4. Conclusion
A new compound and four process-related impurities of VTXTwere isolated using standard HPLC-UV methods, and identified bymeans of MS,1H NMR,13C NMR, and FT-IR spectroscopy analy-ses. We also proposed possible mechanisms of their formation.The structural elucidation of the five impurities was also firstreported in this paper. A new HPLC method was developed andvalidated based on the ICH Guidelines with respect to specificity,accuracy, sensitivity, and system suitability. The newly developedHPLC method can be applied to the separation and quantification ofpotential impurities in VTXT. Furthermore, the VTXT sample pre-pared by our synthetic route was analyzed by the newly developedHPLC method, demonstrating the efficient separation of four impu-rities. The presence of impurities in VTXT was also confirmed byLC-MS. This is the first report of the development of an effectiveHPLC method for the separation and quantification of all impuritiesin VTXT.