title: Crystal structure and physical properties of two polymorphs of ropivacaine HCl.
abstract: The crystal structure of two polymorphs of ropivacaine HCl have been determined, as well as their relative stability up to 100 degrees C. A geometric restriction for a solid-state transition between the two polymorphs has been identified. The packing density along the H-bonded chains form the basis for a model explaining the kinetic crystallization of the metastable form. The difference in stability and physicochemical properties between the two polymorphs can be attributed to the difference in crystal structure.
authors.affiliation: Preformulation and Biopharmaceutics AstraZeneca R & D, Södertälje, Sweden. per-olov.bergstrom@astrazeneca.com
authors.forename: Per-Olov
authors.initials: PO
authors.lastname: Bergström
authors.forename: Andreas
authors.initials: A
authors.lastname: Fischer
authors.forename: Lars
authors.initials: L
authors.lastname: Kloo
authors.forename: Tesfai
authors.initials: T
authors.lastname: Sebhatu
mesh_terms: D019840:2-Propanol / Q000737:chemistry; D000577:Amides / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D003460:Crystallization; D000077212:Ropivacaine; D012995:Solubility; D013816:Thermodynamics; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D000577:Amides; D014867:Water; D000077212:Ropivacaine; D019840:2-Propanol