Drug Substance Impurity Strategy

Drug substance impurity strategy establishes systematic approaches for identification, quantification, and control of manufacturing-related and degradation impurities within active pharmaceutical ingredients. Analytical method development detects specified impurities at ICH concentration thresholds. Unspecified impurity limits establish maximum acceptable levels for unknown contaminants. Stress testing generates representative impurity profiles predicting stability-related contamination.

Risk-based approaches prioritise investigation of potentially genotoxic or pharmacologically active impurities. Manufacturing process optimisation minimises impurity formation at source. Specification limits balance analytical detection capability against product safety requirements. Regulatory submissions justify impurity control strategies and specification appropriateness. Post-approval monitoring detects emerging impurities warranting enhanced investigation. Supplier qualification programmes ensure raw materials meet purity standards preventing downstream contamination.