Validation of Related-Substances Determination Methods for Detecting Unidentified Substances (A Review)

The review justifies the need to validate the linearity, relative accuracy, and precision of Related Substances methods for detecting unidentified substances. Various approaches and methods for the estimation of linearity, precision, relative accuracy, and other validation characteristics for unidentified impurities are considered. The conditions necessary for the correct application of these approaches are discussed. The term “main unidentified impurities” is proposed and justified for assessing the validation results. Acceptance criteria, examples, and recommendations are provided.