Resonance Rayleigh scattering study of the inclusion complexation of chloramphenicol with β-cyclodextrin

The interaction of chloramphenicol and beta-cyclodextrin (beta-CD) in aqueous solution was studied using resonance Rayleigh scattering (RRS) technology. The molar ratio of the inclusion complex was 1 : 1 established by spectrophotometry. The RRS technology was first applied to the determination of the inclusion constant of chloramphenicol to beta-CD. The RRS peak of chloramphenicol was at 331 nm. When beta-CD interacted with chloramphenicol to form an inclusion complex, the RRS intensity was enhanced and increased with an increase in beta-CD concentration. The inclusion constants at different temperatures were measured by the RRS technology. The determination results using the RRS technology corresponded with those of the UV-spectrophotometric method. Therefore, the RRS method can be used as a new technology for the determination of the inclusion constant. The thermodynamic parameters (Delta H, Delta S and Delta G) associated with the inclusion process were also determined. These values indicated that van der waals forces and hydrogen bonding could be considered as a main driving force for the encapsulation of chloramphenicol by beta-CD. (c) 2004 Elsevier B.V. All rights reserved.