueous phase of most mobile phases. Since phosphate is easy to clog the liquid chromatography system, the mobile phase used in the present invention is methanol and pure water. After mixing in a certain proportion, the peak shape is symmetrical, the separation efficiency is high, the operation is simpler, and the loss of the chromatographic instrument is smaller.

[0117] 3. Selection of detection wavelength

[0118] (1) Preparation of solution

[0119] Acetaminophen reference solution: Accurately weigh acetaminophen, add methanol-water mixed solvent (methanol and water volume ratio is 30:70) to dissolve and make a solution containing approximately 0.011 mg of acetaminophen per 1 mL to obtain the acetaminophen reference solution.

[0120] p-Aminophenol reference solution: Accurately weigh p-aminophenol, add methanol-water mixed solvent (methanol and water volume ratio is 30:70) to dissolve and make a solution containing approximately 0.0067 mg of p-aminophenol per 1 mL to obtain the p-aminophenol reference solution.

[0121] p-Chlorophenylacetamide reference solution: accurately weigh p-chlorophenylacetamide, add methanol-water mixed solvent (methanol and water volume ratio is 30:70) to dissolve and make a solution containing about 0.0045 mg of p-chlorophenylacetamide per 1 mL to obtain p-chlorophenylacetamide reference solution.

[0122] Methylparaben reference solution: Accurately weigh methylparaben, add methanol-water mixed solvent (methanol and water volume ratio is 30:70) to dissolve and make a solution containing approximately 0.0083 mg of methylparaben per 1 mL to obtain the methylparaben reference solution.

[0123] Ethyl hydroxybenzoate reference solution: Accurately weigh ethyl hydroxybenzoate, add methanol-water mixed solvent (methanol and water volume ratio is 30:70) to dissolve and make a solution containing approximately 0.0078 mg of ethyl hydroxybenzoate per 1 mL to obtain the ethyl hydroxybenzoate reference solution.

[0124] Propylparaben reference solution: Accurately weigh propylparaben, add methanol-water mixed solvent (methanol and water volume ratio is 30:70) to dissolve and make a solution containing approximately 0.0091 mg of propylparaben per 1 mL to obtain the propylparaben reference solution.

[0125] Acetaminophen tablets (Manufacturer A) sample solution: Take acetaminophen tablets (Manufacturer A), grind into powder, accurately weigh, add methanol-water mixed solvent (methanol and water volume ratio of 30:70) to dissolve and make a solution containing approximately 0.0056 mg of acetaminophen per 1 mL, filter, and obtain the acetaminophen tablets (Manufacturer A) sample solution.

[0126] Acetaminophen tablets (Manufacturer B) sample solution: Take acetaminophen tablets (Manufacturer B), grind into powder, accurately weigh, add methanol-water mixed solvent (methanol and water volume ratio of 30:70) to dissolve and make a solution containing approximately 0.0087 mg of acetaminophen per 1 mL, filter, and obtain the acetaminophen tablets (Manufacturer B) sample solution.

[0127] Acetaminophen tablets (Manufacturer C) sample solution: Take acetaminophen tablets (Manufacturer C), grind into powder, accurately weigh, add methanol-water mixed solvent (methanol and water volume ratio of 30:70) to dissolve and make a solution containing approximately 0.0077 mg of acetaminophen per 1 mL, filter, and obtain the acetaminophen tablets (Manufacturer C) sample solution.

[0128] (2) The solutions prepared above were subjected to UV scanning respectively. Figures 10 to 18 .

[0129] The existing standard for determining the content of acetaminophen tablets uses 0.4% sodium hydroxide aqueous solution as a solvent, and the detection wavelength of the ultraviolet spectrophotometry is 257nm.

[0130] The solvent used in the invention is a mobile phase with a starting ratio of gradient elution: methanol-water=30:70 (volume ratio); ultraviolet scanning of commercially available test solution and reference solution dissolved by the solvent shows that the maximum absorption wavelength is 245nm, in particular, the maximum absorption wavelength of the p-aminophenol reference solution is 297nm and 231nm, the maximum absorption wavelength of the p-chlorophenylacetamide reference solution is 246nm, and the maximum absorption wavelengths of three antibacterial agents (methylparaben, ethylparaben, propylparaben) are all 256nm; because the external standard method is used for quantification, 245nm is finally selected as the detection wavelength after comprehensive consideration.

