Recently, we worked on a case involving a two-part palliative cancer treatment delivered via a dual-syringe system. While the concept was sound, an unexpected issue emerged during development: solvent loss through the connecting seal.

The device consisted of two separate syringes connected by a sealed interface, designed to keep components stable until the moment of mixing. However, during testing, it became clear that solvent was permeating through the seal and evaporating.

Although the losses were not visually obvious, their effects were substantial:

• Reduced formulation integrity, risking efficacy
• Manufacturing delays, due to failed quality checks
• Limited patient access, as devices could not be released

This wasn’t just a materials issue, it was a transport problem happening at a microscopic level.

Understanding the Root Cause Through Modelling

To tackle this, we turned to computational modelling to simulate how the solvent moved through the seal over time. This allowed us to:

• Quantify permeation rates under different conditions
• Visualise diffusion pathways through the seal material
• Identify critical regions where losses were most pronounced

Rather than relying solely on trial-and-error testing, modelling provided a fast and detailed understanding of the underlying physics driving the problem.

Key Insights

The simulations revealed several important factors contributing to solvent loss:

• Material permeability of the seal was higher than expected
• Seal geometry created localised regions of higher diffusion flux
• Temperature and storage conditions amplified evaporation effects

These insights made it clear that the issue wasn’t a single failure point, but a combination of design and material considerations.

The Impact: Getting Treatment Back on Track

With a refined design in place, the client can now proceed with manufacturing, reducing delays and ensuring the device meets performance requirements.

Most importantly, this means patients can access the treatment they need.

This project highlights the power of computational modelling in medical device development. When physical testing alone can’t easily reveal the root cause, simulation bridges the gap, turning invisible processes into actionable insights.

In healthcare, where time and reliability are critical, that advantage can make all the difference.