Full and direct traceability of elastomers used in bioprocessing is one of the key safeguards pharmaceutical manufacturers have to help prevent potential contamination incidentsHow much garden hosepipe have you installed in your biopharmaceutical processing plant recently?
Hopefully none – the risk of contamination associated with such a reckless act would be catastrophic! Of course, there is a certain amount of non-stainless steel material in every system, but have you ever stopped to think just how much. If you made the calculation, you’d be horrified at the result.
Recognizing the potential risks, the Cwmbran-based R&D team at Crane Process Flow Technologies (CPFT) has developed a tool which calculates the total wetted surface area for a mix of valves and weirs, and for a simple comparison (as it turned out a frighteningly graphic picture of the magnitude of that risk) illustrates the conclusion as a length of hose.
For example, a typical processing system incorporating 1000 sanitary and aseptic valves of varying sizes would contain a total diaphragm wetted surface area of around 10.25m², which equates to an astonishing 161m of 20mm nominal bore hose.”It’s not uncommon for a biopharmaceutical processing plant to use hundreds, even thousands of diaphragm valves,” says David Birch, product manager for CPFT’s range of valves, marketed under the Saunders HC4 brand. “The diaphragm itself is the key performance component within the valve, but it can be a potential source of process environment contamination. So if you consider the combined wetted surface area of these diaphragms, the issue of elastomer selection is seen in full perspective.”
“The tool allows us to visibly demonstrate the importance of using fully traceable diaphragm material on hygienic applications. It also allows the user to visualize his total diaphragm wetted area, and hopefully, understand the implications and associated risks of not using fully traceable components.”
It is important that elastomers employed in aseptic applications conform to the FDA Code of Federal Regulations, Chapter 1, Title 21, Part 177, para 2600 Rubber Articles Intended for Repeated Use and para 1550 Perfluorocarbon resins, Issue Revised April 2002. However, as we will explore, FDA conformance is just the starting point in ensuring the diaphragm supplied meets quality and performance characteristics.
CPFT elastomeric diaphragms used in the Saunders HC4 range are manufactured from a formulation of raw materials which have been precisely weighed and combined into a compound by controlled intermixing and milling operations. The un-cured or un-vulcanized compound is then ‘calendered’ into continuous 100m sheets, forming the basis of the diaphragm’s internal structure.
Physical properties of the elastomer are determined during the latter stages of the blending process and a representative sample is subjected to a number of analyses, including rheometer (a measure of vulcanisation characteristics), tensile strength, hardness and elongation parameters.
Unique identification numbers are moulded onto the finished diaphragm which trace its manufacturing history right back to the initial blend. The historical information enables the product to be rigorously investigated right back to its source, a vital route in the event of a problem during use and acts as a guarantee that it conforms to the supplier’s specification.In addition, CPFT provides certification of the physical properties of each batch to ensure product consistency, supported by a complete documentation validation package for all diaphragms which make contact with bioprocess media.
“Elastomers are a complex mix of ingredients and are selected to provide the desired properties for both the functions of the component and its intended application,” continues Birch. “The ingredients will certainly include a base polymer, activators, fillers and curing agents, and may be augmented with process aids and accelerators. All can affect the properties of the elastomer.”
“Unfortunately, some users underestimate or even overlook the critical importance of elastomeric components and the consequences of these oversights may lead to contamination of the line media or even plant stoppages and their associated financial implications.”All Saunders diaphragms are developed and manufactured in-house, allowing CPFT to take complete control of their technological advancement and design.
Saunders diaphragms have also been tested and certified in accordance with USP Class V and VI by an accredited independent test laboratory. “Don’t you think it’s odd that for many years the bioprocessing industry has demanded that all stainless steel components be supplied with full traceability but relegated polymers to merely complying with the FDA Drop Register,” muses Birch. “As valuable as FDA compliance is, it does not provide the customer with either physical characteristics or any indication of performance levels within the process.
“Thankfully now, however, we are seeing a shift in focus toward fully traceable polymer components and the industry is beginning to demand real vigilance in this key area.”In conclusion, the role of elastomers in bioprocessing systems tends to be underestimated but can be critical. The technology is available to manufacture diaphragms to the traceability requirements of EN 10204.3 1b to compliment the stainless steel content of processing systems. In short, choosing a diaphragm manufactured from an elastomer compound that complies with FDA and is certified to USP 25 can mean ease of validation and confidence in product quality and purity.
It also helps to ask the same guys who supplied the valve to supply the diaphragm.