Product description
Single-use mixing bags are disposable bioprocess containers designed for liquid-liquid and solid-liquid mixing in pharmaceutical and biotechnology production. They combine a flexible process bag with an integrated mixing element, inlet and outlet lines, sampling access and optional sensor connections.
Mixing systems are available with different magnetic drive concepts to support applications ranging from buffer and culture-media preparation to intermediate product preparation and batch homogenisation.
Standard configurations cover nominal volumes from approximately 20 L to 3,000 L. Tubing, connectors, powder ports, sampling connections, sensors and other fluid-path components can be adapted to the application.
Technical overview
Single-use mixing bags provide an alternative to reusable mixing vessels for processes where a disposable product-contact path is preferred. The flexible bag is installed in a compatible support container and connected to the appropriate mixing drive.
Two principal mixing concepts are available: magnetically driven mixing for applications requiring comparatively strong mixing action, and magnetic levitation mixing for applications where gentler, lower-shear mixing is preferred.
Standard assemblies typically incorporate an inlet, bottom outlet, dedicated sampling line and powder-addition port. Additional sensor interfaces, tubing, connectors and filters can be configured according to the process.
Operating principle
The disposable mixing element is integrated into the bottom region of the flexible bag. A reusable external drive transfers rotational energy to the mixing element magnetically without requiring a conventional mechanical shaft through the bag wall.
As the impeller rotates, liquid circulates through the container and promotes mixing throughout the bag volume.
Magnetic drive mixing
Magnetically driven impeller configurations provide strong mixing action and are suitable for processes requiring effective liquid-liquid or solid-liquid mixing. Typical reference rotational speeds depend on the selected impeller and bag volume.
Magnetic levitation mixing
Magnetic levitation configurations suspend and drive the mixing element magnetically. This provides a low-friction mixing concept that can be considered for applications where gentler mixing and reduced mechanical contact within the mixing system are desirable.
The appropriate mixing principle should be selected according to the process fluid, required mixing intensity, shear sensitivity, powder-loading requirements and batch volume.
Material options
Standard mixing bags use a multilayer co-extruded process film designed for bioprocess fluid handling.
The film construction includes polymer layers based on:
- ULDPE
- EVA
- EVOH barrier material
- LDPE
This multilayer construction combines a suitable product-contact surface with mechanical and gas-barrier properties required for bioprocess storage and mixing applications.
Mixing-element materials depend on the selected mixing configuration and can include:
- HDPE
- Polypropylene (PP)
- PEEK components in suitable configurations
- Zirconia bearing components in certain mixing designs
Tubing and connection materials are configured separately according to the fluid path and process requirements.
Available micron ratings
Not applicable to the mixing bag itself. A mixing bag is a process container and mixing system rather than filtration media and therefore has no micron or pore-size rating.
Where sterile filtration, vent filtration or another filtration step is required, a suitable filter can be incorporated into the associated single-use fluid path and specified separately.
Design and construction
Mixing bags are available in multiple impeller and drive configurations covering small, intermediate and large production volumes.
Available volumes
Across the available mixing-system configurations, nominal bag volumes include:
- 20 L
- 50 L
- 100 L
- 200 L
- 400 L
- 500 L
- 650 L
- 1,000 L
- 1,500 L
- 2,000 L
- 2,500 L
- 3,000 L
Volume availability depends on the selected mixing technology and impeller configuration.
Working volume
For complete mixing, the typical minimum working volume is approximately 20% of the nominal bag volume.
In applications where only a basic mixing effect is required, operation may be possible at a lower volume provided that the liquid level sufficiently covers the mixing element.
The maximum working volume can be up to approximately 110% of nominal bag volume. Actual usable volume can be influenced by air introduced during filling and by the required headspace.
Standard fluid-path design
A typical mixing bag configuration includes three process lines:
- One inlet line
- One bottom outlet / drain line
- One dedicated sampling line
A 4-inch powder-addition port can be incorporated at the top of the bag for introduction of media powder, buffer components or other dry process materials.
Inlet and outlet tubing
Standard configurations use pharmaceutical-grade silicone tubing. Typical standard dimensions include:
- 50–200 L configurations: 3/8" ID × 5/8" OD silicone tubing
- 500 L and larger configurations: 1/2" ID × 3/4" OD silicone tubing
Typical inlet tubing length is approximately 150 cm. Outlet-line length can vary according to bag volume, with longer drain lines available for large-volume systems.
