Bioavailability study of two different formulations of azithromycin

In a single-dose, balanced, two-period crossover study, we evaluated the bioavailability of two different commercial formulations of azithromycin in 18 healthy male volunteers, Both the test formulation (500-mg tablet) and the reference formulation (500-mg capsule) were administered to each subject, The two treatment phases were separated by a 15-day washout period, Blood samples were drawn before and up to 48 hours after dosing; we used high-performance liquid chromatography to determine drug plasma concentrations, We calculated the area under the plasma concentration-time curve (AUG), maximum plasma concentration (C-max), and time of maximum plasma concentration (t(max)) for each subject, Logarithmic transformation of the AUC and C-max was used for the statistical analysis and to assess the bioavailability of the two formulations, Analysis of variance (ANOVA) for t(max) In(C-max), and In(AUC) provided the appropriate intrasubject variance estimate to evaluate the 90% confidence interval for the difference between study variables after administration of the test and reference formulations. The ANOVA showed no significant effect in the model other than a subject effect. The intrasubject coefficient of variation indicated that the two formulations were equivalent with regard to the rate and extent of absorption.