Tamper Evident Vial Seals

A tamper evident vial seal is a crimped aluminium or aluminium-plastic closure with a feature that breaks or detaches irreversibly the first time the vial is opened, so interference is visible on inspection. Autofits supplies them in 13, 20, 28, 32 and 34 mm across four designs: FlipTop® Optima flip-off (including the Button design, whose intrinsic tamper evidence comes from a 12-stem flower moulded under the button disc), Pull Ring, Tear-Down and all-aluminium tear-off. Maximum opening force runs 30 N at 13 mm to 65 N at 32 mm, and every seal is 100% camera inspected under ISO 15378:2017.

This page is the product and supply view: which design gives which mechanism, the dimensions that go with each, materials and forms of supply. For the underlying concept, see the explainer on tamper-evident vial closures.

Key takeaways

Tamper evidence is a one-way feature: once the button, ring, disc or metal top is disturbed it cannot be reseated.
The Optima Button design carries intrinsic tamper evidence, with a 12-stem flower moulded under the button disc.
The Tear-Down design opens by pulling and rotating the polypropylene disc anticlockwise, taking the whole seal off the neck.
The Pull Ring design detaches wholly once the polypropylene disc is detached: pull the ring, open anticlockwise, the seal comes away.
Tamper evidence and container closure integrity are separate jobs; the crimp holds the sterile barrier, the tamper feature only reveals opening.
Sizes 13, 20, 28, 32 and 34 mm, with maximum opening force 30 N, 35 N, 35 N and 65 N at 13, 20, 28 and 32 mm.

What makes a vial seal tamper evident

A vial seal is tamper evident when opening it destroys a feature that cannot be restored by hand, so anyone handling the vial afterwards can tell it has been entered. The seal does not prevent opening. It makes opening legible.

That legibility comes from two places. The crimped aluminium skirt is rolled under the vial neck flange during capping and cannot be lifted and reseated without visible deformation. On top of it, each design adds a purpose-built break point: a moulded scoreline on a flip button, a riveted disc that lifts the whole seal, or a perforation in the metal top. Repeatability is then a manufacturing property rather than a design property, because a seal whose geometry or aluminium thickness drifts across a batch breaks unevenly, and an uneven break is harder to read as evidence.

Tamper evidence by closure family

Design	Construction	Tamper-evidence mechanism	Sizes
Optima Button	Aluminium shell, PP button disc	Intrinsic: a 12-stem flower moulded under the button disc, disturbed when the button is lifted	13, 20, 28, 32, 34 mm
Optima Bridge and Flower	Aluminium shell, PP disc	The plastic top snaps at its moulded break point and cannot be reseated; the aluminium stays crimped	13, 20, 28, 32, 34 mm
Pull Ring	Aluminium shell, PP disc with pull ring	Once the PP disc is detached the whole seal detaches: pull the ring, open anticlockwise	20 mm (bridge), 32 mm (flower)
Tear-Down	Aluminium shell, PP disc riveted to alu	The disc is opened, then pulled and rotated anticlockwise so the whole seal comes off	13, 20, 32 mm
Tear-off	All-aluminium, no plastic	The metal top is torn away at the perforation and cannot be reformed	13, 20, 32 mm
Pilfer-proof (ROPP) caps	Aluminium screw cap with tamper band	The band shears from the cap body on first unscrewing	Common ROPP sizes, full range on request

Specify the Button design when tamper evidence is the primary requirement rather than a side effect of the opening action: the 12-stem flower is part of the closure geometry, not an add-on. Where the whole closure has to leave the neck in one visible action, Pull Ring and Tear-Down do that instead, and are the usual choice for oral presentations.

Tamper evidence is not container closure integrity

Tamper evidence shows whether a vial was opened. Integrity keeps the contents sterile, and comes from the stopper held in compression by the crimp. Flipping the button on an Optima seal gives tamper evidence without breaking the sterile barrier, because the aluminium stays crimped. Integrity is verified separately by the methods in USP General Chapter <1207>, covered under container closure integrity testing.

Specifications and sizing

From the Autofits engineering drawings, by design and size. Shipper box 420 × 270 × 320 mm. Values not carried on a drawing are shown as on request.

Design and size	Inner Ø alu (D1)	Outer Ø disc (D2)	Total height	Alu thickness	Bridges or fins
Optima 13 mm	13.36 min	14.99 max	7.62–8.38	0.16–0.20	6 taper
Optima 20 mm	20.22 min	23.14 max	9.02–9.91	0.16–0.20	6 taper
Optima 28 mm	27.60–28.20	30.10–31.10	11.06–12.06	0.17–0.23	8
Optima 32 mm	32.10–32.90	35.50–36.50	14.30–15.50	0.21–0.25	12 taper
Optima 34 mm	33.60–34.00	35.50–36.50	15.00–16.00	0.20–0.25	8 taper
Pull Ring 20 mm	20.00–20.60	22.00–23.00	9.00–10.00	0.18–0.22	6 taper bridges
Pull Ring 32 mm	32.15–32.40	36.20–36.60	14.30–15.30	0.20–0.26	8 fins (flower)
Tear-Down 13 mm	13.30–13.50	14.80–15.40	6.80–8.30	0.18–0.22	Bridge
Tear-Down 20 mm	20.00–20.60	22.00–23.00	8.80–9.80	On request	Bridge
Tear-Down 32 mm	32.40–33.15	35.70–36.70	14.30–15.30	0.20–0.26	8 fins

All dimensions in millimetres. Maximum opening force by size is 30 N at 13 mm, 35 N at 20 and 28 mm and 65 N at 32 mm, varying with the number of bridges. Standard packing runs from 15,000 per box at 13 mm to 1,400 at 32 mm; per-size detail is on the 20 mm and 32 mm pages.

