Pull out all the stops — new developments in stopper processing equipment

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In this article, Stephen Morley from Steelco, looks at the new developments in stopper processing equipment.

For more than two decades, stopper processors (or more generically, closure processors) have fallen into two categories: rotating drum style machines and systems in which the processing vessel is detachable and mobile for transfer of the treated components to the downstream process.

While both target the same result for the closures — cleaning, (siliconisation), sterilisation and drying — each has their own merits in terms of the workflow/production application: the rotating drum style was primarily adopted for high capacity production; while the mobile processing vessel solution was and remains mainly suited to feeding a high throughput barrier isolated filling line.

In more recent years, there has been an increasing focus on single use technologies, with a trend towards the use of ported bags for delivery of clean and pre-sterilised ‘ready to use’ closures to isolated filling lines. Such solutions are ideal for smaller scale, lower speed lines under barrier isolation, but have practical and financial challenges as line speed increases.

As the market for such systems has developed, so too has the need for systems for processing the closures and filling them into the ported bags — automated bag filling with accurate dosing capability. While the capacity/output requirement of the stopper processor for this application may be similar to that of a high speed/high throughput filling line, this application is quite a different challenge.

Whatever the workflow, usage pattern or equipment style, all current commercially available stopper processors operate as a batch process, with, until now, several steps of manual handling, often requiring the installation and operation of heavy duty mechanical lifting equipment in the GMP manufacturing area. Irrespective of manufacturer, for point-of-use processing (i.e., not stopper manufacturing), both loading and unloading of closures is traditionally performed manually, in GMP controlled space.

Loading typically requires manual opening of bags followed by manual transfer into the processor, for example using a hopper or funnel. Unloading of treated closures from the processor typically involves use of a mechanical device to lift, rotate and position the processing or transfer vessel close to the infeed hopper of the filling line and then transfer the closures via some form of transfer port (typically but not always a rapid transfer port).

Most usually, the processing or transfer vessel is an insulated stainless steel pressure vessel and typically weighs more than one hundred kilograms when full. As such the lifting equipment must typically be integrated with the building structure and requires significant height in the cleanroom to be able to place the outlet of the vessel above the hopper to enable gravity transfer. Additionally, while suitable for elastomeric/rubber components, this gravity feed system can be problematic for more delicate closures such as crimp caps and lined seals.

Stopper processors represent a significant capital investment and typically have a lifetime of more than 20 years. The market is rapidly evolving, and moving towards flexibility of design, with filling lines capable of handling multiple formats, and incorporating continuously developing single use technologies. With this in mind, the stopper processor must also be flexible and adaptable to be able to maximise the return on the investment over the lifetime of the equipment.

With these trends and challenges in mind, Steelco (Riese Pio, Italy) redesigned the ICOS brand stopper processor and introduced the SPE, or stopper processing equipment. Based on the LST model, the SPE is available in a range of capacities, to suit a variety of filling line speeds, as well as the production needs of stopper manufacturers.

Moreover, the processor may be automatically loaded, incorporating a visual inspection system for an automated line clearance check to avoid cross-contamination between batches. The loading infeed may be outside the fill-finish suite/clean area such that cartons, bags and the initial manual operations are in a lower grade area.

The SPE processing chamber is designed to allow multiple discharge/offload systems to be configured, with simple retasking of the processor for:

  • Ported bagging systems — DPTE or Sartorius Biosafe
  • Heat sealed bags
  • Ported pre-sterilised containers (pre-sterilised as part of the treatment process)

As example, a full load/treated batch of closures may be sub-divided into one or more DPTE ported transfer vessels for delivery to a barrier isolated filling line. Multiple, smaller transfer containers allow less heavy duty lifting equipment to be used, and require less height in the clean area. This latter option combines the benefits of the rotating drum style processor with that of the mobile transfer vessel solution.

As the ultimate solution for high throughput applications, direct connection of the output port to the filling line is also possible, allowing seamless, fully automated processing and delivery with no manual intervention.

With the advent of the routine use of barrier isolators in the pharmaceutical industry during the early 1990’s, stopper processing equipment underwent a step-change to adapt to the challenges presented by isolation technology. In recent years, the adoption of single use technologies has gone some way to fill the gap where the capital expense of local stopper processing for smaller scale production cannot be justified.

However, it is clear that challenges and gaps in the stopper processing equipment portfolio remains, and there is a need for continued innovation in flexible, configurable and retaskable solutions.