The vaginal microbiota, bacterial biofilms and polymeric drug-releasing vaginal rings

Louise Carson, Ruth Merkatz, Elena Martinelli, Peter Boyd, Bruce Variano, Teresa Sallent, Robert Karl Malcolm*

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

14 Citations (Scopus)
251 Downloads (Pure)


The diversity and dynamics of the microbial species populating the human vagina are increasingly understood to play a pivotal role in vaginal health. However, our knowledge about the potential interactions between the vaginal microbiota and vaginally administered drug delivery systems is still rather limited. Several drug-releasing vaginal ring products are currently marketed for hormonal contraception and estrogen replacement therapy, and many others are in preclinical and clinical development for these and other clinical indications. As with all implantable polymeric devices, drug-releasing vaginal rings are subject to surface bacterial adherence and biofilm for- mation, mostly associated with endogenous microorganisms present in the vagina. Despite more than 50 years since the vaginal ring concept was first described, there has been only limited study and reporting around bacterial adherence and biofilm formation on rings. With increasing interest in the vaginal microbiome and vaginal ring technology, this timely review article provides an over- view of: (i) the vaginal microbiota, (ii) biofilm formation in the human vagina and its potential role in vaginal dysbiosis, (iii) mechanistic aspects of biofilm formation on polymeric surfaces, (iv) poly- meric materials used in the manufacture of vaginal rings, (v) surface morphology characteristics of rings, (vi) biomass accumulation and biofilm formation on vaginal rings, and (vii) regulatory con- siderations.
Original languageEnglish
Article number751
Number of pages29
Issue number5
Publication statusPublished - 19 May 2021


  • controlled release
  • drug delivery system
  • silicone elastomer
  • ethylene vinyl acetate copolymers
  • thermoplastics
  • polyurethanes
  • vaginal microbiome
  • lactobacillus
  • Gardnerella vaginalis


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