自身对照外标法定量测定β-内酰胺类抗生素中的高分子杂质

Quantitative determination of high molecular weight impurities of β-lactam antibiotics by external standard method of reference oneself

β-内酰胺类抗生素中高分子杂质的控制问题目前已引起人们的普遍关注，尽管SephadexG－10凝胶色谱系统可用于对高分子杂质的分离，但对分离出的杂质峰如何进行精确定量，仍是质量控制工作中的难点．虽然理论上外标法和面积规一化法均可用于定量，但由于高分子杂质的不均一性及其含量极微，故不能适用。我们利用特定条件下β-内酰胺类抗生素可以缔合形成表观分子量较大的缔合物，缔合物在SephadexG－10凝胶色谱系统中的色谱行为和高分子杂质一样，都在Kav＝0处表现为单一的色谱峰这一特点，在SephadexG－10凝胶色谱系统中发展了新的定量方法——自身对照外标法。自身对照外标法集外标法和面积规一法的优点为一体，既不需专门的标准品，又可象外标法一样精确对高分子杂质峰进行定量。文中还对自身对用外标法应用中的诸影响因素进行了讨论。

The control of high molecular weight impurities in β-lactam antibiotics hasbeen paid a great attention by pharmaceutical manufacturer, clinical medicine and drugadministrator in the world. A novel gel filtration chromatography on Sephadex G-10 toseparate the high molecular weight impurities has been developed recently[5]. But accuratequantitation is still a remaining problem to be resolved. Although external standard methodor normalization method theoretically could be used, it is difficult to perform in the polymerquantity due to its heterogeneity and the small content. Based on some second interactionsamong β-lactam themselves which bind the antibiotics together forming a non-covalentpolymers in a special condition,which caused the antibiotics like the high molecular weightimpurities showing only one peak with Kav = 0 in Sephadex G-10 gel chromatographicsystem, a novel quantitative method, termed external standard method of reference oncsclf(ESMOROS), for determination of the high molecular weight impurities is developed inSephadex G-10 gel filtration chromatographic system. The ESMOROS method thatcombines the advantages of an external method and of a normalization method, does not needsome special reference standards, but can accurately quantitate thc impurities. Some effectsinfluencing the accuracy of the ESMOROS are also discussed.