Characterisation of Silicone Elastomer Vaginal Rings Containing HIV Microbicide TMC120 by Raman Spectroscopy

Karl Malcolm, Steven Bell, Louise Fido, Clare Toner, David Woolfson, Andrew Dennis

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


Silicone elastomer vaginal rings are currently being pursued as a controlled-release strategy for delivering microbicidal substances for the prevention of heterosexual transmission of HIV. Although it is well established that the distribution of drugs in delivery systems influences the release characteristics, in practice the distribution is often difficult to quantify in-situ. Therefore, the aim of this work was to determine whether Raman spectroscopy might provide a rapid, non-contact means of measuring the concentrations of the lead candidate HIV microbicide TMC120 in a silicone elastomer reservoir-type vaginal ring. Vaginal rings loaded with TMC120 were manufactured and sectioned before either Raman mapping an entire ring cross-section (100 µm resolution) or running line scans at appropriate time intervals up to 30 h after manufacture. The results demonstrated that detectable amounts of TMC120, above the silicone elastomer saturation concentration, could be detected up to 1 mm into the sheath, presumably as a consequence of permeation and subsequent reprecipitation. The extent of permeation was found to be similar in rings manufactured at 25 and 80°C.
Original languageEnglish
Pages (from-to)203-207
Number of pages5
JournalJournal of Pharmacy and Pharmacology
Issue number2
Publication statusPublished - Feb 2007

ASJC Scopus subject areas

  • Pharmaceutical Science
  • Pharmacology


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