The most important document in a Design History File (DHF) should also be the first document you create when you are developing a new medical device–the design plan. However, I find a number of companies that are preparing to submit regulatory submissions with missing elements of the DHF. The primary reason for this is that the design plan was either never created or was not updated.

In theory you can create a design plan and any other missing documents from your DHF retroactively, but that only helps you with compliance during an FDA inspection. The purpose of a design plan is to make sure that you conduct all the necessary steps required to design and develop a medical device, and to make sure that you have adequate resources. For example, how did you make sure that all the required tests were performed that are required for a 510(k) submission?

Verification tests are the tests you perform prior to a 510(k) submission in order to make sure that your design outputs (also known as drawings and specifications) meet the design inputs. Both the outputs and the inputs must be reviewed and approved. Ideally, every requirement you document in a drawing or material specification should have a purpose and the purpose is to ensure that the medical device will pass your verification testing. For example, you might specify a specific brand and quantity of adhesive to be applied to two plastic parts in order to bond them together. The purpose (i.e., “User Need”) is to ensure that the product is biocompatible and the adhesive bond is strong enough that it won’t break during use.

Biocompatibility should have a specific set of design inputs based upon a recognized standard–ISO 10993-1. Compatibility with the manufacturing process is verified by performing process validation. There should be a protocol and report for the cleaning validation and for the steam sterilization. Steam sterilization also has a recognized standard–ISO 17665. You also need to make sure the final assembly is strong enough. This could be done several ways. Ideally, you will use a combination of design verification and design validation. If appropriate, you might use an ASTM standard for a tensile test to verify the assembly is strong enough. The ASTM standard would be a design input, and the testing would be design verification. You might also test the device in simulated use. In this case, you would write a protocol for design validation.

Your initial design plan might only specify that you will have four design reviews: 1) review and approval of design inputs, 2) review and approval of design outputs (i.e., design freeze), 3) review and approval of verification/validation testing for your 510(k) submission, and 4) review and approval of product launch–pending 510(k) clearance. As your project progresses, you need to update your design plan. You need to identify and document potential hazards–a required element of a risk management file. You need to use these potential hazards as inputs into your design process, by identifying design inputs to verify that each potential hazard has been evaluated.

Unfortunately, if you wait until after you submit your 510(k) to write your design plan then you may not have all the required tests identified. If you forgot to test for the strength of an adhesive bond between two parts during design verification and validation, the best-case scenario is that the FDA reviewer will place your 510(k) submission on hold and request testing data. The worst-case scenario is that your product will malfunction in the field and you will have to recall product, redesign the product and submit a new 510(k) for the device modification.

source: https://www.linkedin.com/groups/2070960/2070960-6181154504566677507