Commission Implementing Regulation (EU) 2025/2154 of 17 October 2025 laying down good manufacturing practice for active substances used as starting materials in veterinary medicinal products in accordance with Regulation (EU) 2019/6 of the European Parliament and of the Council

Specifications and test procedures shall be in compliance with the terms of the marketing authorisation. There can be specifications in addition to those in the terms of the marketing authorisation.

Specifications, sampling plans and test procedures, including changes to them, shall be drafted by the appropriate organisational unit and reviewed and approved by the quality unit.

Appropriate specifications shall be established for active substances in accordance with accepted standards and consistent with the manufacturing process.

The specifications for the active substance shall include a control of the impurities (e.g. organic impurities, inorganic impurities and residual solvents). If the active substance has a specification for microbiological purity, appropriate action limits for total microbial counts and objectionable organisms shall be established and met. If the active substance has a specification for endotoxins, appropriate action limits shall be established and met.

Laboratory controls shall be monitored and documented at the time of performance.

Procedures shall be established for the investigation and documentation of out-of-specification results. Those procedures shall require analysis of the data, assessment of the criticality of the out-of-specification result, allocation of the tasks for corrective actions and conclusions. Any re-sampling or retesting after out-of-specification results shall be performed according to a documented procedure.

Procedures shall be established for the preparation of reagents and standard solutions and the labelling thereof. Expiry dates shall be applied as appropriate for analytical reagents or standard solutions.

Primary reference standards shall be suitable for their intended use. The source of each primary reference standard shall be documented. Records shall be maintained of each primary reference standard’s storage and use in accordance with the supplier’s recommendations.

Primary reference standards obtained from an officially recognised source may be used without testing if stored under conditions consistent with the supplier’s recommendations.

Where a primary reference standard is not available from an officially recognised source, an “in-house primary reference standard” shall be established. Appropriate testing shall be performed to establish fully the identity and purity of the in-house primary reference standard. Appropriate documentation of that testing shall be maintained.

Secondary reference standards shall be appropriately prepared, identified, tested, approved, and stored. The suitability of each batch of secondary reference standard shall be determined prior to first use by comparing against a primary reference standard. Each batch of secondary reference standard shall be periodically requalified in accordance with a written protocol.

Appropriate laboratory tests to determine conformity to specifications shall be conducted for each batch of active substance and intermediates thereof.

An impurity profile describing the identified and unidentified impurities present in a typical batch produced by a specific controlled production process shall be established for each active substance. The impurity profile shall include:

By way of derogation from paragraph 2, impurity profiles are not necessary for active substances from herbal or animal tissue origin.

The impurity profile shall be compared at appropriate intervals against the impurity profile in the terms of the marketing authorisation or compared against historical data in order to detect changes to the active substance resulting from modifications in raw materials, equipment operating parameters, or the production process.

Appropriate microbiological tests shall be conducted on each batch of intermediate and active substance where microbial quality is specified.

Upon request, certificates of analysis shall be issued for each batch of intermediate or active substance.

The certificate of analysis shall contain at least:

Certificates shall be dated and signed by authorised personnel of the quality unit and shall include the name, address and telephone number of the original manufacturer.

Where the analysis has been carried out by entities involved in repackaging or reprocessing, the certificate of analysis shall include the name, address and telephone number of the entity involved in repackaging or reprocessing and a reference to the name of the original manufacturer.

Whenever new certificates are issued by or on behalf of entities involved in repackaging or reprocessing, those certificates shall include the name, address and telephone number of the laboratory that performed the analysis. They shall also contain a reference to the name and address of the original manufacturer and to the original batch certificate, a copy of which shall be attached.

Manufacturers shall put in place a documented, on-going stability programme to monitor the stability data of active substances. The results shall be used to confirm appropriate storage conditions and retest or expiry dates.

The test procedures used in stability studies shall be appropriate for the active substance and validated.

Stability samples shall be stored in containers that simulate the market container.

The first three production scale batches shall be placed on the on-going stability programme to confirm the retest or expiry date.

By way of derogation from paragraph 4, where data from previous studies show that the active substance is expected to remain stable for at least two years, fewer than three batches may be used.

