Identification of Novel Impurities in Minomustine by Liquid Chromatography–Mass Spectrometry

Abstract

A simple and sensitive LC–MS method was developed for the separation and identification of impurities of Minomustine (MIN). MIN and its impurities were separated with gradient elution LC system and detected using a hybrid quadrupole ion trap mass spectrometer. Forced degradation experiments were also performed under acid/base hydrolysis, heat, light, and oxidation conditions. Four impurities were detected in MIN bulk drug, among which the contents of three increased under the stress conditions. The structures of these impurities were elucidated based on the QTRAP MSn data and further validated by accurate mass data. To the best of our knowledge, three of these impurities were identified for the first time. In addition, the 1H and 13C NMR data of impurity IV were first assigned in this paper.