Why essential drug delivery outputs? 

The shift from requirements to outputs.

Understanding Essential Drug Delivery Outputs: Why Outputs and not Inputs?

The medical device industry has seen a significant shift in how we approach the design and development of drug delivery devices. Gone are the days of simply meeting ‘Essential Performance Requirements’—a term previously used by the FDA. Today, we focus on Essential Drug Delivery Outputs (EDDOs), which have raised questions about their role in the design control process. Are they inputs or outputs? Let’s dive into the regulations and definitions to clear the confusion. 

Design Inputs and Outputs: The Foundation of Device Design

Let us take a closer look at the regulations and definitions of these terms: 

• Design Inputs: § 820.3(f) Design input means the physical and performance requirements of a device that are used as a basis for device design. 

• Design Outputs: § 820.3(g) Design output means the results of a design effort at each design phase and at the end of the total design effort. The finished design output is the basis for the device master record. The total finished design output consists of the device, its packaging and labeling, and the device master record.  

• Specifications: § 820.3(y) Specification means any requirement with which a product, process, service, or other activity must conform. 

• EDDO: EDDOs are the design outputs necessary to ensure delivery of the intended drug dose to the intended delivery site. Drug delivery includes successful product preparation and the initiation, progression, and completion of dose delivery. EDDOs are system level outputs for which device drug-delivery function is dependent on the device design. 1 

EDDOs: Bridging the Gap Between Requirements and Specifications

EDDOs are crucial as they ensure the delivery of the intended drug dose to the right place. They encompass the entire drug delivery process, from product preparation to the completion of dose delivery. These outputs are dependent on the device design and are considered at a system level, making them integral to the device’s performance. 

Navigating the Design Control Process

The design control process can be visualized as a waterfall diagram from FDA’s “Design Control Guidance for Medical Device Manufacturers” (March 1997)2 (Figure 1), with design inputs at the start of the process and design outputs at the finish line. Complete design inputs are foundational, but they don’t explicitly dictate how a device achieves its intended use. That’s where EDDOs come in, serving as a throughline from design inputs to outputs, ensuring that the device is safe and effective for its intended use. 

Figure 1: Design Control Waterfall Design Process 

Specifications vs. Requirements: A Closer Look 

It’s important to differentiate between requirements and specifications. Requirements describe what the device must achieve without specifying how. They are written from a user’s perspective, focusing on desired functionality and performance. Specifications, however, provide detailed, measurable information on how the device shall achieve these requirements, including technical aspects like tolerances and dimensions. 

The FDA’s Guidance on EDDOs 

The FDA’s guidance on EDDOs provides a step-by-step process for identifying them, emphasizing the importance of controlling and maintaining EDDOs throughout the design process. By doing so, we reinforce the key principles of design controls, ensuring that our devices meet the highest standards of safety and effectiveness. 

In Appendix A the guidance provides the examples of ‘Deliverable volume, cap removal force, breakloose force, glide force, needle safety activation force’ as the EDDOs. This can be confusing as the actual EDDOs would be the specification associated with each of these. Of course the guidance cannot provide specific values as this might be seen as the FDA enforcing certain specifications for device types as this was not the intent of the guidance.  

So are EDDOs design inputs or design outputs? EDDOs are outcome of the design controls process, they embody the elements of the physical device that make it safe and effective for drug delivery. By identifying, controlling and maintaining EDDOs you are enforcing the key principals of design controls – ultimately not a new concept. **mind blown**   

Conclusion: Embracing the EDDO Framework 

As we navigate the complexities of medical device design, it’s clear that EDDOs play a pivotal role in ensuring that our devices deliver drugs safely and effectively. By understanding and implementing the EDDO framework, we can continue to innovate and lead the industry in drug delivery technology. 

AUTHOR

Carolyn Dorgan, Director, Technical Services – Carolyn Dorgan has 10+ years of experience in the Medical Device and Combination Product industries, including 6 years at the FDA leading the Infusion Devices team. Carolyn is active in the international regulatory community through speaking engagements and has participated in over a dozen international standards ranging from infusion devices, to needle-based injection systems, on-body delivery systems, and infant incubators.