[0131] 4. Selection of column temperature

[0132] (1) Preparation of mixed positioning solution

[0133] Take appropriate amount of acetaminophen, p-aminophenol, p-chlorophenylacetamide, methylparaben, ethylparaben, and propylparaben reference substances, weigh accurately, add methanol-water mixed solvent (methanol and water volume ratio is 30:70) to dissolve and make a solution containing approximately 0.18 mg acetaminophen, 0.08 mg p-aminophenol, 0.04 mg p-chlorophenylacetamide, 0.03 mg methylparaben, 0.07 mg ethylparaben, and 0.05 mg propylparaben per 1 mL, filter with a 0.45 μm microporous filter membrane to obtain a mixed positioning solution.

[0134] (2) HPLC conditions

[0135] The HPLC conditions were as follows:

[0136] Chromatographic column: octadecylsilane bonded silica gel as filler (150 mm × 4.6 mm, 5 μm);

[0137] Mobile phase A: methanol;

[0138] Mobile phase B: water;

[0139] Injection volume: 20 μL;

[0140] Flow rate: 1.0 mL / min;

[0141] Detection wavelength: 245nm;

[0142] Column temperature: 25℃, 30℃ or 35℃;

[0143] Gradient elution;

[0144] The gradient elution program parameters are shown in Table 3.

[0145] (3) Inject the mixed positioning solution obtained in step (1) into a high performance liquid chromatograph for analysis and detection, and record the chromatogram. Figure 19 to Figure 21 .

[0146] Experimental results: The separation degree of each component under the three column temperatures is greater than 2. Since the 25℃ column temperature has high requirements for laboratory temperature control and too high a column temperature is not conducive to maintaining the life of the chromatographic column, 30℃ was selected as the optimal column temperature.

[0147] 5. Selection of flow rate

[0148] (1) Preparation of mixed positioning solution

[0149] Take appropriate amount of acetaminophen, p-aminophenol, p-chlorophenylacetamide, methylparaben, ethylparaben, and propylparaben reference substances, weigh accurately, add methanol-water mixed solvent (methanol and water volume ratio is 30:70) to dissolve and make a solution containing approximately 0.09 mg acetaminophen, 0.04 mg p-aminophenol, 0.06 mg p-chlorophenylacetamide, 0.009 mg methylparaben, 0.01 mg ethylparaben, and 0.007 mg propylparaben per 1 mL, filter with a 0.45 μm microporous filter membrane to obtain a mixed positioning solution.

[0150] (2) HPLC conditions

[0151] The HPLC conditions were as follows:

[0152] Chromatographic column: octadecylsilane bonded silica gel as filler (150 mm × 4.6 mm, 5 μm);

[0153] Mobile phase A: methanol;

[0154] Mobile phase B: water;

[0155] Injection volume: 20 μL;

[0156] Flow rate: 0.9mL / min, 1.0mL / min or 1.1mL / min;

[0157] Detection wavelength: 245nm;

[0158] Column temperature: 30°C;

[0159] Gradient elution;

[0160] The gradient elution program parameters are shown in Table 3.

[0161] (3) Inject the mixed positioning solution obtained in step (1) into a high performance liquid chromatograph for analysis and detection, and record the chromatogram. Figure 22 to Figure 24 .

[0162] Experimental results: When the mixed solution of 6 substances was injected at 0.9mL / min, 1.0mL / min, and 1.1mL / min, the separation degree of each component was still greater than 2. Therefore, the conventional flow rate of 1.0mL / min was selected.

[0163] 6. Selection of column length

[0164] Using a 25 cm C18 column, it takes more than 30 minutes to separate all 6 substances, while using a 15 cm C18 column can separate all 6 substances within 22 minutes. In order to improve analysis efficiency and save resources, a 15 cm C18 column was selected.

