Analytical Sciences

Electrochemical Studies of the Interaction of Clarithromycin with Bovine Serum Albumin

She-Ying DONG,* Chun-Xia XUE,* and Ting-Lin HUANG**

*College of Sciences, Xi'an University of Architecture and Technology, Xi'an, Shaanxi 710055, P. R. China
**School of Environment and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi 710055, P. R. China

The interaction of clarithromycin (CAM) with bovine serum albumin (BSA) was investigated in pH 4.5 - 8.0 phosphate buffer solutions in which three irreversible reduction waves P₁, P₂ and P₃ of CAM appeared on linear-sweep voltammetry on a static dropping mercury working electrode. In the acidic media, with the addition of BSA into the CAM solution, a new electrochemically active complex was formed and there was interaction between the carbonyl group C=O in the C-9 position of CAM and BSA. It was found that electrostatic and hydrophobic forces played an important role in the binding reaction. However, new electrochemically non-active complexes were formed at physiological pH condition. The study showed that the formation constant and formation ratio of the interaction between CAM and BSA were 1.51 × 10¹² and 3:1 for P₂ wave, and 4.53 × 10⁵ and 1:1 for P₃ wave, respectively. The ion strength enhanced the hydrophobic interaction between CAM and BSA.

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