ISO TC 76/SC

ISO/DIS 11040-5:2026(en)

Secretariat: DIN

Fourth edition

2025-12-17

Prefilled syringes — Part 5: Plunger stoppers for injectables

Seringues préremplies — Partie 5: Bouchons-pistons pour produits injectables

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Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 11040‑5 was prepared by Technical Committee ISO/TC 76, Transfusion, infusion and injection, and blood processing equipment for medical and pharmaceutical use.

This fourth edition cancels and replaces the third edition (ISO 11040‑5:2012), which has been technically revised by:

— inclusion of thermoplastic elastomer (TPE) in the introduction

— update of scope to cover plastic barrels and intended use

— update of normative references

— omission of classification

— addition of section “terms & definitions”

— addition of drawing for plungers with cone, thread & coated

— update of dimensions table

— addition of dimensions table for coated plunger stoppers

— addition of dimensions table for plunger stoppers of plastic barrels

— addition of drawing for sterile barrier zone

— omission of designation section

— update of hardness section

— addition of ISO 10993-1 reference in biological requirements

Introduction

Primary packaging components made of either rubber or thermoplastic elastomer (TPE) materials are an integral part of medicinal products. Therefore, the principles of current good manufacturing practices (cGMP) apply to the manufacturing of these components.

Principles of cGMP are described in e.g. ISO 15378 or in the GMP Guidelines published by the European Community and the United States of America.

Prefilled syringes — Part 5: Plunger stoppers for injectables

This part of ISO 11040 specifies the baseline shape, dimensions, material, performance requirements and labelling of plunger stoppers for glass barrels (single-chamber design) for injection preparations in accordance with ISO 11040‑4 and plastic barrels as per ISO 11040-6. The plunger stoppers used in a pharmaceutical packaging/delivery system is proven suitable for its intended use by the customer.

Plunger stoppers specified in this part of ISO 11040 are intended for single use only.

NOTE The potency, purity, stability and safety of a medicinal product during its manufacture and storage can be significantly affected by the nature and performance of the primary packaging.

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 48‑4, Rubber, vulcanized or thermoplastic — Determination of hardness — Part 4: Indentation hardness by durometer method (Shore hardness)

ISO 3302‑1, Rubber — Tolerances for products — Part 1: Dimensional tolerances

ISO 8871‑1, Elastomeric parts for parenterals and for devices for pharmaceutical use — Part 1: Extractables in aqueous autoclavates

ISO 8871‑4, Elastomeric parts for parenterals and for devices for pharmaceutical use — Part 4: Biological requirements and test methods

ISO 11040‑4, Prefilled syringes — Part 4: Glass barrels for injectables and sterilized subassembled syringes ready for filling

ISO 11040‑6, Prefilled syringes — Part 6: Plastic barrels for injectables and sterilized subassembled syringes ready for filling

For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http://www.electropedia.org/

— ISO Online browsing platform: available at http://www.iso.org/obp

3.1

customer

business entity which purchases primary packaging components and conducts further processing or filling as appropriate

[SOURCE: ISO 11040-4:2024, 3.1 – modified: “primary packaging components” instead of “syringe barrels or sterilized subassembled syringes ready for filling”]

3.2

manufacturer

business entity which performs or is otherwise responsible for the manufacturing of primary packaging components for the customer

[SOURCE: ISO 11040-4:2024, 3.4 – modified: “primary packaging components” instead of “syringe barrels or sterilized subassembled syringes ready for filling”]

3.3

plunger stopper

elastomeric syringe closure, which seals the back end of the syringe

[SOURCE: ISO 11040-4:2024]

3.4

laminated/coated plunger stopper

laminated/coated plunger stopper consists of a bulk of rubber, bearing on its surface or part of its surface a layer of a different polymer having barrier characteristics.

[SOURCE: Ph. Eur. 3.2.9 – modified: added “laminated”]

3.5

syringe barrel

cylindrical glass/plastic body with front end and finger flange as back end

[SOURCE: ISO 11040-4:2024, 3.9 – modified: added “plastic”]

3.6

prefilled syringe

container system filled with the injectable product ready for injection

[SOURCE: ISO 11040-4:2024]

4.1 The shape and dimensions of plunger stoppers shall be as shown in Figure 1 and given in Tables (1, 2 & 3) for glass and plastic barrels. The plunger designs can have two or more ribs. The customer should perform a dimensional analysis to ensure that their selection of plungers and barrels, within the ranges of table 1, table 2 and table 3, will ensure appropriate sealing.

