A review.Monitoring chem. processes for the formation of an active pharmaceutical ingredient is the first step to ensuring quality in pharmaceutical manufacturingHaving reliable and reproducible methods will enable the production plant to guarantee the consistency of drugs batch after batch.In addition, it may simplify the characterization of such processes and their chem. profile.Various guidelines have been published to shed light on anal. method validation.However, no guidances about the validation of in-process control methods have been described.Therefore, a strategy for classifying and validating in-process testing methods is proposed, with a goal of providing a foundation for assessing the parameters and acceptance criteria needed for validation.