Characterization of silicone elastomer vaginal rings containing HIV microbicide TMC120 by Raman spectroscopy
Authors: Bell, Steven E.J.1; Dennis, Andrew C.2; Fido, Louise A.2; Malcolm, R. Karl3; Sirimuthu, Narayana M.S.1; Toner, Clare F.3; Woolfson, A. David3
Source: Journal of Pharmacy and Pharmacology, Volume 59, Number 2, February 2007 , pp. 203-207(5)
Publisher: Pharmaceutical Press
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Abstract:
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.Document Type: Research article
DOI: 10.1211/jpp.59.2.0007
Affiliations: 1: Innovative Molecular Materials Group, School of Chemistry and Chemical Engineering, Queen's University, Belfast BT9 5AG, UK 2: Avalon Instruments Ltd, 1 Chlorine Gardens, Belfast BT9 5DJ, UK 3: School of Pharmacy, Queen's University, 97 Lisburn Road, Belfast BT9 7BL, UK
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