An oral strip is a thin hygroscopic film, so the sachet is part of the formulation. Use a foil laminate (PET/aluminum/PE) for anything with a shelf-life claim or a moisture- or oxygen-sensitive active; metallized film is a cost option only when the data supports it. Carton counts from 10 to 60 cover retail, and every sachet needs lot and expiry coding.
| Structure | OTR | WVTR | Use for strips |
|---|---|---|---|
| PET / aluminum foil / PE | about 0.001 to 0.1 | about 0.001 to 0.1 | Default; any dated product |
| PET / metallized PET / PE | 1 to 5 | 0.5 to 3 | Short-dated, bland, with data |
| Oxide-coated PET laminate | 0.5 to 2 | 1 to 3 | Clear window; rarely justified |
| Plain PE or PP | > 100 | > 10 | Not for strips |
The film and the sachet are one system
Cast films equilibrate with the air. In one study water content rose from about 2 % at 44 % RH to 7 % at 75 % RH and tensile strength fell with it; pullulan films took up the most. A strip that leaves the line at 5 % moisture and reaches 8 % in a leaky pouch is soft, tacky, and slower to dissolve.
Laminate numbers
Foil laminates (PET/AL/PE, foil 6 to 20 μm) are effectively impermeable: published OTR and WVTR sit around 0.001 to 0.1 per m² per day. Metallized PET is the next tier at roughly 1 to 5 cc and 0.5 to 3 g, with pinholes and flex cracking as failure modes. Plain PE is above 100 and 10. Our default is PET/aluminum/PE with no desiccant: a foil pouch does not need one, and a desiccant beside a strip that dissolves in the mouth is a hazard.
A decision rule
Foil if any of these is true: a 12 month or longer shelf-life claim, a hygroscopic or oxidizable active, a probiotic or enzyme, a volatile flavor, or humid export markets. Metallized film only for short-dated, bland strips backed by 40 °C/75 % RH data in that structure. Unpouched strips in a flip-top case, as PocketPaks are sold, suit breath strips with no dose to protect.
Cartons and counts
The buprenorphine/naloxone film comes 30 per carton in child-resistant polyester/foil pouches. A DailyMed-listed simethicone strip is sold 10, 30, or 100 per carton in peel-open pouches labeled "use strip immediately after opening" and "store below 77 °F (25 °C)." A retail 3 mg melatonin strip is 30 per box with "keep strips individually sealed until use." Our cartons run 10 to 60; the pilot is 500 boxes at 20 or 30.
Artwork fields and review
Sachet: product name, strip content, lot, expiry. Carton: full label panel, barcode, storage line, count. Lot and expiry are coded at packaging, so leave a window on both. Seal integrity and coding are checked on every lot, and the material ID and artwork version go in the Lot Release Packet.
Worked example: a 30-count melatonin strip
A hypothetical brand, Harbor Sleep, ships 3 mg melatonin strips at 30 per box. The 22 × 32 mm strip goes in a 45 × 60 mm peel-open sachet of 12 μm PET / 7 μm aluminum / 40 μm PE. Thirty stack flat in a tuck-end carton. The 500-box pilot is 15,000 sachets, about 900 m of web at a 60 mm pitch before setup waste, which is the number your converter quotes against.
Questions for your packaging quote
Components in scope, minimums, print lead time, proofing, laminate structure in microns, whether the stock is proven with the coder, and what happens to leftover printed web.
Common questions
Not in a foil sachet. The film's moisture is set at drying and the laminate holds it there. A desiccant in a carton of loose sachets does nothing; a desiccant inside a single-strip sachet is a hazard.
Only for undosed products. Once opened, every strip in the pouch equilibrates to room humidity within days.
Primary sources
- Orally disintegrating films: the effects of water content on disintegration and mechanical properties (J Drug Deliv Sci Technol, 2021)
- High-barrier packaging for pet supplements: OTR/WVTR by structure
- Aluminized PET film vs aluminum foil: barrier performance
- PET/AL/PE barrier bags and flexible packaging
- PET/VMPET/PE barrier packaging guide (typical layer gauges)
- SUBOXONE sublingual film prescribing information (FDA label, 2021)
- DailyMed: Anti-Gas Strip, simethicone 62.5 mg oral strip (Drug Facts label)
- Solves Strips Melatonin Dream Mint, 3 mg, 30-count product label
- Listerine PocketPaks Cool Mint breath strips, ingredient listing (CVS)
Formula feasibility, packaging, testing, claims, timing, and final quantities depend on the exact product. Use this guide to prepare better questions, then confirm the production plan for your project.