A Randomized, Open-Label, Two-Sequence, Crossover Trial Evaluating the Bioequivalence, and Pharmacokinetics of Two Sulfamethoxazole/Trimethoprim Tablet Formulations in Healthy Chinese Volunteers Under Fasting Conditions.

The compound sulfamethoxazole (SMZ)/trimethoprim (TMP), a dual-agent formulation comprising SMZ and TMP, exhibits synergistic bacteriostatic and bactericidal activity by disrupting folate metabolism pathways. This study assessed the bioequivalence (BE) of a generic compound SMZ/TMP tablet versus its innovator counterpart under fasting conditions (n = 24). In a meticulous, single-site, randomized, open-label, 2-period, 2-sequence crossover trial, 24 healthy Chinese adults were allocated to receive a single administration of either the test or reference medication, with a 7-day interval between doses. Venous blood samples were obtained pre-dose and at intervals up to 48 hours postdose for subsequent analysis. The plasma levels of SMZ and TMP were determined using a validated ultra-performance liquid chromatography-tandem mass spectrometry technique. Safety monitoring was conducted with precision throughout the trial for all subjects. The study's results indicated no significant differences in the peak plasma concentrations (C) of the drug when comparing the 2 SMZ/TMP formulations. Furthermore, the 90% confidence intervals for the ratios of the geometric means of C, the area under the curve from 0 time to the last quantifiable concentration point (AUC), and the area under the curve extrapolated to an infinite time point (AUC) were all within the BE range accepted as 80%-125%. Notably, there were no reports of severe adverse events. These outcomes demonstrate the BE and favorable tolerability of the generic compound SMZ/TMP tablet in healthy Chinese subjects.