During clinical IV infusion therapy, 1鈥? drugs are typically added to a base infusion solution. The mixing process 鈥?involving punctures and blending 鈥?alters the physicochemical properties of the solution, generating substantial amounts of insoluble particles. These microparticles can enter the bloodstream and block capillaries, causing thrombosis and granulomas. The preparation process also carries risks of dosing errors, bacterial contamination, increased nursing workload, and higher incidence of needlestick injuries. Moreover, the time required for manual preparation undermines emergency medication delivery.
In response to these challenges, a new generation of infusion packaging has emerged: the liquid-liquid and powder-liquid multi-chamber IV infusion bag (multi-chamber bag).
1. Multi-Chamber Bag Advantages
Multi-chamber bag technology is one of the most advanced packaging solutions in the industry today:
Medication Safety. Multi-chamber technology enables drug mixing in a sealed environment by opening frangible seals between chambers, eliminating the risk of microbial contamination and preparation errors. It prevents nosocomial infections and requires no dedicated sterile compounding room.
Fast Operation. No pumps, syringes, or tubing needed. Drug mixing time is dramatically reduced while ensuring rational medication administration.
Environmental Compatibility. The bag uses non-PVC film free of phthalate plasticizers such as DEHP (di(2-ethylhexyl) phthalate), reducing environmental impact from medical waste.
Space Efficiency. Reduces storage space requirements throughout the distribution chain and in healthcare facilities.
Emergency Readiness. Suited for disaster relief, field rescue, military operations, and other emergency scenarios.
2. Film Types and Formulations
2.1 Packaging Film Categories
By drug state: liquid-liquid and powder-liquid types, each with different frangible seal heat-seal strength requirements. By drug solubility: lipophilic and aqueous formulations, requiring significantly different inner-layer material selection. By oxygen sensitivity and moisture absorption: low-barrier and high-barrier grades, with substantially different water vapor and gas transmission requirements.
2.2 Film Structures and Formulations
Two mainstream structures dominate the market:
Type 1 鈥?Five-layer structure (Sealed Air, USA): Modified ethylene-propylene copolymer / PE / PE / ethylene-methyl methacrylate polymer / ester copolymer. Layer thickness ratio: 15%/5%/65%/5%/10%. The inner layer is a PP binary copolymer blended with SEBS (styrene-ethylene-butylene-styrene block copolymer) elastomer. By adjusting ethylene monomer content in the copolymer and the SEBS ratio, the heat-seal window is tuned to achieve both permanent (real) and frangible (peelable) seals. The middle PE layer provides softness, while the outer ester copolymer layer offers heat resistance and printability.
Type 2 鈥?Three-layer structure (Polycine/B. Braun, Germany; Baxter, USA): PP/PE/PB copolymer + SEBS blend / PP/PE copolymer + SEBS blend / PP + SEBS blend. Layer thickness ratio: 15%/70%/15%. The inner layer is a PP terpolymer with SEBS; adjusting ethylene-butylene monomer content and SEBS ratio controls the heat-seal window. The middle layer combines PP binary copolymer with SEBS for flexibility, toughness, and low-temperature performance. The outer homopolymer PP + SEBS provides heat resistance and printability. All three layers incorporate SEBS to improve softness and reduce crystallinity, preventing heat-induced crystallization during sterilization that would cause opacity and embrittlement.
Limitations of the above: The non-polar inner layers are incompatible with high-frequency welding. During high-temperature heat sealing, inner-layer melt crystallization causes embrittlement and high finished-bag leakage rates. Additionally, both film types have poor gas barrier properties, making them unsuitable for direct packaging of oxygen-sensitive drugs such as lipid emulsions and amino acids. These require expensive high-barrier overwrap bags with vacuum packaging 鈥?adding complexity to production and sterilization while narrowing the application scope.
New Five-Layer Structure 鈥?Hubei Hengtai Rubber & Plastic Co., Ltd.: EVA (ethylene-vinyl acetate) / COC (cyclic olefin copolymer) / PE / ethylene-acrylate polymer / ester copolymer. The inner EVA layer 鈥?copolymerized from ethylene and vinyl acetate without plasticizers or stabilizers 鈥?delivers high transparency, superior flexibility, low-temperature resistance, aging resistance, and better heat-seal performance than PVC. EVA is a polar polymer compatible with both thermal and high-frequency welding for real and frangible seals, reducing leakage rates. Critically, it is also suitable for packaging lipophilic drugs. The sub-inner COC layer replaces conventional polyolefins: COC contains no unsaturated double bonds, triple bonds, or aromatic ring structures, giving it excellent thermal stability and oxidation resistance with thermal decomposition temperature above 400掳C. COC uses non-toxic cyclic olefin monomers, achieves extremely high polymer purity, and offers transparency, very low water vapor transmission, no cytotoxicity, no mutagenicity, no irritation, and FDA compliance 鈥?dramatically improving barrier properties, thermal resistance, and safety compared to conventional films.
3. Production Processes
All currently used non-PVC multi-chamber IV infusion films in China are produced by blown film extrusion:
- Five-layer upward-blown air-cooled process (Sealed Air type) 鈥?five-layer co-extrusion with upward bubble cooling via dual-lip air ring
- Three-layer downward-blown water-cooled process (Polycine/B. Braun type) 鈥?three-layer co-extrusion with downward bubble quenching via water cooling ring
Internationally, only Fresenius (Germany) and Baxter (USA) are known to use cast film extrusion for multi-chamber IV films, primarily for in-house pharmaceutical production with limited output not available commercially.
