title: Single- and multiple-dose pharmacokinetics of darunavir plus ritonavir and etravirine in semen and rectal tissue of HIV-negative men.
abstract: BACKGROUND
  Antiretroviral therapy has become a central component of combination in HIV prevention efforts. Defining the individual exposure of commercially available antiretroviral therapy in genital secretions and vulnerable mucosal tissues is paramount to designing future prevention interventions.
  
  
  METHODS
  A pharmacokinetic (PK) study was performed in 12 HIV-negative men receiving 600 mg of darunavir, 100 mg of ritonavir, and 200 mg of etravirine orally, twice daily for 8 days. Seven blood plasma (BP) samples were collected over 12 hours on day 1 (PK1) and days 7 and 8 (PK2). One rectal tissue (RT) sample from each subject was collected during PK1 and PK2. During PK1, 2 seminal plasma (SP) samples were collected from each subject. During PK2, 6 SP samples were collected from each subject over 2 days.
  
  
  RESULTS
  Antiretrovirals were detected in SP and RT within 1 hour after a single dose. Over PK1 and PK2, SP exposures were lower than BP by 80%-92% (DRV), 89-95% (RTV), and 83-88% (ETR). However, protein binding in SP (14% for darunavir, 70% for ritonavir, and 97% for etravirine) was lower than in BP. Rectal tissue exposures were higher than BP by 39- to 155-fold for darunavir, 12- to 61-fold for ritonavir, and 20- to 40-fold for etravirine.
  
  
  CONCLUSIONS
  Lower SP protein binding resulted in higher pharmacologically active darunavir and etravirine concentrations compared with BP. High RT concentrations may also be favorable for suppressing viral replication in the gastrointestinal mucosa. The high protein-unbound exposures in SP and total exposures in RT support further investigations of darunavir plus ritonavir and etravirine in secondary prevention.
authors.affiliation: Division of Pharmacotherapy and Experimental Therapeutics University of North Carolina Eshelman School of Pharmacy, Chapel Hill, NC, USA.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Brown
authors.forename: Kristine B
authors.initials: KB
authors.lastname: Patterson
authors.forename: Steven H
authors.initials: SH
authors.lastname: Jennings
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Malone
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Shaheen
authors.forename: Heather M
authors.initials: HM
authors.lastname: Asher Prince
authors.forename: Melissa
authors.initials: M
authors.lastname: Spacek
authors.forename: Myron S
authors.initials: MS
authors.lastname: Cohen
authors.forename: Angela D M
authors.initials: AD
authors.lastname: Kashuba
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000069454:Darunavir; D006805:Human Experimentation; D006801:Humans; D008297:Male; D009570:Nitriles; D010949:Plasma / Q000737:chemistry; D011724:Pyridazines / Q000008:administration & dosage / Q000493:pharmacokinetics*; D011743:Pyrimidines; D012007:Rectum / Q000737:chemistry*; D019438:Ritonavir / Q000008:administration & dosage / Q000493:pharmacokinetics*; D012661:Semen / Q000737:chemistry*; D013449:Sulfonamides / Q000008:administration & dosage / Q000493:pharmacokinetics*; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents; D009570:Nitriles; D011724:Pyridazines; D011743:Pyrimidines; D013449:Sulfonamides; C451734:etravirine; D019438:Ritonavir; D000069454:Darunavir