Overview
ISO 13926-2:2017 defines requirements for plunger stoppers for pen-injectors for medical use. The standard covers material, performance, labelling and gives recommended shapes and dimensions for elastomeric plunger stoppers that form the primary contact surface between drug and container. It emphasises the role of primary packaging in maintaining potency, purity, stability and safety of medicinal products.
Key topics and technical requirements
- Scope and classification: Plunger stoppers are classified as Type A1 (with ribs), A2 (without ribs) and A3 (with ribs and dome).
- Shape & dimensions: Typical dimensional examples are provided; final dimensions (including heights and certain diameters) are agreed between manufacturer and user. Spacers to prevent adhesion are required (height ≤ 0.3 mm).
- Materials: Elastomeric formulations must be those originally tested and approved by the end user. Materials must withstand two autoclave cycles at (121 ± 2) °C for 30 min without functional impairment; alternative sterilization routes must be evaluated.
- Physical performance:
- Hardness: Agreed nominal hardness ±5 Shore A (or ±5 IRHD if tested per ISO 48) on appropriate test specimens (ISO 7619-1 referenced).
- Freedom from leakage: Cartridges must be leak-free at the plunger when tested per the Annex A leakage test (force is calculated using the glass cylinder inner diameter and a correction factor of 0.64 N/mm²).
- Initiating/sustaining forces and resistance to ageing: Requirements reference system-level testing and stability validation; shelf-life performance must be demonstrated by the medicinal product stability programme.
- Chemical & biological: Extractables/chemical and biological requirements reference ISO 8871-1 and ISO 8871-4.
- Labelling & designation: Standardized designation format (example: “Plunger ISO 13926-2 – 6,85 – A1”) for compliant packed plungers.
Applications and who uses this standard
ISO 13926-2:2017 is used by:
- Manufacturers of pen-injector plunger stoppers and elastomeric components
- Pen-injector system designers and drug-device combination developers
- Pharmaceutical formulation and primary packaging teams validating container-closure compatibility
- Quality, regulatory and contract testing laboratories performing physical, chemical and biological testing
- Suppliers of glass cylinders and seals who must validate compatibility per ISO 11608-3
Practical applications include component specification, supplier contracts, product validation, leakage testing, sterilization qualification and stability programmes for drug-delivery systems.
Related standards
Keywords: ISO 13926-2:2017, plunger stoppers, pen-injectors, elastomeric materials, leakage test, primary packaging, medical device standards.
