4. Conclusion
A new compound and four process-related impurities of VTXT were isolated using standard HPLC-UV methods, and identified by means of MS,1H NMR,13C NMR, and FT-IR spectroscopy analyses. We also proposed possible mechanisms of their formation.The structural elucidation of the five impurities was also first reported in this paper. A new HPLC method was developed and validated based on the ICH Guidelines with respect to specificity,accuracy, sensitivity, and system suitability. The newly developed HPLC method can be applied to the separation and quantification of potential impurities in VTXT. Furthermore, the VTXT sample prepared by our synthetic route was analyzed by the newly developed HPLC method, demonstrating the efficient separation of four impurities. The presence of impurities in VTXT was also confirmed by LC-MS. This is the first report of the development of an effective HPLC method for the separation and quantification of all impurities in VTXT.