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WHO TRS 961: GMP Annexes for Pharmaceutical Manufacturing

WHO TRS 961: GMP Annexes for Pharmaceutical Manufacturing

WHO Technical Report Series 961 is the World Health Organization report that carries several of the WHO good manufacturing practice (GMP) annexes, including the WHO GMP main principles and WHO GMP for sterile pharmaceutical products. Published in 2011 as the forty-fifth report of the WHO Expert Committee on Specifications for Pharmaceutical Preparations, TRS 961 is a widely referenced GMP source, particularly for manufacturers supplying WHO-prequalified products and for exporters in markets like India. It sets out how medicines, including sterile injectables, should be manufactured and controlled, which reaches through to the packaging and container closure system.

This guide explains what TRS 961 is, which GMP annexes it contains, why it matters for Indian exporters and WHO-prequalified vaccine supply, and how a primary-packaging supplier supports it.

Key takeaways

  • WHO TRS 961 is a WHO Technical Report Series volume (2011) that publishes several WHO GMP annexes, adopted by the WHO Expert Committee on Specifications for Pharmaceutical Preparations.
  • Its most cited annexes are Annex 3, WHO GMP main principles for pharmaceutical products, and Annex 6, WHO GMP for sterile pharmaceutical products; it also carries annexes on blood establishments and HVAC for non-sterile dosage forms, among others.
  • WHO GMP is the basis for WHO prequalification, so manufacturers supplying UN agencies (for vaccines and other medicines) work to these principles.
  • For sterile products, Annex 6 covers cleanroom classification, aseptic processing, and sterilisation, all of which frame how a sterile vial closure is handled and validated.
  • WHO GMP is a set of principles and guidance, not a national law; national regulators such as India’s CDSCO implement equivalent GMP in their own rules.
  • A packaging supplier supports WHO GMP indirectly, through its own quality system and by supplying qualified, documented, and where required sterile components.

What is WHO TRS 961?

WHO TRS 961 is the volume of the WHO Technical Report Series that contains the forty-fifth report of the WHO Expert Committee on Specifications for Pharmaceutical Preparations, together with its annexes. It is published by the World Health Organization, which convenes the expert committee to adopt norms and standards for medicines quality.

The WHO Technical Report Series is how the WHO issues the reports and adopted guidance of its expert committees. TRS 961 gathers a set of GMP and quality-assurance texts as numbered annexes, so referring to “TRS 961” usually means referring to one of those annexes. Because WHO guidance is used worldwide, especially where national standards defer to or build on it, TRS 961 has been a standard reference for GMP, particularly for sterile products.

The GMP annexes in TRS 961

TRS 961 carries several annexes; the two most relevant to injectable packaging are the WHO GMP main principles and WHO GMP for sterile pharmaceutical products. The key annexes include:

Annex Subject
Annex 3 WHO good manufacturing practices for pharmaceutical products: main principles
Annex 4 WHO GMP for blood establishments
Annex 5 WHO GMP: heating, ventilation and air-conditioning systems for non-sterile dosage forms
Annex 6 WHO good manufacturing practices for sterile pharmaceutical products

Annex 3 sets the general GMP framework: quality management, personnel, premises and equipment, documentation, production and in-process controls, and the control of materials, including packaging. Annex 6 addresses the specific demands of sterile manufacturing: cleanroom air classification (Grades A to D), aseptic processing, and terminal sterilisation, along with the controls that keep a sterile product sterile. For a vial closure, Annex 6 is the frame within which the closure is washed, sterilised, and handled in the fill-finish environment.

Why TRS 961 matters for Indian exporters and WHO-prequalified supply

WHO GMP underpins WHO prequalification and WHO-type GMP certification, which Indian exporters and vaccine suppliers often need to reach international and UN-agency markets. India is a large exporter of generic medicines and vaccines, and access to many public-sector and donor-funded markets runs through the WHO prequalification programme or through GMP recognition based on WHO principles.

  • WHO prequalification. Manufacturers seeking to supply UN agencies (for example for vaccines through UNICEF and Gavi) must demonstrate GMP compliance consistent with WHO standards, which trace back to texts like those in TRS 961.
  • WHO-GMP certification. Indian manufacturers frequently obtain a WHO-GMP certificate (a Certificate of Pharmaceutical Product, or CoPP-linked GMP evidence) to support exports, benchmarked against WHO GMP.
  • Sterile and vaccine supply. For injectable vaccines, Annex 6 sets the aseptic and sterilisation expectations that shape how the whole container closure system, including the seal, is prepared and handled. The closure choices behind that are set out under vaccine vial closures.

For a packaging supplier serving these exporters, that means supplying components, and where relevant sterile, ready-to-use components, that fit into a WHO-GMP-compliant fill-finish operation.

