Avantor (NYSE: AVTR) announced an expansion of its NuSil brand's collaboration with the Population Council to support development of a three-month dapivirine vaginal ring for HIV prevention, according to a company press release.

NuSil originally partnered with the International Partnership for Microbicides, which the Population Council acquired in 2022, to supply high-purity silicones for a one-month version of the dapivirine vaginal ring. That product has received regulatory approval in 12 countries in sub-Saharan Africa and is recommended for women ages 16 and older, including those who are breastfeeding.

The extended three-month ring would require only four rings per year, compared to 12 for the monthly version. The Population Council submitted the three-month ring for regulatory review by the European Medicines Agency in November 2025, with plans to seek subsequent approvals in sub-Saharan Africa and other regions. The product has not received regulatory approval in most jurisdictions and remains investigational.

Clinical studies have shown the three-month ring delivers higher levels of dapivirine compared to the monthly version. NuSil's medical-grade silicones are used in the ring's design to support consistent drug release and mechanical performance over the three-month period.

"NuSil has developed and supplied high-purity specialized silicones for our medical devices and drug delivery systems for nearly two decades and we are proud to continue our collaboration to develop this innovative product," said Kyle Kleinbeck, Senior Scientist at the Population Council.