An analytical method for methyl iodopentanoate in β-lactam antibiotics

Abstract

The invention belongs to the technical field of medical detection and analysis, and provides an analytical method for iodomethyl pivalate in a beta-lactam antibiotic. The analytical method provided by the present invention uses an octadecylsilane bonded silica gel chromatographic column as a chromatographic column, and a mixed solution of a buffered saline solution and an ion pair reagent dissolved in methanol is used as a mobile phase system for gradient elution, and a trace amount of iodomethyl pivalate residue in a beta-lactam antibiotic can be detected, and the sensitivity is high (the quantitative limit is 0.1563 μg / mL, and the detection limit is 0.0134 μg / mL), the separation is good, simple and fast, and the specificity is strong, and it can be used for the detection of iodomethyl pivalate residues in a variety of beta-lactam antibiotics bulk drugs, and the quality of the bulk drugs is effectively controlled.

Description

Technical Field

[0001] The invention relates to the technical field of medical detection and analysis, and in particular to an analysis method for iodomethyl pivalate in beta-lactam antibiotics. Background Art

[0002] Iodomethyl pivalate is iodomethyl 2,2-dimethylpropionate, which is often used as a key material in the synthesis of β-lactam antibiotics. It has a boiling point of 197°C, is insoluble in water, and is soluble in organic reagents such as alcohol, ether, and ketone. At present, there are no reports on the toxicological data of iodomethyl pivalate. According to the relevant requirements of the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use, the limit of iodomethyl pivalate is set at 0.05%. Its chemical structure is shown in Formula 1:

[0003]

[0004] Iodomethyl pivalate is easily decomposed at high temperatures, and it is difficult to accurately quantify trace amounts of iodomethyl pivalate residues in complex matrices using gas chromatography. The use of high performance liquid chromatography can solve the problem of quantifying trace amounts of iodomethyl pivalate. At present, there are no relevant literature or detailed reports on the determination method of iodomethyl pivalate residues in β-lactam antibiotics.

[0005] The following is an explanation of the iodine methyl pivalate residues in several representative β-lactam antibiotics and their raw materials.

[0006] Cefditoren Pivoxil is a third-generation oral cephalosporin antibiotic, which shows excellent therapeutic effect on experimental infections caused by Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae, Proteus, etc. In addition, the therapeutic effect on β-lactamase producing strains is also equal to or superior to similar drugs. A Chinese patent with publication number CN104513256A discloses a preparation method of cefditoren pivoxil, which proposes to generate cefditoren pivoxil by reacting cefditoren sodium with iodomethyl pivalate.

[0007] Cefcapene Pivoxil Hydrochloride is a broad-spectrum oral antibiotic with propyloxymethyl group and stable to β-lactamase developed by Shionogi Co., Ltd. of Japan. It was launched in Japan in July 1997 under the trade name of Flomox. It is used to treat respiratory and urinary system infections, ophthalmic and ENT infections, and skin and soft tissue infections, and has strong clinical application advantages. A Chinese patent with publication number CN102485727A discloses a method for preparing cefcapene hydrochloride and its intermediates, and proposes an esterification reaction of cefcapene acid with iodomethyl pivalate to obtain cefcapene hydrochloride. Summary of the invention

[0008] In view of this, the object of the present invention is to provide an analysis method for iodomethyl pivalate in β-lactam antibiotics. The analysis method provided by the present invention can detect trace amounts of iodomethyl pivalate residues in β-lactam antibiotics with high sensitivity, and can effectively control the quality of β-lactam antibiotics.

[0009] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0010] The present invention provides an analysis method for iodomethyl pivalate in β-lactam antibiotics, comprising the following steps:

[0011] Dissolve the β-lactam antibiotic to be tested and the iodomethyl pivalate standard respectively to obtain a test solution and a reference solution;

[0012] The test solution and the reference solution are respectively subjected to high performance liquid chromatography to obtain chromatographic information of the test solution and the reference solution;

[0013] Comparing the chromatographic information of the reference solution with the chromatographic information of the test solution to obtain the residual amount of iodomethyl pivalate in the β-lactam antibiotic to be tested;

[0014] The parameters of the HPLC detection include:

[0015] The chromatographic column is an octadecylsilane bonded silica gel chromatographic column;

[0016] The mobile phase system includes mobile phase A and mobile phase B;

[0017] The mobile phase A is a buffered saline solution;

[0018] The mobile phase B is a methanol solution of an ion pair reagent;

[0019] The elution mode is gradient elution;

[0020] The procedure of the gradient elution is shown in Table 1:

[0021] Table 1 Gradient elution program

[0022]

[0023]

[0024] Preferably, the β-lactam antibiotic to be tested includes cefditoren pivoxil or cefcapene pivoxil hydrochloride.

