Design Input/Output and Design V&V (Verification and Validation) Interpretations

[deethreepio]

Hi Julie,

I need more posts to respond to private messages. I will work on it.

Thanks

 

[Ronen E]

I am dealing with a little different situation. It's a little off subject but I was hoping to get your opinion on the following:
If design validation is proving that a representative device meets the user requirements using objective evidence, and process validation is proving that a process can reliable create that same device, should IQ/OQ activities for process validation occur prior to design validation?

Thank you

Hello and welcome to the Cove

Design Validation and Process Validation are related but not directly / rigidly connected. For Design Validation it is important that you use devices built on the commercial production line (full scale or pilot), or at least closely representative of such devices (strong documented rationale must be in place), and that are proven to be within the finalised device specification for that point in time. Whether or not the processes were validated prior to that is usually a secondary question. Pay attention though that for critical processes where the outcome can't be practically verified (sterilization for instance), you'd have no choice but to validate the process first.

Cheers,
Ronen.

 

[deethreepio]

Thanks for the response. If your statement holds true for sterilization, then it would also be necessary to perform full process validation on other processes that cannot be practically verified (injection molding and welds) prior to the design validation, correct?

 

[dblnkl]

Here is a MUCH MUCH abbreviated example of the concepts addressed by the primary questioner relating to design controls. In practice, for such a complex product below, there may be many branches and levels of design inputs and specifications from one set of user requirements.


Sample Product: Steerable ablation catheter


User requirement: (testable during product validation/clinical trials)
Physician must be able use the catheter to deliver an ablation to the medial wall of the left atrium via venous access and transeptal puncture.
(One of many potential user requirements for this product.)


Design Input: (testable during verification/animal studies)
Catheter must be long enough to reach heart from femoral venous entry and have length and flexibility sufficient to move freely within all chambers of the heart.
Distal segment curvature must be controlled by operator.
Distal catheter segment much be able to enter right atrium via IVC and cross septum via septal puncture into left atrium (steerable distal segment must have length no less than x).
Curvature of distal segment must permit catheter to be able to bend catheter tip back onto catheter body with a radius no greater than x, while remaining in the same plane.
Etc.

Design Specifications: (testable during verification/bench studies)
Reliability = x operations without failure
Catheter body material, diameter, thickness, length = w, x, y, z
Catheter distal segment material, diameter, thickness, length = w, x, y, z
Pull wire material, size, length = x, y, z
Pull wire attachment = x
Material bonding = x
Handle = x
Etc.

 

[Ronen E]

Thanks for the response. If your statement holds true for sterilization, then it would also be necessary to perform full process validation on other processes that cannot be practically verified (injection molding and welds) prior to the design validation, correct?

It might be so. The answer depends on the criticality of the output you can't verify (assuming it is the case), to the ability of the device as a whole to satisfy user/patient needs. WRT sterility it's obvious. WRT welding, it depends on the weld's role. WRT injection molding, some outcomes are hard / impossible to practically verify, but others - like dimensions - should be easy; so again, it comes down to the part's role.