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Thermal and X-ray powder diffraction structural characterization of two benfluorex hydrochloride polymorphs
Elisabetta Maccaroni1, Luciana Malpezzi, Walter Panzeri
1Dipartimento di Scienze Chimiche e Ambientali, Università dell'Insubria, via Valleggio 11, I-22100 Como, Italy. elisabetta.maccaroni@chem.polimi.it
Journal of Pharmaceutical and Biomedical Analysis
|March 30, 2010
Summary
This study characterizes two benfluorex hydrochloride polymorphic forms, I and II, using X-ray diffraction. Form II transitions to the stable Form I upon heating, with significant hysteresis observed during cooling.
Area of Science:
- Solid-state chemistry
- Crystallography
- Pharmaceutical science
Background:
- Benfluorex hydrochloride exhibits polymorphism, impacting its physicochemical properties.
- Understanding different crystalline forms is crucial for drug formulation and stability.
Purpose of the Study:
- To isolate and structurally characterize two polymorphic forms (I and II) of benfluorex hydrochloride.
- To investigate the phase transition behavior and thermal properties of these forms.
Main Methods:
- Ab initio X-ray powder diffraction (XRPD) with simulated annealing for structural determination.
- Differential scanning calorimetry (DSC) and thermodiffractometry for thermal analysis.
Main Results:
- Form I (monoclinic, P2(1)/n) and Form II (orthorhombic, Pbca) were structurally elucidated.
- Ionic packing with protonated benfluorex and chloride anions characterizes both forms.
- Form II transforms to stable Form I upon heating (160°C), followed by melting (165°C); cooling shows hysteresis with recrystallization to Form I near 130°C.
Conclusions:
- The study provides detailed structural insights into benfluorex hydrochloride polymorphs.
- Thermal analysis reveals a reversible phase transition from Form II to Form I with significant hysteresis, important for manufacturing and storage.
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