Impurity Identification Using LC-MS and in silico Reaction Enumeration
In this study, we show that using an LC-MS, together with an Excel add-on, named Reactor, impurities can be easily identified at the beginning of the process. Molecular mass values of impurities are detected by LC-MS. Known molecules, like API, known impurities, compounds used during manufacturing etc. can be added to an Excel sheet. Possible reactions, such as dehydration, lactonization, oxidation, adduct formation etc. can also be added to the Excel sheet. Reactor add-on can create reaction products, considering all possible reactants i.e. all known molecules and all possible reactions. Molecular mass values of created (enumerated) products can automatically be compared to measured molecular mass values, which can be a first step to the identification of unknown impurity peaks. These impurities can be submitted for a database search, in order to check their toxicity or genotoxicity.