Materials and quality

Shells are AA8011 aluminium alloy to EN 15088:2005, supplied with EN 10204 3.1 certification and tested to BS EN 485-2:2008, REACH and RoHS compliant, with an epoxy lacquer coating to 21 CFR 175.300. Polypropylene buttons, discs and rings are moulded in-house on Japanese Toyo injection machines to IS 10910 and IS 10909, FDA 21 CFR 177.1520 and EC 1895/2005, with BADGE, NOGE and BFDGE not used. Heavy metals (chrome-VI, cadmium, mercury, lead) are limited to a maximum 100 ppm total to EN 602 and EC 94/62, and components are BSE/TSE-free to EMEA/410/01 rev. 3.

Combination seals are made to ISO 8362-6; all-aluminium seals relate to ISO 8362-3. Production runs under ISO 15378:2017, ISO 9001:2015 and ISO 14001:2015, with a Drug Master File (DMF 18100) and CFDA registration, in the 75,000 sq ft Nashik facility. Assembly is in an ISO Class 8 cleanroom, washing is fully automated, and every seal passes 100% high-speed camera inspection. AQL is critical nil, major NMT 2.5%, minor NMT 4%, tailorable. Certificate numbers are on the quality page.

Forms of supply

Tamper evident seals ship Regular (non-sterile), Ready-to-Use or Ready-to-Sterilize. Ready-to-Use seals are washed and assembled in the ISO Class 8 cleanroom, double-lacquered, sterilized by gamma irradiation or ethylene oxide and double-bagged for aseptic areas. Shelf life is 3.5 years before capping for non-irradiated seals, plus 5 years after capping, and 2 years before capping for Ready-to-Use. Tyvek bagging is available.

Colour, finish (glossy, matte, embossed or printed) and marking are set per order, which is how most sites combine the tamper feature with strength coding. Pull Ring seals are often marked for oral use. Minimum order quantities, pricing and lead times are available on request.

Applications

Tamper evident seals are specified wherever the closure has to be checkable before use: multi-dose vaccines, high-value oncology products, and emergency drugs held on trolleys, where an intact seal is the only routine audit check. Match the seal to the vial neck finish first, using the size hub or the serum vial seals page, then choose the design by opening action.

Frequently asked questions

What is a tamper evident vial seal?

A tamper evident vial seal is a crimped aluminium or aluminium-plastic closure with a feature that breaks or detaches irreversibly the first time the vial is opened. The crimped aluminium skirt cannot be lifted and reseated without visible damage, and the plastic button, ring or disc on top gives way at a designed break point. A user can inspect the closure before use and see whether it is intact.

Which vial seal design gives the strongest tamper evidence?

The Optima Button design carries intrinsic tamper evidence: a 12-stem flower is moulded under the button disc, so the evidence is part of the closure geometry rather than a consequence of the opening action. Where the entire closure has to visibly leave the neck, the Pull Ring and Tear-Down designs remove the whole seal in one action instead.

How does a tear-down seal show that a vial has been opened?

A tear-down seal is opened by pulling and rotating the polypropylene disc anticlockwise, which takes the whole seal off the vial neck. The disc is riveted to the aluminium, so the two parts come away together and cannot be refitted. A vial with a missing or partly removed tear-down seal has clearly been entered.

Is tamper evidence the same as container closure integrity?

No. Tamper evidence reveals whether the vial has been opened; container closure integrity keeps the contents sterile and sealed. Integrity comes from the rubber stopper held in compression by the crimped aluminium, and is verified by leak and package-integrity testing. Flipping the button on a flip-off seal gives tamper evidence without breaking the sterile barrier, because the aluminium stays crimped.

What sizes are tamper evident vial seals available in?

Autofits makes them in 13, 20, 28, 32 and 34 mm. The flip-off Optima covers all five sizes; Tear-Down covers 13, 20 and 32 mm; Pull Ring is made at 20 mm as a bridge design and 32 mm as a flower design; all-aluminium tear-off covers 13, 20 and 32 mm. The size refers to the vial neck finish, not the fill volume.

Sources

ISO: ISO 8362-6, Injection containers and accessories, Part 6: Caps made of aluminium-plastics combinations for injection vials (https://www.iso.org/)
ISO: ISO 15378, Primary packaging materials for medicinal products, GMP requirements (https://www.iso.org/standard/70729.html)
USP: General Chapter <1207>, Package Integrity Evaluation, Sterile Products, in the USP-NF (https://www.usp.org/)
EudraLex Volume 4, EU GMP Annex 1, Manufacture of Sterile Medicinal Products (https://health.ec.europa.eu/medicinal-products/eudralex/eudralex-volume-4_en)
Autofits engineering drawings and FlipTop Seals dossier (internal, on file)

*Last updated: 2026-08-18. This page is general technical and product information, not regulatory or compliance advice; confirm current standard editions, material specifications and your own specification with the Autofits technical team and the issuing bodies.*