Purification of an ascomycin derivative with simulated moving bed chromatography. A case study

A purification process was developed for the separation of a semi-synthetic ascomycin derivative from its by-products. The process consists of a silic a gel filtration and crystallization step prior to two simulated moving bed (SMB) separations, where in the first part the polar by-products and in th e second part the apolar by-products were removed. The desired purity was a chieved in a final crystallization step. Key elements of the whole process were the design of the first crystallization to obtain a product feasible f or SMB chromatography and the specification of operating parameters for the two corresponding SMB steps. Starting from a crude product with an assay o f only 44.9% an overall yield for the whole process of 81.0% was achieved w ith a final purity of >98%. (C) 2000 Elsevier Science B.V. All rights reser ved.