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Thermal behaviour and stability in Olanzapine.
Griselda I Polla1, Daniel R Vega, Hilda Lanza
1Unidad de Actividad Física, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, San Martín, 1650 Buenos Aires, Argentina.
International Journal of Pharmaceutics
|July 26, 2005
Summary
Investigating Olanzapine solid forms reveals that apparent interconversions are melting-recrystallization artifacts. The (Olanzapine)2 dimer is the core building block in all studied anhydrate and solvate phases.
Area of Science:
- Pharmaceutical Sciences
- Solid-State Chemistry
- Materials Science
Background:
- Olanzapine is an atypical antipsychotic medication.
- Understanding the solid-state properties of Olanzapine is crucial for its formulation and stability.
- Previous studies have identified different crystalline forms of Olanzapine.
Purpose of the Study:
- To investigate the stability and thermal behavior of Olanzapine anhydrate and a novel mixed water:DMSO solvate.
- To elucidate the structural basis of Olanzapine's solid forms.
- To clarify the nature of observed interconversions between solid states.
Main Methods:
- Differential Scanning Calorimetry (DSC) for thermal analysis.
- X-ray Powder Diffraction (XRPD) for structural characterization.
- Raman Scattering (RS) for vibrational spectroscopy.
- Single crystal X-ray diffraction for detailed structural determination.
Main Results:
- Characterization of two anhydrate phases and a new mixed water:DMSO solvate of Olanzapine.
- Confirmation of the (Olanzapine)2 dimer as the fundamental structural unit across all known phases.
- Demonstration that apparent solid-state form interconversions are artifacts of melting-recrystallization.
Conclusions:
- The (Olanzapine)2 dimer is a conserved structural motif in both anhydrate and solvated forms.
- The observed transitions are not true polymorphic interconversions but rather melting-recrystallization events.
- This study provides critical insights into Olanzapine's solid-state behavior, impacting drug development and manufacturing.