Identification of degradation products of brivaracetam using liquid chromatography quadrupole time-of-flight tandem mass spectrometry: Degradation pathway elucidation.

RATIONALE: Pyrrolidone-based drugs find widespread use in treating conditions such as epilepsy and Alzheimer's disease, and in various other medical applications. Brivaracetam, the latest generation of pyrrolidone drugs, has exhibited significant promise owing to chemical structure modifications. Its affinity to the SV2A receptor is double that of the previous-generation drug, levetiracetam. Consequently, brivaracetam holds substantial potential for diverse applications. As a novel drug not yet included in the pharmacopeias of developed nations, comprehensive analysis and research are necessary to guarantee its safe utilization in clinical settings. METHODS: A liquid chromatography quadrupole time-of-flight tandem mass spectrometry (LC/QTOFMS) method has been developed to effectively separate, identify and characterize both the degradation products and process-related substances of brivaracetam. Stress testing of the sample was carried out following the guidelines outlined in ICH Q1A(R2). The structures of these impurities were identified through positive electrospray ionization QTOF high-resolution MS and NMR spectroscopy. Additionally, the formation mechanism of each degradation product is thoroughly discussed. RESULTS: Under the analytical conditions outlined in this paper, brivaracetam and its degradation products were effectively separated. Thirteen degradation products were detected and characterized, shedding light on their origins and degradation pathways. Among these, three degradation products align with previously reported impurities, and two unreported degradation products were synthesized and confirmed through NMR spectroscopy. The stress testing results revealed the instability of brivaracetam under acidic, alkaline, oxidative and thermal stress conditions, while it exhibited relative stability under photolytic stress conditions. CONCLUSION: The study developed an analytical method for brivaracetam that enabled the effective detection and separation of brivaracetam and its 13 degradation products. This method addresses a gap in both current domestic and foreign drug standards. The structures of all the major degradation products were characterized by high-resolution LC/QTOFMS, which is essential for quality control during the drug production process, stability evaluation and the establishment of proper storage conditions.

Danggui Buxue Decoction enhances the anticancer activity of gemcitabine and alleviates gemcitabine-induced myelosuppression.

ETHNOPHARMACOLOGICAL RELEVANCE: Danggui Buxue Decoction (DBD) as a traditional Chinese medicine (TCM) has been widely used to treat blood deficiency. With the immune regulation and hematopoietic effect, DBD improved the quality of life in non-small-cell lung cancer (NSCLC) patients. We previously reported that DBD sensitized the response of NSCLC to Gemcitabine (Gem); however, the synergism and attenuation mechanism on the combination of Gem and DBD has not yet been elucidated. AIM OF THE STUDY: To investigate the mechanisms of DBD in enhancing the anticancer activity of Gem and alleviating Gem-induced myelosuppression. MATERIALS AND METHODS: A549 nude mice model was established to study the effect on the combination of Gem and DBD. The organ indices, peripheral blood cells and the hematopoiesis-related cytokines were analyzed in Gem-induced myelosuppressive mice. Then we studied the whole process from Gem-induced bone marrow suppression to self-healing, and the mechanism of DBD's attenuation by the experiments of bone marrow nucleated cells (BMNCs). RESULTS: There were an enhanced anticancer effect and an improvement of hematopoietic function by combining of Gem and DBD in A549 nude mice model. DBD regulated Hu antigen R (HuR), deoxycytidine kinase (dCK) and nuclear factor erythroid 2-related factor (Nrf2), increased the expression of thrombopoietin (TPO) and granulocyte-macrophage colony stimulating factor (GM-CSF). For Gem-induced myelosuppressive mice, DBD improved the number of peripheral blood cells and the levels of hematopoiesis-related cytokines. Moreover, DBD was observed to reduce deoxyribonucleic acid (DNA) content at the G1 phase, promoted BMNCs proliferation and up-regulated cycle-related proteins. CONCLUSIONS: The results indicated that DBD not only improved the sensitivity of Gem but also alleviated Gem-induced myelosuppression. This study may provide a pharmacological basis for the combination of DBD and Gem in clinical application.