Assessment of the effect of two times oral 100 mg ritonavir capsules on pharmacokinetics of a single dose of BILR 355 BS dissolved in PEG 400

Inclusion Criteria:

• All participants in the study should be healthy males
• Age range from 21 to 50 years
• Body mass index (BMI) be within 18.5 to 29.9 kg/m2
• In accordance with Good Clinical Practice and the local legislation all volunteers will have given their written informed consent prior to admission to the study

Exclusion Criteria:

• Any finding of the medical examination (including blood pressure, pulse rate and ECG) deviating from normal and of clinical relevance
• Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders
• Diseases of the central nervous system (such as epilepsy) or psychiatric disorders or neurological disorders
• 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) within at least one month or less than ten half-lives of the respective drug before enrolment in the study or during the study
• Use of any drugs which might influence the results of the trial up to 7 days prior to enrolment in the study or during the study
• Participation in another trial with an investigational drug (≤ two months prior to administration or during the trial)
• Smoker (> 10 cigarettes or > 3 cigars of > 3 pipes/day)
• Inability to refrain from smoking on trial days
• Alcohol abuse (> 60 g/day)
• Drug abuse
• Blood donation (≥ 100 mL within four weeks prior to administration or during the trial)
• Any laboratory value outside the clinically accepted reference range
• Excessive physical activities within the last week before the trial or during the trial

Following exclusion criteria are of special interest for this study:

• Erythema, exanthema and comparable skin alterations