To Investigate Safety, Tolerability, and Pharmacokinetics of Treatment With BI 660848 Rising Single Doses (From 2 mg to 600 mg) Administered as Oral Drinking Solution (Powder in Bottle).

2 mg oral drinking solution

10 mg oral drinking solution

20 mg oral drinking solution

50 mg oral drinking solution

100 mg oral drinking solution

150 mg oral drinking solution

200 mg oral drinking solution

400 mg oral drinking solution

600 mg oral drinking solution

10,0 mg immediate release tablet

50,0 mg immediate release tablet

matching placebo (oral drinking solution and IR tablets)