Countercurrent Chromatography, Scope and Perspectives: Application to Chirotechnology

Abstract

Countercurrent chromatography (CCC) is a liquid-liquid separation technique particularly adapted to preparative separations. In spite of the broad range of applications possible, CCC is mainly applied to the purification of natural products from complex mixtures, field in which some of the characteristics of CCC make it advantageous over other more common chromatographic modalities. Nevertheless, CCC has much to offer in biotechnological purification and enantioseparation. The general characteristics, advantages and drawbacks of CCC, together with its application in dieverse contexts, in paricular enantioseparations, are discussed. IntroductionThe purity requirements demanded in the production of biopharmaceuticals and fine chemicals for the manufacture of active pharmaceutical ingredients (API) have led to a renewed and widespread interest in preparative chromatography [1,2]. The theoretical understanding of the main factors controlling the process, and therefore the possibility to predict its outcome [3,4], has promoted a change in the industrial mentality from the previous reticence. After the wide realization of the cost effectiveness of this purification approach, chromatography has recently become the preferred method for rapidly accessing products of high added value, such as enantiomers [5,6] and biopharmaceuticals [7,8]. Simulated moving bed (SMB), a continuous liquid-solid technique that permits an improved use of the expensive stationary phase, has played a significant role in bringing chromatography closer to the industrial users. Nevertheless, one of the main disadvantages of SMB is the considerable investment required in equipment.Among the possible alternatives easily adapted to be run in continuous mode, countercurrent chromatography (CCC), a liquid-liquid technique in which the separation of components in a mixture is based on their different partitioning into two immiscible liquids [9][10][11][12], can be considered. Although CCC was described in the 1960s [13] and therefore cannot be contemplated as a new technique, in the recent years the increasing development and adoption of preparative chromatography have had a knock-on effect on CCC. As a consequence, the number of publications and studies dealing with CCC has considerably increased. The particular selectivity, high loading capacity and low solvent demand per amount of substrate processed are the reasons that justify the interest in CCC. CCC versus HPLC: Advantages and DrawbacksThe most characteristic feature of CCC, the absence of a solid support, greatly determines its properties, advantages and limitations. Two immiscible liquids, acting as stationary and mobile phase, respectively, are involved in the chromatographic process. The usual way to maintain one of the liquids stationary while the other is passing through requires the establishment of a centrifugal force in the instrument. The difference in density of the two liquids involved completes the job. Nevertheless, to handle liquids in such a way demands moving parts, rotors, gears...

Separation and purification of steroidal saponins from Paris polyphylla by microwave‐assisted extraction coupled with countercurrent chromatography using evaporative light scattering detection

“…As stated before, saponins may decrease the surface tension and cause emulsion problems during the vigorous mixing process in CCC and multiple steps were frequently required to obtain high purity saponins. Based on recent reviews of solvent selection and the solvent selection procedure proposed by Hopmann et al , a solvent system composed of n‐ heptane/ n‐ butanol/acetonitrile/water (HBAW) was evaluated for CCC separation. The HBAW solvent system was found to provide not only suitable K values but also a higher retention of stationary phase during the CCC separation process.…”

Chiral Separations in Preparative Scale: A Medicinal Chemistry Point of View

“…In addition to LC and SFC, also counter-current chromatography (CCC) has been successfully applied, over the last few decades, in the field of chiral separation to obtain pure enantiomers [85,86]. This chromatographic technique has been widely used in the field of natural products chemistry [87,88].…”

Enantioseparation of 3‐phenyllactic acid by chiral ligand exchange countercurrent chromatography

“…Therefore, countercurrent chromatography has been widely used for separation of chemical components from natural products or synthetic mixtures . Recently, increasing number of papers has been published about enantioseparations by countercurrent chromatography . Chiral ligand exchange countercurrent chromatography was derived from the traditional chiral ligand exchange chromatographic techniques, in which a stereospecific ternary complex formed by enantiomer, transitional metal ion, and chiral ligand was also necessary for a successful enantioseparation .…”