Bioequivalence and Safety of Two Oseltamivir Phosphate for Oral Suspension in Healthy Chinese Subjects Under Fasting and Fed Conditions: A Randomized, Open‑Label, Single‑Dose, Crossover Study

Abstract This randomized, open‐label, single‐dose crossover study evaluated the bioequivalence of a Chinese‐manufactured oseltamivir phosphate oral suspension (7.5 mg/12.5 mL) against Tamiflu under fasting and fed conditions. A total of 42 healthy Chinese adults were enrolled in each group, with 39 completing the fasting group (3 withdrew) and 40 completing the fed group (1 withdrew in washout, 1 lost to follow‐up). Plasma concentrations of oseltamivir and its active metabolite oseltamivir carboxylate were measured via LC‐MS/MS, and pharmacokinetic parameters were calculated using non‐compartmental models. The 90% confidence intervals of key parameters fell within the 80.00‐125.00% range, confirming bioequivalence. No serious adverse events occurred, indicating similar safety profiles. The test formulation is bioequivalent to Tamiflu under both fasting and fed conditions.