Pharmaceutical MKT Calculator (CRT)

Controlled room temperature (CRT) is defined by USP as 20–25 °C with permitted excursions of 15–30 °C, provided the MKT does not exceed 25 °C. 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.

Quite possibly, and MKT is how you prove it. CRT explicitly permits excursions to 15–30 °C provided the mean kinetic temperature over the period stays at or below 25 °C. Enter the full temperature history — including the cool nights and the warm afternoon — and if the MKT computes ≤ 25 °C, the storage condition was met. If it exceeds 25 °C, follow your excursion-management SOP and check product-specific stability data before releasing or rejecting the stock.

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.