[0025] Preferably, the dissolving reagent independently comprises anhydrous methanol or a methanol aqueous solution with a volume percentage of 50%.

[0026] Preferably, the concentration of the test solution is 1.5-3.0 mg / mL.

[0027] Preferably, the buffered saline solution is a potassium dihydrogen phosphate aqueous solution; the concentration of the potassium dihydrogen phosphate aqueous solution is 30 mmol / L to 50 mmol / L.

[0028] Preferably, the ion pair reagent is tetrapentylammonium bromide; and the concentration of the methanol solution of the ion pair reagent is 4 mmol / L to 10 mmol / L.

[0029] Preferably, the particle size of the filler of the octadecylsilane bonded silica gel chromatographic column is 3-5 μm, and the column temperature is 20-30°C.

[0030] Preferably, the flow rate of the mobile phase system is 0.7 mL / min to 1.0 mL / min.

[0031] Preferably, the parameters of the HPLC detection also include: the injection volume is 20 μL to 50 μL.

[0032] Preferably, the parameters of the HPLC detection also include: a detection wavelength of 240 nm to 250 nm.

[0033] The invention provides an analysis method for iodomethyl pivalate in a beta-lactam antibiotic. The method comprises the following steps: respectively dissolving a beta-lactam antibiotic to be tested and a standard product of iodomethyl pivalate to obtain a test solution and a reference solution; respectively performing high performance liquid chromatography detection on the test solution and the reference solution to obtain chromatographic information of the test solution and the reference solution; comparing the chromatographic information of the reference solution with the chromatographic information of the test solution to obtain the residual amount of iodomethyl pivalate in the beta-lactam antibiotic to be tested; the parameters of the high performance liquid chromatography detection include: a chromatographic column is an octadecylsilane bonded silica gel chromatographic column; a mobile phase system comprises a mobile phase A and a mobile phase B; the mobile phase A is a buffered saline solution; the mobile phase B is a methanol solution of an ion pair reagent; the elution mode is gradient elution; and the procedure of the gradient elution is as shown in Table 1. The analytical method of the invention uses an octadecylsilane bonded silica gel chromatographic column as a chromatographic column and a mixed solution of a buffered saline solution and an ion pair reagent dissolved in methanol as a mobile phase system for gradient elution, and can detect trace amounts of iodomethyl pivalate residues in beta-lactam antibiotics, and has high sensitivity (quantitative limit of 0.1563 μg / mL, detection limit of 0.0134 μg / mL), good separation, simplicity, rapidity, and strong specificity. The method can be used for detecting iodomethyl pivalate residues in various beta-lactam antibiotic raw materials, and effectively controlling the quality of the raw materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 HPLC diagram of the reference substance solution in Example 1;

[0035] Figure 2 for Figure 1 A partial enlarged view of

[0036] Figure 3 HPLC diagram of the test solution in Example 1;

[0037] Figure 4 for Figure 3 A partial enlarged view of

[0038] Figure 5 HPLC chart of the recovered solution added in Example 2;

[0039] Figure 6 for Figure 5 A partial enlarged view of

[0040] Figure 7 HPLC diagram of the reference substance solution in Example 6;

[0041] Figure 8 This is the HPLC chart of the test solution in Example 6. DETAILED DESCRIPTION

[0042] The present invention provides an analysis method for iodomethyl pivalate in β-lactam antibiotics, comprising the following steps:

[0043] Dissolve the β-lactam antibiotic to be tested and the iodomethyl pivalate standard respectively to obtain a test solution and a reference solution;

[0044] The test solution and the reference solution are respectively subjected to high performance liquid chromatography to obtain chromatographic information of the test solution and the reference solution;

[0045] The chromatographic information of the reference solution and the chromatographic information of the test solution are compared to obtain the residual amount of iodomethyl pivalate in the β-lactam antibiotic to be tested.

[0046] In the present invention, unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0047] The invention dissolves the beta-lactam antibiotic to be tested and the iodomethyl pivalate standard respectively to obtain a test solution and a reference solution.

