Objective: To evaluate the relative bioavailability of a new formulation containing a combination of emtricitabine 200 mg and tenofovir disoproxil fumarate 300 mg (T) and compare this formulation with the branded formulation (R) to meet regulatory criteria for marketing the test product in Argentina.

A randomized-sequence, open-label, two-period crossover study was conducted on 24 healthy Caucasian volunteers in a fasting state. A single oral dose of either T or R formulations was followed by a 7-day washout period. Blood samples were collected at baseline and 0.25, 0.50, 0.75, 1, 1.25, 1.5 2, 2.5, 3, 4, 7, 12, 24 and 48 h after administration. Emtricitabine and tenofovir concentrations were determined using a validated LC (liquid chromatography) - MS (mass spectrometry) / MS method. Adverse events were monitored based on clinical parameters and volunteer reports.

Inclusion Criteria:

1. Subjects of both sexes between 21 and 55 years.
2. Subjects with body mass index (BMI) between 19 and 27 kg / m².
3. Subjects whose complementary tests (ECG, blood and urine) are within normal and / or clinically insignificant according to the judgment of the investigator. Women of childbearing age should have a negative pregnancy test and use a reliable method of contraception during the study (IUD or condoms)
4. Subjects with systolic blood pressure between 110 mmHg and 139 mmHg; diastolic pressure between 70 mmHg and 89 mmHg; heart rate between 50 and 90 beats per minute.
5. Subjects who signed informed consent.

Exclusion Criteria:

1. Background of clinically significant allergies (except untreated asymptomatic seasonal allergies), drug hypersensitivity and / or hypersensitivity to any component of the formulations studied.
2. Drop of more than 20 mmHg in systolic blood pressure or more than 10 mmHg diastolic pressure in the first 3 minutes of postural change.
3. Active smoker more than 10 cigarettes / day.
4. Pregnant or lactating women.
5. Current clinical evidence of severe digestive disorders, surgery of the digestive tract (except appendectomy).
6. Current clinical evidence of kidney disease.
7. Current evidence of liver disorders
8. Current clinical evidence of respiratory and heart diseases.
9. The presence of diabetes mellitus, thyroid dysfunction or other endocrine disorder.
10. Evidence of gastroduodenal disease.
11. Current presence of any malignancy.
12. History of abuse or addiction to drugs or alcohol during the past three years.
13. Participation in a clinical trial within the last three months.
14. Use of any drug within fourteen days before the start of the study.
15. Subject donated or suffered blood loss during the last twelve weeks before the start of the study, or intends to donate blood within three months of the completion of the study.
16. Excessive drinking of tea, cocoa, mate, coffee and / or beverages containing caffeine (> 5 cups / day) or wine (> 0.5 L / day) or alcohol (> 50 ml / day).
17. ECG abnormalities.
18. Positive serology for HIV, hepatitis B or hepatitis C.
19. Women who are not using effective contraception (IUD, condom)