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Synthesis and Characterization of Functionalized Metal-organic Frameworks

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Published on: September 5, 2014

Two polymorphs of afobazole from powder diffraction data.

Vladimir V Chernyshev¹, Sanita Petkune, Andris Actins

¹Department of Chemistry, M. V. Lomonosov Moscow State University, Moscow 119991, Russian Federation. vladimir@struct.chem.msu.ru

Acta Crystallographica. Section C, Crystal Structure Communications

|March 6, 2013

Summary

Two Afobazole polymorphs were analyzed using powder diffraction. Crystal structures reveal different packing, explaining why one form (II) is more hygroscopic than the other (IV).

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Area of Science:

Pharmaceutical Chemistry
Solid-State Chemistry
Crystallography

Background:

Afobazole is a novel anxiolytic drug.
Four polymorphic modifications of Afobazole were previously described.
Understanding polymorphism is crucial for drug development and stability.

Purpose of the Study:

To determine the crystal structures of two monoclinic polymorphs of Afobazole.
To investigate the differences in crystal packing and conformation between these polymorphs.
To explain the observed differences in hygroscopicity.

Main Methods:

Laboratory powder diffraction data were used.
Crystal structures of two monoclinic polymorphs (II and IV) were established.
Analysis of crystal packing and dication conformation.

Main Results:

The crystal structures of Afobazole polymorphs (II) and (IV) were successfully determined.
Significant differences in crystal packing and dication conformation were observed between polymorphs (II) and (IV).
Polymorph (II) exhibits channels facilitating water molecule penetration, leading to higher hygroscopicity.

Conclusions:

The distinct crystal structures of Afobazole polymorphs directly influence their physical properties, specifically hygroscopicity.
The presence of [001] channels in polymorph (II) accounts for its increased water uptake.
This study provides valuable insights into the solid-state behavior of Afobazole, relevant for its pharmaceutical formulation and storage.