[0048] In the present invention, the β-lactam antibiotic to be tested preferably includes cefditoren pivoxil or cefcapene pivoxil hydrochloride. In the present invention, the dissolved reagent independently preferably includes anhydrous methanol or a methanol aqueous solution with a volume percentage of 50%.

[0049] In the present invention, the concentration of the test solution is preferably 1.5 to 3.0 mg / mL, more preferably 2 mg / mL. In the present invention, the concentration of the iodomethyl pivalate standard in the reference solution is preferably 0.001 to 0.002 mg / mL.

[0050] After obtaining the test solution and the reference solution, the present invention performs high performance liquid chromatography on the test solution and the reference solution respectively to obtain chromatographic information of the test solution and the reference solution.

[0051] In the present invention, the parameters of the HPLC detection include:

[0052] The chromatographic column is an octadecylsilane bonded silica gel chromatographic column; the octadecylsilane bonded silica gel chromatographic column is preferably Cosmosil 5C18-MS-Ⅱ or YMC Pack ODS-A; the particle size of the filler of the octadecylsilane bonded silica gel chromatographic column is preferably 3 to 5 μm, more preferably 5 μm; the size of the octadecylsilane bonded silica gel chromatographic column is preferably 4.6×150 mm; the column temperature is preferably 20 to 30° C., more preferably 25° C.;

[0053] The mobile phase system includes mobile phase A and mobile phase B;

[0054] The flow rate of the mobile phase system is preferably 0.7 mL / min to 1.0 mL / min, more preferably 0.8 mL / min to 0.9 mL / min;

[0055] The mobile phase A is a buffered saline solution; the buffered saline solution is preferably a potassium dihydrogen phosphate aqueous solution; the concentration of the potassium dihydrogen phosphate aqueous solution is preferably 30 mmol / L to 50 mmol / L, and more preferably 40 mmol / L.

[0056] The mobile phase B is a methanol solution of an ion pair reagent; the ion pair reagent is preferably tetrapentylammonium bromide; the concentration of the methanol solution of the ion pair reagent is preferably 4 mmol / L to 10 mmol / L, and more preferably 5 mmol / L.

[0057] The elution mode is gradient elution;

[0058] The gradient elution procedure is shown in Table 1.

[0059] In the present invention, the parameters of the HPLC detection also include: the injection volume is preferably 20 μL to 50 μL, more preferably 30 μL to 40 μL; the detection wavelength is preferably 240 nm to 250 nm, more preferably 245 nm.

[0060] In the present invention, the parameters of the HPLC detection also include: the detector is preferably an ultraviolet detector; the ultraviolet detector is preferably a DAD ultraviolet detector or a PDA ultraviolet detector.

[0061] In the present invention, the HPLC detection is preferably performed on a Shimadzu LC-20AT HPLC or an Agilent 1260Ⅱ.

[0062] After obtaining the chromatographic information of the test solution and the reference solution, the present invention compares the chromatographic information of the reference solution with the chromatographic information of the test solution to obtain the residual amount of iodomethyl pivalate in the β-lactam antibiotic to be tested.

[0063] The present invention does not specifically limit the method for comparing the chromatographic information of the reference solution with the chromatographic information of the test solution to obtain the residual amount of iodomethyl pivalate in the β-lactam antibiotic to be tested, and the operation well known to those skilled in the art can be used.

[0064] The analysis method of iodomethyl pivalate in the β-lactam antibiotics provided by the present invention is described in detail below in conjunction with the examples, but they should not be construed as limiting the scope of protection of the present invention.

[0065] Example 1

[0066] Instrument: Shimadzu LC-20AT high performance liquid chromatograph, DAD UV detector;

[0067] Chromatographic column: Cosmosil 5C18-MS-Ⅱ (4.6×150mm, 5μm);

[0068] Mobile phase A: 40mmol / L potassium dihydrogen phosphate aqueous solution;

[0069] Mobile phase B: 5 mmol / L tetrapentylammonium bromide in methanol;

[0070] The gradient elution procedure is shown in Table 1 ;

[0071] Flow rate of mobile phase system: 0.8 mL / min;

[0072] Detection wavelength: 245nm;

[0073] Column temperature: 25°C;

[0074] Injection volume: 30 μL;

[0075] Test steps:

[0076] Reference solution: Accurately weigh 100.05 mg of iodomethyl pivalate standard, place in a 100 mL volumetric flask, dilute to the mark with anhydrous methanol, and shake well; Accurately pipette 1 mL of the above solution into a 100 mL volumetric flask, dilute to the mark with a 50% by volume methanol aqueous solution, and shake well to prepare the iodomethyl pivalate reference stock solution; Accurately pipette 5 mL of iodomethyl pivalate reference stock solution into a 50 mL volumetric flask to which 10 mL of anhydrous methanol has been added, dilute to the mark with a 50% by volume methanol aqueous solution, and shake well (500 ppm).

