Case Studies  -  Continuous Carousel Filters and Dryers  

Live Trials available - begin your Continuous Filtration trials with CMAC 

An AWL Continuous Filter Dryer is permanently based at CMAC / Strathclyde University in Glasgow, Scotland. If you would like to test samples in our continuous filtration unit, a team of experts can perform a series of feasibility and detailed process optimisation trials. If you would like to know more information regarding continuous filtration trials, please contact us at enquiries@a-w-l.co.uk 

Specialised API LOVASTATIN

The EPSRC CMAC Future Manufacturing Research Hub investigated research into a lab scale microfactory and its digital twin that addresses the challenge provided by making tablets out of drugs with difficult needle like morphology. The drug that was being processed in the microfactory was Lovastatin, used for lowering cholesterol levels.

 

Lovastatin was crystallized by cooling antisolvent crystallization and was spherically agglomerated. The AWL CCFD was physically coupled with a continuous crystallization system implemented with periodic slurry discharge. In this system, a cooling antisolvent crystallization combined with spherical agglomeration of lovastatin was used to build a fumehood size lovastatin crystallization-spherical agglomeration and isolation microfactory. Despite the very low solid loading (approximately 1% w/w) and instability and fragility of the particles during the process, the CCFD was able to achieve successful isolation of the lovastatin.

Fine Chemical ANTISEPTIC

An antiseptic / disinfectant product was processed with the AWL CCFD for a Fine Chemical company. The trials were carried out at the University of Strathclyde / CMAC (Glasgow). The CFD25 in production mode was coupled with two continuous crystallization units (MSMPR and Rattlesnake) to crystallize, purify and isolate the compound.

 

A challenging slurry was processed with a high solid loading of 40-50% w/w and particle size of approximately 400 microns. The CCFD was able to successfully filter the product despite the challenging slurry properties. Solid blockages that occurred during the slurry transfer could be easily solved by replacing a transfer valve with a pinch valve. This could then allow slurry to be transferred. A slurry of 10%w/w, the minimum cake volume was also tested. The system for this specific case required multiple doses to approach the minimum cake volume necessary to run the isolation. The minimum cake volume for the CFD25 unit is 12 ml, corresponding to the minimum cake height which can be detected by the camera.

Generic pharma API

API continuous filtration trials were carried out for a UK Pharma with the AWL CCFD Vision at the University of Strathclyde / CMAC (Glasgow) with two different compounds. One of the products had a very slow sedimentation time. When non-settling particles are being processed in the CCFD, or the particles take too long to settle, the camera is not able to visualize the liquid and cake levels to halt filtration at dryland.

 

A new isolation mode named ‘Non-settling mode’ was developed by AWL to address this problem. In this mode the operator runs a set of preliminary tests by using the non-settling calibration method. The calibration requires two different slurry volumes to be transferred into the carousel filter and two corresponding cake volumes are measured by the camera system. After the non-settling calibration was carried out for the API products, the experiments were run successfully in non-settling mode and the unit was able to automatically stop filtration and washing to dryland using the calculated cake height from the calibration.

©  ​AWL 2019