The problem is not choosing an average temperature
A product arrives with an approved storage condition, a thermal history and a particular packaging configuration. The installation instead encounters air, variable loads, doors and intervention delays. A temperature-control strategy must connect these levels: translate what preserves medicine quality into conditions that can be measured and managed throughout storage, handling and transfers.
[GUIDEGXP] A useful strategy defines product families, the sources of conditions, operating boundaries, margins, monitoring, event response and decision ownership. It is not the selection of a standard range for the whole portfolio. This article concerns storage and distribution interfaces; it does not cover stability-study design, laboratory chambers or formulation development.
Organise sources before interpreting numbers
[REQUIREMENT] Within their applicable scope, European GDP require manufacturer-defined conditions to be maintained. Gather approved documents, marketing authorisation holder instructions and relevant contractual conditions for each product. Record version, market, presentation and the person responsible for interpretation: the same brand name does not guarantee identical conditions for every formulation or pack.
[GUIDANCE] ICH Q1A(R2) addresses stability data for new substances and products. Study conditions are not automatically warehouse conditions. On verification dated 21 September 2026, consolidated ICH Q1 remains labelled draft Step 2b. It is not treated here as an already effective replacement for existing guidelines.
If a technical sheet, label and commercial communication appear inconsistent, do not select the most convenient condition. Obtain clarification from the authorised information owner and retain the decision. Until resolved, use a scientifically justified conservative arrangement, or prevent introduction of the product where the information necessary for appropriate storage remains unavailable.
Distinguish four sets of conditions
Approved product conditions define intended storage. The operating envelope describes what the site and equipment must maintain during qualified use. Alarm limits anticipate or detect a situation requiring action. Any excursion data support specific assessments after unplanned events. Confusing these sets can turn an exceptional tolerance into the assumed normal capability of the process.
A setpoint may sit inside the permitted range, but its distance from boundaries is not chosen simply by finding the midpoint. Consider spatial distribution, control cycling, measurement uncertainty, probe response and intervention time. Where freezing sensitivity dominates, the consequences of a downward departure may be very different from those of an upward one.
| Element | Decision question | Misuse to avoid |
|---|---|---|
| Approved condition | Which controlled document establishes it? | Replacing it with a generic category |
| Operating target | What margin does the system maintain in real conditions? | Equating it with the controller display |
| Alarm threshold | When must an effective response begin? | Treating it automatically as a release limit |
| Excursion data | Which profile and product are actually covered? | Turning evidence into permanent permission |
| Batch decision | Who evaluates all available evidence? | Delegating it to an unjustified average or algorithm |
Build product families without hiding differences
[QRM] Group products only when relevant features are compatible: approved conditions, heat and cold sensitivity, physical state, packaging and intended operations. A family simplifies a decision using evidence; it must not conceal the most sensitive member. Document inclusion rules, exclusions and the process for adding new stock-keeping units to an existing family.
The same commercial family may require different strategies before and after thawing, opening or repacking. Keep shelf life, cumulative time outside specified conditions and time after an irreversible event separate. A timer restarted at every transfer may erase relevant history; a cumulative timer without scientific support can create an equally unsupported acceptance criterion.
Give each family an operational sheet covering conditions, required safeguards, handling units, restrictions, operator information and the function authorised to assess anomalies. This sheet can feed the system URS while retaining the link to the original source. Avoid making the URS the only copy of a product requirement that may subsequently change.
Reconstruct exposure from receipt to dispatch
Draw the physical route and assign a condition to each stage: unloading, document checks, quarantine, storage, picking, assembly, waiting and carrier handover. Protection may come from the environment, packaging or a qualified container. Transitions between these protections must be clear, including the point at which ownership of monitoring changes between organisations or teams.
Identify uncontrolled waiting: operator availability, congestion, vehicle delay, label checks and IT interruptions. A daily average dwell time hides queues. Examine infrequent but plausible events such as simultaneous deliveries or a blocked door. Selection of representative cases should remain traceable to observations or to assumptions that have been explicitly declared and assessed.
For transport, the qualified distribution strategy should receive the same product conditions and return its restrictions to the warehouse. A technically suitable shipment can fail if it waits beyond the intended profile before collection. The handover point therefore needs acceptance criteria, defined information transfer and an identified owner.
Use risk to select verifiable controls
[GUIDANCE] ICH Q9(R1) connects risk, knowledge and uncertainty. [QRM] For each scenario describe cause, potential exposure, quality consequence, detection capability and available action. A table giving every product identical scores does not demonstrate understanding; explain the physical or operational mechanism that makes the risk credible.
Separate prevention, detection and mitigation. A physical barrier may prevent a loading error; a probe may detect a departure; an alternative store may limit its duration. Detection alone does not prevent harm. Also verify that the person receiving the alarm has access, competence and equipment to act while useful time remains.
Record uncertainty as part of the decision. Missing evidence on load behaviour may call for an engineering experiment or targeted qualification, not a more favourable score. QRM cannot create an unproven product tolerance or justify habitual departure from an approved condition. If uncertainty affects a critical conclusion, make the evidence gap visible to the decision owner.
Derive margins and alarms from actual dynamics
[GEP] Examine the complete sequence between event onset and effective action: physical response, sampling, processing, configured delay, notification delivery, acknowledgement and intervention. No stage should disappear because it occurs in a different system. Adding these stages does not establish a universal duration; it helps determine whether the response fits the available margin.
Consider air behaviour separately from product behaviour. An air probe responds quickly to an open door; a simulated mass behaves differently. The latter may answer a specific question, but can also conceal a rapid threat to small containers. The measurement location and medium should match the stated function and the product configuration actually represented.
