Stability Chamber MKT Calculator

ICH long-term storage is commonly 25 °C ± 2 °C / 60% RH (zone II) or 30 °C ± 2 °C (zones III/IVa/IVb); chambers must hold the condition, and any deviation's MKT is assessed against the setpoint. The authoritative limit is whatever your product's labelled storage condition and stability data specify — read it off the marketing authorisation, the manufacturer's storage statement or the governing pharmacopoeia, and enter your real temperature history against it.

Assess the excursion's MKT against the ICH condition setpoint. ICH conditions carry a ± tolerance (e.g. 25 °C ± 2 °C) and an MKT requirement; a brief drift that leaves the MKT at the labelled condition generally preserves the study, while a prolonged drift that moves the MKT off-condition may invalidate affected timepoints or require a deviation and impact assessment. Document the chamber's full temperature (and humidity) record, compute the MKT, and have QA judge it against the protocol and ICH guidance. The whole reason MKT exists in stability work is to make this a quantitative, defensible decision rather than discarding a long, costly study reflexively.

Because degradation is not linear with temperature — it accelerates roughly exponentially (Arrhenius). A simple average treats an hour at 30 °C the same as an hour at 20 °C either side of 25 °C, but the product is harmed far more by the hot hour. MKT weights each reading by exp(−ΔH/RT), so it reflects the true cumulative chemical stress. It is always ≥ the arithmetic mean, and it is the figure regulators expect for storage and distribution compliance.

Use a representative series with durations — typically the logger's interval readings, or summarised blocks of 'X hours at Y °C' if you only have an excursion summary. The more granular the data, the more accurate the MKT, but the result is dominated by the warm excursions, so capturing those accurately matters most. Don't average data before entering it — that defeats the point; enter the temperatures and let the calculator do the kinetic weighting.