Low-Energy Electrons Have Pharma Beaming

Low-voltage electron beams have found an expanding niche within pharma sterile processing—a review and talk with Baxter’s John A. Williams.

By Paul Thomas, Senior Editor

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Editor’s Note:

For a look at studies that Amgen has done regarding the potential impact of e-beam radiation on protein products, click here. For a podcast interview with Skan COO Jim Spolyar on his company’s electron-beam work with GSK, Wyeth, and others, click here.

A clear advance in the world of pharmaceutical aseptic processing has been the popularization of low-energy electron beam technology for sterilization—the topic generated quite a bit of buzz at 2008’s ISPE annual meeting in Boca Raton, as well as at Pack Expo in Chicago. While high-energy electron beams have been used in a variety of industries for some time, low-energy e-beams have only come on the scene within the last decade.

 ASTM’s Sixth International Workshop on Dosimetry for Radiation Processing

The topic of electron beam radiation for pharmaceutical processes will be one key area
of discussion during this every-five-year
event, to be held October 2009
in Karlsruhe, Germany.
Click here for more information.

One advantage of the technology is that the energy, while strong enough to eradicate surface contaminants of, say, a vial or syringe—or even a tub filled with syringes—does not penetrate either packaging material or product.

Another advantage of low e-beam technology is its high degree of efficiency, with the ability to reduce bioburden in milliseconds at room temperature, says Dave Icke, VP of Marketing for Advanced Electron Beam (Wilmington, Mass.). From inches away, the beam can break the chemical bonds of, and render inert, spores, viruses, molds and other potential contaminants.

AEB is one of the firms driving and capitalizing upon advances in low-energy electron beam technology. It manufactures electron beam emitters and has the backing of GE Energy Financial Services. AEB’s devices have found their way into processing equipment commercialized by companies such as Getinge Linac (Orsay, France),  Metall+Plastic (Radolfzell-Stahringen, Germany) and Skan AG (Basel, Switzerland). (Getinge Linac is also developing in-line sterilization tunnels using medium-energy electron beams for sterilizing bulk-filled syringes.)

A low-voltage emitter can run between $50,000 and $125,000, Icke says, with a typical application requiring multiple units. An emitter filament tends to burn out after about 2,000 hours of use, requiring replacement on occasion. Yet there are clear cost benefits to be derived in the elimination of other sterilization process steps.

 “The important distinction is that we are doing surface sterilization, not terminal sterilization,” says Icke. Whereas terminal sterilization by, for instance, gamma irradiation or ethylene oxide, is usually done offsite by a contractor, electron beams can sterilize product or packaging in-line and eliminate the need to go outside the sterile facility. Icke claims that this can reduce a typical sterilization cycle for vials or syringes from 21 days to less than 48 hours.

One company with a long history of electron beam usage (and the patents to prove it) is Baxter Healthcare. Pharmaceutical Manufacturing recently spoke with one of Baxter’s experts on the subject, John A. Williams, Manager of Baxter’s Sterility Assurance Research Center:

PhM: What first piqued your interest in electron beam technology for pharmaceutical applications? What possibilities did you envision, and what were the limitations at the time?

J.W.: Baxter has used electron beam technology for terminal sterilization since 1989. Electron beam technology is one of the “tools in our toolbox” with regard to sterilization options we consider for new and existing applications. One of the limitations of the technology was the availability of lower energy electron beam systems designed specifically for sterilization. Many of the initial electron beam system providers were concentrating on large, higher energy systems that were designed to sterilize products in their final cartons to compete directly against irradiation with gamma. Now you have electron beam equipment providers that recognize the unique sterilization applications that low-energy electron beam could be utilized for—that is, ones that are much more product specific.

PhM: Where is the technology today in terms of its development for pharma? Where is it on the adoption curve within the industry?

J.W.: Technology has advanced significantly in that the use of low-energy electron beams for the sterile transfer of materials into an isolator is becoming commonplace. The first system for this application was delivered in 2001 and now you have over 20 electron beam sterile transfer systems installed throughout the world.

PhM: Do you consider this to be a “breakthrough” technology, or is there another term you would use?

J.W.: The commercial availability of small, low-energy electron beam systems for sterilization is relatively recent (<10 years). I consider it an “enabling technology” as it enables manufacturers to economically and reliably sterilize the surface of a product. I remember several years ago asking a pharma company director why his company implemented electron beam technology and he indicated that by using radiation he eliminated many of the concerns and questions associated with assuring the sterility of those items transferred into his filling isolator. Quite simply, he stated that every regulator understands terminal sterilization with radiation.

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