BFS (blow-fill-seal) technology is a process that is used to fill liquids or viscous products (e.g. gels and ointments) into polymer containers. The moulding, filling and sealing of the containers – usually separate steps – are carried out in one continuous operation. There are currently more than 1,800 BFS-systems installed worldwide for filling various materials into containers. A great deal of emphasis is placed on the packaging of pharmaceutical products, especially in the case of sterile dosage forms.
BFS technology was developed based on the classical processes used for manufacturing and filling polymer containers where the container is manufactured by a separate machine. The container in its final form can be manufactured in one step, or a so-called preform is manufactured which is finished by another machine (e.g. using the stretch blow moulding process). The containers manufactured in both processes have to be sterilised before aseptic filling. This process corresponds to the manufacturing process used during the aseptic filling of glass containers.
BFS technology avoids the disadvantage of having to carry out additional sterilisation by manu-facturing the container immediately before filling. The container is sterile and can be filled straight away provided that the preconditions outlined below are met.
BFS technology was used for pharmaceutical products at a very early stage. The first machines for pharmaceutical applications were already in use at the beginning of the 1960s. The technology for filling simple products has developed into a technology that is an excellent alternative to the classic process of filling pharmaceutical products into glass or polymer containers. Annex 1 of the EU GMP Guidelines contains a section on BFS which is an indication of the growing importance of the technology [EU GMP Guidelines, Annex 1 (26, 27)].
Today, a large number of different types of BFS machine with various production capacities are available on the market. Machines with a lower performance but higher flexibility with regard to change of format as well as high-performance machines that, depending on the filling volume, can process 30,000 or more containers per hour are available. There are also machines that work in tandem. They share part of the machine aggregates but offer twice the machine capacity of single machines. The different types of machine are described in detail in the following section.
There are at present two fundamentally different system types whose characteristics are outlined in Figure 1.
|Cycle machines||Rotary machines|
|Number of moulding tools||Machines with one up to four moulds with up to 40 mould cavities||
Up to 20 moulds on the rotary chain with up to 30 mould cavities
|Scope of application (volumes)||0.1ml - 10l||0.1ml - 50ml|
Depending on the number of moulds:
|Special feature||Polymer parison is cut off||Polymer parison remains closed|
Figure 1 Types of BFS system
The decision on which system to use usually depends strongly on the required production capacity and whether the system should be able to produce various formats.
Based on the fact that rotary systems require a significantly larger number of tools, this type of system is the preferable solution if only one type of container is to be produced over an extended period. If, however, high flexibility with regard to moulding tools is required, cycle machines are the better choice despite their lower production capacity.
The decision taken to choose one type of machine rather than another is normally based on a number of different factors in each individual case. The required retooling time, the intended production output and the available space are all possible decision-making criteria, as are the container size, the type of polymer that will be used and other properties that the containers require.
It was very quickly realised during the development of this technology that the manufacture of containers using polymer granulate (blowing), with filling and sealing taking place at the same time represented an extremely interesting application for filling sterile products. As a result, the filling of pharmaceutical products and food was the focus of this technology from the very start. In addition, technical products such as windscreen cleaning agents and two-stroke oils were also filled.
Meanwhile, a wide range of products from the pharmaceutical and medical technology industry are filled using BFS technology. Particular emphasis is placed on sterile dosage forms including:
Sterile filtration of the product is carried out as a standard feature on the BFS machine. There are, however, increasing numbers of applications where filtration cannot take place due to certain ingredients (vaccines, suspensions, etc.), and the entire process from the manufacture of the product to filling must be carried out aseptically.
The text is an excerpt of the GMP MANUAL, Chapter 13.D Blow-fill-seal technology.
Dr.-Ing. Manfred Grüneberg
Holopack Verpackungstechnik GmbH, Germany