title: A New, More Stable Polymorphic Form of Otilonium Bromide: Solubility, Crystal Structure, and Phase Transformation.
abstract: A new polymorphic form of otilonium bromide is presented (Form I), and a thorough analysis of its crystal and molecular structure is performed. The compound suffers a temperature-driven first-order phase transition at about 396 K, which transforms it into the polymorph reported by Dapporto P and Sega A (Acta Cryst. 1986;C42:474-478) (Form II). Through thermal analysis and solubility experiments the relative stability of both crystal modifications were determined, confirming that at room temperature this new Form I is the more stable one, Form II existing just in a metastable state.
authors.affiliation: Gerencia de Investigación y Aplicaciones, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Buenos Aires, Argentina; Escuela de Ciencia y Tecnología, Universidad Nacional General San Martín, Buenos Aires, Argentina.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Vega
authors.affiliation: Gerencia de Investigación y Aplicaciones, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Buenos Aires, Argentina; Escuela de Ciencia y Tecnología, Universidad Nacional General San Martín, Buenos Aires, Argentina.
authors.forename: Emilia
authors.initials: E
authors.lastname: Halac
authors.affiliation: Gerencia de Investigación y Aplicaciones, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Buenos Aires, Argentina.
authors.forename: Luciano
authors.initials: L
authors.lastname: Segovia
authors.affiliation: Gerencia de Investigación y Aplicaciones, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Buenos Aires, Argentina. Electronic address: baggio@cnea.gov.ar.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Baggio
mesh_terms: D003460:Crystallization / Q000379:methods*; D018360:Crystallography, X-Ray / Q000379:methods; D004355:Drug Stability; D015394:Molecular Structure; D044367:Phase Transition; D000644:Quaternary Ammonium Compounds / Q000032:analysis* / Q000737:chemistry*; D012995:Solubility
chemical_list: D000644:Quaternary Ammonium Compounds; C013934:octylonium
keywords: Raman spectroscopy; calorimetry (DSC); crystal structure; phase transition; solid state stability; solubility