Note: In order to ensure functional performance during certain storage & intended use conditions (like Container Closure Integrity), plunger stoppers with alternate dimensions can be used, as agreed upon between the manufacturer and the customer.

Key

1 film laminated surface

2 coated surface

Figure 1 — Shape and dimensions of plunger stoppers for a prefilled syringe

NOTE Thread pitch dimensions can be agreed between the manufacturer and the customer.

Table 1 — Dimensions of plunger stoppers used in glass barrels

Dimensions in millimeters

Table 2 — Dimensions of laminated/coated plunger stoppers used in glass barrels

Dimensions in millimeters

Table 3 — Dimensions of plunger stoppers used in plastic barrels

4.2 The plunger stopper is designed to move for administration of the injectable product, but unintended movement can compromise container closure integrity and sterility. Such movement may occur due to air pressure or temperature changes, phase transitions, or assembly forces. Risks related to plunger stopper movement shall be assessed during the delivery system design and development. If the plunger stopper moves beyond the length of the sterile barrier zone, defined by the sealing contact areas at its first and last ribs, sterility may be lost. To maintain sterility, the movement of the plunger stopper should not exceed the length of the sterile barrier zone, Lsb. The theoretical length of this zone is determined by the design features of the respective plunger stopper ribs. The complete system testing is described in ISO 11040-8.

Key

L_SB length of sterile barrier zone

Figure 2 — Sterile barrier zone of plunger stopper

4.3 If not otherwise specified, general dimensional tolerances shall be Class M3 in accordance with ISO 3302‑1.

4.4 In order to prevent the plunger stoppers from adhering to each other, there should be anti-stick features (when needed). The height of the anti-stick features shall not exceed 0,3 mm.

The shape of the anti-stick features should be agreed upon between the manufacturer and the syringe assembler/customer.

4.5 Sprues, if present on the surface of the plunger stopper, shall not protrude beyond the surface of the plunger stopper.

4.6 The performance and dimensions of the plunger stopper thread shall be compatible with the plunger rod. The plunger stopper shall not detach itself from the rod under the intended use, e.g. aspiration.

The elastomeric material used shall meet the requirements specified in Clause 6.

Plunger stoppers shall be made from the elastomeric formulation originally tested and approved by the customer. The manufacturer of the plunger stopper shall ensure the conformance of each delivery with the type sample and compliance with previously agreed functional and compendial requirements.

The requirements specified in 6.2 to 6.4 constitute minimum requirements concerning the condition of the elastomeric plunger stopper on receipt by the customer.

The hardness agreed between manufacturer and customer shall not differ from the nominal value by more than ±5 International Rubber Hardness Degrees (IRHD, for highly elastic rubber comparable to Shore A) when tested in accordance with ISO 48-4 on a special test specimen.

The manufacturer should provide suitable test specimens upon request.

The plunger stoppers shall maintain their performance characteristics throughout the entire shelf-life of the component, established by the manufacturer.

NOTE Ageing depends on storage and handling conditions. A guide to storage of vulcanized rubber and TPE is given in ISO 2230.

The outer surface of the plungers may be lubricated. Limit values of the amount of lubricant are subject to agreement between the manufacturer and the customer.

NOTE 1 Lubrication of the outer surface of the plunger is applied in order to improve gliding properties. This is usually done by siliconization (i.e. by application of a silicone oil or silicone emulsion) or lamination/coating.

NOTE 2 ISO 11040-4:2024, Annex E, includes a suitable test method for the determination of the quality and consistency of the lubrication using a gliding force test. 6.3 Chemical requirements

The aqueous extractables of the plunger stopper material shall not exceed the limits specified for elastomeric parts defined in ISO 8871‑1.

The requirements in ISO 8871‑4 shall apply.

If relevant, biological hazard assessment can be performed according to ISO 10993-1.

Labelling is subject to agreement between the manufacturer and the customer.

Bibliography

[1] ISO 2230, Rubber products — Guidelines for storage

[2] ISO 3302‑2, Rubber — Tolerances for products — Part 2: Geometrical tolerances

[3] ISO 10993‑1, Biological evaluation of medical devices — Part 1: Requirements and general principles for the evaluation of biological safety within a risk management process

[4] ISO 11040‑8, Prefilled syringes —Part 8: Requirements and test methods for finished prefilled syringes

[5] ISO 15378, Primary packaging materials for medicinal products — Particular requirements for the application of ISO 9001:2015, with reference to good manufacturing practice (GMP)