A bioequivalence study of two memantine formulations in healthy Chinese male volunteers

Objective: The aim of the current study is to evaluate the bioequivalence between the test and reference formulations of memantine in a single-dose, two-period and two-sequence crossover study with a 44-day washout interval. Materials and methods: A total of 20 healthy Chinese male volunteers were enrolled and completed the study, after oral administration of single doses of 10 mg test and reference formulations of memantine. The blood samples were collected at different time points and memantine concentrations were determined by a fully validated HPLC-MS/MS method. The evaluated pharmacokinetic parameters (test vs. reference) including C-max (18 +/- 3.2 vs. 17.8 +/- 3.4), AUC(0-t) (1,188.5 +/- 222.2 vs. 1,170.9 +/- 135.7), and AUC(0-infinity) (1,353.3 +/- 258.6 vs. 1,291.3 +/- 136.7) values were assessed for bioequivalence based on current guidelines. Results: The observed pharmacokinetic parameters of memantine test drug were similar to those of the reference formulation. The 90% confidence intervals of test/reference ratios for Cmax, AUC(0-t), and AUC(0-infinity) were within the bioequivalence acceptance range of 80 - 125%. Conclusion: The results obtained from the healthy Chinese subjects in this study suggests that the test formulation of memantine 10 mg tablet is bioequivalent to the reference formulation (Ebixa (R) 10 mg tablet).