ICH Q1C - Stability Testing for New Dosage Forms

What it says

When an already-approved drug substance is formulated into a new dosage form, a reduced but scientifically justified stability data package may be acceptable at the time of submission, building on existing knowledge of the drug substance while still addressing stability considerations specific to the new dosage form, as a complement to the full stability program described in ICH Q1A(R2).

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

What it means in practice

• This guideline exists because requiring a full ICH Q1A(R2)-scale stability program for every new dosage form of an already well-characterized drug substance would be disproportionate to the actual uncertainty involved, so it defines where a reduced package is scientifically justified.
• The reduction in required data applies to confirming already-understood drug substance behavior, not to dosage-form-specific stability concerns, such as a new excipient interaction or a different container-closure system, which still need their own supporting data.
• A company relying on this guideline's reduced data package still needs a clear, documented rationale connecting what is already known about the drug substance to what can be safely assumed about the new dosage form.

What inspectors look for

• Whether the reduced stability data package relied on for a new dosage form is accompanied by a documented scientific justification connecting it to existing drug substance knowledge.
• Whether dosage-form-specific stability concerns, such as new excipients or packaging, were still adequately addressed despite the reduced overall package.
• Whether post-approval changes to the new dosage form were evaluated against the stability data actually submitted, not assumed covered by the original drug substance's history.

Related regulations