title: Surface Mediated Structures: Stabilization of Metastable Polymorphs on the Example of Paracetamol.
abstract: The preparation of typically thermodynamically unstable polymorphic structures is a challenge. However, solid surfaces are well established aids for the formation and stabilization of polymorphic structures within, for instance, organic electronics. In this study, we report the stabilization of a pharmaceutically relevant substance via a solid surface at ambient conditions. Form III of paracetamol, which is typically unstable in the bulk at standard conditions, can be stabilized with a model silica surface by a standard spin coating procedure followed by rapid heat treatment. Such a preparation technique allows the use of atomic force microscopy and grazing incidence X-ray diffraction measurements revealing detailed information on the morphology and structure of the polymorph. Furthermore, the results exhibit that this polymorph is stable over a long period of time revealing surface mediated stabilization. These findings demonstrate a novel approach to provide thermodynamic stability when applied to similar molecules with specific applications.
authors.affiliation: Institute of Pharmaceutical Science, Department of Pharmaceutical Technology, Karl-Franzens University of Graz , Universitätsplatz 1, 8010 Graz, Austria.
authors.forename: Heike M A
authors.initials: HM
authors.lastname: Ehmann
authors.affiliation: Institute of Pharmaceutical Science, Department of Pharmaceutical Technology, Karl-Franzens University of Graz , Universitätsplatz 1, 8010 Graz, Austria.
authors.forename: Oliver
authors.initials: O
authors.lastname: Werzer