[0165] 7. Standard curve

[0166] Weigh the standard samples of 6 target substances (acetaminophen, para-aminophenol, para-chlorophenylacetamide, methylparaben, ethylparaben, and propylparaben) accurately, dilute them with methanol-water mixed solvent (methanol and water volume ratio is 30:70), and prepare standard working solutions of different concentrations. Inject the samples into the high performance liquid chromatograph and record the chromatogram, with concentration as the horizontal axis and peak area as the vertical axis, and obtain the linear regression equation. The results are shown in Table 5. Detection was carried out by high performance liquid chromatography, and the specific high performance liquid chromatography conditions are as follows:

[0167] Chromatographic column: octadecylsilane bonded silica gel as filler (150 mm × 4.6 mm, 5 μm);

[0168] Mobile phase A: methanol;

[0169] Mobile phase B: water;

[0170] Injection volume: 20 μL;

[0171] Flow rate: 1.0 mL / min;

[0172] Detection wavelength: 245nm;

[0173] Column temperature: 30°C;

[0174] Gradient elution;

[0175] The gradient elution program parameters are shown in Table 3.

[0176] Table 5 Standard curve experimental results

[0177]

[0178]

[0179] The results showed that under this method, acetaminophen and its two special impurities (p-aminophenol and p-chlorophenylacetamide) and three antibacterial agents (methylparaben, ethylparaben and propylparaben) all showed good linearity within a certain concentration range.

[0180] 8. Limit of Quantitation and Limit of Detection Tests

[0181] The signal-to-noise ratio method was used to determine the detection limit and quantification limit of acetaminophen and two special impurities (para-aminophenol and para-chlorophenylacetamide) and three antibacterial agents (methylparaben, ethylparaben, and propylparaben). The high performance liquid chromatography method was used for detection, and the specific high performance liquid chromatography conditions were as follows:

[0182] Chromatographic column: octadecylsilane bonded silica gel as filler (150 mm × 4.6 mm, 5 μm);

[0183] Mobile phase A: methanol;

[0184] Mobile phase B: water;

[0185] Injection volume: 20 μL;

[0186] Flow rate: 1.0 mL / min;

[0187] Detection wavelength: 245nm;

[0188] Column temperature: 30°C;

[0189] Gradient elution;

[0190] The gradient elution program parameters are shown in Table 3.

[0191] Reference stock solutions of acetaminophen, two special impurities (p-aminophenol and p-chlorophenylacetamide) and three antibacterial agents (methylparaben, ethylparaben and propylparaben) were prepared respectively, diluted to a certain concentration and injected into the HPLC. The ratio of peak height to noise (signal-to-noise ratio) was calculated. The sample detection amount with a signal-to-noise ratio (S / N) of about 10 was the quantification limit, and the sample detection amount with a signal-to-noise ratio (S / N) of about 3 was the detection limit. The results are shown in Table 6.

[0192] Table 6 Results of quantitation limit and detection limit tests

[0193]

[0194]

[0195] The results showed that this method had a high response to the six target analytes and could accurately control their contents.

[0196] Example 3: The detection method of the present invention is used to determine the content of the main component, two special impurities and three antibacterial agents in acetaminophen tablets

[0197] (1) Preparation of mixed reference solution

[0198] Take appropriate amounts of acetaminophen, p-aminophenol, p-chlorophenylacetamide, methylparaben, ethylparaben, and propylparaben reference substances, weigh them accurately, add methanol-water mixed solvent (methanol and water volume ratio is 30:70) to dissolve and make a solution containing approximately 0.20 mg acetaminophen, 0.0002 mg p-aminophenol, 0.0002 mg p-chlorophenylacetamide, 0.0004 mg methylparaben, 0.00008 mg ethylparaben, and 0.00006 mg propylparaben per 1 mL, filter with a 0.45 μm microporous filter membrane to obtain a mixed reference substance solution.

[0199] (2) Paracetamol tablet sample solution: Take paracetamol tablets (from manufacturer A, manufacturer B or manufacturer C), grind them into powder, weigh accurately, add methanol-water mixed solvent (methanol:water volume ratio of 30:70) to dissolve and make a solution containing approximately 0.20 mg of paracetamol per 1 mL, filter through a 0.45 μm microporous filter membrane to obtain the paracetamol tablet sample solution.