After the first three production scale batches being placed on the on-going stability programme, at least one batch per year of the active substance manufactured shall be included into the on-going stability programme, unless none are produced in a given year or a different frequency is otherwise justified.

In case of active substances with short shelf life, stability testing shall be done more frequently. When data exist confirming that the stability of the active substance is not compromised, elimination of specific test intervals may be considered.

Where appropriate, the stability testing of active substances shall be performed in accordance with the conditions set out in the Guideline on stability: stability testing of new veterinary drug substances and medicinal products (5).

Where an intermediate is intended to be transferred outside the control of the manufacturer and an expiry or retest date is assigned, supporting stability information shall be available (e.g. published data, test results).

The expiry or retest date of an active substance shall be based on an evaluation of data derived from stability studies.

Preliminary active substance expiry or retest dates may be based on pilot scale batches where the following conditions are fulfilled:

Reference samples shall be kept for the purpose of potential future evaluation of the quality of batches of active substance and not for future stability testing purposes.

Reference samples of each active substance batch shall be retained for one year after the expiry date of the batch, or for three years after distribution of the batch, whichever is the longest.

For active substances with retest dates, reference samples shall be retained for three years after the batch is completely distributed by the manufacturer.

Reference samples shall be stored in the same packaging system in which the active substance is stored or in one that is equivalent to or more protective than the marketed packaging system.

Sufficient quantities shall be retained to conduct at least two full compendial analyses or, when there is no pharmacopoeial monograph, two full specification analyses.

The manufacturers’ overall policy and methodology for validation, including the validation of production processes, cleaning procedures, analytical methods, in- process control test procedures, computerised systems and the appointment of persons responsible for design, review, approval and documentation of each validation phase, shall be established and documented.

The critical process parameters or attributes of the active substances shall be identified during its development stage or from historical data, and the ranges necessary for the reproducible operation shall be defined, including:

Validation shall extend to those operations determined to be critical to the quality and purity of the active substance.

A written validation protocol, specifying how validation of a particular process will be conducted, shall be established. The protocol shall be reviewed and approved by the quality unit and other designated units.

The validation protocol shall specify:

A validation report that refers to the validation protocol shall be prepared. That validation report shall contain:

Any deviations from the validation protocol shall be documented with appropriate justification.

Before starting the process validation, appropriate qualification of critical equipment and ancillary systems shall be completed.

Qualification may be carried out by conducting the following activities, individually or combined:

Prospective validation shall be used for all active substance processes.

Prospective validation performed on an active substance process shall be completed before the commercial distribution of the veterinary medicinal product manufactured from that active substance.

By way of derogation from paragraph 1, concurrent validation may be conducted in the following cases:

Prior to the completion of concurrent validation, batches may be released and used in the manufacturing of a veterinary medicinal product based on thorough monitoring and testing of the active substance batches.

By further way of derogation from paragraph 1, retrospective validation may be performed for well-established processes that have been used without significant changes to active substance quality due to changes in raw materials, equipment, systems, premises or the production process. That validation approach may be used if all the following conditions are met:

Batches selected for retrospective validation shall be:

Retained samples may be used for retrospective validation testing.

The number of process runs for validation shall depend on the complexity of the process or on the criticality of the process change being considered.

A minimum of three consecutive successful production batches shall be used for prospective and concurrent validation. In situations where additional process runs are warranted to prove consistency of the process (e.g. complex active substance processes or active substance processes with prolonged completion times), this number shall be increased.

For retrospective validation, data from ten to thirty consecutive batches shall be examined to assess process consistency.

By way of derogation from paragraph 3, fewer batches can be examined for retrospective validation, if justified.

Critical process parameters shall be controlled and monitored during process validation studies. Process parameters unrelated to quality, such as variables controlled to minimise energy consumption or equipment use, may be excluded from the process validation.

Process validation shall confirm that the impurity profile for each active substance is within the specified limits. The impurity profile shall be comparable to or better than historical data and, where applicable, comparable to or better than the profile determined during process development or for batches used for pivotal clinical and toxicological studies.

Validated systems and processes shall be periodically reviewed.

