Test cases

Can someone please tell me how many times each test case should be executed as part of validation? Typically three times to see repeatability? Or just one time execution. Some kind of regulatory guidelines reference will help.

It really depends on the type of test. If, for example, you’re verifying a certain software requirement is met, running a test 3x won’t give you any information. If you’re running a process that could vary based on different factors, then multiple executions are warranted.

I don’t know of any regulation or guidance (maybe GAMP has something?) but 3x does seem to be the de facto standard when multiple executions are performed.

Generally what I’ve seen (and there are plenty of valid reasons where this could deviate) is IQ and OQ are single pass and PQ is done over 3 passes (each for whatever configuration is done).

There are a lot of factors involved in that decision, and not a lot of hard and fast rules. The most important thing here is to thoroughly understand what you are testing and why you are testing it. If you have that understanding, you will know if, and how many times you need to repeat a test.

What is it that you are trying to validate? I strongly suggest you go to the appropriate guidance document published by FDA; it will go a long way toward helping you understand what you need to do.