ICH Q7 - Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients 12.8: Validate analytical methods (or verify compendial ones under actual use) per the ICH validation guidelines, qualify analytical equipment first and record any method modification with supporting data

What does 12.8 require?

Analytical methods should be validated unless they appear in the relevant pharmacopoeia or another recognised standard reference, and every method's suitability should still be verified and documented under actual conditions of use. Validation should consider the characteristics in the ICH guidelines on analytical method validation, to a degree matching why the analysis is run and how far along production the material is. Analytical equipment should be suitably qualified before method validation starts. Complete records of any modification to a validated method should give the reason and data showing the changed method gives results as accurate and reliable as the original.