A bioequivalence study of two tamsulosin sustained-release tablets in Indonesian healthy volunteers

The bioavailability of two 0.4 mg tamsulosin sustained-release film-coated tablet formulations was compared; using generic tablets (Prostam®) as test formulation and the originator product as reference formulation. Twenty-four subjects were included in this single- dose, open-label, randomized two-way crossover design following an overnight fasting. A one-week washout period was applied. Blood samples were drawn up to 72 h following drug administration. Plasma concentration of tamsulosin was determined by liquid chromatography- tandem mass spectrometry method with TurboIonSpray mode. Pharmacokinetic parameters AUC_0-t, AUC_0-∞, C_max and t_1/2 were determined and used for bioequivalence evaluation after log-transformation, whereas tmax ratios were evaluated non-parametrically. The estimated point and 90% confidence intervals (CI) for AUC_0-t, AUC_0-∞, C_max and t_1/2 were 109.55% (96.41-124.49%), 109.94% (96.85-124.81%), 105.87% (92.88-120.67%) and 100.00% (90.56-110.43%), respectively. These results indicated that the two formulations of tamsulosin were bioequivalent; therefore they may be prescribed interchangeably.