Comparative Bioavailability of a Fixed-Dose Combination of Etoricoxib and Betamethasone in Healthy Volunteers

This study evaluated the pharmacokinetic profiles and comparative bioavailability of etoricoxib 90 mg tablets and betamethasone 0.25 mg/0.5 mL solution, administered individually (reference drugs), versus a fixed-dose combination (FDC) tablet containing etoricoxib 90 mg and betamethasone 0.25 mg (test drug) under fasting conditions in healthy Mexican volunteers. A randomized, open-label, three-period, crossover, single-dose study with a 14-day washout period was conducted. Study drugs were administered orally following a 10-h overnight fast with 250 mL of water and fasting continued for at least 4 h post-dose. Serial blood samples were collected pre- and post-dose, and the drug concentrations were quantified using Liquid Chromatography coupled to Tandem Mass Spectrometry (LC-MS/MS). Forty-two subjects (22 women, 20 men; mean age 22.7 years; mean weight 64.7 kg) were enrolled, and 39 completed the study. Comparative bioavailability was established if the 90% confidence intervals of log-transformed C_max and AUC_{0-72 h} fell within the predefined range of 80%-125%. Two non-serious adverse events were reported. Results demonstrated that the pharmacokinetic profile and bioavailability of the etoricoxib/betamethasone FDC were comparable to those of reference formulations, with no evidence of pharmacokinetic interactions.