Study to characterize the effects of two dose combinations of Tipranavir (TPV)/Ritonavir (RTV) (TPV 750 mg/RTV 200 mg and TPV 500 mg/RTV 100 mg), administered twice-daily, on the pharmacokinetics of Norethindrone-Ethinyl Estradiol (NET/EE) 1 mg/ 0.035 mg administered as a single dose.

Inclusion Criteria:

1. Female subjects between 18 and 50 years of age inclusive
2. A Body Mass Index (BMI) between 18 and 29 kg/m2
3. Signed informed consent prior to trial participation
4. Ability to swallow numerous large capsules without difficulty
5. Acceptable laboratory values that indicate adequate baseline organ function are required at the time of screening. Laboratory values are considered to be acceptable if severity is less than or equal to Grade 1, based on the AIDS Clinical Trials Group Grading Scale. All abnormal laboratory values greater than Grade 1 are subject to approval by the trial clinical monitor.
6. Acceptable medical history, physical examination and ECG, and chest X-ray (if not conducted within the last 12 months) are required prior to entering the treatment phase of the study
7. Willingness to abstain from alcohol for 48 hours prior to Study Day 0 and abstain from alcohol for the duration of the study. In addition, red wine must not have been ingested within 5 days prior to Day 0 (Visit 2)
8. Willingness to abstain from ingesting grapefruit, grapefruit juice, or products containing grapefruit juice, within 10 days before Day 0, Visit 2 and for the duration of the study
9. Willingness to abstain from ingesting Seville oranges, garlic supplements, St. John's Wort, Milk Thistle, or methylxanthine-containing drinks or food (coffee, tea, cola, energy drinks, chocolate, etc) within 5 days of Day 0, Visit 2 and for the duration of the study
10. Willingness to abstain from over the counter herbal medications for the duration of the study
11. Reasonable probability for completion of the study

Exclusion Criteria:

1. Female subjects who are of reproductive potential who:

   • Have positive serum beta-human chorionic gonadotropin at Visit 1, or on Day 0 or Day 1
   • Have not been using a barrier contraceptive method for at least 3 months prior to Visit 3 (Day 1)
   • Are not willing to use a reliable method of double-barrier contraception (such as diaphragm with spermicidal cream/jelly or condoms with spermicidal foam), during the trial and 30 days after completion/termination
   • Are breast-feeding

2. Participation in another trial with an investigational medicine within 30 days prior to Day 0 (Visit 2)

3. Use of any medication listed in the protocol within 30 days prior to Day 0 (Visit 2)

4. Use of any other pharmacological contraceptive (including oral, patch or injectable contraceptives) for 1 month prior to study initiation and for the duration of the study

5. Administration of antibiotics within 10 days prior to Day 0 (Visit 2) or during the trial

6. History of central nervous system (CNS), gastrointestinal, hepatic, or renal disorders within the past sixty (60) days. Subjects will be excluded for these disorders greater than sixty days if, in the opinion of the investigator, the subject does not qualify as a healthy volunteer

7. History of thrombotic disease

8. History of migraine headache

9. Have serological evidence of hepatitis B or C virus

10. Have serological evidence of exposure to HIV

11. Recent history of alcohol or substance abuse (within 6 months of study period)

12. Cigarette smoking (greater than 10 cigarettes per day)

13. Blood or plasma donations within 30 days prior to Day 0 (Visit 2) or during the trial.

14. Subjects with a seated systolic blood pressure either <100 mm Hg or >150 mm Hg; resting heart rate either <50 beats/min or >90 beats/min. For subjects with a resting heart rate below 50, due to a high fitness level, the investigator may discuss exclusion with the medical monitor on a case-by-case basis

15. Subjects with a history of any illness or allergy that, in the opinion of the investigator, might confound the results of the study or pose additional risk in administering Tipranavir, Ritonavir or NET/EE to the subject

16. Subjects who have had an acute illness within 2 weeks prior to Day 0 (Visit 2)

17. Subjects who are currently taking any over-the-counter drug within 7 days prior to Day 0,(Visit 2) or who are currently taking any prescription drug that, in the opinion of the investigator in consultation with the clinical monitor, might interfere with either the absorption, distribution or metabolism of the test substances

18. Known hypersensitivity to TPV, RTV, or NET/EE

19. Inability to comply with the protocol