At Ypsomed, our focus is on developing self-injection devices that not only meet regulatory standards but are also intuitive and accessible for a wide range of users with varying impairments and limitations . In our latest research, "Quantifying Patient Capabilities and Setting the Stage for Future Development", we aim to better understand the physical capabilities of patients using pen injectors. By measuring the forces applied during key handling steps, this study sheds light on how device design can be optimised to improve usability for individuals with varying levels of dexterity and hand strength.
Understanding real-world patient challenges
Self-injection devices are essential for patients with chronic conditions, but not all users interact with them in the same way. And neither is traditional usability work designed to describe in detail the capabilities and limitations of users that shape contextual user-device interactions. To better understand these interactions, our team conducted a simulated use study involving 46 participants, including both healthy individuals and those with dexterity impairments. The objective of the study was to measure the physical efforts required to perform key tasks such as removing the cap, setting the dose, and injecting — while considering each participant’s physical limitations. Specifically, we asked patients to conduct different self-injection pen user steps at what they considered a comfortable force level and then at their maximum force.
Read the full publication here
Using sensors embedded in pen injector dummies, we gathered precise data on the forces applied during each step. The results were enlightening:
- Cap removal forces: the average maximum force required for the control group was approximately 40 Newtons (N), while participants with dexterity impairments exerted around 29N. This highlights the challenge faced by users with limited hand strength.
- Dose setting (torque): for setting the dose, the control group applied a maximum torque of about 0.2 Newton meters (Nm), while the impaired group showed a slight reduction, indicating that torque can be influenced by both hand strength and device geometry.
- Injection forces: the force needed to press the dose button also varied. For small doses, healthy participants exerted up to 15N comfortably, while impaired participants exerted about 10N. For larger doses, forces reached up to 25N for the control group and 18N for those with impairments.
These specific measurements help quantify how much effort is required during each step of using a pen injector.
On a broader level:
- Participants with dexterity challenges exerted noticeably less force compared to the control group.
- Factors such as device design and how the pen was gripped significantly influenced the force applied.
- Force requirements tended to decline with age and reduced hand strength, impacting both comfort and usability.
Why these findings matter for device development
This research provides key information that can guide the future design of injection devices. By quantifying how much effort different users can comfortably apply, we can better tailor devices to meet diverse patient needs. The study highlights the importance of balancing functionality with comfort , especially for users with physical impairments who require easier-to-use devices.
Our findings underscore the need for device designs that not only perform well but are also intuitive and accessible to a broad spectrum of users. As healthcare continues to shift towards patient-centered solutions, this data becomes crucial in designing products that truly enhance the user experience and support long-term treatment adherence.
Moving forward
As we work to develop more advanced self-injection devices, this research gives us a clearer roadmap for meeting patient needs. By understanding how various users interact with these tools, we can continue to create solutions that improve the everyday experience of patients managing chronic conditions.
We invite you to explore the full study for a detailed look at our findings and how they could shape the future of drug delivery.
Andreas Schneider
Andreas Schneider is Head of Innovation at Ypsomed Delivery Systems. He leads business development, strategy, and engineering teams to drive new drug delivery device platforms and service offerings such as next generation autoinjectors and pens, smart connected systems and digital solutions. Andreas has published various articles and given presentations in the areas of innovation management and drug delivery. He holds a PhD in Innovation Management from ETH Zurich, Switzerland.
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