Rationale: Drug stability is an important quality-control issue for pharmaceutical and clinical practices. Among the analytical techniques that address this issue, liquid chromatography/mass spectrometry (LC/MS) can be very useful, especially when assessing the quality of liquid formulations, because it is intrinsically sensitive, selective, and a rapid analytical technique. However, LC/MS suffers from technical drawbacks, e.g., matrix effects, and the production of in-source degradation products, which can limit its usefulness.
Methods: To overcome the aforementioned drawbacks associated with LC/MS, we introduce an innovative approach (2D-LC/SACI-ESI-MS/MS) that incorporates two-dimensional liquid chromatography (2D-LC) in conjunction with an MS system consisting of a surface-activated chemical ionization-electrospray ionization chamber (SACI-ESI), an ion trap MS analyzer, and tandem mass spectrometry.
Results: To validate our 2D-LC/SACI-ESI-MS/MS system stability studies were performed on the computerized tomography contrast agents, iohexol, iodixanol, iopamidol, iomeprol, iopromide, and iobitridol, either alone or in binary combination. The matrix effects, in-source analyte degradation, and analytical performance were compared with those obtained using a one-dimensional LC/MS configuration. The accuracy coefficient of variance (CV) = 1-4%, and degradation (loss of water and other chemical moieties) was greatly reduced, attesting to the usefulness of this system for drug stability measurements.
Conclusions: Our new approach improves the performance (sensitivity, accuracy, and signal stability) of LC/MS instrumentation for drug stability measurements by reducing signal suppression effects and in-source chemical reactions.
Copyright © 2013 John Wiley & Sons, Ltd.