Identification of impurities in a new API

Situation: A new API for injectable application showed nine different impurities when analyzed by HPLC/UV methodology.  The identification of these unknown peaks was critical for the continuation of the project in the upcoming clinical stages.

Task: Positively identify as many impurity peaks as possible using retention time/elution order, masses, and MS/MS fragmentation patterns.  For peaks with inconclusive data, verify the structures by obtaining synthesized standards with the suggested structures.

Action: Initial experiments yielded masses/molecular weights and key MS/MS fragmentation pattern data for all the impurity peaks.  LC/MS/MS analysis of stressed samples along with samples from the intermediate steps of the synthetic process provided unambiguous identification of seven peaks. The data also suggested the necessary synthetic steps for obtaining reference standard materials for the remaining two peaks.   

Result: The prompt elucidation of the entire API impurity profile alleviated regulatory concerns and allowed the development program to move to the next steps without timeline delays.