Amino acid IV infusion solutions require extremely high oxygen barrier protection. Non-PVC soft bag infusion packaging has become the preferred format due to its light weight, environmental friendliness, and transport convenience. However, amino acids such as tryptophan are highly susceptible to oxidative degradation ??higher dissolved oxygen leads to faster degradation, darker color, and reduced product quality. Even with nitrogen blanketing during filling, approximately 3% residual oxygen remains inside non-PVC bags after filling.
Non-PVC Soft Bag Limitations
Per YBB standards, three-layer co-extruded films allow ~700 cc/m²·24h·0.1MPa oxygen transmission and five-layer films ~200 ??both meeting the standard but far exceeding the <5 cc/m²·24h·0.1MPa required for amino acid stability. The common solution: add a high-barrier transparent outer bag around the non-PVC inner bag.
Three oxygen sources affect the inner bag environment: residual oxygen inside the non-PVC bag, oxygen permeating through packaging materials, and residual oxygen between inner and outer bags. Oxygen scavengers provide continuous oxygen removal to maintain product quality.
Packaging Methods with Oxygen Scavengers
Vacuum Packaging
After evacuating air between inner and outer bags (80–150 KPa vacuum), an oxygen scavenger is placed inside. This suits the common “package-first, sterilize-second” process. Benefits: vacuum removes most oxygen initially, the scavenger consumes residual and permeating oxygen, and the tight bag-to-bag contact accelerates heat transfer for sterilization. Drawbacks: wrinkled appearance, potential pinhole formation at fold lines during sterilization, expensive vacuum chamber equipment, and the need for sterilization-resistant (121°C, 20 min) scavengers and packaging.
Atmospheric Packaging with Scavenger
The simplest approach ??place the scavenger between inner and outer bags under normal atmospheric conditions. Benefits: simple operation with no special equipment, scavenger reduces oxygen to <0.1% within ~24 hours, continuous scavenging compensates for permeation, flat appearance without wrinkles, and broader material selection since sterilization resistance isn’t needed. Drawbacks: air between layers reduces heat transfer efficiency, making this method suitable only for “sterilize-first, package-second” processes.
Nitrogen-Flush Packaging
After evacuating to a predetermined vacuum level, nitrogen (99.5%+ displacement rate) is injected before sealing. Benefits: nitrogen displaces oxygen effectively, provides cushioning to reduce transport damage, maintains product shape and appearance, and works with scavengers for near-zero oxygen conditions. Drawbacks: similar to vacuum ??higher equipment cost, lower efficiency, and unsuitable for package-first sterilization.
Outer Bag Material Requirements
The high-barrier outer bag must meet: oxygen transmission ≤5 cm³/m²·24h·0.1MPa, WVTR ≤3 g/m²·24h, sufficient mechanical strength for vacuum and sterilization pressure changes, heat resistance for sterilization, and excellent seal integrity. Common barrier layers include PVDC or EVOH co-extruded films, K-coated films, modified PVA coated films, and transparent metallized films.
References
- Wikipedia: Oxygen Scavenger: Overview of oxygen absorber technology and packaging applications
- FDA: Pharmaceutical Quality: U.S. FDA guidance on drug packaging and quality
- ISO 11607 ??Medical Device Packaging: International standard for terminally sterilized medical packaging
- ASTM D3985 ??Oxygen Transmission Rate: Standard test method for oxygen gas transmission through plastic film
- PDA ??Parenteral Drug Association: Industry association for pharmaceutical manufacturing and packaging