Effect of Different Boosting Agents on Pharmacokinetics of BILR 355 BS Dissolved in Polyethylene Glycol 400 (PEG 400) in Healthy Male Volunteers

Inclusion Criteria: * All participants in the study were to be healthy males, range from 21 to 50 years of age and their body mass index (BMI) be within 18.5 to 29.9 kg/m2 (BMI calculation: weight in kilograms divided by the square of height in meters) * In accordance with good clinical practice (GCP) and the local legislation all volunteers had to give 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 * For the boosting agents atazanavir and atazanavir plus ritonavir, subjects with a PQ interval length in the screening ECG of \> 200 ms or any higher degree of atrio-ventricular (AV) block were to be excluded