Where no significant changes have been made to the system or process, and a quality review confirms that the system or process is consistently producing material meeting its specifications, no revalidation is required.

Cleaning procedures shall be validated. Cleaning validation shall be directed to situations or process steps where contamination or carryover of materials poses the greatest risk to active substance quality.

Validation of cleaning procedures shall reflect actual equipment usage patterns. Where various active substances or intermediates are manufactured in the same equipment and the equipment is cleaned by the same process, a representative intermediate or active substance may be selected for cleaning validation. This selection shall be based on:

The cleaning validation protocol shall describe:

Sampling shall include swabbing, rinsing or alternative methods (e.g. direct extraction), as appropriate, to detect both insoluble and soluble residues. The sampling methods used shall allow the quantitative measurement of the levels of residues remaining on the equipment surfaces after cleaning.

Validated analytical methods sensitive to detect residues or contaminants shall be applied. The detection limit for each analytical method shall be sufficiently sensitive to detect the established acceptable level of the residue or contaminant. The method’s attainable recovery level shall be established. Residue limits shall be practical, achievable, verifiable and based on the most deleterious residue. Limits may be established based on the minimum known pharmacological, toxicological, or physiological activity of the active substance or its most deleterious component.

Equipment cleaning or sanitisation tests shall address microbiological and endotoxin contamination for those processes where there is a need to reduce total microbiological count or endotoxins in the active substance, or for other processes where such contamination could be of concern (e.g. non-sterile active substances used to manufacture sterile products).

Cleaning procedures shall be monitored at appropriate intervals after validation to ensure that those procedures are effective when applied during routine production. Equipment cleanliness may be monitored by analytical testing and visual examination, where feasible. Visual inspection may allow detection of gross contamination concentrated in small areas that could otherwise go undetected by sampling or analysis.

Analytical methods shall be validated unless the method employed is included in the relevant pharmacopoeia or other recognised standard reference. The suitability of all testing methods used shall be verified under actual conditions of use and this verification of suitability shall be documented.

The validation of the analytical methods shall be performed in accordance with the requirements set out in the guideline on validation of analytical procedures: methodology (6). The degree of analytical validation performed shall reflect the purpose of the analysis and the stage of the active substance production process.

Complete records shall be maintained of any modification of a validated analytical method. Such records shall include the reason for the modification and appropriate data to verify that the modification produces results that are as accurate and reliable as the established method.

A formal change control system shall be established to evaluate all changes that may affect the production and control of the intermediate or active substance.

Written procedures shall describe the identification, documentation, appropriate review and approval of changes in raw materials, specifications, analytical methods, premises, support systems, equipment (including computer hard- and software), processing steps, labelling and packaging materials.

Any proposals for changes relevant to the good manufacturing practices shall be drafted, reviewed and approved by the appropriate organisational unit, and reviewed and approved by the quality unit.

The potential impact of proposed changes on the quality of the active substances or intermediates thereof shall be evaluated. A classification procedure may contribute to determine the level of testing, validation and documentation needed to justify changes to a validated process. Changes shall be classified (e.g. as minor or major) depending on the nature and extent of the changes and the effects those changes may have on the process.

A scientific assessment shall be carried out to determine which additional testing and validation studies are appropriate to justify a change in a validated process.

All documents affected by the changes shall be revised and updated where approved changes are implemented.

After implementation of the change, an evaluation of the first batches produced or tested under the change shall be performed.

The potential for critical changes to affect established retest or expiry dates shall be evaluated. Where necessary, samples of the active substances or intermediates thereof produced by the modified process shall be placed on an accelerated stability programme and added to the on-going stability programme.

Manufacturers of the veterinary medicinal product shall be notified of changes from established production and process control procedures that may impact the quality of the active substance used in the veterinary medicinal product.

An intermediate or an active substance, including one that does not comply with standards or specifications, may be introduced back into the manufacturing process and reprocessing by repeating a crystallisation step or other appropriate chemical or physical manipulation steps (e.g. distillation, filtration, chromatography, milling) that are part of the established manufacturing process. Whenever such reprocessing is used for the majority of batches, that reprocessing shall be included as part of the standard manufacturing process.