Alarms should distinguish thermal events, measurement failures and communication loss. Delaying a notification to reduce nuisance alarms requires evidence: a delay must not convert an out-of-limit record into a compliant one. When the system operates chronically near boundaries, correct capacity, flows or settings instead of simply widening the acceptance window.
Include ambient conditions and degraded operation
Controlled temperature also includes stores that must limit both summer heating and winter cooling. A strategy focused only on refrigeration can fail when external conditions become colder than expected. Specify which systems provide heating, cooling or passive protection, and how performance changes during shutdown, maintenance or reduced ventilation.
Humidity, light and condensation belong in the strategy when the product, pack or operation makes them relevant. Do not add standard limits without an applicable source. A transfer between environments can affect label readability, packaging integrity or surface conditions even when product temperature remains acceptable. Define the checks needed and the evidence that establishes a controlled transfer.
Finally describe authorised degraded modes. A unit may remain usable at reduced capacity only when its configuration, duration and controls have been assessed. “Still running” does not mean that the original performance remains available. Staff should understand the conditions for continuing, restricting or suspending storage before a failure occurs.
Define excursion assessment before an event occurs
The strategy should specify the evidence to collect: complete profile, duration, extremes, location, batch identities, packaging, product state, previous events and measurement reliability. A photograph of the display after recovery cannot reconstruct exposure. Data availability should also be verified during temporary network loss, when the event may otherwise remove the information needed to evaluate it.
Mean kinetic temperature is not a universal release mechanism. Its use requires an applicable model, adequate data and justification for the degradation mechanism. It must not conceal freezing, physical changes, significant peaks or missing records. Full event handling belongs within excursion investigation and product-impact assessment, with the method selected for the actual product.
Define segregation and decision authority before an emergency. The technical owner may restore the system, but that does not automatically release the batch. Product disposition needs the authorised function and, where necessary, the marketing authorisation holder or manufacturer. Record technical recovery, material disposition and preventive actions separately so that one completed activity does not falsely close the others.
Handle uncertainty near a boundary
When a measurement approaches a limit, the decision cannot depend only on the displayed number. Consider available accuracy, resolution, relevant calibration, location and response time. Decide before use how results close to a boundary will be treated. The rule should match the risk and measurement purpose: equipment control, storage surveillance and event reconstruction do not ask identical questions.
Do not automatically subtract a supplier's stated error to make a result compliant. A correction needs a metrological basis and controlled application; remaining uncertainty still matters. If two instruments disagree, check identity, time, position, measurement medium and calibration before attributing the difference to the product. Measuring air and simulated mass can produce different results without either instrument being faulty.
The decision record should explain which evidence supports the conclusion and what remains unknown. Where evidence is insufficient, the strategy may require segregation and further information gathering. That route is more useful than an automatic rule that hides uncertainty. Information supplied to the manufacturer should support assessment of the real profile, not just the final exceedance summary produced by software. Preserve relevant context rather than presenting a detached maximum value.
Hypothetical example: a new cold-sensitive presentation
A hypothetical warehouse introduces a new presentation with the same approved range as existing products but particular sensitivity to freezing. The current system controls its central area consistently; near the air supply, some arrangements show lower values. The team does not conclude that the new presentation is compatible merely because it belongs to the same storage category.
Quality checks product instructions, Engineering examines distribution and uncertainty, and Operations reconstructs the positions actually used. The solution could exclude certain positions physically, change the load arrangement or use a separate unit. The chosen approach is tested under relevant conditions and reflected in instructions and monitoring. No numerical margin is assumed without supporting evidence.
The review also identifies an unrecorded manual transfer. The team assigns a suitable container and an owner to that stage. This demonstrates why a product-centred strategy must cover the full operating sequence: correcting the cold room while leaving the transfer uncontrolled would not resolve the original risk.
Strategy approval checklist
- Every condition comes from a controlled source for the product, pack and market concerned.
- Families, exclusions and conditions following particular events are explicit.
- Every physical stage has a protective measure and an owner.
- Setpoints, operating limits, alarms and excursion evidence remain distinct.
- Margins and response times are supported by actual system evidence.
- Missing data and measurement failures trigger a defined response.
- Batch disposition is separate from technical recovery.
- New products, new packaging and operational changes trigger review.
Recognise mistakes and maintain the strategy
Red flags include thermal categories used as the sole source, evidence from one product applied to another, averages concealing extremes, exceptional tolerances becoming routine and alarms without a feasible response. Even a well-written document loses value if the portfolio grows without control of new entries or review of operating restrictions.
[GUIDEGXP] Review the strategy using deviations, trends, real loads, supplier performance and product changes. Set review intervals and triggers through risk and the quality system rather than assuming a universal calendar. The output must be a decision: retain controls, collect evidence, change the process or temporarily restrict use. A complete strategy makes those choices possible before an event forces improvisation.
Keep the decision record useful
For each review, preserve the question being answered, the evidence considered, the uncertainty remaining and the person accepting the conclusion. A statement that nothing has changed is useful only if the relevant sources and operating conditions were actually checked. Compare proposed changes with the assumptions behind the earlier strategy, including packaging, access patterns and emergency capacity.
Where an action is deferred, state the interim control and the trigger that requires reconsideration. This creates a practical connection between the strategy and daily operation. It also helps a new team member understand why a restriction exists, instead of removing it because its original rationale is no longer visible.
Sources and interpretation of labels
Primary sources linked above: GDP 2013/C 343/01; ICH Q1A(R2), EMA version effective from 1 August 2003; ICH Q9(R1), effective from 26 July 2023; draft ICH Q1 Step 2b, April 2025. Checked on 21 September 2026. [REQUIREMENT] identifies a requirement within its scope; [GUIDANCE] a guideline; [GEP], [QRM] and [GUIDEGXP] distinguish engineering practice, a risk decision and an editorial proposal.
