Shelf-Life
Assessment

Shelf life is the period during which a peptide product remains within its quality specifications when stored under defined conditions. Establishing shelf life requires two complementary types of stability data: real-time and accelerated. Real-time stability studies store the product at its intended storage condition—typically 2–8 °C for liquid formulations or −20 °C for lyophilized products—and test at intervals over months to years. This data is the gold standard for shelf-life assignment because it directly measures degradation under actual use conditions.

Accelerated stability studies, conducted at elevated temperature and humidity (commonly 25 °C / 60% RH and 40 °C / 75% RH), generate degradation data faster but require extrapolation to predict real-time behavior. The Arrhenius equation provides the theoretical basis for this extrapolation, but it assumes that the degradation mechanism does not change between temperatures—an assumption that must be verified, not assumed. When accelerated data and real-time data are consistent, the accelerated data supports earlier shelf-life claims. When they diverge, real-time data takes precedence.

The shelf life is set at the point where the lower 95% confidence limit of the stability trend line intersects the acceptance criterion for the most stability-limiting attribute. In practice, this means plotting purity (or potency, or aggregate content) versus time, fitting a regression line, and determining where the product is statistically expected to fall outside specification. For peptides, the most common shelf-life-limiting attributes are chemical purity (due to deamidation, oxidation, or hydrolysis) and aggregation.

During early development, shelf life may be assigned based on available real-time data (e.g., 6 months of real-time data supports a 6-month shelf life) with the expectation that it will be extended as additional data accumulates. ICH Q1E provides guidance on statistical approaches for shelf-life estimation, including when and how to extrapolate beyond the observed data range. For most peptide programs, a 12-month real-time study at the intended storage condition provides sufficient data to support initial clinical supply and IND-enabling toxicology studies.

Stability data directly determines the labeled storage condition. A lyophilized peptide that remains within specification at 25 °C / 60% RH for 6 months can be labeled for room temperature storage—a significant advantage for distribution and patient convenience. A peptide that degrades at 25 °C but is stable at 2–8 °C requires refrigerated storage and cold chain distribution. In some cases, stability data reveals that the product requires frozen storage (−20 °C or below), which increases distribution complexity but may be necessary for inherently unstable sequences. The stability program should test at least two storage conditions so you can make an informed recommendation rather than defaulting to the most conservative option.