Identification of undescribed key impurities of homoharringtonine bulk drug.

The knowledge of impurities is an important issue and the base of quality control in modern drugs. To date, the quality control of the antitumor drug homoharringtonine (HHT) is still not sufficiently solved and needs to be improved. Six main impurities, drupacine, cephalotaxine, desmethylcephalotaxinone, harringtonine, 3-O-acetyl-cephalotaxine and 2'R,3'S-isoharringtonine were traced during HHT drug production by HPLC and LC-MS analyses. Additionally, we were able to isolate and identify three undescribed key trace impurities, neohomoharringtonines A-C. Their structures were established by 1D-, and 2D NMR experiments combined with mass spectrometry. An improved quality inspection ability of HHT was constructed.