Pharmacokinetics of azithromycin as measured by HPLC-MS in health volunteers

Objective: To develop a HPLC-MS method for determining azithromycin in human plasma,and to investigate pharmacokinetics of azithromycin in healthy volunteers.Methods: In 18 healthy male volunteers,a single crossover oral dose of the test and reference azithromycin tablets(500 mg) were randomly administered.Azithromycin concentrations in plasma samples were determined by HPLC-MS after taking the drug.Results: The calibration curve of azithromycin concentration was linear in the range from 10 to 1 000 μg·L-1.The intra-day and inter-day RSD was less than 10%.The main pharmacokinetic parameters of the test and reference azithromycin tablets were as follows: Cmax(594.9±195.7) vs.(586.3±186.5) μg·L-1;Tmax(2.02±0.91) vs.(1.70 ± 0.80) h;T1/2(29.20±8.38) vs.(27.28±7.62) h;AUC0~t(4 736±1 317) vs.(4 567±1 129) μg·h·L-1.The relative bioavalability of test tablets was(104.0±14.6) %.Conclusion: HPLC-MS method established in this study is simpler and more sensitive with better accuracy,which is adapted to study azithromycin pharmacokinetics.The two preparations of azithromycin are bioequivalent.