title: Pressure-temperature state diagram for the phase relationships between benfluorex hydrochloride forms I and II: a case of enantiotropic behavior.
abstract: The active pharmaceutical ingredient racemic benfluorex hydrochloride (benfluorex-HCl) has an interesting phase behavior due to an elusive solid-solid phase transition. The stability hierarchy between different phases is often determined based on heat-related experiments only or slurry interconversion. It is shown that if pressure and volume are taken into account, not only the phase equilibria are correctly positioned in the pressure-temperature phase diagram, but the experimental data also improves. Thus, it has been found that the racemic benfluorex-HCl is enantiotropic under "ordinary conditions" with polymorph II and polymorph I, respectively, being the low- and the high-temperature phases. Above ∼ 151 MPa, the system becomes monotropic and polymorph II is the single stable phase.
authors.affiliation: Grup de Caracterització de Materials, Departament de Física i Enginyeria Nuclear, ETSEIB, Barcelona 08028, Catalonia, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Barrio
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Maccaroni
authors.forename: Ivo B
authors.initials: IB
authors.lastname: Rietveld
authors.forename: Luciana
authors.initials: L
authors.lastname: Malpezzi
authors.forename: Norberto
authors.initials: N
authors.lastname: Masciocchi
authors.forename: René
authors.initials: R
authors.lastname: Céolin
authors.forename: Josep-Lluis
authors.initials: JL
authors.lastname: Tamarit
mesh_terms: D003460:Crystallization; D004355:Drug Stability; D005277:Fenfluramine / Q000031:analogs & derivatives* / Q000737:chemistry; D000960:Hypolipidemic Agents / Q000737:chemistry*; D044367:Phase Transition; D011312:Pressure; D013696:Temperature
chemical_list: D000960:Hypolipidemic Agents; D005277:Fenfluramine; C001584:benfluorex