This paper elaborates on the design of intravaginal drug-releasing rings (IVRs). Besides providing background on IVR development, which includes polymer selection and drug release kinetics, the topic of simultaneous drug release is covered. The simultaneous release of two or more drugs is required for several applications, including contraception, HIV-PrEP, and dual prevention technologies, and it adds an additional layer of complexity to IVR design.

In this paper, it is emphasized that unnecessary design complexity should be avoided against the background of general principles of Design for Manufacturability. In IVR development, however, numerous concepts comprised of multiple segments or other drug-releasing parts have been proposed, and only by exception attention is given to the end game, i.e., industrialization, which is required for large-scale commercial production.

A versatile, easy-to-scale-up, one-compartment design based on co-extrusion technology and thermoplastic polymers is proposed to reduce complexity. This technology was first developed in the late zeros and further sophisticated within Sever Pharma Solutions (SPS). It has been used successfully for the design of several rings that are currently in distinct phases of development.