Design Input

 

This blog talks about design input, 21 CFR 820.30(c), an important requirement of design control. A procedure to handle design input is warranted.

Normally, Research & Development and Engineering should bear the responsibility to initiate this design input requirements. The input requirement includes product concepts such as product engineering sketches, models and rough prototypes of the device.

Basically the general product descriptions at this stage are translated into more specific engineering term such as actual product specifications like product sizes, weight, electrical power, and perhaps Interphasing with computer software. More often, the product specifications shall be specific enough to provide acceptance criteria for design verification later on. Design Verification and Validation will be blogged later.

Of course, all design input requirements are documented systematically, chronologically and logically. Examples of design input documents are engineering data sheets, drawings, photographs, samples, intended use of the device, performance characteristics, prototypes, product’s computer software, electrical specification, IFU etc.   

All the design input requirement needed to be captured systematically into Product Requirement Document (PRD). Examples of design input are shown below:

·       Intended use and indications for use. This is very critical of the factor of design input, many of the testing, verification, validation and device classification will be predicated on the intended use.

·       User / patient / clinical characteristics. What can the device do in a clinical settings like disease diagnosis or treat a disease.

·       Physical / chemical characteristics. Length, weight, size, what materials.

·       Limits and tolerances.

·       Performance characteristics. What can this device do to the patients and diseases?

·       Risk analysis: What method deployed? Top Down and Bottom Up. FMEA, FTA etc.

·       Product safety. A detail description of the safety. Safety should be mentioned in the IFU and labeled on the product.

·       Toxicity and biocompatibility. Materials may have some biocompatibility issue if have contact with human tissue. Sponsor should choose a material as biocompatibility with human tissue if possible.

·       Electromagnetic compatibility. When the product is used in a hospital setting, what effect of the device with the environment.

·       Compatibility with accessories and auxiliary devices

·       Compatibility with the environment of intended use. Here the working environment shall be established like relative humidity, temperature etc.

·       Human factors. How well any user use the device.

·       Labeling / packaging. Sample of labeling like IFU.

·       Voluntary industry standards like IEC 60601 etc.

·       Manufacturing processes: How to make this device?

·       Sterility: How this product is sterilized? Gamma or E-beam.

Another key concept is Traceability Matrix, all design inputs or in fact any things change or happen to the development of the device will be traced in the matrix. There are a lot of changes in the life-cycle of the medical device, therefore, the traceability matrix must be updated diligently. 

Of course, all the design requirements must be documented, reviewed and approved by designated personnel. It is prudent to involve all R&D, engineering, regulatory, chemist and even marketers so they are on board early on to give design input. Needless to say, these design input documents requirement must be approval with date and signatures.

Reference	Criteria
21 CFR 820.30(c)	Has the company established and maintained procedures to ensure that the design requirements relating to a device are appropriate and address the intended use of the device, including the needs of the user and patient?
21 CFR 820.30(c)	Do the procedures include a mechanism for addressing incomplete, ambiguous, or conflicting requirements?
21 CFR 820.30(c)	Are the design requirements documented, reviewed, and approved by a designated individual?
21 CFR 820.30(c)	Is the approval, including the date and signature of the individual(s) approving the requirements documented?

Disclaimer: Although the author had exhaustively researched all sources to ensure the accuracy and completeness of the information contained in this blog, but no warranty and fitness is implied. I assumed no responsibility and implied warranty of any kind for errors, inaccuracies, omission, or any inconsistency herein. No liability is assumed for incidental or consequential damages in connection with the use of the information contained herein. Readers should always use their own judgment and review all related regulatory guidelines. Guidelines can change over time.