State of the art in intravaginal rings: from material engineering to 3D-printed multipurpose delivery systems

Intravaginal rings (IVRs) are redefining women's health by enabling sustained, localized and user-independent drug delivery that overcomes the limitations of conventional vaginal dosage forms. This review provides a comprehensive perspective on next generation IVR technologies, emphasizing the convergence of biomaterials engineering, advanced manufacturing and clinical translation. We critically discuss how key elastomeric platforms -including ethylene-vinyl acetate, silicones and thermoplastic polyurethanes- govern drug release, mechanical performance and compatibility with the dynamic vaginal microenvironment. Particular focus is placed on the technological evolution of IVR fabrication, from traditional injection molding to disruptive additive manufacturing strategies like three-dimensional (3D) printing and photopolymerizable resin-based systems. These emerging technologies unlock unprecedented opportunities for personalized medicine and sophisticated multi-compartment architectures capable of delivering multiple therapeutics with independently tunable release profiles. In parallel, we examine analytical and regulatory considerations underpinning IVR development, including physicochemical characterization, in vitro release testing and bio-relevant in vivo pharmacokinetic and safety models. Beyond their established role in contraception and hormone replacement, IVRs are rapidly expanding into anti-infective and preventative applications targeting candidiasis, bacterial vaginosis and HIV-1 transmission. In this context, multipurpose prevention technologies (MPTs) are emerging as a transformative strategy capable of simultaneously addressing contraception and sexually transmitted infections within a single long-acting platform. Finally, we discuss the critical challenges that continue to shape the field, including microbiome preservation, user acceptability, regulatory complexity and large-scale manufacturing. Collectively, this review highlights IVRs as a versatile and rapidly evolving drug delivery platform poised to drive the future of personalized and long-acting therapeutics in women's health.