surgeon performing catheter based surgery

Achieving direct-to-organ drug delivery via a catheter

Delivering therapies directly to target locations during surgery has numerous benefits, both for improving treatment accuracy and reducing systemic exposure. Our client set out to develop a novel catheter capable of safely navigating to a target site and enabling controlled drug delivery in a surgical setting.

We supported the programme from early concept to final product, designing, building and testing a catheter ready for in vivo testing and progression towards formal design for manufacture.

Tackling the challenges of catheter drug delivery

Targeted drug delivery via a catheter requires precise navigation through the body, as well as maintaining consistent and controlled therapy delivery at the target site. Our client’s device had several key requirements:

Ability to navigate a tortuous path and reach the target site through a viable anatomical access route
Deliver therapy reliably via a custom designed distal tip
Maintain distal tip stability, structural integrity and performance under surgical conditions
Meet constraints on pressure, flow rate and overall device diameter

To achieve these requirements, we needed to address several detailed design considerations, including:

Tube flexibility and axial stiffness
Material compatibility with both drug formulation and internal human use
Reliable joining methods between changes in tube diameter and fixing hubs, tips, needles and other related components
Design of handles (mouldings) for the proximal ends to allow users to successfully position the catheter during treatment and administer the therapy

Meeting clinical requirements and user needs for catheter-based delivery

As catheters are used in demanding surgical environments, we engaged Key Opinion Leaders (KOLs) and representative users early in the development to understand their specific needs and clinical requirements. Common themes from these discussions were the importance of simplicity, familiarity, positioning, reliability and reassurance for users.

In a high-pressure surgical environment, clinicians rely on devices that are intuitive, predictable and easy to operate. The catheter therefore needed to integrate seamlessly into existing workflows and support confident use during procedures. We also carried out formative work, including exploratory research to evaluate concepts and simulate parts of the procedure with KOLs to gather feedback.

This research shaped a set of core user requirements:

Size – small enough to access the target anatomy
Durability – able to withstand unforeseen challenges, such as force and flexibility required during navigation and positioning
Familiarity – the use model must fit user expectations and existing workflows, with a familiar design close to current products.

Achieving effective usability through human factors research

To help inform key product requirements and reduce development risk, we conducted multiple simulated-use studies in a pre-clinical laboratory setting, using representative models to evaluate the catheter’s performance across the full procedure. This included KOLs carrying out realistic treatment scenarios to assess both navigation through tortuous anatomical pathways, distal tip positioning and stability, and the effectiveness of drug delivery at the target site. The studies also enabled us observe how the device integrated into existing clinical workflows and to collect objective performance data on the catheters use.

This work provided early evidence that the device could be used safely and effectively as intended, while identifying opportunities to refine the design. The findings also informed key product requirements and gave the client greater confidence in progressing the catheter towards in vivo testing and further development.

De-risking the development through robust engineering analysis

Maintaining controlled fluid flow was critical to the success of the device. As an inlet and outlet catheter, the device needed to isolate the region around the target organ and enable controlled perfusion. Alongside this, the design had to meet minimum flow rates for patient safety while remaining within strict diameter constraints. Our early analysis indicated that performance would sit close to these limits, meaning further modelling was needed to validate designs. To reduce development risk, we carried out detailed flow modelling and built early-stage test models to validate performance. The strong correlation between predicted and observed results gave us confidence to progress quickly to fully integrated catheter prototypes for on-site testing and accelerating the path to in vivo testing.

To address potential flexibility and stiffness issues, we also spent considerable effort on FEA (Finite Element Analysis) to predict the catheter performance when varying various factors, including: material, wall thickness, inner and outer diameters and the effect of differing laser cut patterns to metal hypo-tubes.

Rapid, bespoke catheter prototype development

We translated the validated design into representative prototypes using clinically relevant materials and processes. This included:

Plastic lumens and hypotubes
Reinforcing braids
Balloons
Radiopaque markers

Using our in-house capabilities, we iterated rapidly to validate flow, pressure and navigation performance, de-risking the design against demanding clinical requirements.

Stress testing drug delivery performance

The next stage of the development involved testing the device against key performance requirements using established catheter test methods, including:

Tortuous path testing to evaluate navigation to the target site
Flow testing to confirm delivery performance of predicted flows
Pressure testing to ensure ability to contain pressures under load from the flow
Leak testing to validate integrity during use

Surgeon unwrapping catheter from packaging

Reducing use-related risk through IFU and packaging design

As the design matured, we supported the development of the device’s Instructions for Use (IFU), packaging. This work focused on developing effective instructions and a usable packaging solution. Additionally, design controls to address key use-related risks were included, ensuring that critical safety information was clearly presented through the labelling, packaging and user-facing elements. We evaluated how users interacted with the device throughout the procedure, helping to define effective risk controls and reduce the potential for use errors.

We also supported the client’s regulatory activities by generating the documentation and evidence needed for submission. This included risk management records, product specifications, engineering drawings and usability engineering documentation, helping to strengthen the technical file and support progression towards regulatory submission.

Illustration showing target organ in human body x-ray

Outcome

We developed, built and tested a novel multi-lumen catheter, enabling our client to undertake in-vivo preclinical research and achieve a key milestone in their development. The device is now ready to progress to design for manufacture.