Estudo de bioequivalência entre duas formulações de topiramato comprimidos revestidos de 100 mg, em voluntários sadios após administração de dose única

The study was performed to compare the bioavailability/bioequivalence of two topiramate 100 mg coated tablet formulations (Topiramate from Ache Laboratorios Farmaceuticos S/A as test formulation and (Topamax®) from Janssen Cilag Farmaceutica Ltda.as reference formulation) in 28 volunteers of both sexes. The study was conducted as an open randomized two period crossover design with a wash out phase of 14 days. Plasma samples from 23 from the 28 initially included volunteers were obtained over a 120 hour interval. Plasma concentrations of Topiramate were determined by LC-MS-MS equipment using prednisone as internal standard. From the data obtained, the following pharmacokinetics parameters were calculated: AUC0-t, AUC0-" and Cmax. Geometric mean ratios of Topiramate/Topamax® coated tablet 100 mg was 100,97% for AUC0-t, 101,38% for AUC0-" and 96,94% for Cmax; the 90% confidence intervals were 107.02% - 107.40%, 104.45% - 110.42% and 90,98% - 103,29%, respectively. Since the 90% confidence intervals for Cmax, AUC0-t and AUC0-" were within the range of 80% - 125% proposed by Food and Drug Administration and ANVISA (the National Health Surveillance Agency of Brasil), it was concluded that Topiramate 100 coated tablets was bioequivalent to Topamax® 100 mg coated tablets, and so the test product can be considered interchangeable in normal medical practice