title: The importance of screening solid-state phases of a racemic modification of a chiral drug: thermodynamic and structural characterization of solid-state phases of etiracetam.
abstract: In this contribution different solid-state forms of the racemic compound (RS)-2-(2-oxo-pyrrolidin-1yl)-butyramide are studied from a structural and thermal point of view. Three different solid-state phases were identified, including two polymorphs and one hydrate phase. Comparison is made with the structure of the (S)-enantiomer, for which only one solid-state phase is known. The basic structural motif found in both polymorphs of the racemic compound is similar, but the basic motif observed for the hydrate differs. These synthons could in principle be used in future polymorph prediction studies to screen for possible alternative forms of the enantiopure compound. Based on the structure of the hydrate, further efforts should therefore be made in order to identify a hydrate structure of the enantiopure compound. Studying the different phases of a racemic compound can therefore help to guide polymorphic screening of an enantiopure compound.
authors.affiliation: TIPS Chemical Engineering UNIT, Université Libre de Bruxelles, Avenue Frankelin Roosevelt 50, Brussels 1050, Belgium. christelle.herman@ulb.ac.be
authors.forename: Christelle
authors.initials: C
authors.lastname: Herman
authors.forename: Valérie
authors.initials: V
authors.lastname: Vermylen
authors.forename: Bernadette
authors.initials: B
authors.lastname: Norberg
authors.forename: Johan
authors.initials: J
authors.lastname: Wouters
authors.forename: Tom
authors.initials: T
authors.lastname: Leyssens
mesh_terms: D002152:Calorimetry, Differential Scanning; D018360:Crystallography, X-Ray; D000077287:Levetiracetam; D008958:Models, Molecular; D015394:Molecular Structure; D010889:Piracetam / Q000031:analogs & derivatives* / Q000737:chemistry; D033362:Powder Diffraction; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D000077287:Levetiracetam; D010889:Piracetam
keywords: (RS)-2-(2-oxo-pyrrolidin-1yl)-butyramide; etiracetam; levetiracetam; racemic compound; solid-state phases