Paste the study results at two or more temperatures. The calculator fits the degradation rate, carries it to the storage temperature with Arrhenius or Q10 and estimates how long the product takes to reach the specification limit.
Pre-sizing and estimating tool: results do not replace design, calculations or reports signed by a licensed professional, nor verification against the applicable codes and standards.
Measured points, curves fitted with the chosen order and the specification limit.
ln k versus 1000/T, with the line extended to the storage temperature and the conservative limit.
Fit at each temperature and time to the limit there.
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How long a product takes to reach its specification limit when stored at a given temperature, based on an accelerated study at higher temperatures. It helps screen formulations, plan the long-term study and set a provisional date, not register the product. In the example, with data at 104, 122 and 140 °F, assay takes about 30 months to drop from 100% to 90% at 77 °F, or 27 months on the conservative estimate.
One line per test: temperature, time and result. Use at least three temperatures, such as 104, 122 and 140 °F (40, 50 and 60 °C), with time zero and three or four more time points at each, up to a 10% to 20% loss at the hottest one. Test all samples with the same validated method and set whether the result falls (assay) or rises (impurity).
In zero order the product loses the same amount each month; in first order, the same fraction of what is left. Up to 10% to 15% loss both give similar shelf lives; the calculator compares R² for both and warns if the other fits better. First order is the most common in solutions.
It tells how much heat speeds up degradation. In the example, Ea of about 85 kJ/mol gives a Q10 of 3.0 near 77 °F: every 18 °F (10 °C) warmer, the product degrades three times faster. That is why shelf life at 86 °F (30 °C, climatic zone IV) is much shorter than at 77 °F.
Because the estimate is an extrapolation from points that carry error. The conservative value uses the upper 95% limit of the degradation rate, as ICH Q1E does with the regression line. For labeling, use that value rounded down and confirm it with real-time data.
When the mechanism changes with temperature: melting, loss of hydrate water, protein denaturation, microbial growth or reaction with the package. Also when humidity rather than temperature drives degradation. If the Arrhenius plot is not straight, with low R², the extrapolation does not hold.
Not on its own. 21 CFR 211.166 requires a written stability program, and expiry dates must be backed by long-term data at the storage condition, evaluated per ICH Q1E. Accelerated modeling helps plan studies and justify a tentative date; real-time data set the labeled expiry.
Important notice: Indus Metrics tools produce estimates and pre-sizing results from the data you enter and from published engineering methods. They do not replace design, calculations or reports signed by a licensed professional engineer (PE), nor verification against the applicable codes, standards and regulations, such as OSHA rules and the ASME codes. Material and fuel properties vary: check manufacturer data or your own process analyses before deciding. By using this site you agree to the Terms of Use.
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