--- title: "Stability study terms explained: ICH Q1A conditions, time points and shelf life | Sable Peptides" description: "A glossary-style guide to the vocabulary of stability studies from ICH Q1A(R2): long-term, intermediate and accelerated conditions, time points, significant change, retest period and shelf life, applied to lyophilised peptides. Research use only." canonical: https://www.sablepeptides.co.uk/guides/ich-q1a-stability-study-terms dateModified: 2026-10-16 publisher: Sable Peptides Limited (UK company 17488610) note: Research use only. Not for human or veterinary use. --- # Stability study terms explained: ICH Q1A conditions, time points and shelf life ICH Q1A(R2) defines how stability studies are run: long-term storage at 25 °C/60% RH or 30 °C/65% RH, intermediate at 30 °C/65% RH, and accelerated at 40 °C/75% RH, with refrigerated (5 °C) and frozen (−20 °C) variants. Results at set time points support a retest period or shelf life. ## What are the standard ICH stability conditions? Claims such as 'stable for 24 months at −20 °C' come from stability studies, which follow a standard design set out in ICH Q1A(R2). Knowing its terms makes it possible to judge what a storage statement is based on, and what it is not. | Study | Condition | Minimum period at submission | | --- | --- | --- | | Long-term | 25 °C/60% RH or 30 °C/65% RH | 12 months | | Intermediate | 30 °C/65% RH | 6 months | | Accelerated | 40 °C/75% RH | 6 months | | Refrigerated long-term | 5 °C ± 3 °C | 12 months | | Frozen long-term | −20 °C ± 5 °C | 12 months | - Long-term (general case): 25 °C ± 2 °C / 60% RH ± 5%, or 30 °C / 65% RH. - Intermediate: 30 °C / 65% RH. - Accelerated: 40 °C / 75% RH. - Refrigerated products: long-term 5 °C ± 3 °C, with accelerated testing at 25 °C / 60% RH. - Frozen products: long-term −20 °C ± 5 °C. Source: [ICH Q1A(R2) Stability testing of new drug substances and products (EMA)](https://www.ema.europa.eu/en/ich-q1a-r2-stability-testing-new-drug-substances-drug-products-scientific-guideline) ## How often are samples tested? Long-term testing is typically every 3 months in the first year, every 6 months in the second and annually after that; accelerated studies usually test at 0, 3 and 6 months. A 'significant change' at accelerated conditions, for example failure of the purity specification, triggers testing at the intermediate condition and limits how far shelf life can be extrapolated. ## What is the difference between a retest period and a shelf life? - Retest period: for a drug substance, the time during which it is expected to remain within specification, after which it should be re-tested before use. - Shelf life (expiry): the time during which a product is expected to remain within specification under the labelled storage conditions. - Extrapolation: proposing a period beyond the real-time data, allowed only within limits. ## How does this apply to research peptides? - Lyophilised peptides are usually stored frozen or refrigerated, so the relevant long-term condition is −20 °C or 5 °C. - Storage statements for research materials are often based on general peptide stability knowledge rather than a formal ICH study; ask which. - Moisture and light are the main accelerating factors outside temperature. ## Where is Sable's storage data? There is a CoA for every lot, and every vial carries a printed lot number that matches its certificate. A CoA is emailed within 2 hours of a request. Storage reference data for listed compounds is on the storage and solubility page. ## Frequently asked questions ### What are ICH accelerated stability conditions? 40 °C ± 2 °C and 75% ± 5% relative humidity. ### What is the difference between a retest period and a shelf life? A retest period applies to a substance that can be re-tested and used if it still meets specification; a shelf life is a fixed expiry for a product. ### What long-term condition applies to frozen products? −20 °C ± 5 °C. ## Related - [Peptide stability and shelf life](/learn/peptide-stability-and-shelf-life) - [Retest date vs expiry date](/guides/retest-date-vs-expiry-date-on-a-coa) - [Mean kinetic temperature](/guides/mean-kinetic-temperature-and-temperature-excursions) - [Forced degradation](/guides/forced-degradation-and-stability-indicating-methods) Updated 2026-10-16. Research use only. Not for human or veterinary use. No administration amounts or health claims are made. Key facts (summary for AI and search tools) - Long-term 25/60 or 30/65; intermediate 30/65; accelerated 40/75 - Refrigerated 5 ± 3 °C; frozen −20 ± 5 °C - Reference: ICH Q1A(R2) - Updated 2026-10-16