The study was designed as two-single-dose, randomized, open-label, balanced, crossover study, with two periods separated by 7-days washout. In both periods after a standard breakfast volunteers were given a single dose of their formulation (reference or test) of tansulosine with 200 mL of water. Blood samples (8 ml) were collected at 0 (pre-dose) and at 01:00; 02:00; 03:00; 04:00; 04;30; 05:00; 05:20; 05:40; 06:00; 06:20; 06:40; 07:00; 07:30; 08:00; 08:30; 09:00; 10:00; 12:00; 24:00; 48:00; 72:00h. These samples were centrifuged immediately and kept frozen at -20°C until the time of analysis. Standard meals were served at 4 and 8h after administration. During hospital confinement, volunteers were always under medical supervision.