RPK Medical explores the engineering behind next-generation autoinjectors in OnDrugDelivery

RPK Medical is featured in OnDrugDelivery Issue 191 with a new technical article, “Engineering the Next Generation of Autoinjectors,” authored by Iker Ibisate, Head of Stamped and Formed Products for Medical Applications.

The article looks at a fundamental shift in autoinjector development. These devices are no longer simple spring-driven mechanisms. New biologics, higher-concentration formulations, dual-chamber systems, advanced safety requirements and connected therapies are increasing the number of functions that must fit within the same limited device envelope.

For device developers, this creates a clear engineering challenge: how can they achieve more force, more functions, and greater reliability without simply making the device larger or more complex?

More functionality within the same device envelope

Precision metal components can provide part of the answer.

The new OnDrugDelivery article explores several areas where spring and stamped metal technologies can expand the design space available to autoinjector developers:

• High-viscosity drug delivery: compression springs provide high drive forces, while constant-force springs can deliver a more uniform force profile over longer strokes. Wave springs offer another option when high loads or preload functions must fit within very limited axial space.
• Dual-chamber and reconstitution devices: precision springs and metal components can control force, release thresholds, and mechanical sequencing when several actions must occur in a defined order.
• Safety and function integration: stamped and formed components can combine preload, locking, retention, and guidance functions in a single part, reducing component count and simplifying the internal architecture.
• Connectivity: miniature conductive components, spring contacts and stamped terminals can support battery, sensor, signal and data-transfer functions while maintaining the mechanical precision required by increasingly compact devices.

From individual components to integrated solutions

The opportunity is not simply to make each component smaller.

By considering springs and stamped metal parts early in development, device developers can integrate several mechanical-and even electrical- functions into fewer high-precision components.

RPK Medical brings together a broad range of technologies for this purpose:

• High-performance compression springs for power and actuation.
• Constant-force springs for long strokes and controlled force delivery.
• Wave springs for compact preload and high loads in restricted spaces.
• Stamped and formed metal components for locking, retention, guidance and multifunctional mechanisms.
• Miniature conductive parts for power, sensing and data transfer.

Combined with co-engineering, simulation, prototyping, and industrialization capabilities, these technologies allow RPK Medical to work alongside device developers from early design through serial production.

As autoinjectors continue to evolve, the smallest components inside the device can significantly affect its overall architecture.

The challenge is no longer just to generate force. It is to engineer more functionality into every millimeter of the device.

The challenge is no longer just to generate force. It is to engineer more functionality into every millimeter of the device.

Read Iker Ibisate’s “Engineering the Next Generation of Autoinjectors” in OnDrugDelivery, Issue 191, October 2026, pages 100–103.