It is also important to define the application and to evaluate what technologies are available for each specific process application.
Then, the company should evaluate how those technologies are used, and their benefits and limitations.
A cost–benefit analysis of rival technologies also is needed. For example, technology ease of use, ease of installation, and
the level of service support that the system manufacturers guarantee all must be analyzed. Technical specifications and performance
data comparisons can be complicated by the fact that different suppliers do not necessarily use the same test methods.
Supplier validation packages for given technologies also must be examined and compared. (This is examined further later in
Conceptual design and facility layout
A disposable process must be planned to match production requirements, bearing in mind that wide implementation of disposables
can radically change the facility design. Key points to consider include:
- The degree of flexibility that the company seeks. Is the facility single-product or multi-product? What are the capacity requirements?
Does expansion capacity need to be planned from the outset?
- How important is it to the company to reduce utility usage in a retrofit or process upgrade environment?
- Is the company looking to increase capacity in an existing facility?
- Are there project-specific limitations in terms of containment?
The first stage of developing a disposable concept is to understand the process characteristics and workflow constraints of
the manufacturing operation. From this information, a layout is developed that takes into account the definition of room requirements;
process and material flows; and cGMP compliance.
In addition, some workflow considerations are specific to disposable technology. These include logistics and manual handling
considerations; process connection and aseptic transfer philosophies; and waste management.
Logistics and manual handling.
In evaluating logistics and manual handling, one must consider:
- the volumes of solutions to be made up and stored, and when they are required
- floor area requirements for work in progress
- the logistics of moving the single-use systems around the facility. Unlike a fixed pipe system, which normally has a large
solution makeup and storage area located away from the processing rooms, with a pipe dropping into all of the user points,
disposable solutions require corridor access to each of the rooms that the utility will be serving.
Process connection and aseptic transfer philosophies.
In evaluating approaches to process connections and aseptic transfer, one must consider aseptic transfers, people flows, and
design and layout.
Aseptic transfer. The concept of segregation—both by space and by closed processing—is an area in which single-use systems can create new standards
in operational excellence and containment (Figure 1). Alpha/beta aseptic transfer port technology, for example, can make this
kind of segregation possible. This technology solves a recurring problem in bioprocessing—namely, how to transfer processing
solutions aseptically—and enables totally closed disposable bioprocessing across different area grades without compromising
any area. For example, the preparation and storage of voluminous media and buffer solutions can be segregated from the main
process areas and fed through the wall using the disposable aseptic transfer technology.
People flow. Segregation makes it possible to have two separate teams working in the facility, one dedicated to support and the other dedicated
to the process areas, thus reducing the risk of microbial contamination or the need to increase containment. This greatly
simplifies operations, reduces the amount of equipment, simplifies flows of material and people, and improves final product
integrity by minimizing or removing aseptic operations.
Design and layout. The segregation of process and support areas reduces the surface area of the higher classification cleanrooms, which in turn
has a significant impact on overall cost of goods.
Process connections. Industry end-users tend to choose air classifications that are higher than needed when implementing disposable systems (consider
the Bavarian Nordic example above).