Strategy On Evaluation Of β-Lactam Antibiotics Chromatographic System With Reference Materials Containing Mixed Degradation Products

The quality control is the basis to guarantee the safety and effectiveness of drugs, and the control of impurities in drugs is the main content of it. With the concept of “impurity profile control” becoming mature, selecting an analysis method that can effectively separate all impurities is essential. At present, the main method for impurity profile control is related substances analysis with reversed-phase high performance liquid chromatography.It is particularly important to ensure the validity and reproducibility of the chromatographic system when transferring an established related substances HPLC analysis method between different laboratories. In this paper, we propose a strategy on evaluation of chromatographic system through system suitability test with reference materials containing mixed degradation products.Taking β-lactam antibiotics as the object of study, the evaluation strategy includes the following five parts. First, evaluation of reference materials containing mixed degradation products. Determine the target impurities to be included, and design acid, alkali, heat, light or oxidation forced degradation experiments according to the sources of target impurities. Then obtain the target impurities including critical peak pairs which are difficult to separate under specific degradation conditions and develop the reference materials containing mixed degradation products. At last, evaluate the developed reference materials whether it is in conformity with the above design requirements. Second, suggesting chemical structures of impurities in the reference materials. Suggest the chemical structures of impurities by combining column switching LC-MS technology with MS fragmentation rules of cephalosporin antibiotics and their known impurities. Make the sources and structures of each impurity clear. Third, establishing the evaluation criteria for system suitability test by using reference materials containing mixed degradation products. Analyse the reference materials with 12 columns which parameters are in appropriate range. Choose a chromatogram in which the retention times are appropriate and all impurities have been effectively separated as the standard HPLC chromatogram. Establish the evaluation criteria for system suitability test with each impurity identified, and set the number of theoretical plates, resolution, tailing factor and other indicators. Fourth, evaluation of chromatographic system by using reference materials containing mixed degradation products. There is complementary between the stationary phase and the mobile phase, according to the different selectivity of columns between different laboratories, reproduce the standard chromatogram by adjusting the ratio of mobile phase, p H, column temperature, flow rate, and so on. If the system suitability test criteria is met, the chromatographic system can achieve the purpose of separating and controlling the impurities, and it is proved that the receiving laboratory has the ability of completing the analysis. Fifth, optimizing HPLC method by using DOE method. In the system suitability test, if adjusting the mobile phase can not compensate for the retention behavior differences between different columns or reproduce the standard chromatogram, it means that the chromatographic separation system can not meet the requirements of quality control. In order to improve the separation ability of the chromatographic system, take the resolution of critical peak pairs as the indicator, and optimize HPLC method by using DOE method on the base of full exploration of key factors affecting the separation of critical peak pairs.