Cross contamination in the pharmaceutical industry is not just an issue for those working in it, but for the wider public as a whole. As general awareness of the potential issues has increased, more questions are being asked of manufacturers and health professionals about the safety, integrity and potential side effects of a range of products and medicines.

Protecting People and Planet

Understandably, most of the attention on contamination in pharmaceutical manufacturing and processing is focused on cross contamination between products or agents, or from the spread of agents such as biological cultures within a facility.

Such an approach is highly understandable, and the health of patients, consumers and staff must be paramount. However, there is a further risk that managers and designers should consider: external contamination beyond the production facility.

The potential harm of biological and other agents escaping from production sites has recently been highlighted by environmental pollution from antibiotics in a number of countries, which is believed to be a contributing factor to rising levels of antibiotic resistance around the world.[1] Furthermore, viral contamination also can be a serious threat for any type of bio-processing laboratory or manufacturing facility.[2]

Heat exchangers

Heat exchangers such as this one have been designed to meet the strict sanitary requirements of the pharmaceutical industry.

As a result of the increasing use of outsourced production, developing technologies and continually evolving biological and microbiological techniques, ensuring safe pharmaceutical manufacturing has become increasingly complex.[3] Designers, manufacturers and operators must take concerns seriously. Even relatively small issues can quickly escalate, not only in terms of the actual effects they may have on consumers, clients and the environment, but also the potential damage they can cause to company reputation and valuable brands.

The best option is to prevent contamination from occurring in the first place, and there are many laws and regulations to enforce such an approach. Many pharmaceutical, cosmetic and medical ingredients have tight temperature tolerances during manufacture. The production of ancillaries such as saline solution, purified water and water for injection (WFI) also require the highest standards of hygiene. By adhering to these standards through the use of robust procedures and well-designed equipment, manufacturers also are reducing the risk of contamination.

Heat exchangers

Heat exchangers that have been specifically designed for pharmaceutical use include a double tubeplate to prevent potential contamination between the product-side and service-side materials.

Designing Heat Exchangers for Pharmaceutical Use

Heat exchangers that have been specifically designed for pharmaceutical use include a number of key features. These include features such as a double tubeplate to prevent potential contamination between the product-side and service-side materials — a prerequisite for many pharmaceutical applications. Such designs prevent contamination and also provide leak detection. Using a double tubeplate design in conjunction with the manufacturer’s standard design features may allow all of the usual benefits of a particular type of heat exchanger to be retained. For instance, using corrugated tubes might help reduce fouling, improve heat transfer and reduce pressure drop.

Other design features can provide benefits. Expansion bellows may absorb different expansion rates between the shell and inner tubes. This can improve performance and equipment longevity while reducing material stress and the likelihood of fatigue, which could lead to cracking and potential contamination. The quality of the materials and surface finishes used, such as stainless steel and surfaces between 0.4 to 0.8 µm, will ensure that sanitary conditions are maintained in all pharmaceutical and hygienic applications. The surface finish reduces product fouling and adhesion, which can improve cleaning efficiency and help prevent contamination. Features like this should be the minimum considerations for any heat exchanger being specified for pharmaceutical use.

Water for injection (WIF)

Water for injection (WIF) needs to be cooled effectively while maintaining sterility.

Water for Injection: A Real-Life Example

Water for injection is a key ingredient in many pharmaceutical products. It also is used in medical and first-aid procedures such as to irrigate wounds. Globally, water for injection is vital for the safe and effective operation of pharmaceutical manufacturing plants. As such, it must meet stringent regulatory standards of purity.

Typically, during product manufacture, water for injection is recirculated at temperatures in excess of 167°F (75°C) to prevent microbial growth. The take-off points for product manufacturing, however, often require water for injection at ambient temperatures.

A major global pharmaceutical company recently upgraded the water for injection production system at its manufacturing facility in Melbourne, Australia. This included the installation of three heat exchangers to cool water for injection, which is then used at various end points around the site. The facility uses innovative technology to produce advanced sterile liquid medicines, which are exported to more than 30 countries. The site in Melbourne uses water for injection as the bulk excipient ingredient in the formulation of sterile pharmaceutical products as well as in equipment-cleaning processes.

The overall engineering design for the new WFI production line was overseen by a third-party contractor. Corrugated multi-tube heat exchangers that are specifically designed for pharmaceutical use were chosen to provide the necessary levels of hygiene. (They include all of the features described such as double tubeplates and stainless steel construction.) The new units were more efficient than traditional smooth-tube heat exchangers for the WFI application.

Each of the three supplied units was capable of cooling up to 15.4 tons of water for injection per hour from an average temperature of 176°F down to around 68°F (80°C down to around 20°C) using chilled water, with a pressure drop of just 1.45 psi.