Pharmacokinetics, Safety and Bioequivalence Study of a Single Dose of Two Azithromycin Granules Administered under Fasting and Fed Conditions in Healthy Chinese Volunteers

Abstract Purpose This study aimed to evaluate the pharmacokinetics, safety, and bioequivalence of test and reference Azithromycin granules in healthy Chinese volunteers under fasting and fed conditions. Methods This single-center, randomized, open-label, single-dose, 2-period, 2-sequence crossover study enrolled 108 participants. Participants received a 500-mg dose of either formulation under fasting conditions (n = 40) or fed conditions (n = 68), with a 21-day washout. Plasma Azithromycin concentrations were quantified using liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were calculated noncompartmentally. Bioequivalence was evaluated using 90% confidence intervals (CIs) for test-to-reference geometric mean ratios (GMRs) of C max , AUC 0−t , and AUC 0−∞ . Results Under fasting conditions, GMRs (90% CIs) were 107.07% (99.66%-115.04%) for C max , 102.46% (96.62%-108.65%) for AUC 0−t , and 104.35% (97.95%-111.18%) for AUC 0−∞ . Under fed conditions, values were 102.00% (93.82%-110.91%), 95.00% (88.20%-102.32%), and 96.28% (90.19%-102.79%), respectively. All CIs were within the range of 80.00%-125.00%. One serious adverse event in the fed group (ectopic pregnancy) was assessed as not related to the study drug. No drug-related serious adverse events were observed under fasting or fed condition. Conclusion The test and reference Azithromycin granule formulations met bioequivalence criteria under both fasting and fed conditions. No drug-related serious adverse events were identified in this study. Trial registration The trial was registered in the Chinese Clinical Trial Registry (ChiCTR2300074532; August 9, 2023)