Pharmacokinetic comparison of two formulations of talniflumate 370 mg tablets in healthy Korean volunteers

Background: Talniflumate, a prodrug of niflumic acid, is a potent analgesic and anti-inflammatory drug that has been widely used for the treatment of rheumatoid diseases. Objective: The aim of this study was to compare the pharmacokinetics and to evaluate the bioequivalence of two formulations of talniflumate 370 mg tablets (test formulation: Flumagen® 370 mg tablet; reference formulation: Somalgen® 370 mg tablet). Methods: A randomized, open-label, single dose, two-sequence, two-period crossover clinical study was conducted. After oral administration of the study drug in each period, blood samples were collected up to 15 hours post-dose. The plasma concentration of niflumic acid, a metabolite of talniflumate, was determined using HPLC-MS/MS. The pharmacokinetic parameters were estimated by non-compartmental method. Results: The maximum plasma concentration (C_max) and area under the concentration-time curve from zero to the time point with the last measurable concentration (AUC_last) for the test formulation were 290.7 ± 199 μg/L and 1,154 ± 643 μg×h/L, respectively, and the corresponding values for the reference formulation were 286.8 ± 193 μg/L and 1,151 ± 577 μg×h/L, respectively. The geometric mean ratio and 90% confidence intervals (CI) of the test formulation to the reference formulation for the C_max and AUC_last were 0.983 (0.829 - 1.166) and 0.979 (0.856 - 1.121), respectively. Conclusions: The pharmacokinetic profiles of the test and reference formulations were found not to be significantly different, meeting the Korean regulatory criteria for bioequivalence.