Non-aqueous silicone elastomer gels as a vaginal microbicide delivery system for the HIV-1 entry inhibitor maraviroc

Claire J. Forbes, Deborah Lowry, Leslie Geer, Ronald S. Veazey, Robin J. Shattock, Per J. Klasse, Mark Mitchnick, Laurie Goldman, Lara A Doyle, Brendan C.O. Muldoon, A. David Woolfson, John P. Moore, R. Karl Malcolm

Research output: Contribution to journalArticlepeer-review


Aqueous semi-solid polymeric gels, such as those based on hydroxyethylcellulose (HEC) and polyacrylic acid (e.g. Carbopol®), have a long history of use in vaginal drug delivery. However, despite their ubiquity, they often provide sub-optimal clinical performance, due to poor mucosal retention and limited solubility for poorly water-soluble actives. These issues are particularly pertinent for vaginal HIV microbicides, since many lead candidates are poorly water-soluble and where a major goal is the development of a coitally independent, once daily gel product. In this study, we report the use of a non-aqueous silicone elastomer gel for vaginal delivery of the HIV-1 entry inhibitor maraviroc. In vitro rheological, syringeability and retention studies demonstrated enhanced performance for silicone gels compared with a conventional aqueous HEC gel, while testing of the gels in the slug model confirmed a lack of mucosal irritancy. Pharmacokinetic studies following single dose vaginal administration of a maraviroc silicone gel in rhesus macaques showed higher and sustained MVC levels in vaginal fluid, vaginal tissue and plasma compared with a HEC gel containing the same maraviroc loading. The results demonstrate that non-aqueous silicone gels have potential as a formulation platform for coitally independent vaginal HIV microbicides.
Original languageEnglish
Pages (from-to)161-169
Number of pages9
JournalJournal of Controlled Release
Issue number2
Early online date12 Aug 2011
Publication statusPublished - 10 Dec 2011

Bibliographical note

© 2011, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International


  • intravaginal administration
  • animals
  • cyclohexanes
  • delayed-action preparations
  • female
  • gels
  • HIV fusion inhibitors
  • HIV infections
  • HIV-1
  • humans
  • macaca mulatta
  • silicone elastomers
  • triazoles
  • vagina
  • vaginal creams
  • foams
  • jellies


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