In-vitro and In-vivo Bioequivalence Assessment of Azithromycin Tablet Formulations at Fasting and Fed Conditions

This study aimed to determine the bioequivalence of Azithromycin tablets 500 mg manufactured by ACI HealthCare Limited and ZITHROMAX® (azithromycin) tablets 500 mg from Pfizer Labs Division of Pfizer Inc.It was a randomized, double-blind crossover trial conducted at Raptim Research Pvt. Ltd., India, involving healthy adult male subjects in both fasting and fed conditions.Key pharmacokinetic parameters, including Cmax and AUC0-t, were evaluated.The 90% confidence intervals for the ratio of geometric least square means based on Ln-transformed primary PK parameters were as follows: 1) Cmax (fasting: 91.33-104.86,fed: 89.64 -109.64) 2) AUC0-t (fasting: 93.13-102.76,fed: 90.97-104.79)3) AUC0-inf (fasting: 93.37-102.67,fed: 90.70-105.00).These intervals were found within the acceptable bioequivalence limits of 80.00% to 125.00% for Azithromycin.The study observed a maximum intra-subject coefficient of variation (ISCV) of 27.42% for Cmax.Based on this ISCV and a ratio estimate (Test/Reference) of 93-107%, a sample size of 64 subjects (including a 10% dropout rate) was calculated as sufficient for the study design.The results indicated that Azithromycin tablets 500 mg from ACI HealthCare Limited were bioequivalent to ZITHROMAX® tablets 500 mg under fed conditions.