The most recent FDA Guidance on Process Validation changes the traditional three validation batch approach. One batch okay was lucky, two batches a fluke & three batches a trend. Anyone involved in manufacturing questioned this as the requirement for three consecutive batches meant there was a very narrow window used in the study i.e. less variation in supplier performance, machine factors etc. But three batches used in process validation studies gave some assurance and was achievable in a short time frame. Now we are looking at a statistically valid run number. The challenge is what number of batches is this & when can a validation study be closed. I think we will be using a combination of three batches, annual product review & continual process verification at least where process variability is well defined. This will be harder to determine where biological processes are involved or new innovative technologies. I guess we are saying validation is continuous as we were always checking that we remained in a validated state!
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