A Temperature-Monitoring Vaginal Ring for Measuring Adherence

Peter Boyd, Delphine Desjardins, Sandeep Kumar, Susan M. Fetherston, Roger Le-Grand, Nathalie Dereuddre-Bosquet, Berglind Helgadottir, Asgeir Bjarnason, Manjulaa Narasimhan, R. Karl Malcolm

Research output: Contribution to journalArticle

11 Citations (Scopus)
408 Downloads (Pure)



Product adherence is a pivotal issue in the development of effective vaginal microbicides to reduce sexual transmission of HIV. To date, the six Phase III studies of vaginal gel products have relied primarily on self-reporting of adherence. Accurate and reliable methods for monitoring user adherence to microbicide-releasing vaginal rings have yet to be established.


A silicone elastomer vaginal ring prototype containing an embedded, miniature temperature logger has been developed and tested in vitro and in cynomolgus macaques for its potential to continuously monitor environmental temperature and accurately determine episodes of ring insertion and removal.


In vitro studies demonstrated that DST nano-T temperature loggers encapsulated in medical grade silicone elastomer were able to accurately and continuously measure environmental temperature. The devices responded quickly to temperature changes despite being embedded in different thickness of silicone elastomer. Prototype vaginal rings measured higher temperatures compared with a subcutaneously implanted device, showed high sensitivity to diurnal fluctuations in vaginal temperature, and accurately detected periods of ring removal when tested in macaques.


Vaginal rings containing embedded temperature loggers may be useful in the assessment of product adherence in late-stage clinical trials.
Original languageEnglish
Article numbere0125682
JournalPLoS ONE
Issue number5
Publication statusPublished - 12 May 2015

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