[0077] Test solution: Accurately weigh 100.10 mg of cefditoren pivoxil sample, place in a 50 mL volumetric flask, add 10 mL of anhydrous methanol to dissolve, then dilute to the scale with 50% methanol-water solution by volume, and shake well.

[0078] Take the reference solution and the test solution separately, perform HPLC analysis under the above chromatographic conditions, record the chromatogram, and the results are shown in Figures 1 to 4 ,in, Figure 1 is the HPLC chart of the reference solution. Figure 2 for Figure 1 A partial enlarged view of Figure 3 is the HPLC chart of the test solution. Figure 4 for Figure 3 A partial enlarged view of the Figures 1 to 4 It can be seen that: Figure 1 The chromatographic peak with a retention time of 8.393 min is the chromatographic peak of iodine methyl pivalate, which shows that the residual iodine methyl pivalate in the cefditoren pivoxil sample is less than 500 ppm.

[0079] Example 2

[0080] Instrument: Shimadzu LC-20AT high performance liquid chromatograph, DAD UV detector;

[0081] Chromatographic column: Cosmosil 5C18-MS-Ⅱ (4.6×150mm, 5μm);

[0082] Mobile phase A: 20mmol / L potassium dihydrogen phosphate aqueous solution;

[0083] Mobile phase B: 4 mmol / L tetrapentylammonium bromide in methanol;

[0084] The gradient elution procedure is shown in Table 1 ;

[0085] Flow rate of mobile phase system: 0.8 mL / min;

[0086] Detection wavelength: 250nm;

[0087] Column temperature: 30°C;

[0088] Injection volume: 30 μL;

[0089] Test steps:

[0090] Reference solution: Accurately weigh 99.21 mg of iodomethyl pivalate standard, place it in a 100mL volumetric flask, dilute to the scale with anhydrous methanol, and shake well; Accurately pipette 1 mL of the above solution into a 100mL volumetric flask, dilute to the scale with a 50% by volume methanol aqueous solution, and shake well as the iodomethyl pivalate reference stock solution; Accurately pipette 5 mL of iodomethyl pivalate reference stock solution into a 50mL volumetric flask to which 10 mL of anhydrous methanol has been added, dilute to the scale with a 50% by volume methanol aqueous solution, and shake well (500 ppm).

[0091] Test solution: Accurately weigh 100.07 mg of cefditoren pivoxil sample, place in a 50 mL volumetric flask, add 10 mL of anhydrous methanol to dissolve, then dilute to the scale with 50% methanol-water solution by volume, and shake well.

[0092] Add sample recovery solution: accurately weigh 100.13 mg of cefditoren pivoxil sample, place in a 50 mL volumetric flask, add 5 mL of iodine methyl pivalate reference substance stock solution to dissolve, then dilute to the scale with 50% volume fraction methanol aqueous solution, and shake well.

[0093] The reference solution, the test solution and the sample recovery solution were taken separately, and HPLC analysis was performed under the above chromatographic conditions. The chromatograms were recorded. The specific results are shown in Table 2.

[0094] Table 2 Chromatographic information of reference solution, test solution and sample recovery solution

[0095]

[0096] Figure 5 This is the HPLC chart of the sample recovery solution. Figure 6 for Figure 5 A partial enlarged view of .

[0097] From Table 2 and Figure 5 and 6 It can be seen that the recovery rate of iodomethyl pivalate is 98.4%, indicating that the recovery rate of iodomethyl pivalate remaining in the cefditoren pivoxil sample is high and the accuracy is good.