[0200] (3) The acetaminophen tablet sample solution was injected into a high performance liquid chromatograph and detected by high performance liquid chromatography. The specific high performance liquid chromatography conditions were as follows:

[0201] Chromatographic column: octadecylsilane bonded silica gel as filler (150 mm × 4.6 mm, 5 μm);

[0202] Mobile phase A: methanol;

[0203] Mobile phase B: water;

[0204] Injection volume: 20 μL;

[0205] Flow rate: 1.0 mL / min;

[0206] Detection wavelength: 245nm;

[0207] Column temperature: 30°C;

[0208] Gradient elution;

[0209] The gradient elution program parameters are shown in Table 3.

[0210] (4) Taking three commercially available acetaminophen tablets (manufacturer A, manufacturer B, and manufacturer C) as examples, the main drug (acetaminophen), two special impurities (para-aminophenol, p-chlorophenylacetamide), and three antibacterial agents (methylparaben, ethylparaben, and propylparaben) were determined by high performance liquid chromatography, and the chromatograms were recorded. The peak areas were used for quantification according to the external standard method, and the percentage relative to the labeled amount was calculated.

[0211] Calculation formula:

[0212]

[0213] Where:

[0214] c R ————Concentration of the corresponding component reference substance in the mixed reference substance solution, g / mL;

[0215] K————Purity of the corresponding reference substance;

[0216] A x ————Peak area of ​​the corresponding component in the sample solution;

[0217] A R ————Peak area of ​​the corresponding component reference substance in the mixed reference substance solution;

[0218] V x ————Sample fixed volume, mL;

[0219] ————Average tablet weight of sample, g / tablet;

[0220] m x ————Weighed mass of sample flake powder, g;

[0221] m s ——Sample labeled mass: 0.3g / tablet or 0.5g / tablet.

[0222] Since the antibacterial agent reference substance is ester, if the antibacterial agent is sodium salt, the content of the antibacterial agent needs to be converted according to the molecular weight. The conversion is shown as follows:

[0223]

[0224] M 酯 - Methylparaben molecular weight 152.15, ethylparaben molecular weight 166.18, or propylparaben molecular weight 180.20;

[0225] M 钠盐 -The molecular weight of sodium methylparaben is 174.13, the molecular weight of sodium ethylparaben is 188.16, and the molecular weight of sodium propylparaben is 202.18.

[0226] The specific test results are shown in Table 7, which show that the acetaminophen tablets of manufacturer A contain three antibacterial agents: sodium methylparaben, sodium ethylparaben and propylparaben; the acetaminophen tablets of manufacturers B and C do not contain these three antibacterial agents.

[0227] Table 7 Test results of commercially available acetaminophen tablets samples

[0228]

[0229]

[0230] Comparative Example 1:

[0231] The method for checking para-aminophenol in acetaminophen tablets (manufacturer A) in Part II of the 2020 edition of the Pharmacopoeia of the People's Republic of China was used to record the chromatogram. The acquisition time was 50 minutes. Continuous injection revealed that the main peak was overloaded and the peak was severely broadened. At the same time, the antibacterial agent was located under the chromatographic conditions and it was found that the antibacterial agent could not be eluted within 1 hour. The specific chromatogram is shown in the figure below. Figure 1 , Figure 2 shown.

[0232] Comparative Example 2:

[0233] The method for checking p-chlorophenylacetamide in acetaminophen raw materials in Part II of the 2020 edition of the Pharmacopoeia of the People's Republic of China was used to locate acetaminophen, p-aminophenol, p-chlorophenylacetamide and three antibacterial agents (methylparaben, ethylparaben, and propylparaben). It was found that p-aminophenol could not be completely separated from the main peak, which would interfere with the determination. Moreover, under the gradient chromatography conditions, propylparaben was not eluted until 16 times the retention time of the main peak, and the analysis efficiency was low. The specific liquid chromatogram is shown in the figure below. Figure 3 shown.

