1Controlled room temperature, source by source.
Controlled room temperature (CRT) is a United States Pharmacopeia (USP) term; other pharmacopoeias use other words for similar ranges. MKT below is mean kinetic temperature, a single figure for a varying temperature history.
| Source | Term | Range | Status |
|---|---|---|---|
| USP, current | Controlled room temperature | 20 to 25 °C; excursions 15 to 30 °C; spikes to 40 °C within 24 h; MKT 25 °C or less | Official¹² |
| USP, proposed | Controlled room temperature | 15 to 25 °C; MKT rules unchanged | PF 52(4), in progress³⁴ |
| WHO | Controlled room temperature | 15 to 25 °C; “ambient” 15 to 30 °C | Recommended limits, 2020⁵ |
| European Pharmacopoeia | Room temperature | 15 to 25 °C | As USP’s briefing reports it³ |
| Japan, JP XIX | Ordinary temperature; room temperature | Ordinary 15 to 25 °C; room 1 to 30 °C | General Notice 16, April 2026⁶ |
| Canada | Controlled room temperature | 15 to 30 °C, as a label statement | Listed by WHO⁷ |
On labels, WHO and the draft ICH Q1, due for Step 4 review in December 2026, say “room temperature” should be avoided.⁷⁸⁹
1.1USP’s rule in full.
USP chapter 659 defines CRT as the temperature “maintained thermostatically that encompasses the usual and customary working environment of 20°–25° (68°–77° F)”, on these conditions:¹
- MKT not to exceed 25 °C.
- Excursions between 15 and 30 °C “that are experienced in pharmacies, hospitals, and warehouses, and during shipping are allowed.”
- Spikes. “Provided the mean kinetic temperature does not exceed 25°, transient spikes up to 40° are permitted as long as they do not exceed 24 h. Spikes above 40° may be permitted only if the manufacturer so instructs.”
- Colder storage. Allowed instead, cool or refrigerated, unless the monograph or label says otherwise.
Chapter 1079.2, revised from 1 August 2025, sets how MKT is used:²⁴
- Period. The days the product is in the holder’s possession, or 30 days when that is not known; in transit, from shipment to arrival.
- Limits. For CRT, excursions of 15 to 20 °C and 25 to 30 °C, spikes to no more than 40 °C, a maximum excursion time of 24 hours and MKT no more than 25 °C. New in 2025: zone IVb storage, 15 to 30 °C with MKT up to 30 °C.
- Limits of the tool. MKT “alone is not enough”. It may not suit phase-change products, such as suppositories and creams, or biologics, and must not excuse repeated excursions.
USP told a commenter in 2025 that “For excursions less than 24 hours between 30-40 Celsius, a MKT will need to be calculated”, and 1079.2’s table makes 24 hours the maximum time for any CRT excursion.¹⁰² USP has not yet defined “transient spike”, so count all time outside 20 to 25 °C against the 24 hours, which satisfies both chapters.¹⁰
2What USP proposes, and its status.
USP’s packaging and distribution expert committee proposes revising chapter 659 so that CRT means 15 to 25 °C. Its briefing says this follows comments on a 2025 Stimuli article and gives three reasons: alignment with the Japanese and European pharmacopoeias and WHO, an estimated 10% to 15% saving in heating and cooling energy, particularly in colder climates, and regulatory convergence. MKT stays the tool for short excursions above 25 °C.³¹¹ The briefing says JP defines room temperature as 15 to 25 °C, but JP’s English text calls that range “ordinary temperature”.³¹²
The proposal is in Pharmacopeial Forum 52(4), open for comment from 1 July to 30 September 2026, and USP’s revisions list showed it in progress on 25 September 2026. If it advances without being republished, USP’s schedule puts PF 52(4) proposals in USP–NF 2027, Issue 5, official on 1 October 2027.⁴¹¹
2.1What to review if USP adopts 15 to 25 °C.
A label that prints its own range keeps it, because storage conditions come from stability data.¹³ What changes is anything that leans on the definition:
| Review | What to check | Basis |
|---|---|---|
| Procedures | Warehousing procedures that say only “CRT” inherit the new range; write in each product’s labelled limits | 21 CFR 211.142(b)¹⁴ |
| Alarm limits | Low alarms at 20 °C: 15 to 20 °C would no longer be an excursion, so decide product by product whether it still alarms | EU GDP 3.3; USP briefing¹⁵³ |
| Mapping criteria | Acceptance criteria written as 20 to 25 °C for areas mapped as CRT | EU GDP 3.2.1¹⁵ |
| Contracts and specs | Quality agreements, carrier instructions and supplier specifications that define storage as “CRT” | EU GDP 7.2, 9.2¹⁵ |
| Labels citing USP | “[see USP Controlled Room Temperature]” brings in USP’s rule; distributors store to the label or the current compendium | 21 CFR 205.50(c)¹⁶ |
3Example: does a warehouse excursion stay within CRT?