Introducing unreacted material back into a process and repeating a chemical reaction is considered to be reprocessing unless it is part of the established process. Such reprocessing shall be preceded by careful evaluation to ensure that the quality of the active substance or intermediates thereof is not adversely impacted due to the potential formation of by-products and over-reacted materials.

Batches that do not conform to established standards or specifications shall not be reworked unless an investigation into the reason for non-conformity has been performed.

Batches that have been reworked shall be subject to appropriate evaluation, testing, stability testing if warranted, and documentation to show that the reworked product is of equivalent quality to that produced by the original process.

Concurrent validation may be used as a validation approach for rework procedures. In case only one batch shall be reworked, a report may be written, and the batch may be released once it is proved to be acceptable.

Procedures shall provide for comparing the impurity profile of each reworked batch against batches manufactured by the established process. Where routine analytical methods are inadequate to characterise the reworked batch, additional methods shall be used.

Reactants, intermediates or the active substance may be recovered (e.g. from mother liquor or filtrates), provided that approved procedures exist for the recovery and the recovered materials meet the required specifications.

Solvents may be recovered and re-used in the same processes or in different processes, provided that the recovery procedures are controlled and monitored to ensure that solvents meet established standards before re-use or co-mingling with other approved materials.

Fresh and recovered solvents and reagents may be combined provided that adequate testing has shown their suitability for the intended use.

The use of recovered solvents, mother liquors and other recovered materials shall be adequately documented.

Returned intermediates or active substances shall be clearly labelled as such and quarantined.

If the conditions under which returned intermediates or active substances have been stored or shipped before or during their return or the condition of their containers casts doubt on their quality, the returned intermediates or active substances shall be reprocessed, reworked or destroyed, as appropriate.

Records of returned intermediates or active substances shall be maintained in accordance with the provisions of Article 21(4) of Commission Implementing Regulation (EU) 2021/1280 (7).

A system shall be put in place to ensure that all quality-related complaints, whether received orally or in writing, are recorded and thoroughly investigated and that appropriate actions are implemented, including the recall of the active substance where appropriate. Operating procedures shall be developed describing the actions to be taken upon the receipt of a quality-related complaint.

Complaint records shall include the following:

When a quality defect is discovered or suspected in a batch, consideration shall be given whether it is necessary to check other batches or, as appropriate, other products to determine if they are also affected. Batches that may contain portions of the defective batch or components shall be investigated.

The priority during an investigation shall be to ensure that appropriate risk-minimisation measures are taken. All decisions and measures adopted shall reflect the level of risk and shall be documented. The effectiveness of the corrective and preventive measures implemented shall be monitored.

Procedures for the recall of active substances shall be established, which shall include how a recall is to be initiated, who is to be informed in the event of a recall (including relevant authorities) and how the recalled material is to be treated.

The outsourcing of operations related to the manufacturing or control of active substances shall be made by means of a written contract that provides for clear delineation of the responsibilities of each party.

The following additional aspects shall be covered in the contract:

All outsourced manufacturing or control operations shall comply with the good manufacturing practices for active substances used as starting materials in veterinary medicinal products. Special consideration shall be given to prevent cross-contamination and to ensure traceability.

Contract acceptors shall be audited by the contract giver to ensure compliance with good manufacturing practices for active substances used as starting materials in veterinary medicinal products as regards the specific operations occurring at the contract sites.

Repackaging, relabelling and holding of active substances and intermediates thereof shall be performed under appropriate good manufacturing controls, to avoid mix-ups and loss of active substance or intermediate identity or purity.

Repackaging shall be conducted under appropriate environmental conditions to avoid contamination and cross-contamination.

This chapter applies to active substances or intermediates thereof manufactured by cell culture or fermentation using natural or recombinant organisms.

This Chapter applies as from the point at which a vial of the cell bank is retrieved for use in the manufacturing of an active substance or intermediates thereof.

For active substances or intermediates manufactured by means of cell culture or fermentation, the control of bioburden, viral contamination and endotoxins during the manufacture as well as monitoring of the process at appropriate stages may be necessary depending on the source, method of preparation and the intended use of the active substance or intermediate thereof.

