Storage stability

How well a compound retains its identity and purity over time under stated conditions — a property of temperature, moisture, light and form, not a single shelf-life number.

Stability is the persistence of a compound's identity and purity over time, and it is always relative to conditions: the same peptide can be stable for years as a sealed lyophilised solid in a freezer and measurably degraded within weeks in warm solution. Statements about shelf life are therefore only meaningful with their conditions attached — temperature, light exposure, moisture, and whether the material is dry or in solution.

The chief degradation pathways for peptides — hydrolysis, deamidation, oxidation, aggregation — all accelerate with temperature and, except for oxidation, depend on water. That is why the dry solid is the stable form, why cold storage extends every window, and why a certificate's purity figure describes the test date rather than any later moment: stability determines how far the material may have moved since.

Degradation is gradual rather than binary. A stored compound does not switch from good to spoiled; its purity declines and its degradation products accumulate at rates the conditions set. The stability guide covers the mechanisms and the condition-by-condition behaviour; this entry defines the property those pages measure against.

SourceEMA — ICH Q1A(R2): stability testing of new drug substances and products

For research purposes only. Not for human consumption, diagnosis, treatment, or prevention of any condition. Nothing on this page is medical advice.