How a packaging supplier supports WHO GMP

WHO GMP applies to the drug manufacturer; a primary-packaging supplier supports it by operating a GMP-aligned quality system and supplying qualified, documented, and where required pre-sterilised components. The manufacturer is responsible for its own WHO GMP compliance and for validating its aseptic process, but it depends on packaging that is consistent, traceable, and compatible with sterile handling. A seal supplier supports that by certifying to ISO 15378 (the GMP-aligned standard for primary packaging materials), by offering ready-to-use components sterilised by validated methods, and by providing the certificates and documentation the customer needs. Ready-to-use sterile seals in particular fit an aseptic fill-finish line, reducing the sterilisation and handling steps the drug maker performs in-house. The mechanics of that step are covered under sterile vial sealing, and the seal is one part of the container closure system the annex holds responsible, as set out in rubber stopper and aluminium seal pairing.

Seal specifications for a WHO-GMP fill-finish line

The seal sizes that pair with WHO-prequalified injectable and vaccine formats are 13, 20, 28, 32, and 34 mm, and the figures below are the dimensional and handling data a qualification file needs. Annex 6 does not specify closure dimensions, so the controlling numbers come from the component drawing and the customer’s own vial and crimping setup. These are the values for the FlipTop Optima aluminium-plastic flip-off range, the format most often used on vaccine and parenteral vials.

Size Total seal height (mm) Aluminium thickness (mm) Max opening force (N) Standard packing per box
13 mm 7.62–8.38 0.16–0.20 30 15,000 (5,000 × 3 bags)
20 mm 9.02–9.91 0.16–0.20 35 6,000 (2,000 × 2 bags)
28 mm 11.06–12.06 0.17–0.23 35 3,000 (1,500 × 2 bags)
32 mm 14.30–15.50 0.21–0.25 65 1,400 (700 × 2 bags)
34 mm 15.00–16.00 0.20–0.25 Available on request Available on request

Shipper box dimensions are 420 × 270 × 320 mm across the range, and Tyvek bagging is available where the aseptic transfer procedure calls for it. Maximum opening force varies with the number of bridges on the seal design, so a Bridge, Button, or Flower selection changes the figure within the range the drawing allows. Full dimensional drawings for a given size sit on the seal size index, and the same aluminium-plastic construction is available as pull-ring and tear-down seals where the whole closure has to come away in one action.

How a compliant supply meets WHO GMP

A supply is WHO-GMP-ready when the component’s quality system, material declarations, acceptance sampling, and sterile presentation all carry documentation the drug maker can file. Autofits supplies against that set.

Quality system and registrations. Manufacture runs under ISO 9001:2015, ISO 14001:2015, and ISO 15378:2017, the GMP-specific standard for primary packaging materials that Annex 3’s material-control expectations map onto. A Drug Master File (DMF 18100) and CFDA registration B20200000501 are on record, which is what a customer’s regulatory affairs team references when it files the packaging component.

Acceptance quality limits. Inspection is to AQL critical nil, major NMT 2.5%, and minor NMT 4%, and the limits are tailorable where a customer’s own sampling plan is tighter. Every seal passes 100% high-speed camera inspection before packing, so the AQL sampling sits on top of a full-population check rather than replacing it.

Material compliance. The aluminium is AA8011 alloy conforming to EN 15088:2005 with EN 10204-3.1 certification. The epoxy lacquer conforms to 21 CFR 175.300 and the polypropylene disc to 21 CFR 177.1520 and EC 1895/2005, with BADGE, NOGE, and BFDGE not used. Components are BSE/TSE-free to EMEA/410/01 rev. 3, and heavy metals (chrome-VI, cadmium, mercury, lead) are held to a maximum of 100 ppm total to EN 602 and EC 94/62. For a WHO-prequalified vaccine dossier, those declarations are the material half of the packaging section.

Forms of supply. Seals ship in three forms. Regular is the standard bulk presentation. Ready-to-Use is washed, assembled in an ISO Class 8 cleanroom, sterilised by gamma irradiation or ETO, and double-bagged for direct transfer into an aseptic area, which removes the in-house washing and sterilisation steps Annex 6 would otherwise require the filler to validate. Ready-to-Sterilize is supplied cleaned and bagged for the customer’s own validated sterilisation cycle. The validation basis is set out in sterilization validation for vial closures.

Shelf life. Non-irradiated seals carry 3.5 years before capping plus 5 years after capping. Ready-to-Use sterilised seals carry 2 years before capping. Those figures set the re-test and stock-rotation windows a WHO-GMP inventory procedure has to accommodate.

