Pharmacokinetic Study of Dapivirine Gel Administered Rectally to HIV-1 Seronegative Adults

This study will evaluate the pharmacokinetics (PK) of dapivirine gel administered rectally to HIV-1 seronegative adults. Participants will be randomly assigned to two groups: Sequence A or Sequence B. Participants in Sequence A will receive 2.5 g of dapivirine gel administered rectally via an applicator, followed by a 2- to 4-week washout period. Participants will then receive a second dose of up to 10 g of dapivirine gel administered rectally via a coital simulation device. Participants in Sequence B will receive up to 10 g of dapivirine gel administered rectally via a coital simulation device, followed by a 2- to 4-week washout period. Participants will then receive a second dose of 2.5 g of dapivirine gel administered rectally via an applicator. Participants will be in the study for approximately 1 month and will attend 7 study visits. Study visits may include behavioral assessments, physical examinations, blood and urine collection, throat and anorectal sample collection, and PK sampling.