Bioequivalence Evaluation of Two Oral Formulations of Acetaminophen in Healthy Subjects: Results From a Randomized, Single-Blind, Crossover Study

Despite widespread availability of acetaminophen in Mexico, data on its pharmacokinetic properties in Mexican populations are limited. This single-center, single-blind, randomized, 2-period, 2-treatment, crossover, single-dose-per-period, 2-sequence study evaluated the bioequivalence of a test acetaminophen product available in Mexico compared with a reference 500-mg acetaminophen product in 28 healthy adults under fasting conditions. Blood samples were collected predose and at specified intervals across a 16-hour period following administration and were analyzed for acetaminophen using a validated reverse-phase high-performance liquid chromatography method. Drug products were considered to be bioequivalent if confidence intervals of natural log-transformed C-max, AUC(0-t), and AUC(0-infinity) data were within the range of 80% to 125%. Results were inconclusive for C-max due to high levels of intrasubject variability with this parameter. However, criteria for bioequivalence were met for AUC(0-t) and AUC(0-infinity). All measured acetaminophen concentrations in this study were within a safe therapeutic range, and no adverse events were reported. The level of C-max intrasubject variability observed in this study does not have any apparent clinical implications that could affect either safety or efficacy.