Appropriate equipment and environmental controls shall be used to minimise the risk of contamination. The acceptance criteria for environmental quality and the frequency of monitoring shall depend on the step in the production and the production conditions (open, closed or contained systems).

Process controls shall take into account:

Where appropriate, the removal of media components, host cell proteins, other process-related impurities, product-related impurities or contaminants shall be demonstrated.

Access to cell banks shall be limited to authorised personnel.

Cell banks shall be maintained under storage conditions designed to maintain cell viability and prevent contamination. The international guideline ICH Q5A Guideline shall be taken into account.

Records of the use of the vials from the cell banks and storage conditions shall be maintained.

Where appropriate, cell banks shall be periodically monitored to determine suitability for use.

Where aseptic addition of cell substrates, media, buffers and gases is needed, closed or contained systems shall be used where possible. If the inoculation of the initial vessel or subsequent transfers or additions (media, buffers) are performed in open vessels, there shall be controls and procedures in place to minimise the risk of contamination.

Where the quality of the active substance can be affected by microbial contamination, manipulations using open vessels shall be performed in a biosafety cabinet or similarly controlled environment.

Personnel shall be appropriately gowned and take special precautions handling the cultures.

Critical operating parameters (e.g. temperature, pH, agitation rates, addition of gases, pressure) shall be monitored to ensure compliance with the established process. Cell growth, viability (for most cell culture processes), and where appropriate, productivity shall also be monitored. Critical parameters will vary from one process to another, and for classical fermentation, certain parameters (e.g. cell viability) may not need to be monitored.

Cell culture equipment shall be cleaned and sterilised after use. As appropriate, fermentation equipment shall be cleaned and sanitised or sterilised.

Culture media shall be sterilised before use where appropriate to protect the quality of the active substance.

Appropriate procedures shall be in place to detect contamination and to determine the course of action to be taken. Those procedures shall include instructions on how to determine the impact of the contamination on the product and to decontaminate the equipment and return it to a condition to be used in subsequent batches. Foreign organisms observed during fermentation processes shall be identified as appropriate and the effect of their presence on product quality shall be assessed, if necessary. The results of those assessments shall be taken into consideration in the disposition of the material produced.

Records of contamination events shall be maintained.

Use of shared (multi-product) equipment shall be based on a risk assessment and may warrant additional testing after cleaning between product campaigns, as appropriate, to prevent the risk of cross-contamination.

Harvesting steps, either to remove cells or cellular components or to collect cellular components after disruption, shall be performed in equipment and areas designed to minimise the risk of contamination.

Harvest and purification procedures to remove or inactivate the producing organism, cellular debris and media components (while minimising degradation, contamination, and loss of quality) shall be adequate to ensure that the intermediate or active substance is recovered with consistent quality.

All equipment shall be properly cleaned and, as appropriate, sanitised after use. Multiple successive batching without cleaning may be used if intermediate or active substance quality is not compromised.

If open systems are used, purification shall be performed under environmental conditions appropriate for ensuring product quality.

Additional controls, such as the use of dedicated chromatography resins or additional testing, may be appropriate if equipment is to be used for multiple products. Introduction of those methods is subject to risk assessment.

Viral removal and viral inactivation steps shall be performed within their validated parameters.

Appropriate precautions shall be taken to prevent potential viral contamination from pre-viral to post-viral removal or inactivation steps. Open processing shall be performed in areas that are separate from other processing activities and have separate air handling unit.

The same equipment shall normally not be used for different purification steps. In those cases where the same equipment is used, the equipment shall be appropriately cleaned and sanitised before re-use.

Appropriate precautions shall be taken to prevent potential virus carry-over (e.g. through equipment or environment) from previous steps.

The production of active substance gases through a continuous process (e.g. air separation) shall be continuously monitored for quality. The results of this monitoring shall be kept in a manner permitting trend evaluation.

Transfers and deliveries of cryogenic and liquefied gas and the filling and labelling of cylinders and mobile cryogenic vessels shall comply with the requirements laid down in Sections V.6.1 and V.6.2 of Annex III to Implementing Regulation (EU) 2025/2091 on good manufacturing practice for veterinary medicinal products.