Calculator Inputs
Use first order degradation and Arrhenius behavior to estimate stability across temperature changes.
Example Data Table
| Compound | Reference Temp | Target Temp | Activation Energy | Reference Half Life | Storage Time | Initial Assay | Minimum Assay | Safety Factor | Predicted Half Life | Remaining Assay |
|---|---|---|---|---|---|---|---|---|---|---|
| Sample Compound | 25 °C | 30 °C | 90 kJ/mol | 730 days | 25 days | 100% | 95% | 1.05 | 382.00 days | 95.57% |
| Stabilized Blend | 20 °C | 35 °C | 75 kJ/mol | 420 days | 14 days | 99% | 96% | 1.10 | 85.37 days | 88.36% |
Formula Used
This calculator assumes first order degradation and temperature dependent kinetics. The reference rate constant comes from the supplied half life. The target rate constant is adjusted with the Arrhenius relationship.
k_ref = ln(2) / t_half,ref
k_target = k_ref × exp[(-Ea / R) × (1/T_target - 1/T_ref)]
k_design = k_target × safety factor
C_t = C_0 × exp(-k_design × t)
t_half,target = ln(2) / k_design
t_allowable = ln(C_0 / C_limit) / k_design
Where: Ea is activation energy, R is the gas constant, and absolute temperatures use Kelvin.
Important: This method is useful for screening and comparison. Real products may deviate because of moisture, phase change, catalysis, oxygen exposure, packaging, or non first order behavior.
How to Use This Calculator
- Enter the compound name so exported files stay easy to identify.
- Provide a known reference temperature and a half life measured there.
- Enter activation energy from literature, experiment, or internal modeling.
- Set the target temperature that represents storage, transport, or stress testing.
- Choose planned storage time and the acceptable assay threshold.
- Add a safety factor above 1.00 when you want a conservative design rate.
- Submit the form to see the result block above the input form.
- Review the graph, summary metrics, and export files for reporting.
Frequently Asked Questions
1. What does this calculator estimate?
It estimates how quickly a material degrades at a target temperature. It predicts rate constants, half life, remaining assay after storage, allowable storage time, stability margin, and a Q10 style temperature sensitivity factor.
2. Why is activation energy important?
Activation energy controls how strongly temperature changes alter the degradation rate. Higher values usually mean stronger temperature sensitivity, so a small temperature rise can shorten predicted half life much more sharply.
3. Why does the calculator use Kelvin internally?
The Arrhenius equation requires absolute temperature. Celsius is convenient for input, but the exponential temperature term must use Kelvin to preserve the correct physical relationship between rate and temperature.
4. What does the safety factor do?
The safety factor multiplies the target degradation rate. A value above 1.00 makes the result more conservative by shortening predicted half life and allowable storage time.
5. What is stability margin?
Stability margin is allowable storage time divided by the planned storage time. Values above 1 suggest the material still meets the assay limit at the planned condition. Higher values provide more headroom.
6. Can I use this for pharmaceuticals or food systems?
Yes, as a screening tool. It helps compare scenarios quickly, but regulated decisions should rely on validated stability studies, product specific degradation models, packaging data, and the required quality framework.
7. Why might real results differ from the estimate?
Actual behavior can differ because of humidity, oxygen, pH shifts, light exposure, catalysts, formulation changes, diffusion limits, or multi step reactions. The calculator intentionally simplifies those effects into a practical first estimate.
8. What does the graph show?
The graph shows how predicted half life and remaining assay change across a temperature sweep. It helps you see whether stability falls gradually or collapses quickly as temperature increases.