Pharmaceutical Flow Wrap: Wrapping Blisters, Devices and Kits

Pharmaceutical flow wrap is a horizontal form-fill-seal process that wraps a single item or a group in a film pillow pack, with a fin seal along the back and a crimp seal at each end. In pharma and healthcare it is used for blister strips, small devices, kits and bundles. Define the intended protection role before specifying the film. The flow wrap format guide and flow wrapper film guide cover general operation.

Decide the wrap’s job first

Ordinary sealing or equipment described as clean-room compatible does not establish a validated sterile barrier. For terminally sterilized medical devices, ISO 11607 distinguishes packaging-system requirements from forming/sealing process validation; the medical packaging guide explains this scope.

What gets flow wrapped in pharma

Blister strips and cards

Blisters are often already protected by their forming web and lid. A flow wrap adds another layer. It can hold several blisters together, carry extra print, protect the foil from abrasion and, with the right film, add moisture barrier. For the blister itself see pharmaceutical blister packaging.

Secondary bundling

Blisters or small cartons are bundled in groups for hospital or institutional supply. A flow wrap holds the stack together and keeps it clean, without a carton.

Medical devices and kits

Syringes, swabs, dressings, tubing sets and procedure kits are commonly flow wrapped. If the item must stay sterile through use, the wrap is part of a sterile barrier and must meet medical packaging rules; see medical device packaging materials. Flow wrap used only for hygiene or dust protection has lighter requirements.

Barrier and protective overwraps

For barrier overwraps, evaluate barrier film or metallized film against the declared protection role.

Barrier values depend on test temperature and humidity, so compare supplier numbers only under matching conditions. A film with excellent flat barrier is only as good as its fin and crimp seals, because those are the weak points.

Peelable flow packs for medical items

Medical items in flow wraps often need to open by peeling rather than by tearing the film. Peelable constructions use a seal layer designed to separate cleanly at the seal, so the user can pull the faces apart without cutting. Seal strength has to sit in a window: strong enough to survive distribution, weak enough to open easily. Check the construction against the sterilization method if sterile claims apply, since not every film suits every process.

Film choices

Manufacturer public data distinguish clear, white and metallized BOPP grades. Appearance alone does not prove the light protection needed by a drug; obtain the exact grade’s optical evidence. Film must also run on the machine: stiffness, coefficient of friction, seal temperature range and gauge consistency all affect tracking and sealing.

Running pharma products on a flow wrapper

Confirm infeed and film behavior with the actual product.

• Product infeed: blister strips must be spaced and oriented consistently. Flighted conveyors and servo infeeds reduce jams and avoid seals landing on product.
• No product, no bag: sensors that stop film advance when an item is missing prevent empty packs and wasted film.
• Seal area contamination: powder or dust from tablets can end up in the fin or end seals and cause leaks. Good extraction and clean infeed help.
• Registered print: pre-printed film needs a registration mark sensor and tension control so the print falls in the same place on every pack.
• Pack looseness: a tightly wrapped item can stress blister cavities, so keep film fit snug but not compressive.

Clean-room and hygienic machine considerations

Pharma and medical lines usually work under tighter conditions than food lines.

• Cleanability: smooth surfaces, few crevices, materials that tolerate cleaning agents.
• Particle control: minimize lubricants, dust and abrasion on film paths; low-particle film trims and waste handling.
• Clean-room operation: equipment and film may need to run in a controlled environment, and film reels need appropriate handling and unpacking.
• Changeover and segregation: thorough line clearance between products, with controls against mix-ups.
• Documentation: equipment qualification, material traceability and batch records.

These requirements vary by company, product and market, so settle them with your quality team and machine supplier.

Printing and coding

Flow wraps carry product name, batch and expiry, and sometimes serialization or tracking codes. Options include pre-printed film with registration marks, and inline thermal transfer, inkjet or laser coding. Points to check:

• Registration mark reading so print stays aligned with the product and seals.
• Code contrast and adhesion on the chosen film, including metallized surfaces.
• Vision verification of code content and presence after sealing.
• Cleanliness of coding technologies in the environment.

Line acceptance record

Define pack role, product dimensions/edges, film grade, speed and acceptance criteria before the trial.

ASTM F88/F88M-23 measures force to separate a seal test strip and records failure mode. It does not establish whole-wrap leak tightness, drug stability or sterility. Add the integrity and product/system validation appropriate to the declared wrap role.

The supplier evaluation guide helps organize material traceability, change control and trial evidence.

Sources

Reviewed 8 October 2026: ASTM F88/F88M-23 above covers seal-strength testing. ISO 11607-1:2019 covers materials and sterile barrier/packaging systems for terminally sterilized medical devices; ISO 11607-2:2019 covers validation of forming, sealing and assembly processes. Manufacturer public documentation distinguishes opaque/metallized BOPP grades; the exact grade reference is recorded in the editorial evidence log, without a product endorsement.