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Synthesis of Nine-atom Deltahedral Zintl Ions of Germanium and their Functionalization with Organic Groups
Published on: February 11, 2012
Structural evaluation of crystalline ternary γ-cyclodextrin complex.
Kenjirou Higashi1, Saori Ideura, Haruka Waraya
1Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, chuo-ku, Chiba 260-8675, Japan. ken-h@p.chiba-u.ac.jp
Journal of Pharmaceutical Sciences
|July 29, 2010
Summary
This study reveals a novel crystalline ternary complex of gamma-cyclodextrin (γ-CD) with flurbiprofen (FBP) and salicylic acid (SA). The unique structure and irreversible solid-state transformation offer potential for advanced drug formulation.
Area of Science:
- Supramolecular Chemistry
- Materials Science
- Pharmaceutical Sciences
Background:
- Cyclodextrins (CDs) are widely used to improve drug solubility and stability.
- Ternary complexes offer enhanced properties compared to binary inclusion complexes.
- Understanding the solid-state structure of drug-CD complexes is crucial for formulation development.
Purpose of the Study:
- To investigate the structure of a crystalline ternary complex of gamma-cyclodextrin (γ-CD) with salicylic acid (SA) and flurbiprofen (FBP).
- To characterize the formation and solid-state properties of the SA/FBP/γ-CD complex.
- To explore the potential of this complex for formulating various drugs.
Main Methods:
- Preparation of binary flurbiprofen/γ-cyclodextrin (FBP/γ-CD) inclusion complex by coprecipitation.
- Formation of the ternary complex by sealed heating of SA with the FBP/γ-CD complex.
- Structural analysis using Powder X-ray diffraction (PXRD), Infrared (IR) spectroscopy, and solid-state (13)C Nuclear Magnetic Resonance (NMR) spectroscopy.
Main Results:
- The FBP/γ-CD complex had a 1/1 molar ratio.
- Sealed heating induced a transition to a monoclinic columnar packing in γ-CD, indicating ternary complex formation with an estimated SA/FBP/γ-CD stoichiometry of 2/1/1.
- The ternary complex exhibited irreversible solid-state transformation upon water vapor adsorption/desorption, unlike the reversible transition of the binary complex. One FBP molecule occupied the γ-CD cavity, while two SA molecules were in the intermolecular space. Dimer FBP molecules were sandwiched between two γ-CD molecules, and monomer SA molecules were in the intermolecular space.
Conclusions:
- A novel crystalline ternary complex of γ-CD, SA, and FBP was successfully prepared and structurally characterized.
- The complex formation involves specific arrangements of drug molecules within and between γ-CD structures, leading to unique solid-state properties.
- The demonstrated ability to form such ternary complexes suggests a versatile platform for formulating a variety of drugs.
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