The objectives are:

1. To assess safety, pharmacokinetics, and pharmacodynamics of BIRT 1696 BS in rising single doses.
2. To assess safety, pharmacokinetics, and pharmacodynamics of single dose of 100 mg BIRT 1696 BS after grapefruit juice.
3. To asses safety and pharmacokinetics of single dose of 400 mg BIRT 1696 BS after a 67 g fat and high caloric breakfast.

Inclusion Criteria:

• Healthy male or female subjects as determined by results of screening
• Signed written informed consent in accordance with Good Clinical Practice (GCP) and local legislation
• Age ≥18 and ≤60 years
• Body Mass Index ≥18.5 and ≤29.9 kg/m2

Exclusion Criteria:

• Female subjects who are lactating or of child bearing potential as defined by surgically sterile or post menopausal (no periods for at least 12 months and elevated follicle stimulating hormone with low estradiol while on no estrogen supplementation unless surgically sterile). Females should use barrier contraception (e.g. condoms) prior to administration of study medication, during the study and at least one month after release from the study. Women must have had negative blood pregnancy tests
• Any finding of the medical examination (including blood pressure, pulse rate, and electrocardiogram) deviating from normal and of clinical relevance
• Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunologic or hormonal disorders
• Surgery of gastrointestinal tract (except appendectomy)
• Diseases of the central nervous system (such as epilepsy) or psychiatric disorders or neurological disorders
• Relevant history of orthostatic hypotension, fainting spells or blackouts
• Chronic or relevant acute infections
• History of allergy/hypersensitivity (including drug allergy) which is deemed relevant to the trial as judged by the investigator
• Intake of drugs with a long half-life (> 24 hours) (< 1 month prior to administration or during the trial)
• Use of any drugs, which might influence the results of the trial, (< 10 days prior to administration or during the trial)
• Participation in another trial with an investigational drug (< 2 months prior to administration or during trial)
• Smoker (> 10 cigarettes or >3 cigars or >3 pipes/day)
• Alcohol abuse (> 60 g/day)
• Drug abuse
• Use of methylxanthine-containing drinks or foods (coffee, tea, cola, energy drinks, chocolate, etc.), grapefruit or grapefruit juice, alcohol, green tea, or tobacco < 5 days prior to administration of study drug or during trial
• Blood donation or loss > 400 mL, < 1 month prior to administration or during the trial
• Excessive physical activities < 5 days prior to administration of study drug or during trial
• Clinically relevant laboratory abnormalities
• Any ECG value outside of the reference range of clinical relevance including, but not limited to QRS interval > 110 ms or QTcB > 450 ms (males) or QTcB > 470 ms (females)
• Inability to comply with dietary regimen of study centre
• Inability to comply with the investigator's instructions