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Cephalexin: a channel hydrate.
Alan R Kennedy1, Maurice O Okoth, David B Sheen
1Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, Scotland. a.r.kennedy@strath.ac.uk
Acta Crystallographica. Section C, Crystal Structure Communications
|November 8, 2003
Summary
Cephalexin, an antibiotic, forms various water solvates. Its crystal structure reveals complex channels facilitating rapid water molecule movement, impacting its solvation behavior.
Area of Science:
- Crystallography
- Solid-state chemistry
- Pharmaceutical science
Background:
- Cephalexin is a widely used antibiotic.
- Antibiotics can form solvates, affecting their stability and properties.
- Understanding cephalexin's solvation is crucial for its formulation and efficacy.
Purpose of the Study:
- To characterize the crystal structure of a cephalexin hydrate.
- To investigate the solvation/desolvation behavior of cephalexin.
- To elucidate the role of crystal structure in solvent interactions.
Main Methods:
- Single-crystal X-ray diffraction was used to determine the crystal structure.
- Analysis of the asymmetric unit revealed the number of cephalexin molecules and water molecules.
- Investigation of crystallographic channels to understand solvent mobility.
Main Results:
- The determined structure contains three independent cephalexin molecules (one disordered) and 5.72 water molecules per asymmetric unit.
- The hydration state is close to the maximum possible, indicating significant water incorporation.
- A complex channel network within the crystal lattice was identified, allowing solvent movement along specific directions.
Conclusions:
- Cephalexin exhibits facile solvation/desolvation due to its crystal lattice structure.
- The identified channels are key to the rapid movement of solvent molecules.
- This structural insight is important for understanding cephalexin's solid-state properties and potential formulation strategies.