USP Proposes to Revise the Definition of Controlled Room Temperature in Chapter <659>

In the current Pharmacopeial Forum PF 52(4), the United States Pharmacopeia (USP) published a proposal to revise General Chapter <659> Packaging and Storage Requirements. The revision focuses on the compendial definition of Controlled Room Temperature (CRT).

Background

Historically, USP defined CRT as 20–25 °C, permitting excursions between 15 °C and 30 °C. In contrast, JP, Ph. Eur. and WHO define room temperature as 15–25 °C.

USP notes that the proposal was informed by comments received on the Stimuli article "Aligning Room Temperature Standards for Pharmaceuticals—A Sustainable Approach", which was published in PF 51(5).

USP now proposes aligning CRT with 15–25 °C, thereby reducing the lower limit from 20 °C to 15 °C, while maintaining the use of mean kinetic temperature (MKT) principles to evaluate short-term excursions beyond 25 °C.

Rational for the Revision

The briefing notes cite the following reasons:

• "Global harmonization—Aligning USP’s CRT definition with JP, EP, and WHO standards will promote consistency in pharmaceutical storage practices worldwide.
• Environmental sustainability—Lowering the minimum CRT threshold to 15° can reduce HVAC energy demands, particularly in colder climates, leading to estimated energy savings of 10%–15%.
• Regulatory alignment—Harmonization will support international regulatory convergence and align with ICH principles, which emphasize stability and safety across global markets."

Commenting

The draft can be viewed free of charge after registration on the Pharmacopeial Forum website. The commenting period is open until 30 September 2026.