[0098] Example 3

[0099] Instrument: Shimadzu LC-20AT high performance liquid chromatograph, DAD UV detector;

[0100] Chromatographic column: Cosmosil 5C18-MS-Ⅱ (4.6×150mm, 5μm);

[0101] Mobile phase A: 50mmol / L potassium dihydrogen phosphate aqueous solution;

[0102] Mobile phase B: 10 mmol / L tetrapentylammonium bromide in methanol;

[0103] The gradient elution procedure is shown in Table 1 ;

[0104] Flow rate of mobile phase system: 0.8 mL / min;

[0105] Detection wavelength: 240nm;

[0106] Column temperature: 20°C;

[0107] Injection volume: 30 μL;

[0108] Test steps:

[0109] Reference solution: Accurately weigh 100.13 mg of iodomethyl pivalate standard, place in a 100mL volumetric flask, dilute to the mark with anhydrous methanol, and shake well; Accurately pipette 1 mL of the above solution into a 100mL volumetric flask, dilute to the mark with 50% by volume methanol aqueous solution, and shake well as the iodomethyl pivalate reference stock solution; Accurately pipette 5 mL of iodomethyl pivalate reference stock solution into a 50mL volumetric flask to which 10 mL of anhydrous methanol has been added, dilute to the mark with anhydrous methanol, and shake well (500ppm).

[0110] Take the reference solution and perform HPLC analysis under the above chromatographic conditions, and record the chromatogram results as shown in Table 3.

[0111] Table 3 Chromatographic information obtained in Example 3

[0112]

[0113] It can be seen from Table 3 that the chromatographic peak with a retention time of 8.418 min is the chromatographic peak of iodomethyl pivalate, and the theoretical plate number of the iodomethyl pivalate peak is 9875 (the Chinese Pharmacopoeia requires greater than or equal to 2000), indicating that the analysis method provided by the present invention is suitable for the detection of iodomethyl pivalate residues.

[0114] Example 4

[0115] Instrument: Shimadzu LC-20AT high performance liquid chromatograph, DAD UV detector;

[0116] Chromatographic column: Cosmosil 5C18-MS-Ⅱ (4.6×150mm, 5μm);

[0117] Mobile phase A: 40mmol / L potassium dihydrogen phosphate aqueous solution;

[0118] Mobile phase B: 5 mmol / L tetrapentylammonium bromide in methanol;

[0119] The gradient elution procedure is shown in Table 1 ;

[0120] Flow rate of mobile phase system: 0.7 mL / min;

[0121] Detection wavelength: 240nm;

[0122] Column temperature: 20°C;

[0123] Injection volume: 20 μL;

[0124] Test steps:

[0125] Reference solution: Accurately weigh 99.71 mg of iodomethyl pivalate standard, place in a 100mL volumetric flask, dilute to the mark with anhydrous methanol, and shake well; Accurately pipette 1 mL of the above solution into a 100mL volumetric flask, dilute to the mark with 50% by volume methanol aqueous solution, and shake well as the iodomethyl pivalate reference stock solution; Accurately pipette 5 mL of iodomethyl pivalate reference stock solution into a 50mL volumetric flask to which 10 mL of anhydrous methanol has been added, dilute to the mark with anhydrous methanol, and shake well (500ppm).

[0126] The reference solution was taken and analyzed by HPLC under the above chromatographic conditions. The chromatogram was recorded. The results are shown in Table 4.

[0127] Table 4 Chromatographic information obtained in Example 4

[0128]

[0129] It can be seen from Table 4 that the chromatographic peak with a retention time of 10.435 min is the chromatographic peak of iodomethyl pivalate, and the theoretical plate number of the iodomethyl pivalate peak is 10594 (the Chinese Pharmacopoeia requires greater than or equal to 2000), indicating that the analysis method provided by the present invention is suitable for the detection of iodomethyl pivalate residues.

[0130] Example 5

[0131] Instrument: Shimadzu LC-20AT high performance liquid chromatograph, DAD UV detector;

[0132] Chromatographic column: YMC Pack ODS-A (4.6×150 mm, 3 μm);

[0133] Mobile phase A: 40mmol / L potassium dihydrogen phosphate aqueous solution;

[0134] Mobile phase B: 5 mmol / L tetrapentylammonium bromide in methanol;

[0135] The gradient elution procedure is shown in Table 1 ;

[0136] Flow rate of mobile phase system: 1.0 mL / min;

[0137] Detection wavelength: 250nm;

[0138] Column temperature: 30°C;

[0139] Injection volume: 50 μL;

[0140] Reference solution: Accurately weigh 99.71 mg of iodomethyl pivalate standard, place in a 100mL volumetric flask, dilute to the mark with anhydrous methanol, and shake well; Accurately pipette 1 mL of the above solution into a 100mL volumetric flask, dilute to the mark with 50% by volume methanol aqueous solution, and shake well as the iodomethyl pivalate reference stock solution; Accurately pipette 5 mL of iodomethyl pivalate reference stock solution into a 50mL volumetric flask to which 10 mL of anhydrous methanol has been added, dilute to the mark with anhydrous methanol, and shake well (500ppm).

