Safe and sustained vaginal delivery of pyrimidinedione HIV-1 inhibitors from polyurethane intravaginal rings

Todd J. Johnson, Priya Srinivasan, Theodore H. Albright, Karen Watson-Buckheit, Lorna Rabe, Amy Martin, Chou Pong Pau, R. Michael Hendry, Ron Otten, Janet McNicholl, Robert Buckheit, James Smith, Patrick F. Kiser*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


The potent antiretroviral pyrimidinediones IQP-0528 (PYD1) and IQP-0532 (PYD2) were formulated in polyurethane intravaginal rings (IVRs) as prophylactic drug delivery systems to prevent the sexual transmission of HIV-1. To aid in the selection of a pyrimidinedione candidate and the optimal loading of the drug in the IVR delivery system, four pyrimidinedione IVR formulations (PYD1 at 0.5 wt% [PYD1 0.5wt%], PYD1 1wt%, PYD2 4wt%, and PYD2 14wt%) were evaluated in pigtail macaques over 28 days for safety and pyrimidinedione vaginal biodistribution. Kinetic analysis of vaginal proinflammatory cytokines, native microflora, and drug levels suggested that all formulations were safe, but only the high-loaded PYD2 14wt% IVR demonstrated consistently high pyrimidinedione vaginal fluid and tissue levels over the 28-day study. This formulation delivered drug in excess of 10μg/ml to vaginal fluid and 1μg/g to vaginal tissue, a level over 1,000 times the in vitro 50% effective concentration. The in vitro release of PYD1 and PYD2 under nonsink conditions correlated well with in vivo release, both in amount and in kinetic profile, and therefore may serve as a more biologically relevant means of evaluating release in vitro than typically employed sink conditions. Lastly, the pyrimidinediones in the IVR formulation were chemically stable after 90 days of storage at elevated temperature, and the potent nanomolar-level antiviral activity of both molecules was retained after in vitro release. Altogether, these results point to the successful IVR formulation and vaginal biodistribution of the pyrimidinediones and demonstrate the usefulness of the pigtail macaque model in evaluating and screening antiretroviral IVR formulations prior to preclinical and clinical evaluation.

Original languageEnglish (US)
Pages (from-to)1291-1299
Number of pages9
JournalAntimicrobial agents and chemotherapy
Issue number3
StatePublished - Mar 2012

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)
  • Infectious Diseases


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