Sustained release of drug-loaded nanoparticles from a novel vaginal ring design (360G-Wellcome-211729_Z_18_Z)

Sustained-release drug products are useful in prolonging the action of a drug in the body by maintaining therapeutic concentrations of the drug over extended time periods. Here, we are particularly interested in polymeric vaginal rings for long-acting vaginal administration of drugs (1). Various steroid-releasing vaginal ring products are currently marketed for hormonal contraception and estrogen replacement therapy, and a new ring device – developed in part by the Queen's University Belfast (QUB) and offering sustained release of the antiretroviral drug dapivirine for HIV prevention – is due to reach market soon. However, a major limitation of current vaginal ring technologies is that they are generally not useful for administration of either large molecule drugs or drug-loaded nanoparticles, due to limited solubility and/or diffusion in the polymeric materials used to manufacture rings. Here, we propose for the first time to test a novel vaginal ring developed at QUB for sustained release of drug-loaded nanoparticles, with potential applications in prevention/treatment of sexually transmitted infections, mucosal immunisation, and treatment of cervicovaginal cancers. The ring device comprises orifices in the ring surface which expose the underlying drug-loaded core. The ring is easy to manufacture using highly-scalable and conventional injection molding technologies.