Example, all invented: the product, batch, bay, record number and readings are illustrative, simplified to blocks of whole hours.
| Field | Entry |
|---|---|
| Product | Product R 50 mg tablets, Batch 26-214. Label: “Store at 20°C to 25°C; excursions permitted between 15°C and 30°C [see USP Controlled Room Temperature]” |
| Where | Bay W3, a mapped area; logger L-W3-02, calibrated, hourly readings |
| Period | Received 15 June 2026; MKT over the 30 days to the end of the fault on 14 July, 720 readings |
| Event | Air-handler fault on 14 July: 4 h at 26.0 °C, 10 h at 29.0 °C, 4 h at 26.5 °C; the other 702 hours at 24.5 °C |
| MKT | 24.6 °C over all 720 readings; arithmetic mean 24.58 °C |
| Checks | Peak 29.0 °C, inside 15 to 30 °C. 18 hours outside 20 to 25 °C, under the 24-hour maximum. MKT not above 25 °C |
| Record | Deviation DEV-26-0412, opened by the warehouse lead at the alarm; logger data and this check attached |
| Outcome | Within the labelled allowance. QA closes the deviation, keeps the batch available and logs the excursion for trending; the air handler is repaired under a work order |
Inside the allowance still means a record: USP calls an excursion “a nonconforming event”, and those “within allowances should be documented and can be reviewed for compliance and trending”.² EU GDP wants deviations “documented and investigated” and repairs recorded; in the US the quality unit approves or rejects the drug products the firm holds.¹⁵¹⁷
The arithmetic follows J. D. Haynes’s formula, which ICH Q1A(R2) names for MKT.¹⁸ With temperatures T₁ to Tₙ in kelvin: MKT = (ΔH/R) ÷ −ln[(e^(−ΔH/RT₁) + … + e^(−ΔH/RTₙ)) ÷ n]. With USP’s default ΔH of 83.144 kJ/mol, ΔH/R is 10,000 K.² For an excursion in storage, USP goes back “30 days from (and including) the high excursion temperature”, covering the whole excursion, so the 720 readings end when the fault ends.² Here −ln of the averaged terms is 33.585, and 10,000 ÷ 33.585 = 297.75 K, or 24.6 °C. Change one fact and the answer changes:
- The fault lasts 30 hours (6 h at 26.0, 18 h at 29.0, 6 h at 26.5 °C). MKT is 24.7 °C, but 30 hours is past the maximum, and an excursion outside USP limits “must be evaluated and its impact on the final product determined”: a temperature excursion.²
- Two of the 29 °C hours reach 33.0 °C. MKT stays at 24.6 °C. The printed range ends at 30 °C, but the label points to USP CRT, which permits spikes to 40 °C; check the manufacturer’s data, as some CRT-labelled products “may have stability issues” with USP’s limits.¹²
- Someone adds 10 days in a 5 °C cold room. MKT over 960 readings falls to 22.3 °C, but cold storage cannot offset an excursion.³
4What storage statements mean.
| Statement | Wording | What it allows | Where | Source |
|---|---|---|---|---|
| USP CRT | “Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C and 30°C (59°F and 86°F) [see USP Controlled Room Temperature]” | 20 to 25 °C; short excursions judged by USP’s CRT rules | US | ¹⁹¹ |
| No special conditions | “This medicinal product does not require any special storage conditions” | Stable long term at 25 °C/60% RH or 30 °C/65% RH, and at 40 °C/75% RH accelerated. Still monitored | EU | ²⁰²¹ |
| Below 25 or 30 °C | “Do not store above 25°C” or “Do not store above 30°C” | 25 °C: stable at 25 °C/60% RH long term only. 30 °C: adds 30 °C intermediate data, or 30 °C/65% RH long term | EU | ²⁰ |
A statement with no temperature still needs monitoring: “No labelling statement means that controls should be in place to maintain conditions relevant to climate zones I and II”, EMA says.²¹ Other statements, WHO’s wording for hot markets and the data each needs are in ICH stability storage conditions.
5What inspectors expect.
- EU. Storage areas are mapped before use, monitors sit where the extremes are, and alarms are set and tested; a room-temperature store of a few square metres may instead assess heat sources such as heaters.¹⁵ See temperature mapping.
- UK and Canada, on MKT. MHRA inspectors report that in some cases “attempts were made to inappropriately apply mean kinetic temperature to underestimate impact”. Health Canada allows MKT only as a recognised pharmacopoeia uses it, under a procedure, and warns it may not suit phase-change, cold-chain or biological products.²²²³
- US. FDA’s warning letter of 8 September 2026 to kdc/one Chatsworth, Inc. cited 21 CFR 211.142(b): a released batch sat in a building whose recorded temperatures exceeded its labelled range. To the firm’s promised fixes, FDA replied:
Your response is inadequate. You did not implement immediate corrective actions and did not conduct a thorough retrospective review of product impact for temperature excursions, including for the formation of impurities and degradants when products are exposed to heat.
