Developed by a team from MIT and the Polytechnic University of Turin, a continuous freeze-drier moves vials through a sequence of chambers where the contents are cooled to a uniform temperature, frozen, and then dried. The new technology aims to speed up the freeze-drying of pharmaceuticals, while overcoming problems with both batch and previous continuous processing techniques.
“Batch processes are very inefficient,” explains Bernhardt L. Trout, PhD, professor of chemical engineering at MIT. “And there’s tremendous risk around the management of non-uniformity [of products].”
Batch processes tend to operate non-uniformly, he explains, because the batch is necessarily large and it’s hard to control the transfer of heat and mass. If a million vials are crammed onto shelves in a big freeze-drier, a vial in the top left-hand corner will experience different conditions from one on the left-hand side of the bottom shelf.
“With our process, each vial basically experiences the same conditions through the process, not just at a given movement in time,” explains Trout. According to the team’s recent paper in Industrial & Engineering Chemistry Research, this also overcomes problems with proposed continuous freeze-dry techniques using bulk powders where conditions cannot be easily controlled.
Today fewer than 5% of pharmaceutical manufacturing processes are continuous, the paper explains.
Trout believes his continuous technology is a novel approach. “Others are working to make a bulk powder continuously, but what we’re doing on unit doses is pretty unique.”
In collaboration with Roberto Pisano of the Polytechnic University of Turin, he has finished experimental testing of the technology. They are now building a research-grade machine with support from the FDA, which they hope to finish in 2021.
“We’re very much in touch with potential industrial partners,” says Trout. “We’re going to build a prototype here and hopefully an equipment manufacturing company will bring it to market.”