1. ICH guideline Q3A, Impurities Testing Guideline: Impurities in New Drug Substances, CPMP/ICH/2737/99.
2. ICH guideline Q3B, Impurities in New Drug Products, CPMP/ICH/2738/99.
3. ICH guideline Q6A, Specifications: Test Procedures and Acceptance Criteria for New Drug Substances and New Drug Products: Chemical substances.
4. European Pharmacopoeia, 5th ed., Council of Europe, Strasbourg, France, 2004, p. 40.