[0141] The reference solution was taken and analyzed by HPLC under the above chromatographic conditions. The chromatogram was recorded. The results are shown in Table 5.

[0142] Table 5 Chromatographic information obtained in Example 5

[0143]

[0144] It can be seen from Table 5 that the chromatographic peak with a retention time of 6.137 min is the chromatographic peak of iodomethyl pivalate, and the theoretical plate number of the iodomethyl pivalate peak is 9802 (the Chinese Pharmacopoeia requires greater than or equal to 2000), indicating that the analysis method provided by the present invention is suitable for the detection of iodomethyl pivalate residues.

[0145] Example 6

[0146] Instrument: Agilent 1260Ⅱ, PDA UV detector;

[0147] Chromatographic column: Cosmosil 5C18-MS-Ⅱ (4.6×150mm, 5μm);

[0148] Mobile phase A: 40mmol / L potassium dihydrogen phosphate aqueous solution;

[0149] Mobile phase B: 5 mmol / L tetrapentylammonium bromide in methanol;

[0150] The gradient elution procedure is shown in Table 1 ;

[0151] Flow rate of mobile phase system: 0.8 mL / min;

[0152] Detection wavelength: 245nm;

[0153] Column temperature: 25°C;

[0154] Injection volume: 30 μL;

[0155] Test steps:

[0156] Reference solution: Accurately weigh 100.05 mg of iodomethyl pivalate standard, place in a 100 mL volumetric flask, dilute to the mark with anhydrous methanol, and shake well; Accurately pipette 1 mL of the above solution into a 100 mL volumetric flask, dilute to the mark with a 50% by volume methanol aqueous solution, and shake well as the iodomethyl pivalate reference stock solution; Accurately pipette 5 mL of iodomethyl pivalate reference stock solution into a 50 mL volumetric flask to which 10 mL of anhydrous methanol has been added, dilute to the mark with a 50% by volume methanol aqueous solution, and shake well (500 ppm).

[0157] Test solution: Accurately weigh 100.23 mg of cefcapone hydrochloride sample, place in a 50 mL volumetric flask, add 10 mL of anhydrous methanol to dissolve, then dilute to the scale with 50% methanol aqueous solution by volume, and shake well.

[0158] Take the reference solution and the test solution separately, perform HPLC analysis under the above chromatographic conditions, record the chromatogram, and the results are shown in Figures 7-8 ,in, Figure 7 HPLC chart of the reference solution; Figure 8 The HPLC chart of the test solution is shown in Table 6.

[0159] Table 6 Chromatographic information obtained in Example 6

[0160]

[0161] From Table 6 and Figures 7-8 It can be seen that the chromatographic peak with a retention time of 8.670 min is the chromatographic peak of iodine methyl pivalate, the theoretical plate number of the iodine methyl pivalate peak is 14331 (the Chinese Pharmacopoeia requires greater than or equal to 2000), and the degree of separation is 8.63 (the Chinese Pharmacopoeia requires greater than or equal to 1.5), indicating that the analysis of the present invention is suitable for the detection of iodine methyl pivalate residues in cefcapene hydrochloride samples.

[0162] Example 7

[0163] Instrument: Shimadzu LC-20AT high performance liquid chromatograph, DAD UV detector;

[0164] Chromatographic column: Cosmosil 5C18-MS-Ⅱ (4.6×150mm, 5μm);

[0165] Mobile phase A: 40mmol / L potassium dihydrogen phosphate aqueous solution;

[0166] Mobile phase B: 5 mmol / L tetrapentylammonium bromide in methanol;

[0167] The gradient elution procedure is shown in Table 1 ;

[0168] Flow rate of mobile phase system: 0.8 mL / min;

[0169] Detection wavelength: 245nm;

[0170] Column temperature: 25°C;

[0171] Injection volume: 30 μL;

[0172] Test steps:

[0173] Reference solution: Take 99.21 mg of iodomethyl pivalate reference substance (purity: 90%), accurately weigh, place in a 100mL volumetric flask, dilute to the scale with methanol, and shake well; accurately pipette 1mL of the above solution into a 100mL volumetric flask, dilute to the scale with a 50% by volume methanol aqueous solution, shake well, as a iodomethyl pivalate stock solution; accurately pipette 5mL of iodomethyl pivalate stock solution into a 50mL volumetric flask to which 10mL methanol has been added, dilute to the scale with a 50% by volume methanol aqueous solution, and shake well.

