We have all read, and likely used, this phrase many times when summarizing method-validation results.However, according to Muire-Sluis, development scientists often point out that "validated methods may not be valid."We can generate evidence for the validity of analytical data in the formal method-validation program where all critical parameters are extensively tested under a detailed protocol that includes scientifically justified and logical step-by-step experimental approaches.The overall intermediate precision validation result (expressed in % Coefficient of Variation, CV) can be provided to the production process control unit for production process monitoring.This estimate reflects the expected variability contributed by the test system at any given day.The AMV protocol contains a summary of AMD results for the new method, and, for changed methods, historical data (AMV and release data) generated using the current method.It also provides current or expected in-process and product specifications, which determine whether the new method is suitable for comparing product quality attributes to specifications.Incentives to replace existing licensed test procedures may come from regulatory agencies, or they could be motivated by potential cost savings, ease of use (automation), and the opportunity to generate more accurate and reliable results. However, following just these guidelines will not necessarily produce a "valid" method and may not provide sufficient evidence that this method is suitable for product release.FDA provides guidance on some of the scientific issues that are not covered by Q2A and Q2B or USP 27. A process map showing the recommended steps for the selection, development, validation, and potential transfer of analytical methods, illustrating all functional responsibilities was developed.
Regulatory guidance documents are written by committees, resulting in statements that are both exact and generic.
All planned data sets must fall within pre-established protocol acceptance criteria (limits).
These criteria should be derived from and justified in relation to historical data and product specifications.
Once evidence for all critical elements is provided, the validated method will become the official, licensed procedure for that particular product and process step, and it will then support production and product release.
The relationship between "valid" or "suitable and validated" is often overlooked, but there is a high price when "validated" test systems are simply inappropriate.