Discussion On The Liquid Chromatography Method Development Of Cephalosporin Antibiotics Based On AQbD Concept

High-performance liquid chromatography(HPLC)is one of the most widely used detection techniques in the field of drug analysis,the analytical performance of the HPLC method is the key to envaluating and ensuring the quality of the drug.Previously method development commonly relies on One-Factor-At-a-Time(OFAT)or the trial-and-error approach,expressed by Quality-by-Testing(QbT),which mainly focuses on the impurities present in the sample.In the process of method optimization,one factor is changed at a time until the chromatographic conditions satisfying the analysis target are obtained.This optimization process ignores the interaction between the variables,and finally only obtains a set of fixed and single chromatographic parameter values.Another method development approach which can be defined as Analytical quality by design(AQbD)can effectively solve the above problems,this approach considers both the impurities in the sample and the potential impurities that may be generated during transportation and storage.In the process of optimization,the interaction effects of each factor on the analytical performance of the method are comprehensively considered,and a set of method parameters range that can meet the analysis requirements are finally determined.Regardless of whether it is QbT or AQbD,the existing liquid phase methods focus on the differences between drug structures.Corresponding analysis method was developed for each drug,which leads to a huge difference in chromatographic conditions between different drugs.At the beginning of the method development for new drugs,new factors still need to carry out a large number of preliminary experiments to select appropriate method parameters,which increases the cost of method development and reduces the efficiency.In addition,different drugs may have the same or similar types of degradation impurities,using different LC methods is not conducive to summarizing the retention of the same or similar kinds of impurities,no reference information could be provided for impurity profiling analysis.In fact,structurally similar compounds may retain similar in same LC method,so similar or even identical LC methods can be selected for such solutes for analysis.In response to these practical problems,this study proposes a strategy for the LC method development of similar drugs based on the AQbD concept.Cephalosporin antibiotics that has similar structure and close impurity types are used as research objects,and the feasibility of this development strategy is initially explored.The following three parts are included in this study:1.Establishment of initial chromatographic conditions:With forty cephalosporin as the research object,a universal LC conditions suitable for the analysis of cephalosporin antibiotics were established,and two types of suitable columns were screened from more than 500 columns.The LC conditions and columns were validated by four cephalosporin varieties,and most of the impurities could be effectively separated.It is preliminarily proved that the universal method is applicable to cephalosporin antibiotics and can be used as a basic condition for cephalosporin LC method development.2.Method optimization:For the impurities that cannot meet the analytical requirements under the universal method,the chromatographic conditions are systematically optimized from the mobile phase and column screening based on the AQbD concept.Quantitative relationship between the critical method attributes and critical mobile phase parameters of cefmetazole was established by experimentical design.The mobile phase design space for complete separation of 16 impurities of cefmetazole was determined.Quantitative relationship between the critical method attributes and critical column parameters of cefazolin was established by hydrophobic subtraction model,equivalent columns that meets the analytical requirements was screened out.Development process of the cephalosporin LC method development based on the AQbD concept was fully explored.3.Prediction of new impurities(varieties):The retention of solute is determined by the columns,mobile phase and solute structure.When the mobile phase and column are consistent,the retention behavior is only related to the structure.Prediction retention of mew impurities under universal methods could be achieved through the quantitative structure retention relationships(QSRR).Global QSRR models and local QSRR models based on k-value similarity capable of predicting cephalosporin antibiotic retention were established using 76 solutes on typical columns.Aiming at the problem that new solute k value could not be obtained,a step-by-step prediction strategy was proposed.All the models were validated with 18 kinds of trans-isomer impurities and 10 cefazolin impurities.Predicted value has a good correlation with the actual value,thus the model can be used to predict the retention of cephalosporins under the universal LC method.This thesis proposes a universal LC method for cephalosporin antibiotics,which could improve the efficiency of LC method development.The quantitative structure retention relationships is introduced into the AQbD concept to advance the method development to the prediction stage.The research can provide a basis for the development of LC methods for cephalosporin antibiotics in the future,and provide reference for the establishment of universal LC methods for other similar drugs.