HPLC Behaviour of Diazepam on β‐Cyclodextrin Chiral Stationary Phase. Evidence of Conformational Change

Abstract

The dynamic HPLC was performed with the goal to estimate the influences on the configurational stability of diazepam conformers in chiral environment. The effect of sample solvent, temperature, flow rate, and pH of mobile phase on behaviour of diazepam conformers during their separation on chiral β‐cyclodextrin was studied. The separation of diazepam conformers was complicated due to simultaneous interconversion, which was the result of configurational instability of the diazepam molecule. A statistical approach was used for evaluation of the influence of individual chromatographic parameters on behaviour of diazepam in a given chiral environment. The Principal Component Analysis (PCA) and Cluster Analysis (CA) were applied for accurate interpretation of obtained results.

Keywords:

• Principal component analysis
• Cluster analysis
• Sample solvent effect
• Configurational unstability

Acknowledgments

The authors acknowledge the support of the Grant Agency of Slovak Republic (VEGA 1/2460/05 and VEGA 1/1186/04) and the Agency for International Science and Technology Cooperation in Slovakia (Grant No. 035/2001, USA‐SK).