Determination of clarithromycin in serum by high performance liquid chromatography with pre-column derivatization

A reversed-phase high performance liquid chromatographic method for the determination of clarithromycin in serum with ultraviolet detection after pre-column derivatization with 2,4-dinitrophenylhydrazine was developed. A tert-butyl methyl ether extract, obtained from serum under alkaline condition, was treated with 2,4-dinitrophenylhydrazine (DNPH) for 30 min at 55 degrees C under acidic solution, and chromatographed on an Alltima C-18 coluryin using an eluent composed of acetonitrile-0.05 mol/L pH 7.2 phosphate buffer (48:52). The detection wavelength was set at 340 nm. The linear range for clarithromycin was 0.05 - 3.2 mg/L with correlation coefficient 0.9993. The limit of detection was 30 mu g/L, absolute recovery was more than 89%, RSDs were less than 10%. This method has been applied to pharmacokinetic study of clarithromycin in healthy volunteers.