What Advancements In WFI Tech Mean For Health Care
By Kayla Matthews, Productivity Bytes
WFI Quality Water — or water for injection — is sterilized water that is used in the preparation of some parenteral (typically injected) drugs. WFI in health care needs to be highly sterile to be safe. As a result, special water purification approaches are used to manufacture WFI.
Traditionally, WFI has been manufactured using just one or two similar distillation techniques. However, over the past few decades, the technology used to manufacture WFI has improved significantly, yielding significant benefits for the medical and health care industries.
Here is how WFI technology has been improved, and the benefits that these advancements are bringing to the health care industry.
The Traditional Approach To Manufacturing WFI
The most common method for the production of WFI is through some kind of distillation — typically multiple-effect distillation (ME distillation). This method is also commonly used in other water purification processes, like water desalination and purification.
In the ME distillation process, water is softened, filtered, then fed through a still with multiple columns, or "effects." In each column, the water is heated by steam in tubes. As water passes through the still, the heat causes some of it to evaporate. The steam generated by this then flows into tubes that are used to heat and evaporate more water.
The more effects a ME distillation process has, the more energy-efficient the system will be. However, each additional effect will raise the initial capital cost of the system. These systems are also already more expensive overall than comparable WFI-grade purification systems.
A MECO cost review of the company's systems found that a standard ME distillation system can process around 35 liters of water per minute, with 10 liters of water per minute being rejected. Despite the relative simplicity of the ME system, they remain popular because of their reliability.
Limitations Of Distillation Systems For WFI
However, these systems can struggle in a few areas.
Because the treated water is brought to a high temperature by the distillation process, it needs to be pre-treated to remove chlorine and other contaminants that can damage the stainless steel used to construct most WFI stills. In practice, pre-treatment means that much of the water that enters the still may already be up to WFI standards before treatment even begins.
ME stills may also struggle to produce larger quantities of WFI as efficiently as smaller batches. This became a more pronounced problem in recent years as WFI shortages have left hospitals without sterile water necessary to reconstitute lyophilized (or freeze-dried) drugs that need to be delivered intravenously. Significant health crises can put further strain on hospital stockpiles, increasing the need for efficient and high-output WFI manufacturing.
ME distillation systems are also very hard to scale down, which may make them impractical for manufacturers who only need small batches of WFI at a time.
Other distillation systems, like vapor compression distillation, can offer some advantages over ME distillation, but also suffer from many of the same drawbacks — especially the need for water pre-treatment, due to the high temperatures involved in distillation.
New WFI Manufacturing Methods Offer Benefits To The Health Care Industry
New methods of WFI manufacture, along with updates to regulations, have helped provide manufacturers of WFI with alternatives that can make the manufacturing process more efficient.
Several major pharmacopeias — national drug compendiums that include quality standards for drugs and drug ingredients — have recently approved non-distillation methods for the production of WFI, as well as new methods for WFI quality measurement.
In 2009, the Japanese Pharmacopoeial Forum recognized reverse osmosis (RO) and ultra-filtration (UF) as acceptable methods to produce WFI. In March 2016, the European equivalent adopted revised rules that allowed for the use of RO in WFI manufacture.
While RO was approved by the U.S. Pharmacopoeia in the 1990s, many U.S. companies continued to use distillation because of the limitations of EU regulations until the 2016 rules update.
RO systems use special membrane filters to capture and remove ions and contaminants in water. These systems can operate at ambient temperatures because they don't need to use heat to create WFI. For some facilities, this can eliminate the need for a boiler, reducing overall equipment costs. RO systems, because they don't need to heat or cool water, are also highly space-efficient. In turn, this can result in larger filtration systems that produce greater amounts of WFI.
Advances in automated water analysis have also made the WFI manufacturing process more efficient. Both the E.U. and U.S. pharmacopeias regulate how much total organic carbon (TOC) can be present in WFI. New machines can automatically analyze WFI samples for TOC content without the need for attendance by a lab worker. These automated analysis tools can help speed up the testing process, allowing manufacturers to more quickly ensure that produced WFI meets standards.
Improving WFI Manufacture Methods
Traditionally, WFI is manufactured using a steam distillation process. While reliable and simple, these systems can be highly inefficient in terms of space and remain limited in production capacity. At the same time, hospitals have been struggling for years with WFI shortages.
Recently approved methods for WFI manufacturing, like reverse osmosis, offer some significant benefits over these methods and can help the pharmaceutical industry produce enough WFI to meet growing demand.
About The Author
Kayla Matthews is a MedTech writer whose work has appeared on HIT Consultant, Medical Economics and HITECH Answers, among other industry publications. To read more from Kayla, please connect with her on LinkedIn, or visit her tech blog at https://productivitybytes.com.