Air-Only Refrigeration Solution Expands to Freeze Drying

HOF Sonderanlagen, a German manufacturer specializing in freeze-drying solutions, has developed a novel natural refrigerant system for the pharmaceutical industry.

Called the HOF-Cryoblizzard, the system uses just air to achieve the low temperatures needed for freeze drying medicine, instead of traditional HFC systems.

HOF, located north of Frankfurt, uses a Mirai COLD air-cooling unit to achieve the -70°C to -80°C (-94°F to -112°F) temperature needed for freeze drying, also known as lyophilization. The air-cooling unit is used to cool a reservoir of silicon oil. The oil reservoir then does the heat transfer for the freeze-drying process.

HOF developed the new system by combining the Mirai technology with existing machinery of its own. “We have two Mirai machines on site, and we have equipped an existing freeze dryer, which we have here, and we adapted this technology,” said Alexander Hof, Strategic Manager at HOF.

HOF is still testing the new technology and expects to have specific data in the next few months. But the company expects the new technology to be 10-15% more energy efficient than traditional HFC-based freeze-drying technology, a substantial saving considering freeze drying is a very energy-intensive process.

HOF’s approach means that the technology is suitable not only for new freeze-drying systems, but  also for retrofitting existing machinery to make it “future proof.” There is a “certain level of effort” needed to do such retrofitting, and sometimes the cost can be higher than installing an entirely new system, according to Hof. But the retrofit opportunity is a distinct advantage in an industry where new freeze-drying processes for pharmaceutical use have to be approved by agencies like the U.S. Food and Drug Administration (FDA) to ensure sufficient quality standards; only replacing the cooling unit would result in an “easy validation qualification procedure,” Hof said.

The HOF-Cryblizzard solution is market ready, but HOF is still searching for a company willing to be an early adopter of the new technology. “Other industries are always basically in this arms race of who comes first, but pharma is relying on established methods,” Alexander Hof explained. “All the customers we’ve talked to were really hyped about the technology, but nobody wants to be the first.”

One of the reasons for this reticence is that freeze-drying equipment is long lasting, so first-movers would have to live with new technology – still unproven in the markerplace – for many years. The first freeze dryer built by HOF back in 1988 is still running.

All the existing free-drying solutions built by HOF are customized, so giving a precise price, or return of investment (ROI) period, is difficult, Hof said. It depends on the product produced.

“If you produce personalized medicine to treat cancer, then of course, small batches are extremely expensive, meaning that you don’t need many batches to basically accommodate the investment,” Hof explained. “If you produce more general products like insulin for example, then the ROI is a little longer.”

For more information about the Mirai COLD technology, read our coverage from the October 2019 issue of Accelerate Magazine here.