A simple and sensitive liquid chromatography–mass spectrometry routine method for determination of clarithromycin in human plasma: Application to a clinical pharmacokinetic study

A simple and sensitive liquid chromatography-mass spectrometry (LC-MS) method was developed for the routine determination of Clarithromycin in human plasma, with Alprazolam as the internal standard. The separation was carried out on an Phenomenex (C18 100 × 4.6 mm, i.d 5 µm) column, with Acetonitrile and 10 mM Ammonium acetate Buffer solution (95:5) as the mobile phase under isocratic conditions at a flow rate of 0.2 mL/min. Detection of the analytes was achieved using positive ion electrospray tandem mass spectrometry in selected reaction monitoring (SRM) mode. The standard curves were linear (r2 > 0.99) over the concentration range of 300–5000 ng/mL. The intra- and inter-day precision (RSD) values were below 15%. The method is validated for the estimation of Clarithromycin in human plasma over a concentration range of 300–5000 ng/mL. Expected recoveries were observed. Limit of detection of the methods is 3.0 ng/ mL and limit of quantitation is 10.0 ng/mL that shows that the developed method has adequate sensitivity. The method was successfully applied to the pharmacokinetic study of Clarithromycin tablets in healthy male volunteers after oral administration.