The primary objective of the current study is to investigate the relative bioavailability of three trial formulations of BI 207127, the trial formulation 2 (TFII), the final formulation (FF), and a FF modified formulation. All formulations are supplied as film-coated Tablets and administered as single dose treatments of BI 207127 (3 film-coated Tablets) in healthy volunteers, with the aim to compare the bioavailability of the three formulations. All treatments will be applied fed, 30 minutes after start of the intake of a standard normal breakfast.

Inclusion criteria:

1. Healthy males according to a complete medical history, including a physical examination, vital signs (blood pressure (BP), pulse rate (PR)), 12-lead electrocardiogram (ECG), and clinical laboratory tests
2. Age =21and Age =50 years
3. Body mass index =18.5 and BMI = 29.9 kg/m2
4. Signed and dated written informed consent prior to admission to the study in accordance with Good Clinical Practice (GCP) and the local legislation.

Exclusion criteria:

1. Any finding of the medical examination (including BP, PR and ECG) deviating from normal and of clinical relevance
2. Any evidence of a clinically relevant concomitant disease
3. Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders
4. Surgery of the gastrointestinal tract (except appendectomy)
5. Diseases of the central nervous system (such as epilepsy) or psychiatric disorders or neurological disorders
6. History of relevant orthostatic hypotension, fainting spells or blackouts
7. Chronic or relevant acute infections
8. History of relevant allergy/hypersensitivity (including allergy to drug or its excipients)
9. Intake of drugs with a long half-life (> 24 hours) within at least 10 half-lifes prior to administration of the trial drug or during the trial
10. Use of drugs which might reasonably influence the results of the trial within 10 days prior to administration or during the trial
11. Participation in another trial with an investigational drug within two months prior to administration of the trial drug or during the trial
12. Smoker (> 10 cigarettes or > 3 cigars or > 3 pipes/day)
13. Alcohol abuse (more than 40 g/day)
14. Drug abuse
15. Blood donation (more than 100 mL within four weeks prior to first administration of the trial drug or during the trial)
16. Excessive physical activities (within one week prior to first administration of the trial drug or during the trial)
17. Any laboratory value outside the reference range that is of clinical relevance
18. Inability to comply with dietary regimen of trial site
19. A marked baseline prolongation of QT/QTc interval (e.g., repeated demonstration of a QTc interval >450 ms)
20. A history of additional risk factors for Torsades de points (TdP) (e.g., heart failure, hypokalemia, family history of Long QT Syndrome)
21. History of photosensitivity or recurrent rash
22. Subject is not willing to avoid sun exposure from the first administration of the trial drug until the end of the study.

Adverse events (AE) occurring up to 2 days (48 h) after single intake of Deleobuvir tablets were assigned to the respective treatment period.

The volunteers were required to report spontaneously any AEs (and time of onset, duration, intensity). In addition, each volunteer was assessed regularly by the medical staff throughout the clinical trial (including prior to discharge from the trial centre) as well as at the end of observation and whenever necessary as deemed by the investigator.