Feasibility of scaling from pilot to process scale

The pharmaceutical industry is looking for new technology that is easy to scale up from analytical to process scale and is cheap and reliable to operate. Large scale counter-current chromatography is an emerging technology that could provide this advance, but little was known about the key variables affecting scale-up. This paper investigates two such variables: the rotor radius and the tubing bore. The effect of rotor radius was studied using identical: length, β-value, helix angle and tubing bore coils for rotors of different radii (50 mm, 110 mm and 300 mm). The effect of bore was researched using identical: length, helix angle and mean β-value coils on the Maxi-DE centrifuge (R = 300 mm). The rotor radius results show that there is very little difference in retention and resolution as rotor radius increases at constant bore. The tubing bore results show that good retention is maintained as bore increases and resolution only decrease slightly, but at the highest bore (17.5 mm) resolution can be maintained at very high flow rates making it possible for process scale centrifuges to be designed with throughputs exceeding 25 kg/day.