What parameters are evaluated during analytical method validation for biologics?

Analytical method validation demonstrates method fitness for intended purpose per ICH Q2 guidelines. Parameters include: 1) Specificity/selectivity - ability to detect analyte in presence of other components; stress studies, placebo interference. 2) Accuracy - closeness to true value; spike recovery or comparison to reference method. 3) Precision - repeatability (same conditions), intermediate precision (different days/analysts/equipment), reproducibility (different labs). 4) Linearity - proportional response across concentration range; regression analysis, residual plots. 5) Range - interval with acceptable accuracy and precision. 6) Limit of detection (LOD) and quantitation (LOQ) - for impurity methods. 7) Robustness - response to small deliberate variations in parameters. Additional for biologics: stability-indicating nature (detect degradants), system suitability criteria, and reference standard qualification. Method transfer validated when transferring between labs. Lifecycle approach includes continuous verification.