Discovery of a new stable polymorph of 4-(3-ethynylphenylamino)-6,7-bis(2-methoxyethoxy)quinazolinium methanesulfonate using near-infrared spectroscopy to monitor form change kinetics

Polymorphism is an important property of crystalline organic molecules, par ticularly when used to develop medicines. Discovery of all the polymorphs i n a series is often difficult. This paper highlights the use of near-infrar ed spectroscopy to monitor the kinetics of form changes of polymorphs and s olvates (hydrates). In the case of mesylate salt 5, this led to the discove ry of a new preferred form. Identification and confirmation of unique polym orph crystal states are determined using X-ray powder diffraction patterns. This complements and confirms the kinetic change observed in the near-infr ared. The technique is generally applicable to the study of two-phase solid -liquid crystal slurries under isothermal conditions.