It asked for labelled storage requirements to be compared with recorded temperatures in all buildings.²⁴ The label needs data behind it too: in August 2024 FDA cited 21 CFR 211.166(a) because a firm’s stability studies did “not support storage of the product at room temperature for 24 months as provided on product labeling”.²⁵
6How it runs in Seal.
In Seal, the approved storage profile sets the allowed conditions by product, material state, packaging configuration, lifecycle stage, market and purpose of the journey, and controlled-
The allowance comes from stability work: a shelf-life proposal in Seal records the storage statement with the batch data and analysis behind it (stability LIMS), and the warehouse records time outside controlled storage and connects excursion evidence to the containers and time window affected (warehouse management).
References
- 1Packaging and Storage Requirements, general chapter 659, revision proposal reproducing the chapter text of USP 42, section on storage temperature, United States Pharmacopeia, 2018. https:/
/ www. uspnf. com/ sites/ default/ files/ usp_ pdf/ EN/ notices/ 2018/ c659- proposed. pdf (read 8 November 2026) - 2Mean Kinetic Temperature in the Evaluation of Temperature Excursions During Storage and Transportation of Drug Products, general chapter 1079.2, pre-posted text official 1 August 2025, sections 3 to 5 and Table 1, United States Pharmacopeia, posted 2 December 2024. https:/
/ www. uspnf. com/ sites/ default/ files/ usp_ pdf/ EN/ USPNF/ usp- nf- notices/ PF492_ M13855. pdf (read 8 November 2026) - 3Packaging and Storage Requirements, general chapter 659, proposed revision, briefing, Case ID SUB-2963, USP–NF Pharmacopeial Forum, 2026. https:/
/ doi. usp. org/ USPNF/ USPNF_ M2773_ 60101_ 01. html (read 8 November 2026) - 42024–2026 Cumulative List of USP–NF Revisions, entries for chapters 659 and 1079.2, United States Pharmacopeia, updated 25 September 2026. https:/
/ www. uspnf. com/ sites/ default/ files/ usp_ pdf/ EN/ USPNF/ usp- nf- commentary/ cumulative_ ballot_ results. xlsx (read 8 November 2026) - 5Good storage and distribution practices for medical products, WHO Technical Report Series No. 1025, Annex 7, Appendix 1, Table A7.1, WHO, 2020. https:/
/ cdn. who. int/ media/ docs/ default- source/ medicines/ who- technical- report- series- who- expert- committee- on- specifications- for- pharmaceutical- preparations/ trs1025- annex7. pdf (read 8 November 2026) - 6The Japanese Pharmacopoeia, Nineteenth Edition, Japanese text, General Notice 16, MHLW Notification No. 193, Ministry of Health, Labour and Welfare, 10 April 2026. https:/
/ www. mhlw. go. jp/ content/ 11120000/ 001689414. pdf (read 8 November 2026) - 7Stability testing of active pharmaceutical ingredients and finished pharmaceutical products, WHO Technical Report Series No. 1010, Annex 10, section 2.2.10, Appendix 3 and Table A10.4, WHO, 2018. https:/
/ cdn. who. int/ media/ docs/ default- source/ medicines/ norms- and- standards/ guidelines/ regulatory- standards/ trs1010- annex10- who- stability- testing- of- active- pharmaceutical- ingredients. pdf (read 8 November 2026) - 8ICH Q1 Stability Testing of Drug Substances and Drug Products, Step 2 draft, sections 13.2.5, 14 and 14.1, ICH, endorsed 11 April 2025. https:/
/ database. ich. org/ sites/ default/ files/ ICH_ Q1EWG_ Step2_ Draft_ Guideline_ 2025_ 0411. pdf (read 8 November 2026) - 9ICH Q1 EWG Work Plan, ICH, 10 July 2026. https:/
/ database. ich. org/ sites/ default/ files/ ICH53_ Q1_ EWG_ WorkPlan_ 2026_ 0818. pdf (read 8 November 2026) - 10Commentary for USP–NF 2025, Issue 2, general chapter 1079.2, comment summaries 2 and 3, United States Pharmacopeia, 3 February 2025. https:/
/ www. uspnf. com/ sites/ default/ files/ usp_ pdf/ EN/ USPNF/ usp- nf- commentary/ usp- nf- 2025- issue- 2- commentary- 20250203. pdf (read 8 November 2026) - 11USP–NF Publication and Comment Schedule, United States Pharmacopeia. https:/
/ www. uspnf. com/ publication- comment- schedule (read 8 November 2026) - 12The Japanese Pharmacopoeia, Eighteenth Edition, English version, General Notice 16, Ministry of Health, Labour and Welfare, official from 7 June 2021. https:/
/ www. mhlw. go. jp/ content/ 11120000/ 000945683. pdf (read 8 November 2026) - 1321 CFR 211.166(a), Stability testing, eCFR. https:/
/ www. ecfr. gov/ current/ title- 21/ section- 211. 166 (read 8 November 2026) - 1421 CFR 211.142(b), Warehousing procedures, eCFR. https:/
