Screening of solid commercial pharmaceuticals using ion mobility spectrometry

Ion mobility spectrometry (IMS) was used to analyze vapors generated directly above pharmaceutical solids warmed in air to 100-200 degrees C. Vapors were characterized by IMS/mass spectrometry to evaluate the air-based atmospheric pressure chemical ionization of components in analgesic medicines. A hand-held IMS was used to determine the suitability of membrane-based instrumentation for routine analyses of large polar molecules. Mobility spectra for seven compounds could be individually represented by single or a few intense product ion peaks. Ion source fragmentations were nonexistent with these pharmaceuticals but complex behavior in the IMS involving ion-molecule clustering was pronounced in certain spectra. Mobility spectra were distinct and recognizable for each compound and binary mixtures of individual ingredients and actual over-the-counter medicines produced mobility spectra suggestive of composite spectra. This work represents a first delineation of complex ion mobility spectra for mixtures using spectra from individual components. These findings support further development of IMS for use in quality control during manufacture of such preparations and in routine screening of powders containing analgesic pharmaceuticals.