Aluminium foil for pharmaceuticals capsule packaging
In pharmaceutical manufacturing, packaging plays a crucial role in ensuring product integrity, safety, and efficacy. Among the varied packaging materials, aluminium foil has emerged as a preferred material for capsule packaging owing to its unrivaled barrier properties and mechanical performance.
Pharmaceutical capsules demand a packaging medium that not only preserves the active ingredients but also withstands mechanical stresses during storage, transport, and handling. Aluminium foil meets these criteria by providing:
- Superior barrier effectiveness against moisture, oxygen, light, and contaminants
- Controlled mechanical strength and malleability for versatile packaging formats
- Compatibility with secondary packaging and pharmaceutical regulatory standards
the precise material properties and technological requisites helps explain the widespread use of aluminium foil in pharmaceutical encapsulation.
2. Features of Aluminium Foil for Capsule Packaging
2.1. Pharmacoprotective Barrier Properties
The integrity of capsules containing sensitive active pharmaceutical ingredients (APIs) depends on shielding masses from oxidation, moisture ingress, and ultraviolet (UV) radiation. Aluminium foil naturally serves as a formidable barrier, combining physical and chemical resistance traits:
| Parameter | Specification | Pharmaceutical Advantage |
|---|---|---|
| Moisture Transmission Rate (MTR) | ≤0.01 g/m²/day (depending on thickness) | Prevents hygroscopic degradation |
| Oxygen Transmission Rate (OTR) | Negligible: virtually zero at typical foils >16μm | Shields oxygen-sensitive APIs from oxidation |
| UV & Visible Light Transmission | Near 0% | Prevents photodegradation of photo-labile drugs |
With commercial foils commonly manufactured between 6 to 30 microns thickness, layering of foil with heat-sealable polymer laminates ensures hermetic sealing in complex cold-formed packaging.
2.2. Mechanical and Metallurgical Characteristics
Balancing strength and flexibility is critical, particularly for cold form blister packs involving aluminium foil:
- Temper Conditioning: Aluminium foil of 1000-series alloys (usually 1050A or 1200 series) is supplied in soft (O) temper or various combination tempers (H18, H24) tailored for folding and forming.
- Tensile Strength: 100 – 140 MPa depending on temper state enables foil to resist punctures and breakage during assembly.
- Ductility and Elongation: Typically 10–40% elongation allowing for blister cavity forming with minimal tearing risk.
An explicit of alloying, heat treatments, and temper states improves foils’ mechanical resilience.
3. Aluminium Foil Composition and Temper Specifications
The chemical purity and select alloy tempering impact encapsulated pharmaceuticals efficiency significantly:
| Chemical Element | Max. wt% Content (AL 1050A) | Role/Impact In Pharmaceutical Foils |
|---|---|---|
| Aluminium (Al) | >= 99.5% | Base metal ensuring purity & barrier quality |
| Iron (Fe) | ≤ 0.4% | Minor mechanical strengthening, affects corrosion |
| Copper (Cu) | ≤ 0.05% | Negligible in pharmaceutical-grade foil |
| Silicon (Si) | ≤ 0.25% | Enhances rigidity, small impact on foil forming |
| Zinc (Zn) | ≤ 0.05% | Renders hardness indirectly, often minimized |
| Temper Code | Typical Hardness | Tensile Strength (MPa) | Suitable Application |
|---|---|---|---|
| O (Annealed) | Very soft | 70–90 | Flexible blisters where extreme formability required |
| H18 (Half-hard) | Medium hard | 140–160 | Standard blister forming balancing strength & ductility |
4. Instrumental Applications of Aluminium Foil in Pharmaceutical Capsules Packaging
4.1. Cold Formed Blister Packaging
This involves forming cavities by pressing aluminium foil over capsule units using heat and pressure, creating tightly sealed, moisture-impermeable packaging. benefits include:
- Complete hermetic sealing, including side and bottom protection.
- Capability to modify foil tempers based on the pharmaceutical agent’s sensitivity.
- Improved ease of opening with engineered foil thickness for patient compliance.
4.2. Strip Foil Applications
Simpler pharmaceutical packaging utilizes two-part foil strips formed by laminating thin aluminium foil and sealing every capsule individually. Features of strip foil packaging include:
- High barrierefficiency when coupled with polymer films,
- Customized alloys adjustment to regulatory requirements,
- Flexible laminate structures enhancing printing durability for product traceability.
5. Regulatory and Safety Considerations
Pharmaceutical aluminium foils must conform to international standards such as:
- Ph. Eur. (European Pharmacopoeia) standards that regulate heavy metals and spurious element levels.
- US FDA 21 CFR Part 175.105 specifying food-contact materials requirements for materials simultaneously employed with drugs.
- Purity levels essential to prevent undesired metal migration into capsules.
Robust quality assurance through alloy certification, non-destructive integrity tests, and periodic ICP-MS chemical analysis is critical for quality compliance.
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