Resonance Rayleigh scattering study of the inclusion complexation of chloramphenicol with beta-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 (DeltaH, DeltaS and DeltaG) 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.