Save Money and Scale Your Freeze Drying with Pre-Owned Equipment
Used freeze dryers are plentiful, but there are some factors to weigh when intending to scale up with them
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There are freeze dryers of every size and configuration available on the used market, many of them from established dealers who confirm that they reach all specifications while still pricing them far below retail price. It’s entirely possible to scale your lab’s freeze-drying processes from recipe development to pilot-scale production with only used equipment, saving you tens of thousands of dollars with minimal risk. However, there are some key factors to keep in mind when shopping for pre-owned freeze dryers for recipe development and production.
Recipe development
Because high throughput capabilities aren’t needed, small benchtop freeze dryers are the best fit for developing recipes. A freeze dryer with a condenser 4.5 liters or less in size should more than suffice, and pre-owned units of that size are readily available from reputable sellers. Additionally, consider opting for a tray freeze dryer. Tray models are known for having more precise control over cycle parameters, which is ideal for recipe development.
While shopping for a used freeze dryer, look for rebuilt vacuum pumps as well. Rebuilt pumps perform at a level comparable to new pumps but are more affordable and have comparable lifespans, provided their preventative maintenance is kept up.
Finally, you should be prepared to buy new gaskets and manifold valves. While those parts should be intact if you buy from a reputable vendor, there’s a chance that they will be too corroded to adequately hold a vacuum or temperature, in which case you will have to replace them with new ones.
Scaling up to production
After finalizing your recipes, it’s time to scale up to production. The key consideration in scaling up is ensuring that the larger freeze dryer is as identical as possible to the recipe development freeze dryer. “If equivalent or similar equipment with good instrumentation is used, it is possible to design an optimized cycle including determination of process robust in the laboratory, and save time and money during the scale-up process,” says Stefan Schneid, PhD, in a technical brief about scaling up freeze drying cycles. According to Schneid, the “relevant structural features” consist of the chamber design (single or double), shelf heating and cooling rate, condenser temperature, and radiation effects from the walls and doors of the chamber.
Other factors to consider include condenser capacity, logged usage hours, and software availability.
Condenser capacity
The condenser capacity you need will depend on your scale of production. For light to moderate freeze drying, anything between six and 30 liters may suffice. If you need pilot-scale production, opt for a model with a 30- to 50-liter condenser.
Usage hours
Many freeze dryers are driven by microprocessor controls, which log the total usage hours of the unit as well. If the model you’re considering has a microprocessor, ask the vendor how many hours are logged on it. Generally, the unit with the fewest hours will have the longest remaining lifespan.
Software availability
Is the freeze dryer driven by a PC and software? If so, make sure that they are included with the unit. You should also contact the OEM to make sure they’ll sell you a license key for the software even though you didn’t buy the freeze dryer from them.
By carefully considering present and future needs, as well as a variety of technical factors, you can scale up your lyophilization processes with pre-owned freeze dryers to save thousands of dollars.