Evaluation of the Pharmacokinetic Interaction of Steady State Tipranavir and Ritonavir or Tipranavir and Ritonavir With Single Dose Didanosine in Healthy Volunteers

Inclusion Criteria: * Healthy male or female subjects as determined by results of screening * Female subjects were not lactating and not of child bearing potential as defined by surgically sterile or post menopausal (no periods for at least 12 months and elevated follicle stimulating hormone (FSH) with low estradiol and no estrogen supplementation). Females were to use barrier contraception (e.g. condoms) for at least one month prior to administration of study medication, during the study and at least one month after release from the study. Women were to have negative pregnancy tests * Signed written informed consent in accordance with Good Clinical Practice (GCP) and local legislation * Age \>=18 and \<=60 years * Body mass index (BMI) \>=18.5 and \<=29.9 kg/m2 Exclusion Criteria: * Any finding of the medical examination (including blood pressure, pulse rate and ECG) deviating from normal and of clinical relevance * History or current gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunologic, hormonal disorders, including a clinical history of viral hepatitis, or serological evidence of active Hepatitis B, Hepatitis C, or HIV infection * History of orthostatic hypotension, fainting spells and blackouts * Diseases of the central nervous system (such as epilepsy) or psychiatric disorders or neurological disorders * Chronic or relevant acute infections * History of allergy/hypersensitivity (including drug allergy) which was deemed relevant to the trial as judged by the investigator including study drugs * Intake of drugs with a long half-life (\> 24 hours) or enzyme altering drug within 1 month prior to administration of study drugs * Use of any drugs that might have influenced the results of the trial within 10 days prior to administration or during the trial (in addition to specific medication prohibitions mentioned in exclusion criteria above) * Use of grapefruit or grapefruit juice, alcohol, green tea, methylxanthine-containing products or tobacco within one week of study drug administration * Participation in another trial with an investigational drug within 2 months prior to administration or during the trial * Smoker (\> 10 cigarettes or 3 cigars or 3 pipes/day) or inability to refrain from smoking on trial days * Alcohol abuse (\> 60 g/day) * Drug abuse * Blood or plasma donation within 1 month prior to administration or during the trial * Excessive physical activities within 5 days prior to administration or during the trial * Following specific laboratory findings: activated partial thromboplastin time (aPTT), prothrombin time international normalised ratio (INR), aspartate transaminase (AST), alanine transaminase (ALT), gamma-glutamyl-transferase (GGT), amylase, lipase, or triglyceride above the normal range * Any other laboratory value outside the clinically accepted reference range and of clinical relevance * History of any familial bleeding disorder * Inability to swallow multiple large capsules * Inability to comply with dietary regimen of study centre * Inability to comply with investigator's instructions