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Published on: March 28, 2011
Crystallization of carbamazepine pseudopolymorphs from nonionic microemulsions
Anna Kogan1, Inna Popov, Vladimir Uvarov
1Casali Institute of Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Langmuir : the ACS Journal of Surfaces and Colloids
|January 1, 2008
Summary
Microemulsion structure dictates carbamazepine (CBZ) crystal form and morphology. This control over crystallization offers significant pharmaceutical applications for producing specific CBZ polymorphs.
Area of Science:
- Materials Science
- Chemical Engineering
- Crystallography
Background:
- Carbamazepine (CBZ) is a vital antiepileptic drug with polymorphic variations impacting its efficacy.
- Controlling crystallization is crucial for pharmaceutical drug development and manufacturing.
Purpose of the Study:
- To investigate the influence of nonionic microemulsion structures on carbamazepine crystallization.
- To correlate microemulsion microstructure (W/O, bicontinuous, O/W) with resulting CBZ crystalline structure and morphology.
- To explore the potential for predictable polymorph and habit formation in pharmaceutical applications.
Main Methods:
- Precipitation of carbamazepine (CBZ) from various microemulsion systems.
- Characterization using Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Powder X-ray Diffraction (PXRD), and Single-Crystal X-ray Diffraction (SCXRD).
- Morphological analysis via Scanning Electron Microscopy (SEM) and optical microscopy.
Main Results:
- Microemulsion microstructure significantly influences CBZ crystallization, yielding distinct polymorphs and crystal habits.
- Water-in-oil (W/O) nanodroplets produced anhydrous CBZ with a prismlike habit (monoclinic, P21/n).
- Bicontinuous structures resulted in platelike dihydrate CBZ (orthorhombic, Cmca).
- Oil-in-water (O/W) nanodroplets formed needlelike dihydrate CBZ (monoclinic, P21/c).
- CBZ crystal morphology is predetermined by unit cell symmetry and parameters.
- Oriented attachment mechanism explains pseudopolymorph formation in supersaturated microemulsions.
Conclusions:
- Microemulsion systems offer precise control over carbamazepine crystallization, enabling the production of specific polymorphic forms.
- The ability to predict and control CBZ crystal structure and morphology has significant implications for pharmaceutical formulation and drug delivery.
- This approach facilitates the development of tailored drug substances with desired physicochemical properties.
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