目的 建立HPLC-UV-ESI-MSⁿ的方法,分析阿莫西林钠克拉维酸钾片的杂质谱。方法 采用Agilent 1100 LC /MSD Trap液质联用仪,Shim-pack CLC-ODS RP18(4.6 mm×250 mm, 5 μm)色谱柱,以20 mmol·L^-1乙酸铵(调pH至6.0)为流动相A,20 mmol·L^-1乙酸铵-乙腈(20∶80)(调pH至6.0)为流动相B,梯度洗脱,流速1.0 mL·min^-1,质谱检测器采用电喷雾离子源(ESI),正负离子分段方式检测;扫描范围:m/z 100~1 500; 雾化室压力275.8 kPa;干燥气流速9 L·min^-1;柱后分流1∶5。根据有无杂质对照品选择检出杂质结构的鉴定,对于已有对照品的杂质,通过比较其与对照品的色谱和质谱行为来确定结构;对于无对照品的未知杂质,则以已知结构物质如阿莫西林、克拉维酸为模型,通过分析已知物与未知杂质多级质谱行为的异同性推定其结构,并结合Shimadzu LCMS-IT-TOF高分辨质谱进行数据验证。结果 阿莫西林克拉维酸钾片中检出阿莫西林噻唑酸、阿莫西林二聚体等15个有关物质,包括已知杂质9个和未知杂质6个。结论 研究结果对阿莫西林钠克拉维酸钾片的质量控制和工艺评价具有指导意义。

OBJECTIVE To establish an HPLC-UV-ESI-MSⁿ method for the study of impurity profile of amoxicillin and clavulanate potassium tablets. METHODS Agilent 1100 LC/MSD Trap liquid chromatography-mass spectrometry was used, and the column was Shim pack CLC-ODS RP18(4.6 mm×250 mm, 5 μm). The mobile phase A was 20 mmol·L^-1 ammonium acetate (pH adjusted to 6.0), and the mobile phase B was 20 mmol·L^-1 ammonium acetate-acetonitrile (20∶80) (pH adjusted to 6.0). Gradient elution was performed at a flow rate of 1.0 mL·min^-1. ESI source was used. Positive and negative ion scan was conducted with a scanning range of m/z 100-1 500. The nebulizing pressure was 275.8 kPa, dry gas flow was 9 L·min^-1, and post-column diversion ratio was 1∶5. Some related substances were identified by comparing the retention time in the chromatography, [M+H]⁺ spectrum and MS² spectrum with those of the reference substances, while the others which do not have reference substances were deduced or speculated by analyzing the MS² or MSⁿ fragmentation with the help of a rule summarized from the MS² fragmentation of amoxicillin, clavulanic acid and system suitability impurity reference substances. RESULTS A total of 15 related substances were separated and characterized including nine known impurities like amoxicilloic acid, amoxicillin dimer, etc. and six unknown impurities. CONCLUSION The method can be applied in the identification and qualitative analysis of the related substances in amoxicillin and clavulanate potassium tablets and is helpful for the quality control and optimization of the synthetic process.