Impurity profiling of Cefteram pivoxil based on Fourier transform ion cyclotron resonance MS.

Profiling impurities for the active pharmaceutical ingredients (APIs) is an indispensable step in drug development process. Nowadays, high resolution mass spectrometry is the first choice for determining the chemical formula of organic impurities. However, merely base on the accurate mass to screen the formula is obviously not a flawless method. In this paper, a reliable strategy based on Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was presented to profile the related impurities. Firstly, Cefteram pivoxil was subjected to forced degration under hydrolytic (acidic and basic), oxidative, photolytic and thermal conditions according to ICH guidelines. Then, a highly specific and efficient HPLC-FT-ICR MS compatible method was developed and it was used to separate and characterize the process related substances and the major degradation products in Cefteram pivoxil. Next, isotopic fine structures (IFSs) of all impurities were acquired to decisively determine their elemental composition. Finally, the possible chemical structures of impurities were predicted by combining the information of accurate mass, retention time, IFSs and characteristic fragmentation ions. As a result, a total of 20 related substances including 6 process related substances and 14 degradation products were identified and characterized. To the best of our knowledge, 13 of these related substances were not reported in the previous literature. It indicates that the developed strategy is accurate and standard independent to determine the chemical formulae of organic impurities in APIs. In conclusion, the impurity profiles obtained in this study are critical to the quality control and stability study of Cefteram pivoxil. Moreover, the developed method can be used as a versatile workflow to profile the impurities in APIs in the future, especially for the unknown impurities.

Brain metabolomics study for the protective effects of Rhodiola crenulata extract on Alzheimer's disease by HPLC coupled with Fourier transform-ion cyclotron resonance mass spectrometry.

In order to investigate the protective effects of Rhodiola crenulata extract on Alzheimer's disease, a brain metabolomics study in rats was conducted by high performance liquid chromatography coupled with Fourier transform ion cyclotron resonance mass spectrometry. Rat model was constructed by bilateral hippocampal injection of amyloid-ß peptide and immunohistochemistry was performed to evaluate the pharmacological effect of Rhodiola crenulata extract. Multivariate statistical analysis was used to discover potential biomarkers in rat brain and related metabolic pathways analysis was conducted to elucidate the action mechanism of Rhodiola crenulata extract. As a result, a total of 19 metabolites contributing to Alzheimer's disease progress were identified and nine of them were restored to the normal levels after drug administration. Pathway analysis revealed that the protective effects of Rhodiola crenulata extract are related to the regulation of glutathione metabolism and arachidonic acid metabolism in rat brain. In conclusion, this work demonstrates that the developed metabolomics method is useful to investigate the protective effects of Rhodiola crenulata extract against Alzheimer's disease. These outcomes may further provide reliable evidence to illuminate the intervention mechanism of other traditional Chinese medicines on Alzheimer's disease.