(537c) Continuous Downstream Processing Using Intermittent Counter-Current Extraction – Theory and Feasibility Studies

The pharmaceutical industry requires high throughput, lower solvent usage extraction, separation and purification methods to minimise drug development times and reduce both costs and environmental impact.

Intermittent Counter-current extraction (ICcE) has been demonstrated as a potential liquid-liquid extraction method for high throughput, continuous separation of compounds into two product streams and for the isolation, concentration and enrichment of a low abundance target compound [1].  Scale up, using industrial type instruments supplied by Dynamic Extractions Limited, has also been successfully demonstrated [2, 3].

Both theory and methodology for determining optimal operating parameters will be presented. Experimental results for the scaling of ICcE separations from the semi preparative instrument (143 mL column volume) to preparative instrument (912 mL) and on to pilot scale instrument (4.6 L) using a model mixture of pharmaceutical compounds from across a polarity range with hexane/ethyl acetate/methanol/water (HEMWat) two phase systems. These results are compared to a theoretical model of ICcE to confirm the predicted order of compound elution.  Throughput and solvent usage are compared for both ICcE and batch extractions.

[1]  P. Hewitson, S. Ignatova, H. Ye, L. Chen I. Sutherland, J. Chromatogr. A 1216 (2009) 4187

[2]  I. Sutherland, P. Hewitson, S. Ignatova, J Chromatogr. A. 1216 (2009) 8787

[3]P. Hewitson, S. Ignatova, I. Sutherland, J. Chromatogr. A. 1218 (2011) 6072