Pharmacokinetics and relative bioavailability of azithromycin in soft capsules in healthy Chinese volunteers

Objective To determine azithromycin in human plasma by a HPLC-MS method, and to study its pharmacokinetics and relative bioavailability in healthy volunteers. Methods A single oral dose 500 mg of two formulations of azithromycin was given to 18 healthy volunteers in an open randomized cross-over study.The pharmacokinetic parameters were calculated by 3P97 software. Bioequivalence was determined by a two one-side t–tests.Results The main pharmacokinetic parameters of test and reference capsules for azithromycin were as follows: Cmax were (676.6±283.1) and (663.4±298.3) ng·mL-1,tmax were (1.9±0.5) and (2.0±0.6) h,t1/2 were (50.4±14.3) and (49.1±14.5) h, AUC0-144 were (5025.1±881.9) and (4857.5±46.8) ng·h·mL-1, AUC0-∞ were (5827.3±898.0) and (5638.9±998.5) ng·h·mL-1.The relative bioavailability of the test formulation was F0-144= (105.8 ± 22.8) %.Conclusion The two formulations are bioequivalent.