[0234] Comparative Example 3:

[0235] The impurities and antibacterial agents were located using the related substance method for acetaminophen tablets in USP-NF 2024. The chromatogram was recorded. The acquisition time was 15 minutes. 4-Chlorophenylacetamide and the antibacterial agent ethylparaben were continuously injected. The retention times of the two were very close and could not be separated. The specific representative liquid phase chromatogram is shown in the figure below. Figure 4 , Figure 5 shown.

[0236] The present invention provides a kind of thought and method of acetaminophen tablet quality detection method, and there are many methods and approaches to specifically realize the technical scheme, and the above is only a preferred embodiment of the present invention, and it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications should also be regarded as the protection scope of the present invention. Each component not clearly defined in the present embodiment can be realized by existing technology.

Claims

1. A method for detecting the quality of acetaminophen tablets, characterized in that: The quality inspection includes simultaneous inspection of active pharmaceutical ingredients, impurity ingredients and antibacterial ingredients; The active pharmaceutical ingredient includes acetaminophen; The impurity components include p-aminophenol and p-chlorophenylacetamide; The antibacterial agent ingredients include methylparaben, ethylparaben, and propylparaben; The quality detection method comprises the following steps: (1) Preparation of mixed reference solution Take acetaminophen, p-aminophenol, p-chlorophenylacetamide, methylparaben, ethylparaben, and propylparaben standard products, dilute to volume with a methanol-water mixed solvent, and filter to obtain a mixed reference solution; (2) Preparation of acetaminophen tablet sample solution Take acetaminophen tablets, grind them into powder, weigh accurately, add methanol-water mixed solvent to make up to volume, filter, and obtain acetaminophen tablet sample solution; (3) High performance liquid chromatography analysis and result calculation The mixed reference substance solution obtained in step (1) and the acetaminophen tablet sample solution obtained in step (2) are respectively injected into a high performance liquid chromatograph, and the chromatogram is recorded. The chromatogram is quantified by the peak area according to the external standard method to calculate the content of the corresponding substance; Among them, high performance liquid chromatography was used for determination, and the specific high performance liquid chromatography conditions were as follows: Chromatographic column: Octadecylsilane bonded silica gel as filler, specification (150mm~250mm)×4.6mm, 5μm; Mobile phase A: methanol; Mobile phase B: water; Injection volume: 15-25 μL; Flow rate: 0.9mL / min~1.1mL / min; Detection wavelength: 245nm; Column temperature: 25℃~35℃; Gradient elution; The gradient elution program is as follows:

2. The quality inspection method according to claim 1, characterized in that: In the methanol-water mixed solvent, the volume ratio of methanol to water is 30:

70.

3. The quality inspection method according to claim 1, characterized in that: The chromatographic column has specifications of 150 mm×4.6 mm and 5 μm.

4. The quality inspection method according to claim 1, characterized in that: The injection volume is 20 μL.

5. The quality inspection method according to claim 1, characterized in that: The flow rate is 1.0 mL / min.

6. The quality inspection method according to claim 1, characterized in that: The column temperature is 30°C.

7. Use of the quality detection method according to any one of claims 1 to 6 in the simultaneous separation of paracetamol and para-aminophenol, p-chlorophenylacetamide, methylparaben, ethylparaben and propylparaben in paracetamol tablets.

8. Use of the quality detection method according to any one of claims 1 to 6 in the simultaneous determination of the content of acetaminophen and the content of para-aminophenol, the content of p-chlorophenylacetamide, the content of methylparaben, the content of ethylparaben, and the content of propylparaben in acetaminophen tablets.

9. Use of the quality detection method according to any one of claims 1 to 6 in simultaneously separating acetaminophen and para-aminophenol, p-chlorophenylacetamide, methylparaben, ethylparaben, and propylparaben in acetaminophen tablets, and simultaneously determining the content of acetaminophen and the content of para-aminophenol, the content of p-chlorophenylacetamide, the content of methylparaben, the content of ethylparaben, and the content of propylparaben in acetaminophen tablets.

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