ICH Q1 (2025): Understanding the Shift in Pharmaceutical Stability Testing
ICH Q1, From Standard Testing to Stability Strategy Design
The release of the ICH Q1 Draft Guideline (Step 2b) introduces a significant transformation in pharmaceutical stability testing. While previous guidelines provided a robust regulatory framework, they were based on a more prescriptive and fragmented approach.
The new ICH Q1 (2025) introduces a science-based, risk-driven stability strategy, aligned with modern pharmaceutical development. As of March 2026, with the public consultation phase completed, these principles represent the current scientific thinking of regulatory authorities.
A Structural Change: Consolidation & Expansion
One of the most visible changes is the consolidation of the entire Q1 series (Q1A–F) together with Q5C into a single guideline. This reflects the need to address a broader range of products, including:
- Small molecules
- Biologics
- Vaccines
- ATMPs
- Combination products
This unified framework promotes harmonisation and reduces regulatory complexity.
Enhanced Approach: from Fixed Protocols to Scientific Strategy
The new ICH introduces an “Enhanced Approach” moving away from predefined study designs. Stability studies must now be:
- Risk-based and aligned with product-specific characteristics
- Scientifically justified and linked to Critical Quality Attributes (CQAs)
- Integrated with Quality by Design (QbD) principles (ICH Q8, Q9, Q10)
Stability Across the Product Lifecycle
The new guideline integrates stability into the entire lifecycle, supporting:
- Development decisions
- Shelf-life justification
- Post-approval changes
This lifecycle perspective aligns stability with ICH Q12 and strengthens predictive stability strategies.
Expanded Scope of Stability Studies
The new guideline reinforces:
- In-use stability, particularly relevant for complex formulations
- Short-term and transport-related conditions
- Processing and holding time studies
- Stability of reference materials and excipients
This expansion reflects a more realistic view of how products behave in real-world conditions and across the supply chain.
Predictive Stability & Modelling
The new ICH Q1 strengthens statistical modelling and extrapolation, allowing:
- Earlier shelf-life estimation
- Reduced development timelines
- Cost optimisation
- Improved decision-making
Why this Matters: From Compliance to Understanding
Taken together, these changes redefine the purpose of stability studies. The objective of stability studies is no longer limited to demonstrating compliance.
It is to understand how a product evolves, under different conditions, and throughout its lifecycle. This understanding becomes essential to:
- Reduce development risks
- Support regulatory interactions
- Ensure product quality and patient safety
ICH Q1: Supporting your Stability Strategy
Adapting to the new ICH Q1 (2025) framework requires both technical capabilities and strategic thinking. Mérieux NutriSciences | Pharma & Healthcare provides integrated stability and storage solutions, supporting:
- Strategic stability study design: long-term, accelerated, and customised stability studies
- Specialized testing capabilities: photostability, in-use stability, and transport simulation
- Controlled storage infrastructure: controlled storage environments compliant with ICH conditions
- Regulatory-ready data generation: high-quality data generation aligned with regulatory expectations and data integrity standards.
