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Q1 Stability Testing of Drug Substances and Drug Products: Draft Guidance for Industry

DraftCenter for Drug Evaluation and Research Center for Biologics Evaluation and Research06/23/2025
Good Guidance PracticeGMPCAPAGMPsPQSPharmaceutical Quality SystemQuality Management SystemMicrobial control strategyGood distribution practicesGood manufacturing practicesProduct Lifecycle ManagementRisk ManagementQuality by DesignCritical Quality AttributesQuality Risk Management

Description

The Food and Drug Administration (FDA or Agency) is announcing the availability of a draft guidance for industry entitled “Q1 Stability Testing of Drug Substances and Drug Products.” The draft guidance was prepared under the auspices of the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). The draft guidance outlines stability data expectations for drug substances and drug products to support drug product marketing, including marketing authorization applications and, where applicable, drug master files. This draft guidance is a consolidated revision of the ICH Q1A(R2), Q1B, Q1C, Q1D, Q1E, and Q5C series of stability guidances, published November 2003, March 1996, May 1997, January 2003, June 2004, and July 1996, respectively. The revision also provides stability related guidance for product categories such as advanced therapy medicinal products, vaccines, and other complex biological products including combination products that were not previously covered under the existing stability guidances. The draft guidance is intended to provide an internationally harmonized approach to conducting and presenting data on stability testing for drug substances and drug products, as well as providing alternative, scientifically justified approaches that may be encountered due to scientific considerations and characteristics of the data being evaluated.

Key Topics

Terms and concepts identified from this document

Scope & Applicability

Product Classes

10
Drug Substances

Scope of the analytical procedures

Tissue-Engineered Products

ATMPs involving structural or functional tissue repair.

Somatic Cell Therapy

A category of ATMPs involving cell-based products.

Gene Therapy

A type of ATMP involving recombinant nucleic acids or viral vectors.

Solid synthetic chemical drug substance

May obey humidity modified Arrhenius equation

Synthetic Solid Oral Tablet

Example 1 – Reduction from Primary Stability Study to the Commitment Study

ATMP

Advanced Therapy Medicinal Products

Biological Products

Requires analytical comparability per ICH Q5E

Biological drug substance

Extrapolation rules for well characterised biologicals; Less amenable to modelling by humidity modified Arrhenius equation

Synthetic Chemical Entity Drug Substances

Decision tree for data evaluation and shelf life estimation

Stakeholders

3
Applicant

Entity submitting development data and knowledge; Entity performing the work process for change

Regulators

Early engagement recommended for novel model types

Competent authority

Regulatory body receiving proposed actions

Regulatory Context

Regulatory Activities

8
Marketing Application

Submission for product approval

Marketing Authorisation

Introduction of reduced protocols after original approval.

Post-approval Change

Changes to manufacturing or product after initial approval; risk-based reduced protocol is used to support a post-approval change

Commitment stability studies

Studies conducted post-approval to confirm shelf life

Initial Regulatory Submission

The first filing of stability data for approval

Regulatory Submission

Stability package provided to support re-test period or shelf life; Initial filing requiring stability data; Initial filing where photostability information is required; Stability data provided with the regulatory submission; Where stability models and risk management descriptions are provided

Post-approval changes

Stability studies required to support PACs.

Regulatory submissions

FDA generally recommends that qualitative data are coded for these submissions

Document Types

5
Stability Protocol

Protocol design for formal stability studies; Incorporates information to establish re-test period or shelf life; Design and execution of a stability protocol to support formal studies; Design for supporting drug substance or drug product shelf life; Design of the stability study including frequency and conditions; Written protocol for holding time studies; Design of in-use stability study protocols; Reduced Stability Protocol Design discussed in Annex 1; Including intermediate storage condition

Commitment Study

Reduction from Primary Stability Study to the Commitment Study

Marketing application

Submission containing stability data

Master files

Applicable to regulatory submissions.

Regulatory Submission

Where stability protocol summaries and data are provided; Document where stability data and justifications are provided

Attributes

10
Shelf Life

Determined based on stability data; Established through stability testing; also called dating period.; Established through formal stability studies; Establishing the period during which a drug product is expected to remain within specifications; Period for drug products; The period during which a drug product is expected to remain within specifications; Duration product remains within acceptance criteria; Period during which product remains within specifications; Established for intermediates pu

Stability Profile

The measured changes of quality attributes over time

Purity

specifications for the purity, strength, and composition of dietary supplements

Water Activity

Lack of change to water activity

Moisture Vapour Transmission Rate

supporting data could be supplied showing relative moisture vapour transmission rates

Climatic zone

Environmental condition determining storage statements

pH

Intrinsic characteristic affecting the growth of L. monocytogenes; intrinsic characteristic used as a process control; parameter to monitor for control; Process control parameters such as pH; Used to define listeristatic formulations

Assay

Significant change defined as 5% change from initial value

Degradation kinetics

Complex and decelerating profiles like biphasic degradation

Zero-order kinetics

Assumed for certain quantitative chemical attributes during storage

Technical Details

Substances

10
Excipients

Differences in excipients may affect product stability

Autologous CAR-T cells

Patient-specific cellular ATMPs

Viral Vectors

Used in gene therapy products to modify cells.; Used to modify cells ex vivo

Active Pharmaceutical Ingredients

Subject of WHO stability testing guidelines.

