Pharmacokinetics and Bioequivalence of 2 Azithromycin Tablet Formulations: A Randomized, Open‐Label, 2‐Stage Crossover Study in Healthy Volunteers

Abstract The current study aimed to assess the bioequivalence of a new branded azithromycin with the reference formulation. An open‐label, randomized, 2‐stage, crossover study design was implemented involving 77 healthy volunteers under fasting conditions. Each volunteer received a single dose of 250‐mg azithromycin tablets test and reference formulations separated by a 21‐day washout period. Twenty‐two samples were collected at pre‐dose and until 72 hours post‐dose. Azithromycin concentrations were analyzed using a high‐performance liquid chromatography‐mass spectrometry validated method following a solid‐phase plasma extraction. Noncompartmental analysis was carried out to estimate the pharmacokinetic parameters, which were compared between the test and reference products using a multivariate analysis of variance. The difference between C max and AUC 0‐72 of the test and reference formulation was not significant. The 94.1% confidence intervals of ln‐transformed C max and AUC 0‐72 of azithromycin were within the bioequivalence acceptance limits of 80%–125%, therefore it can be concluded that the tested formulation is bioequivalent to the reference formulation.