Characterization of Progesterone Derivatives by LC-DAD-ESI/MSn and Its Application to the Identification of Impurities in Flurogestone Acetate

The fragmentation behaviors of progesterone derivatives were studied by high-performance liquid chromatography electrospray ionization tandem mass spectrometry. Under tandem MS conditions, most of the fragments were formed by the cleavage of peripheral groups. Analyses of the fragmentation pathways revealed that the presence of substituents of a progesterone derivative could be deduced from characteristic losses. Characteristic cleavages of 28 and 58 Da were observed from ring cleavages with compounds containing two specific double bonds in the progesterone backbone. In addition, UV spectra were acquired to support MS-based analysis. The presence of nine impurities in crude flurogestone acetate samples were characterized, followed by their tentative assignments based on mass spectral fragmentation patterns.