Impurity

Any component of the drug substance or drug product which is not the active ingredient or excipient

Degradation Product

Molecular variants or impurities resulting from chemical or biochemical changes; Shelf Life Estimation Based on a Degradation Product

Degradation Products

Failure to meet specification constitutes significant change

IgG therapeutic monoclonal antibody

Example of biological drug substance where re-test period may apply

Reference Materials

used in the analytical procedure and SST

Adjuvants

Stability of the adjuvant should be assessed by formal stability studies

Testing Methods

10
Linear Regression

Plotting the results and using the slope to represent beta results in the following graphs.

Infectious titre

Stability-indicating CQA for viral drug products

Cell Viability Assays

Used to evaluate potency for cell-based products.

Orthogonal Assays

Used to mitigate uncertainty in stability CQAs due to high assay variability.

Artificial Intelligence Machine Learning

Novel model types likely to emerge

Bayesian statistics

Alternative to Frequentist statistics for evaluating prior knowledge

Arrhenius equation

Used for thermo-kinetic reactions in stability data fit

Mixed Effects Model

chosen when five or more batches are available

Fixed Effects Model

chosen when limited batches are available

Analysis of Covariance

ANCOVA used to evaluate attribute stability profile

Processes

10
Stability Testing

Primary process described in the guideline; Core activity described in the guidance; General process for evaluating product quality over time; Formal stability studies to assess adjuvant stability; Evaluation of attributes at all storage conditions; The process of evaluating product quality over time under specified conditions.; Evaluation of product quality over time

Accelerated Stability Testing

Studies designed to increase the rate of chemical degradation or physical change using exaggerated storage conditions.

Manufacturing processes

Characteristic evaluated for prior knowledge molecule grouping

Long-term stability studies

Primary studies that models are not intended to replace

Stress Studies

Studies undertaken to assess the effect of severe conditions on the drug substance or product

Long-term Testing

Stability studies under the recommended long-term storage condition

Accelerated Studies

Testing conducted under conditions intended to increase the rate of physical, chemical and/or biochemical change

Manufacturing Process Change

A change that may potentially impact the stability profile

Transport simulation studies

Used to evaluate effects of excursions

Stability Modelling

Practice of using a known data set to infer information about future data; Enhanced techniques for extrapolation; Annex 2 Stability Modelling; scientific and regulatory considerations for enhanced stability model development; The use of mathematical models to predict stability profiles

Identified Hazards

Hazards

8
Microbiological Contamination

Environmental factors affecting biological products

Degradation Profile

The description of degradation products observed during stability studies.

Leachables

prior knowledge from product development, e.g., on leachables

Freezing and thawing

Environmental stress impacting biological molecules

Photochemical Degradation

Degradants likely to arise from light exposure

Photodegradation

Risk identified during photostability studies

Water Loss

Potential concern for aqueous-based products in semi-permeable containers

Degradation pathways

Important for developing suitable analytical procedures; Essential to establish via stress testing

Standards & References

Specifications

5
Acceptance Criteria

limits for solid state form and particle size; Tightening acceptance criteria; Numerical limits or ranges for tests

Registration release specification

Batches must meet these criteria for registration

Release specification

May be more stringent than shelf life specification

Shelf life acceptance criteria

Criteria to ensure quality through the end of shelf life

CQAs

Critical Quality Attributes monitored during stability testing

ICH References (10)

ICH Q1

Stability Testing of Drug Substances and Drug Products; Consolidated revision that supersedes ICH Q1A-F and Q5C guidelines.; Stability testing of drug substances and drug products; Stability studies for drug substances and drug products; Main guideline for stability studies of drug substances and drug products; Main guideline for stability studies of drug substances and products; Core guideline for stability studies of drug substances and drug products.; Stability Studies for Drug Substances and

ICH Q5D

Recommendations for cell bank stability

ICH Q9

Quality Risk Management recommended for combination products

ICH Q7

Good Manufacturing Practice Guidance for Active Pharmaceutical Ingredients; Reworking needs more evaluation and testing according to ICH Q7; Good manufacturing practice for API starting materials; Referenced regarding the definition of intermediates.

ICH M4Q

The CTD — Quality

ICH Q10

Pharmaceutical Quality System

ICH Q13

Referenced for continuous manufacturing and pilot batch definitions; Guideline for continuous manufacturing batch selection; Referenced for Continuous Manufacturing (CM); Continuous Manufacturing.

ICH Q5E

Comparability of Biotechnological/Biological Products Subject to Changes in Their Manufacturing Process

ICH Q3E

Extractables and leachables considerations

ICH Q3D

Elemental impurities and interaction with storage containers

Related MFDS Guidelines

Korean regulatory guidelines covering similar topics

See Also (8)