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www.fdanews.com/articles/159777-us-bioanalytical-methods-guidance-defines-three-levels-of-validation

U.S. Bioanalytical Methods Guidance Defines Three Levels of Validation

October 24, 2013
A U.S. Food and Drug Administration draft guidance on validating bioanalytical methods for evaluating drugs, their metabolites and biomarkers — techniques the agency calls “critical” for conducting successful clinical and nonclinical pharmacology studies — has been revised 12 years after it was first issued.
International Pharmaceutical Regulatory Monitor