title: Morphologies of Phenytoin Crystals at Silica Model Surfaces: Vapor Annealing versus Drop Casting.
abstract: The controlled preparation of different crystal morphologies with varying preferential orientation with respect to the substrate is of crucial importance in many fields of applications. In this work, the controlled preparation of different phenytoin morphologies and the dependency of the preferential orientation of those crystallites is related with the preparation method (solvent annealing vs drop casting), as well as the physical-chemical interaction with the solvents in use. While solvent annealing induces the formation of particular structures that are partially dewetted, the drop casting technique from various solvent results in the formation of needle-like and elongated structures, with each having a distinct morphology. The morphologies are explained via the Hansen solubility parameters and correlated with the solvent vapor pressures. X-ray diffraction experiments reveal preferential orientations with respect to the solid substrate and indicate the surface-mediated stabilization of an unknown polymorph of phenytoin with an elongated unit cell in theb-axis.
authors: Institute of Pharmaceutical Science, Department of Pharmaceutical Technology, University of Graz , 8010 Graz, Austria.
authors: Heike M A
authors: HM
authors: Ehmann
authors: Research Center Pharmaceutical Engineering GmbH, 8010 Graz, Austria.
authors: Ramona
authors: R
authors: Baumgartner
authors: Institute for Solid State Physics, Graz University of Technology , 8010 Graz, Austria.
authors: Birgit
authors: B
authors: Kunert
authors: Institute of Pharmaceutical Science, Department of Pharmaceutical Technology, University of Graz , 8010 Graz, Austria.
authors: Andreas
authors: A
authors: Zimmer
authors: Institute of Pharmaceutical Science, Department of Pharmaceutical Technology, University of Graz , 8010 Graz, Austria ; Research Center Pharmaceutical Engineering GmbH, 8010 Graz, Austria.
authors: Eva
authors: E
authors: Roblegg
authors: Institute of Pharmaceutical Science, Department of Pharmaceutical Technology, University of Graz , 8010 Graz, Austria.
authors: Oliver
authors: O
authors: Werzer