Bioequivalence and Safety of Two Amisulpride Formulations in Healthy Chinese Subjects Under Fasting and Fed Conditions: A Randomized, Open‑Label, Single‑Dose, Crossover Study.

Background And Objectives: Amisulpride is a second-generation antipsychotic drug that selectively binds to D2 and D3 dopaminergic receptors in the limbic system. In this study, the bioequivalence of an amisulpride formulation manufactured in China with the original formulation Solian® was evaluated under fasting and fed conditions in healthy Chinese subjects.

Methods: A single-centre, randomized, open, two-preparation, single-dose, two-period crossover trial in healthy adult subjects was conducted under fasting and fed conditions. A total of 42 and 36 eligible healthy subjects were enrolled in the fasting and fed studies, respectively. The subjects were randomly assigned to receive either the test or the reference formulation with a washout period of 7 days. The concentration of amisulpride in plasma was determined by liquid chromatography‒tandem mass spectrometry (LC‒MS/MS), and the pharmacokinetic (PK) parameters of amisulpride were calculated via the noncompartmental method.

Results: The geometric mean ratios (GMR) of the maximum observed concentration (C), the area under the plasma concentration‒time curve (AUC) from time zero to the last sampling time (AUC), and the AUC from time zero to infinity (AUC) from the test/reference formulation under fasting conditions were 93.83, 101.90, and 102.35, respectively, with corresponding 90% confidence intervals (CIs) of 83.93-104.89, 97.58-106.42, and 98.24-106.63. The GMRs of C, AUC, and AUC under fed conditions were 102.23, 106.09, and 101.87, respectively, with corresponding 90% CIs of 92.49-112.99, 102.44-109.87, and 97.49-106.44. These data all satisfied the bioequivalence criteria (90% CIs in the range of 80-125%). In terms of safety, no serious adverse events were observed.

Conclusions: The test and reference amisulpride formulations were bioequivalent under fasting and fed conditions. Both formulations showed similar safety and tolerability in the population studied.