⏱️ Stability Science
Stability Shelf Life Estimator
Use Arrhenius kinetics to predict pharmaceutical shelf life at ICH long-term conditions (25°C / 60% RH). Enter degradation rate constants from accelerated stability studies at elevated temperatures to extrapolate.
Degradation Rate Data
% degradation that defines end of shelf life (e.g. 5% loss of API)
First-order: ln(k) linear with 1/T. Zero-order: k directly linear with 1/T.
Accelerated Study Temperatures
Temperature (°C)
Rate constant k (day⁻¹)
Temperature (°C)
Rate constant k (day⁻¹)
Temperature (°C)
Rate constant k (day⁻¹)
ICH Zone I/II long-term: 25°C; Zone III/IV: 30°C; Refrigerator: 5°C
ICH Climatic Zones
Zone I/II (Long-Term)
25°C / 60% RH
Zone I/II (Accelerated)
40°C / 75% RH
Zone III/IVb (Long-Term)
30°C / 65–75% RH
Refrigerator
5°C ± 3°C
Arrhenius Equation: k(T) = A · e^(−Ea/RT)
Linearised: ln(k) = ln(A) − Ea/R · (1/T)
R = 8.314 J·mol⁻¹·K⁻¹
Reference: ICH Q1E Evaluation for Stability Data; Laidler KJ, Chemical Kinetics (1987)
Linearised: ln(k) = ln(A) − Ea/R · (1/T)
R = 8.314 J·mol⁻¹·K⁻¹
Reference: ICH Q1E Evaluation for Stability Data; Laidler KJ, Chemical Kinetics (1987)
Shelf Life Prediction
Enter degradation rate data to estimate shelf life