PSL - Powder Systems Limited

Lab nutsche filter dryers for efficient product development and direct scale up, with the GFD® range

Lab scale filtration and drying made easy with the GFD range, smaller version of production ANFD

The GFD® nutsche filter dryer launched four years ago can now be found in more and more pharmaceutical and drug discovery laboratories around the world. Since the 19th century chemists have used the commonly known method of Buchner filtration which would then be followed by the use of a vacuum dryer or other method to complete the drying phase.

The GFD technology combines filtration, cake washing and drying all in one step and product is fully recovered through the unique filtration basket.
Due to its direct scale-up abilities, this vacuum lab filtration and drying unit is ideal for feasibility studies and trials before investing in a large scale nutsche agitated filter dryer.
The GFD Lab Filter Dryer is now available in glass borosilicate 3.3, stainless steel 316L and alloy C22.

The GFD products range from the smallest size ‘Mini Lab’ GFD with 0.002m² filtration basket for a total volume of 0.3L and can filter a cake volume up to 0.1L; this is a suitable piece of equipment for lab scale trials.
Then the ’Lab’ GFD size includes a removable filtration basket of 0.01m² for a cake volume around 0.5L for small scale synthesis, when the ‘Maxi Lab’ GFD is used within Kilo-Laboratory for a cake volume of 5L with 0.05m² filtration area.

How does it work?
The slurry enters the vessel through one of the nozzles located on the vessel lid. During the filtration phase, vacuum is pulled at the bottom of the vessel whilst the unique filter basket collects the product.

It is then possible to wash the cake, again using a nozzle of choice on the lid to introduce the solvent and the heated vessel jacket if required. It is common practice to apply pressure to the top of the filter cake during filtration whilst the bi-directional motor is running in a clockwise direction to smooth the cake. Optimal filtration is achieved in this way as you can pressure filter with no cracks in the cake.

The heated jacket is then used to heat the vessel for the drying phase.  The vessel is rated to temperatures between -25°C and 150°C, and it is not uncommon for the GFD to be also used for the filtration of unstable products at low temperatures.

The bi-directional motor is lowered into the cake during this phase and is now used in the anti-clockwise direction to dig into the cake thus resulting in the homogeneous drying of the product.

The GFD benefits:

  • Removable filter basket
  • Improved yield
  • Batch homogeneity
  • Process visibility
  • Reduced product exposure
  • Easy cleaning
  • Minimum process disruption

Technology transfer
During laboratories studies and R&D product development, chemists need to work on similar technology to evaluate and determine the parameters discussed above. Traditional filtration and drying methods usually found in laboratories are Buchner filtration, centrifuge and oven drier. These technologies cannot be transferred successfully onto commercial production scale. Therefore, PSL launched a smaller agitated nutsche filter dryer to provide same technology for less than 200 grams batch of final product. These Lab Nutsche Filter Dryer called GFD® can be found in glass for complete process visibility or stainless steel for higher pressure requirement.

Contained GFD® options: The Laboratory FilterBox Technology
The FilterBox is a new technology consisting of a GFD® being completely integrated within a PSL isolator, providing high containment when handling highly potent APIs and other highly active or cytotoxic compounds.

The FilterBox achieves containment to nanogram levels protecting both the product and the operator during operations including charging, sampling, filtration, drying and discharging.
The GFD® FilterBox is an acrylic glovebox surrounding PSL’s MINI LAB or LAB Glass Filter Dryer. Larger options include the MAXI LAB GFD® which can be incorporated within a full scale Isolator in stainless steel for Kilo Lab or Pilot Plant applications.

  • PSL - Powder Systems

  • filter dryers

  • containment systems

  • scale-up

  • pilot plants

PSL - Powder Systems Limited
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