Monday 28 June 2021

Three Times And We’re Alright? Replicates In Validation

Numbers are essential to validation, just as numbers are critical to much of human activity. Numbers represent the continuous variables that we use to describe the world. Numbers can be something directly observable, or they can be theoretical constructs, used as parameters within a model. While both play a part in ‘validation’, it is with the former that this article toys with. The issue at hand is with how much validation is required at the performance qualification stage for a given validation stage? This may be a cleaning cycle on a vessel or an autoclave load.

How many times should such validation exercises be conducted in order to show that the results are reliable? While the number of runs should rest with the outcome of a risk assessment, it is generally the rule that the number of runs is seldom less than three. This begs two questions: why is three considered acceptable?, and is three enough? Before entering this debate it is interesting to consider what is so special about the number 3. After this, this article looks at the issue from the process validation perspective and the analytical assay perspective, concluding that three runs or assays is rarely enough. Moreover, with process validation greater weight should be put onto the lifecycle approach for trending and hence understanding process performance.


To view see: ResearchGate

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (

No comments:

Post a Comment

Pharmaceutical Microbiology Resources

Special offers