To establish the bioequivalence of the new tipranavir oral solution formulation with the current tipranavir oral solution formulation following single-dose administration. In each case, 500 mg tipranavir was coadministered with 200 mg ritonavir.

Inclusion Criteria:

• Healthy males and females according to the following criteria based upon a complete medical history, including the physical examination, vital signs (BP, PR), 12-lead ECG, clinical laboratory tests
• Age ≥ 18 and ≤ 55 years
• BMI ≥ 18.5 and ≤ 29.9 kg/m2 (Body Mass Index) and body weight > 55 kg
• Signed and dated written informed consent prior to admission to the study in accordance with Good Clinical Practice and the local legislation

Exclusion Criteria:

• Any finding of the medical examination (including BP, PR and ECG) deviating from normal and of clinical relevance
• Any evidence of a clinically relevant concomitant disease
• Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders
• Surgery of the gastrointestinal tract (except appendectomy)
• Diseases of the central nervous system (such as epilepsy) or psychiatric disorders or neurological disorders
• History of relevant orthostatic hypotension, fainting spells or blackouts.
• Chronic or relevant acute infections
• History of relevant allergy/hypersensitivity (including allergy to tipranavir or ritonavir or their excipients)
• Intake of drugs with a long half-life (> 24 hours) within at least one month or less than 10 half-lives of the respective drug prior to administration of the trial drug or during the trial
• Cytochrome P 450 (CYP3A4)-inhibiting drugs (e.g. itraconazole, ketoconazole, protease inhibitors, erythromycin, clarithromycin, telithromycin, nefazodone, cyclosporin, verapamil, amiodarone, diltiazem), CYP3A4 inducing drugs (e.g. St. John´s wort [Hypericum perforatum], rifampin, dexamethasone) or CYP3A4 substrates (e.g. triazolam, sertraline); further drugs which might reasonably influence the results of the trial (e.g. drugs which contain polyethylene glycol) or drugs that prolong the QT/corrected QT interval interval (based on the knowledge at the time of protocol preparation) within 14 days prior to first administration of the trial drug or during the trial
• Participation in another trial with an investigational drug within two months prior to administration of the trial drug or during the trial
• Smoker (> 10 cigarettes or > 3 cigars or > 3 pipes/day)
• Inability to refrain from smoking within 24 hours before or after administration of the trial drug
• Alcohol abuse (more than 60 g/day)
• Drug abuse
• Blood donation (more than 100 mL within four weeks prior to administration of the trial drug or during the trial)
• Excessive physical activities (within one week prior to administration of the trial drug or during the trial)
• Any laboratory value outside the reference range that is of clinical relevance
• Inability to comply with dietary regimen of trial site
• A marked baseline prolongation of QT/QTc interval (e.g., repeated demonstration of a QTc interval >450 ms)
• A history of additional risk factors for Torsades de Pointes (TdP), e.g., heart failure, hypokalaemia, family history of Long QT Syndrome
• Known hypersensitivity to antiretroviral drugs (marketed or experimental use as part of clinical research studies)
• Personal or family history of coagulation or bleeding disorders or bleeding tendencies
• Intake of vitamin E within 14 days prior to the first drug administration of this trial or during the trial
• Transaminase values (ALT /AST) greater than the upper limit of the normal laboratory reference range during screening

For female subjects:

• Pregnancy or positive pregnancy test, or planning to become pregnant during the study or within 1 month of study completion
• No adequate contraception during the study and until 1 month of study completion, i.e. not any of the following: implants, injectables, combined oral contraceptives, intrauterine device, sexual abstinence (for at least 1 month prior to enrolment), vasectomised partner (vasectomy performed at least 1 year prior to enrolment), or surgical sterilisation (incl. hysterectomy). Females who do not have a vasectomised partner, are not sexually abstinent or surgically sterile will be asked to additionally use barrier contraception methods (e.g. condom, diaphragm with spermicide).
• Lactation period