Different tubing materials, dimensions and lengths can be configured where required.
Sampling line
Standard configurations can incorporate a dedicated sampling line consisting of approximately 20 cm of 1/4" ID × 7/16" OD silicone tubing with a needle-free sampling valve.
Other sampling interfaces can be specified for custom configurations.
Powder addition
A top-mounted sanitary powder port allows dry process materials to be introduced directly into the mixing bag.
This configuration is particularly relevant for buffer and culture-media preparation where powders must be dispersed and dissolved in the process liquid.
Sensor integration
Sensor ports can be incorporated for online process monitoring.
Available interface concepts can include:
- Vertical threaded sensor ports
- Inclined threaded sensor ports
- Protective sensor sleeves
- Hose-barb sensor ports
- PG13.5-compatible interfaces
- Temperature-sensor interfaces
Exact sensor-port design depends on the measurement technology and mixing system configuration.
Operating conditions
| Nominal volume range | Approx. 20 L to 3,000 L |
| Typical minimum mixing volume | Approx. 20% of nominal volume |
| Maximum working volume | Up to approx. 110% of nominal volume |
| Recommended operating temperature | Approx. 0°C to 40°C |
| Recommended pH range | Approx. pH 2.5 to 11 |
Sterilisation and supply condition
Standard mixing bags are supplied pre-sterilised and ready for integration into the appropriate mixing system.
Gamma sterilisation is performed using a validated irradiation range of approximately 25–45 kGy.
Bags are individually protected using double-layer PE packaging.
Quality and documentation
Mixing bags are manufactured in controlled cleanroom production environments. ISO Class 7 and ISO Class 8 production lines are used for suitable single-use bag and assembly manufacturing.
Available conformity and quality documentation can include:
- USP <788> Particulate Matter
- USP <87> Cytotoxicity
- USP <88> Biological Reactivity
- USP <85> bacterial endotoxin information
- FDA 21 CFR 177–182 material conformity information
- Animal-derived component-free material statements
- TSE / BSE documentation
- Certificate of Analysis / Certificate of Quality
- Bag integrity testing
- Sterility documentation
- Validation documentation where applicable
Exact conformity documentation should be confirmed for the selected bag, mixing element and fluid-path configuration.
Typical applications
- Buffer preparation
- Culture-media preparation
- Powder dissolution
- Solid-liquid mixing
- Liquid-liquid mixing
- Intermediate-product preparation
- Batch homogenisation
- Combining liquid collections from different process batches
- Upstream bioprocessing
- Downstream bioprocessing
- Process-solution preparation
Key benefits
- Wide volume range: mixing configurations cover applications from approximately 20 L to 3,000 L.
- Multiple mixing technologies: magnetic drive and magnetic levitation configurations allow the mixing concept to be selected according to the process.
- Low-shear options: magnetic levitation configurations can be selected for applications requiring gentler mixing.
- Powder addition: suitable configurations incorporate a dedicated powder port for media, buffer and other dry components.
- Integrated sampling: a dedicated sampling line can be incorporated without using the main inlet or outlet.
- Process monitoring: sensor ports can be incorporated for online measurement.
- Custom fluid path: tubing, connectors, filters and sensor interfaces can be configured according to the application.
- Pre-sterilised: standard configurations are gamma irradiated and supplied ready for use.
Configuration and quotation
Mixing-system selection should be based on the required batch volume, process fluid and required mixing intensity rather than bag volume alone.
For technical configuration and quotation, provide the following information where available:
- Nominal batch volume
- Minimum operating volume
- Maximum operating volume
- Liquid-liquid or solid-liquid mixing requirement
- Process fluid
- Powder type and approximate powder loading where applicable
- Required mixing time or process objective
- Shear sensitivity
- Process temperature
- Process pH
- Required inlet and outlet tubing
- Required process connectors
- Powder-addition requirement
- Sampling requirement
- Required sensor interfaces
- Integrated filter requirement
- Existing mixing hardware or support container where applicable
- Required conformity and validation documentation
- Prototype quantity
- Estimated annual demand
If the appropriate mixing technology has not yet been selected, the process volume, liquid characteristics and mixing objective provide a suitable starting point for technical selection.