/ www. ecfr. gov/ current/ title- 21/ section- 211. 142 (read 8 November 2026) - 15Guidelines of 5 November 2013 on Good Distribution Practice of medicinal products for human use (2013/C 343/01), sections 1.2, 3.2.1, 3.3, 7.2 and 9.2, European Commission. https:/
/ eur- lex. europa. eu/ legal- content/ EN/ TXT/ HTML/ ?uri=CELEX:52013XC1123(01) (read 8 November 2026) - 1621 CFR 205.50(c), Storage, eCFR. https:/
/ www. ecfr. gov/ current/ title- 21/ section- 205. 50 (read 8 November 2026) - 1721 CFR 211.22(a), Responsibilities of quality control unit, eCFR. https:/
/ www. ecfr. gov/ current/ title- 21/ section- 211. 22 (read 8 November 2026) - 18ICH Q1A(R2) Stability Testing of New Drug Substances and Products, glossary, ICH, 6 February 2003. https:/
/ database. ich. org/ sites/ default/ files/ Q1A%28R2%29%20Guideline. pdf (read 8 November 2026) - 19Mekinist (trametinib) prescribing information, section 16, How supplied/storage and handling, Novartis, DailyMed, US National Library of Medicine, version of 7 May 2026. https:/
/ dailymed. nlm. nih. gov/ dailymed/ drugInfo. cfm?setid=0002ad27- 779d- 42ab- 83b5- bc65453412a1 (read 8 November 2026) - 20Guideline on declaration of storage conditions, CPMP/QWP/609/96/Rev 2, sections 4 and 5, European Medicines Agency, 19 November 2007. https:/
/ www. ema. europa. eu/ en/ documents/ scientific- guideline/ guideline- declaration- storage- conditions_ en. pdf (read 8 November 2026) - 21Guidance on good manufacturing practice and good distribution practice: questions and answers, GDP, question 1, European Medicines Agency. https:/
/ www. ema. europa. eu/ en/ human- regulatory- overview/ research- development/ compliance- research- development/ good- manufacturing- practice/ guidance- good- manufacturing- practice- good- distribution- practice- questions- answers (read 8 November 2026) - 22A practical example of applying quality risk management in GDP: transportation risks, MHRA Inspectorate blog, 15 July 2020. https:/
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AQuestions and answers
Is controlled room temperature the same as ambient temperature?
No. Ambient is whatever the surroundings happen to be, which can be far outside 20 to 25 °C in a summer warehouse or on a winter loading dock. Controlled room temperature is a defined range that is maintained and monitored. WHO’s distribution guidance gives “ambient” a recommended 15 to 30 °C with no more than 60% humidity, but EU guidance calls “ambient conditions” unacceptable on labels and WHO’s stability guideline says to avoid the term.
Can a 30-day mean kinetic temperature hide a short hot spell?
It can, which is why it should never be the only check. In the example on this page, the 18 hours of the fault alone have an MKT of 27.9 °C, yet the 30-day figure is 24.6 °C. USP pairs MKT with a 24-hour limit on excursion time and a 40 °C ceiling, and says you also need to know how long the excursion lasted and how hot it got, so a long or very hot excursion fails even when the monthly MKT looks fine.
Does FDA have its own definition of controlled room temperature?
No. FDA’s rules point to the compendium. Wholesale distributors must store drugs as the labelling or the official compendium requires, and may hold a drug with no stated storage requirement at controlled room temperature as a compendium such as USP–NF defines it. Manufacturers set storage conditions from their own stability testing, and those conditions go on the label.
Can controlled room temperature products be shipped without temperature control?
Not without evidence. The product has to stay within its labelled conditions in transit, so the temperatures on the route need to be known from risk assessment, profiling or monitoring. Short excursions within the label’s allowance are acceptable; anything beyond it needs stability data. In the EU, even products with no storage statement are expected to be kept within climate zone I and II conditions and monitored.
Does controlled room temperature include a humidity limit?
No. Controlled room temperature is a temperature range. Humidity enters through the stability conditions behind the label, such as 25 °C and 60% relative humidity long term, and through added statements such as “Protect from moisture” or “Store in the original package” where the data show the product is sensitive to it.