Study on the electrochemical detection of the macrolide antibiotics clarithromycin and roxithromycin in reversed-phase high-performance liquid chromatography.

The optimal conditions of the amperometric detection of the macrolide antibiotics clarithromycin and roxithromycin were found by cyclic voltammetric studies and HPLC-electrochemical detection responses obtained in different temperatures (25.5-60 degrees C) and different but almost isoelutropic binary, ternary and quaternary mixtures of aqueous buffer (pH 7), methanol, acetonitrile and isopropanol. These conditions were also proved to be applicable for the quantitative detection of clarithromycin in human plasma using roxithromycin as an internal standard and vice versa. It was demonstrated that increased attention has to be paid to eluent composition and column temperature to ensure sensitive and reproducible electrochemical responses as well as regularly shaped peaks for both macrolides tested.