Pharmaceutical aluminium foil specification
11,450 Views 2025-06-16 01:09:41
Pharmaceutical aluminium foil plays a vital role in protecting medicines from moisture, light and oxygen.
Manufacturers design foil to meet stringent barrier, mechanical and regulatory requirements.
This post unpacks every aspect of pharmaceutical aluminium foil specification so you can understand material choices, key performance metrics and industry standards.
1. Alloy, Temper and Purity
Pharmaceutical foil typically uses high‑purity aluminium (≥ 99.0 %) in alloys such as 8011, 8021 or 1235.
Producers select alloy 8011 when they need superior formability for tight radii; 8021 aluminum foil offers enhanced strength for robust blister packs.
Temper (O for annealed “soft” or H14/H18 “hard”) determines flexibility vs. push‑through force:
- Soft foil (O‑temper) resists tearing, boosts child‑resistance.
- Hard foil (H14/H18) breaks cleanly under low force, easing patient access.
Purity and temper directly influence barrier performance, seal integrity and cold‑forming behavior—cornerstones of any pharmaceutical aluminium foil specification.
Pharmaceutical aluminium foil specification
2. Foil Types and Coating Structure
Producers classify pharmaceutical aluminium foil into four main types:
| Foil Type | Construction | Typical Thickness (µm) | Main Application |
|---|---|---|---|
| Bare Blister Pack | 100% aluminium, uncoated | 20 – 25 | Push‑through blisters |
| Coated Blister Pack | Alu foil + primer + heat‑seal lacquer | 20 – 25 | Heat‑sealed blister packs |
| Strip Pack | 100% aluminium, uncoated | 30 – 40 | Strip‑pack (peel‑push) |
| Pharma Laminate | Alu foil laminated to LDPE/paper + seal lacquers/prints | 30 – 40 | Child‑resistant peel‑off |
Each structure balances barrier efficacy (oxygen & moisture), mechanical strength and manufacturability.
Laminates add secondary layers to improve printability and child‑resistance without compromising foil integrity.
3. Dimensional Range
Pharmaceutical aluminium foil specification always defines width, thickness tolerances and roll geometry. Typical parameters include:
- Width: up to 1,600 mm; many lines run ≤ 610 mm or ≤ 700 mm for blister machines.
- Thickness tolerance: ± 8 % for both bare and laminated foil.
- Roll core: internal diameter 76 mm; maximum outer diameter 240 – 500 mm.
Such strict controls ensure seamless feeding in automated packaging lines and consistent barrier performance across batches.
4. Mechanical Properties
Foil must resist pinholes, maintain bursting strength and seal reliably:
- Pinhole count: fewer than 25 holes/m² at 20 µm; drops to 5 holes/m² above 40 µm.
- Bursting strength: minimums vary by type—higher for strip packs, lower for blister foils.
- Peel strength (pharma laminate): ensures lamination integrity during handling.
- Seal strength (coated blister & laminate): provides consistent heat‑seal performance without micro‑leaks.
Manufacturers measure these properties per ISO 6636 and IS 16011, then agree specific limits with customers.
5. Surface Condition and Printing
Pharmaceutical aluminium foil specification dictates surface finish: one side glossy (for printing), the other matte (for heat seal).
Printers apply multi‑layer primer plus lacquer to the interior surface:
- Primer (1.0 ± 0.5 g/m²) bonds lacquer to foil.
- Heat‑seal lacquer (4 – 6 g/m²) protects drug from inks and ensures hermetic seal.
Outer‑side printing remains crisp on bright finish. Controlled pigment levels prevent contamination.
Pharmaceutical aluminium
6. Regulatory and Quality Standards
Suppliers certify foil to global norms:
- ISO 6636 (Aluminium blister foils)
- ASTM B479 (Aluminium and aluminium‑alloy foil)
- IS 16011 (India: foil for pharmaceutical packaging)
- YBB 00152002‑2015 (China: blister aluminium foil)
They also comply with Good Manufacturing Practices (GMP) from FDA and EMA.
Each lot arrives with a Certificate of Analysis verifying alloy, thickness, tensile strength and chemical safety of rolling lubricants.
7. Barrier Performance
Aluminium foil offers near‑absolute barrier to light, moisture and gases.
Even a 20 µm foil transmits < 1 g/m²·day water vapor and < 1 cm³/m²·day oxygen. Laminated structures trade a slight increase in vapor transmission for added printability or child‑resistance.
Manufacturers adjust thickness and lamination based on the drug’s hygroscopicity, shelf‑life and storage conditions.
8. Child‑Resistance and Accessibility
Regulators require blister packs to resist pediatric opening yet allow elderly patients easy access.
Soft‑foil laminates demand higher push‑through force, while peel‑push designs use paper/foil laminates to enforce peel‑off before push‑through.
Pharmaceutical aluminium foil specification often includes:
- Push‑through force: 10–20 N for adults, ≥ 25 N for child‑resistance.
- Peel strength: 1–5 N peel‑off for “peel‑push” packs in the USA.
Proper balance achieves compliance with ISO 11469 and ASTM D3475 child‑resistant packaging tests.
9. Customization and Supply
Producers customize foil width, thickness and coating weight to customer lines.
They handle small batches (100 m rolls) up to long reels (2,000 m), with customized core diameters and labelling.
They package foil in moisture‑proof boxes and label per batch, ensuring traceability.
10. Selecting the Right Foil
When specifying foil for your product:
- Assess barrier needs: high‑moisture drugs need thicker or laminated foil.
- Check machine compatibility: confirm width, roll OD and core ID match your blister or strip‑pack lines.
- Define push‑through/peel parameters: specify target force levels for end‑user safety.
- Review regulatory region: choose foil compliant with local pharmacopeia and GMP.
Working closely with suppliers during development ensures the chosen pharmaceutical aluminium foil specification meets both production and patient safety goals.
