ICH Q6A - Specifications: Test Procedures and Acceptance Criteria for New Drug Substances and Products

What it says

Specifications for new drug substances and products should be established based on relevant development, stability and clinical data, distinguishing universal tests applicable to essentially all products, such as description and assay, from specific tests applicable based on the particular dosage form or route of administration.

Paraphrased for plain-language clarity. Always verify against the current published regulation text.

What it means in practice

• This guideline provides the foundational logic for what a specification actually should contain and why, connecting directly to the specification-setting decisions that ICH Q2(R2) validated methods and ICH Q3A/Q3B impurity limits ultimately support.
• The distinction between universal and specific tests means specification content should be tailored to what a particular dosage form and route of administration genuinely require, rather than applying an identical generic test panel across fundamentally different product types.
• Specification acceptance criteria should be justified by actual development, clinical and stability data, meaning the criteria reflect a genuine, defensible link to product safety and efficacy rather than being set arbitrarily tight or loose.

What inspectors look for

• Whether specification acceptance criteria are supported by documented development, clinical or stability data providing genuine justification for the specific limits chosen.
• Whether the specification test panel appropriately reflects the product's specific dosage form and route of administration, rather than a generic, undifferentiated approach.
• Whether specifications are periodically reviewed and updated as additional manufacturing experience and data accumulate over a product's lifecycle.

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