Requests for a certificate pack, a DMF letter of authorisation, or a sample against a specific vial format go through the contact page, and the certification set is listed in full on the quality page.

How this works in practice at Autofits

Autofits manufactures aluminium and aluminium-plastic vial seals in India, and supports WHO-GMP and export-oriented customers, including vaccine and biologics fillers, with components suited to sterile fill-finish. Autofits offers its seals in Ready-to-Use form, sterilised by gamma irradiation or ETO and supplied double-bagged for aseptic areas, assembled in an ISO Class 8 cleanroom with fully automated washing to control particles. The FlipTop Optima flip-off seals, tear-off and tear-down aluminium seals, and aluminium pilfer-proof (ROPP) caps are produced under an ISO 15378:2017 quality system, alongside ISO 9001:2015 and ISO 14001:2015 certification, a Drug Master File (DMF 18100), and CFDA registration (B20200000501), in a 75,000 sq ft facility in Nashik. The components carry the documentation a WHO-GMP customer needs. The full seal and cap range can be supplied in that ready-to-use form.

Frequently asked questions

What is WHO TRS 961?

WHO TRS 961 is the volume of the WHO Technical Report Series that contains the forty-fifth report of the WHO Expert Committee on Specifications for Pharmaceutical Preparations (2011) and its annexes. Several of those annexes are WHO GMP texts, so a reference to TRS 961 usually means one of its GMP annexes.

Which GMP annexes are in TRS 961?

The most cited are Annex 3, WHO GMP for pharmaceutical products: main principles, and Annex 6, WHO GMP for sterile pharmaceutical products. TRS 961 also carries annexes on GMP for blood establishments and on HVAC systems for non-sterile dosage forms, among others.

Why does WHO GMP matter for Indian exporters?

WHO GMP underpins WHO prequalification and WHO-GMP certification, which Indian manufacturers often need to export to international, public-sector, and donor-funded markets, including UN-agency vaccine supply. Demonstrating GMP consistent with WHO standards is frequently a precondition for those markets.

How does TRS 961 relate to sterile vaccine vials?

Annex 6 of TRS 961 sets the GMP expectations for sterile manufacturing: cleanroom air classification, aseptic processing, and sterilisation. Those requirements frame how the container closure system for a sterile injectable, including the rubber stopper and the aluminium seal, is prepared, sterilised, and handled on an aseptic fill-finish line.

What documentation should a seal supplier provide for a WHO-GMP filing?

A supplier should be able to provide its quality-system certificates (ISO 9001:2015, ISO 14001:2015, and ISO 15378:2017 for primary packaging), a Drug Master File reference where one exists, material declarations covering the aluminium alloy, the lacquer and the polypropylene disc, a BSE/TSE-free statement, heavy-metals limits, the acceptance quality limits applied at inspection, and the sterilisation validation for any ready-to-use presentation. Autofits holds a Drug Master File (DMF 18100) and CFDA registration B20200000501 and inspects to AQL critical nil, major NMT 2.5%, minor NMT 4%.

Can seals be supplied ready to use for an aseptic line?

Yes. Seals are supplied in three forms: Regular, Ready-to-Use, and Ready-to-Sterilize. Ready-to-Use seals are washed, assembled in an ISO Class 8 cleanroom, sterilised by gamma irradiation or ETO, and double-bagged so they can be transferred into an aseptic area without an in-house sterilisation step. Ready-to-Use seals carry a shelf life of 2 years before capping, against 3.5 years before capping plus 5 years after capping for non-irradiated seals.

Is WHO GMP a law?

No. WHO GMP is a set of internationally recognised principles and guidance, not a national law. National regulators, such as India’s CDSCO through Schedule M, implement equivalent GMP requirements in their own rules, and WHO GMP is used as a benchmark for prequalification and export certification.

Related reading

Sources

  • WHO: WHO Technical Report Series, No. 961, 2011, WHO Expert Committee on Specifications for Pharmaceutical Preparations, forty-fifth report (https://www.who.int/publications/i/item/WHO_TRS_961)
  • WHO: TRS 961 Annex 6, WHO good manufacturing practices for sterile pharmaceutical products (https://www.who.int/docs/default-source/medicines/norms-and-standards/guidelines/production/trs961-annex6-gmp-sterile-pharmaceutical-products.pdf)
  • WHO: Prequalification of medicines programme (https://extranet.who.int/prequal/)
  • Autofits Packaging Pvt. Ltd.: FlipTop Seals product dossier and engineering drawings (dimensions, opening force, packing, forms of supply, shelf life, material declarations)

*Last updated: 2026-08-18. This article is general regulatory information, not legal or compliance advice; confirm current regulatory text and requirements with the WHO and the applicable national regulator.*

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