Each year, billions of medical injections are administered through the use of self-injectors. These devices allow patients to self-administer their injectable medication. Globally, aging populations coupled with a rise in chronic diseases and pressures on healthcare systems are leading to increased prescriptions of biologics and therapeutics to manage these conditions.
This trend is resulting in steady growth in the popularity of self-injection devices. However, the vast majority of these injectors are single-use disposable devices, contributing significantly to the waste generated within the healthcare sector. The circular economy, rooted in principles of designing out waste and using waste as a resource, might offer a solution. Possible circular strategies include reuse, remanufacturing, and recycling. However, given the complexity of the healthcare supply chain and the stringent focus on safety and hygiene within the industry, these strategies still face challenges that need to be overcome.

This thesis explored the redesign of auto-injectors to integrate circular economy (CE) principles, focusing on the Ypsomate auto-injector. Assigned by pharmaceutical company Johnson & Johnson (J&J), who have shown interest in developing circular systems for self-injectors, this study aimed to make CE design principles tangible for J&J. Key research questions addressed included identifying barriers and opportunities for CE in disposable self-injectors and applying potential circular strategies to redesign the Ypsomate.

The project followed a creative problem-solving approach involving literature research, expert interviews, co-creation and a field visit to J&J's innovation site. Findings highlighted industry trends focus on patient safety and usability as well as several sustainability developments. However, end-of-life design considerations remain underexplored. The study identified major barriers to CE integration, such as the challenge of combining safety with reuse strategies due to the low value and high hygiene criticality of auto-injectors.

The most promising opportunity was found in the safe, cost-effective separation of hygiene-critical from non-critical components, reducing reprocessing requirements. An in-depth product analysis of the Ypsomate identified relevant circular strategies: Design for Recycling, Disassembly, Component Reuse, and Extended Life. A redesign concept, the MediLoop was developed and prototyped to demonstrate the feasibility of significantly improving CE strategies for end-of-life recovery.