Inclusion Criteria:  Age 18 to 50 years, inclusive General good health (by volunteer history and per investigator judgment) without any clinically significant systemic disease (including, but not limited to significant liver disease/hepatitis, gastrointestinal disease, kidney disease, thyroid disease, osteoporosis or bone disease, and diabetes) and with an intact gastrointestinal tract, uterus and cervix. Estimated calculated creatinine clearance (eCcr) of at least 80 mL/min Body Mass Index (BMI) of ≥18 and <35kg/m2; and a total body weight >45 kg (99.2 lbs) Willing to give voluntary consent and sign an informed consent form Willing and able to comply with protocol requirements, including swallowing tablets  Must be protected from pregnancy by:  Condoms Hormonal contraceptives Copper or Levonorgestrel IUD Sterilization of either partner Heterosexual abstinence Same sex relationship If in a relationship, must be in a mutually monogamous relationship with a partner who is not known to be HIV positive and has no known risk of STIs  Exclusion Criteria:  Currently pregnant Currently breastfeeding or planning to breastfeed during the course of the study In the last three months, diagnosed with or treated for any STI Positive test for HIV, or Hepatitis B surface antigen (HBsAg) Systemic use in the last two weeks or anticipated use during the study of any of the following: antiretrovirals (e.g. Viread®, Atripla®, Emtriva®, or Complera®), or drugs that may interact with TFV (e.g., protease inhibitors, anticonvulsants, antimycobacterials, St. John's Wort). Participation in any other investigational trial with use of a drug/device within the last 30 days or planned participation in any other investigational trial with use of a drug/device during the study Grade 2 or higher laboratory abnormality, per the 2014 update of the Division of AIDS, National Institute of Allergy and Infectious Disease (DAIDS) Table for Grading the Severity of Adverse Events, or clinically significant laboratory abnormality as determined by the clinician Abnormal finding on laboratory or physical examination or a social or medical condition in the volunteer which, in the opinion of the investigator, would make participation in the study unsafe or would complicate interpretation of data