Abstract

Use of LC-MS Tools for the Characterization of Trace Pharmaceutical Components

Saranjit Singh, Professor/Head, NIPER Mohali

Because of their presence in small or trace quantities, structure characterization of many components, like metabolites, impurities, degradation products, drug-drug and drug-excipient interaction products, drugs as adulterants and environmental pollutants, etc., becomes difficult through the conventional process of isolation and spectral studies. Hence, hyphenated tools, e.g., LC-MS and LC-NMR, are being extensively explored for the purpose in our laboratory. In fact, we have established that an unequivocal characterization of majority of the trace components (except enantiomers, epimers and some positional isomers where LC-NMR is required) can be achieved using a mix of LC-MS tools alone. A strategy has been proposed, which involves establishment of fragmentation pathway of the drug and of minutia based on MSn and MS/TOF data (like molecular formula, number of labile hydrogens, ring double bonds, and isotopic abundance, wherever applicable). The nitrogen rule is also applied. The fragmentation pathways are then compared. The success story of application of this strategy in our laboratory will be highlighted.