Pharmacokinetics and placental transfer of single-dose tenofovir 1% vaginal gel in term pregnancy.

UNLABELLED: Tenofovir (TFV) 1% vaginal gel has been found to decrease sexual transmission of human immunodeficiency virus. To initiate investigations during pregnancy, 16 healthy pregnant women scheduled for cesarean delivery received a single application of TFV gel preoperatively. Maternal serum drug concentrations were determined and fetal cord blood, amniotic fluid, placental tissue, and endometrial tissue specimens were collected. The median maternal peak concentration and cord blood TFV concentrations were 4.3 and 1.9 ng/mL, respectively (∼100- and 40-fold lower than after TFV oral dosing, respectively). No adverse events were related to the use of TFV gel. These findings support ongoing and future investigations of TFV gel in pregnancy. CLINICAL TRIAL REGISTRATION: NCT00572273. http://www.clinicaltrials.gov/ct2/show/NCT00540605?term=mtn-002&rank=1.