Investigational Study of Mesalamine Dissolution Discrepancy: Utilization of Hyphenated Ultrahigh Performance Liquid Chromatography-Charged Aerosol Detection-High-Resolution Mass Spectrometry

Pentasa (mesalamine/MSLM) is a widely prescribed delayed-release capsule formulation for the treatment of inflammatory bowel disease. During dissolution study of Pentasa through ultraviolet (UV) spectroscopy, an unusual end-release of about 110% has been observed. Initial liquid chromatography-UV (LC-UV) analyses of these dissolution samples confirmed three prominent peaks other than MSLM with a significant area percentage. Further systematic investigation was carried out by incubating active pharmaceutical ingredient in dissolution media for a longer duration and at elevated temperature followed by analysis through an inverse gradient LC-charged aerosol detector (CAD). LC-high-resolution mass spectrometry (HRMS) and online hydrogen-deuterium exchange (HDX) mass spectrometry were also employed to identify and characterize these artifact products. The area % of prominent artifacts in LC-UV was found to be way significant when compared to the area % obtained through inverse LC-CAD, as CAD quantifies the peaks independent of the UV wavelength of absorbance. Inverse LC-CAD was suitable to determine the relative response factor, whereas LC-HRMS/MS and online HDX-MS supported the characterization of these artifacts. These artifacts were found to be trimers, tetramers of MSLM formed due to polymerization, imparting additional pi-bonds resulting in high UV absorptivity. These techniques when used in combinations serve complimentary to each other during such investigations.