Capillary electrophoresis‐mass spectrometry in impurity profiling of pharmaceutical products

Generally reversed‐phase high‐performance liquid chromatography (RP‐HPLC) methods are extensively applied during quality control of pharmaceutical products. Since capillary electrophoresis (CE) is based on a different separation principle and consequently results in a unique selectivity compared to RP‐HPLC, it can advantageously be used as an orthogonal technique. CE equipped with a mass spectrometer detector provides even more information that can be helpful for identification and structural elucidation purposes. CE‐MS was recently implemented in the method development approach to support impurity profiling of pharmaceutical products. In this paper the application of CE‐electrospray ionization (ESI)‐MS/MS to the impurity profiling of galantamine hydrobromide in stressed Reminyl® Extended Release (ER) capsules is discussed. Reminyl® ER samples were stressed at different storing conditions. The impurity profile of these samples was compared with the current RP‐HPLC and chiral CE method, but also with CE‐ESI‐MS/MS. The combination of these three methods provided valuable data that allowed understanding comprehensively the impurity profile of these samples. Two impurities were detected at concentrations lower than 0.05%, which did not occur in nonstressed samples. Chromatographic data and the fragmentation patterns of galantamine and related compounds were also examined for identification of these two degradation products.