[0174] Iodomethyl pivalate quantitative limit solution: Accurately pipette 3.5 mL of the reference solution into a 20 mL volumetric flask, add 4 mL of methanol, dilute to the mark with 50% by volume methanol-water solution, and shake well.

[0175] Detection limit solution of iodomethyl pivalate: Accurately pipette 1 mL of the reference solution into a 20 mL volumetric flask, add 4 mL of methanol, dilute to the mark with a 50% methanol-water solution by volume, and shake well. Accurately pipette 3 mL of the above solution into a 10 mL volumetric flask, add 2 mL of methanol, dilute to the mark with a 50% methanol-water solution by volume, and shake well.

[0176] The quantitative limit solution of iodine methyl pivalate and the detection limit solution of iodine methyl pivalate were taken respectively, and high performance liquid chromatography analysis was performed under the above-mentioned chromatographic conditions, and the chromatograms were recorded. The specific results are shown in Table 7.

[0177] Table 7 Quantitative limit and detection limit information obtained in Example 7

[0178]

[0179] It can be seen from Table 7 that the detection limit of iodomethyl pivalate is 0.0134 μg / mL, corresponding to a signal-to-noise ratio of 3.40; the quantification limit of iodomethyl pivalate is 0.1563 μg / mL, corresponding to a signal-to-noise ratio of 12.73, accounting for 15.63% of the limit concentration, indicating that the analytical method of the present invention has a high sensitivity.

[0180] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for analyzing iodomethyl pivalate in β-lactam antibiotics, characterized in that: The following steps are involved: Dissolve the β-lactam antibiotic to be tested and the iodomethyl pivalate standard respectively to obtain a test solution and a reference solution; The test solution and the reference solution are respectively subjected to high performance liquid chromatography to obtain chromatographic information of the test solution and the reference solution; Comparing the chromatographic information of the reference solution with the chromatographic information of the test solution to obtain the residual amount of iodomethyl pivalate in the β-lactam antibiotic to be tested; The parameters of the HPLC detection include: The chromatographic column is an octadecylsilane bonded silica gel chromatographic column, and the octadecylsilane bonded silica gel chromatographic column is Cosmosil 5C18-MS-Ⅱ or YMC Pack ODS-A; The mobile phase system includes mobile phase A and mobile phase B; The mobile phase A is a buffered saline solution, and the buffered saline solution is a potassium dihydrogen phosphate aqueous solution; the concentration of the potassium dihydrogen phosphate aqueous solution is 30 mmol / L to 50 mmol / L; The mobile phase B is a methanol solution of an ion pair reagent, and the ion pair reagent is tetrapentylammonium bromide; the concentration of the methanol solution of the ion pair reagent is 4 mmol / L to 10 mmol / L; The elution mode is gradient elution; The procedure of the gradient elution is shown in Table 1: Table 1 Gradient elution program The parameters of the high performance liquid chromatography detection also include: the detector is an ultraviolet detector; the ultraviolet detector is a DAD ultraviolet detector or a PDA ultraviolet detector, the detection wavelength is 240nm-250nm; the column temperature is 20-30°C.

2. The analysis method according to claim 1, characterized in that The β-lactam antibiotics to be tested include cefditoren pivoxil or cefcapone hydrochloride.

3. The analysis method according to claim 1, characterized in that The dissolving reagents independently include anhydrous methanol or a methanol aqueous solution with a volume percentage of 50%.

4. The analysis method according to any one of claims 1 to 3, characterized in that The concentration of the test solution is 1.5-3.0 mg / mL.

5. The analysis method according to claim 1, characterized in that The particle size of the filler of the octadecylsilane bonded silica gel chromatographic column is 3 to 5 μm.

6. The analysis method according to claim 1, characterized in that The flow rate of the mobile phase system is 0.7 mL / min to 1.0 mL / min.

7. The analysis method according to claim 1, characterized in that The parameters of the high performance liquid chromatography detection also include: the injection volume is 20 μL to 50 μL.

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