For the five-layer structure containing low-melting-point polymers like PE and EVA, electron beam irradiation crosslinking is required to achieve the thermal resistance needed for high-temperature sterilization (115鈥?21掳C, 12鈥?0 min). The electron beam simultaneously provides radiation sterilization, making the film especially suitable for sterile powder drug packaging.
4. Main Production Equipment
4.1 Five-Layer Co-Extrusion Line (Brampton Engineering, Canada)
- Extrusion system: Five extruders (inner/outer screw 蠁45mm, sub-inner/sub-outer screw 蠁40mm, middle screw 蠁75mm), five-layer flat stack die
- Upward bubble forming: Dual-lip air ring, internal bubble cooling (IBC), external bubble cooling, bubble diameter control, primary nip
- Rotating winder: 360掳 oscillating take-off, secondary and tertiary nips, tension control, surface and center winding
- Crosslinking unit: Linear electron accelerator (0.8 MeV, 50 mA)
4.2 Three-Layer Co-Extrusion Line (Guangdong Jinming Plastics Machinery, China)
- Extrusion system: Three extruders (inner/outer screw 蠁45mm, middle screw 蠁75mm), three-layer inclined stack die
- Downward bubble forming: Single-lip air ring, bubble stabilization, water cooling sizing ring, collapsing frame, primary nip, water collection tank
- Rotating winder: 360掳 oscillating take-off, secondary and tertiary nips, tension control, surface and center winding
5. Process Flow and Processing Temperatures
Material is melt-plasticized in extruders, fed into the die, passes through the bubble forming system, and enters the rotating winder to produce finished film rolls.
For the five-layer film, the inner/outer extruder, sub-inner/sub-outer extruder, middle extruder, and die each follow distinct temperature profiles. For the three-layer film, the inner/outer extruder, middle extruder, and die each have their own curves. Processing temperatures must be adjusted when changing formulations or throughput rates. (Refer to original article for detailed temperature tables.)
6. Product Specifications and Performance
6.1 Specifications
Film thickness ranges from 150鈥?50 渭m, with 190 渭m, 200 渭m, and 250 渭m being common. Widths are slit to 170 mm, 220 mm, 320 mm, and other sizes depending on application.
6.2 Key Performance Properties
The film must meet rigorous physical, chemical, and biological performance requirements as specified by China’s national drug packaging material standards (YBB series) and pharmacopoeia. Low-barrier films provide adequate protection for aqueous formulations; high-barrier grades with enhanced gas and moisture resistance are required for oxygen-sensitive and moisture-sensitive drugs. Chemical performance includes extractables testing, heavy metals, pH change, UV absorbance, and residue on ignition. Biological performance covers cytotoxicity, skin irritation, systemic toxicity, and hemolysis testing.
7. Multi-Chamber Bag Production Process
The finished film roll enters the bag-making line where it is formed, sealed (with both permanent perimeter seals and frangible chamber-dividing seals), filled with drug solutions or powders through dedicated ports, and terminally sterilized. The frangible seal between chambers is engineered to open under moderate manual pressure at the point of use, allowing aseptic mixing of the chamber contents directly at the patient bedside without breaking the sterile barrier of the outer bag.
8. Applications and Market Outlook
Non-PVC multi-chamber IV infusion packaging film has broad applications and a substantial market, recognized worldwide for its safety, environmental, and convenience advantages. After nearly 30 years of development abroad, multi-chamber bags now package a wide range of products 鈥?primarily nutritional solutions, biologics, and antineoplastic drugs. Current domestic applications in China include:
- All-in-one parenteral nutrition: lipid emulsions, amino acids, glucose, electrolytes, and trace elements
- Renal and peritoneal dialysis solutions: electrolytes, glucose, bicarbonate, and lactate
- Powder-liquid dual-chamber bags: sterile cephalosporin powder with glucose or sodium chloride diluent
China began producing non-PVC infusion film in the early 2000s. Today there are over 10 non-PVC film production lines in the country, but very few domestic manufacturers can produce multi-chamber grade film with consistent quality. Most packaging film is still imported at high cost, significantly driving up pharmaceutical production costs and constraining market growth.
The nutritional infusion market alone in China approaches RMB 6 billion 鈥?less than one-third the size of the US market 鈥?indicating substantial growth potential. As living standards rise and demand for medication safety and convenience increases, multi-chamber bags are poised for strong growth in China’s infusion packaging market, with enormous development space in both clinical practice and drug safety assurance.
References
- Wikipedia: Ethylene-Vinyl Acetate (EVA) 鈥?Properties and medical applications of EVA as a non-PVC flexible packaging material
- Wikipedia: Cyclic Olefin Copolymer (COC) 鈥?Barrier properties, thermal stability, and pharmaceutical packaging applications of COC
- Wikipedia: SEBS (Styrene-Ethylene-Butylene-Styrene) 鈥?Thermoplastic elastomer used in medical film formulations for softness and seal performance
- Wikipedia: Electron Beam Processing 鈥?Crosslinking and sterilization mechanism for medical packaging films
- FDA: Pharmaceutical Quality Resources 鈥?US regulatory framework for drug packaging materials and containers
- ISO 15747 鈥?Plastic Containers for Intravenous Injections: International standard for plastic IV container performance and safety requirements