Determination of clarithromycin in human plasma by liquid chromatography–electrospray ionization tandem mass spectrometry

A rapid and sensitive method has been developed for the determination of clarithromycin in human plasma with liquid chromatography–tandem mass spectrometry. Clarithromycin and the internal standard, telmisartan were precipitated from the matrix (50 μl) with 200 μl acetonitrile and separated by HPLC using formic acid:10 mM ammonium acetate:methanol (1:99:400, v/v/v) as the mobile phase. The assay based on detection by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring mode was finished within 2.4 min. Linearity was over the concentration range 10–5000 ng/ml with a limit of detection of 0.50 ng/ml. Intra- and inter-day precision measured as relative standard deviation were <3.73% and <9.93%, respectively. The method was applied in a bioequivalence study of two tablet formulations of clarithromycin.