Polymorphs and Hydrates of Sequifenadine Hydrochloride: Crystallographic Explanation of Observed Phase Transitions and Thermodynamic Stability
journal contributionposted on 23.01.2017, 00:00 authored by Artis Kons, Agris Be̅rziņš, Andris Actiņš
In this study, detailed analysis of crystal structures was used to rationalize the observed stability and phase transformations of sequifenadine hydrochloride polymorphs and hydrates, as well as to understand the observed structural diversity. The performed polymorph and hydrate screening revealed the existence of six polymorphs and four hydrates. Crystal structures of these phases were determined either from single crystal or from powder diffraction data. The different possibilities for packing of sequifenadine cations were found to be the main reason for the observed structural diversity of polymorphs. The hydrate structures were found to be structurally similar and related to those of particular polymorphs, which was consistent with the observed easy phase transitions among the related pairs.