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Abstract: Recycling high speed counter-current chromatography (HSCCC) was successfully applied to resolution of (R, S)-naproxen (NAP) using hydroxypropyl-β-cyclodextrin (HP-β-CD) as chiral selector. The two-phase solvent system composed of n-hexane–ethyl acetate–0.1molL−1 phosphate buffer solution with pH=2.67 (8:2:10, v/v/v) was selected. Influence factors for the chiral separation process were investigated, including concentration of HP-β-CD, equilibrium temperature and pH of aqueous phase. Suitable elution mode was selected for HSCCC enantioseparation of (R, S)-NAP. Under optimum separation conditions, 29mg of (R, S)-NAP was separated using preparative recycling HSCCC with the molar ratio HP-β-CD/NAP racemate 83:1. Technical details for recycling elution mode were discussed as for chiral HSCCC separation. The purities of both (S)-NAP and (R)-NAP were over 99.5% as determined by HPLC. Enantiomeric excess of (S)-NAP and (R)-NAP reached 99.4%. Recovery for NAP enantiomers from HSCCC fractions was 82–89%, yielding 13mg of (S)-NAP and 12mg of (R)-NAP. [Copyright &y& Elsevier]

Abstract: Minichaperone sht GroEL191-345 was covalently coupled to NHS-activated Sepharose Fast Flow gel. Refolding of recombinant human interferon gamma (rhIFN-γ) was carried out on a chromatographic column packed with immobilized minichaperone. The effects of salt concentration, urea concentration gradient, elution flow rate and protein loading on the refolding efficiency were investigated. The results indicated that immobilized sht GroEL191-345 chromatography was an effective protocol for the refolding of rhIFN-γ. When loading 100μl denatured rhIFN-γ (17.8mg/ml), the protein mass recovery and total activity obtained in this optimal process reached 74.25% and 6.74×106 IU/ml, respectively with the immobilized minichaperone column which was reused for 10 times with 25% decrease of renaturation capacity. [Copyright &y& Elsevier]

Abstract: This work concentrates on pH-zone-refining counter-current chromatography of two isomeric dicaffeoylquinic acids, 3,5-dicaffeoylquinic acid and 3,4-dicaffeoylquinic acid along with 3-caffeoylquinic acid, from crude extracts of Flos Lonicerae. The elution sequence of the isomeric dicaffeoylquinic acids, the mixing zone and mechanism of separation are discussed. The separation of 2.136g of the crude sample from Flos Lonicerae yielded two isomeric compounds: 0.289g 3,5-dicaffeoylquinic acid and 0.106g 3,4-dicaffeoylquinic acid plus 0.690g 3-caffeoylquinic acid at a high purity of over 92.9%, 94.2% and 97.5%, respectively. [Copyright &y& Elsevier]

The preparation and characterization of mixed-mode adsorbents for a typical separation purpose are of great importance in bioseparation areas. In this work, we prepared a new monolithic cryogel with a combination of ion-exchange and hydrophobic functions by employing benzyl-quaternary amine groups. The fundamental cryogel properties, protein equilibrium adsorption isotherm and chromatographic adsorption in the cryogel were measured experimentally. The results showed that, by using bovine serum album as the model protein, the dual functional cryogel has protein binding capability even in salt solution and the buffer with pH close or below the protein isoelectric point due to both the electrostatic and hydrophobic interactions. A capillary-based adsorption model was developed, which provided satisfied insights of the microstructure, axial dispersion, mass transfer as well as protein adsorption characteristics within the cryogel bed. The chromatographic isolation of bioactive proteins from rabbit blood serum was carried out by the cryogel. Immunoglobulin G antibody with a purity of 98.2% and albumin with a purity of 96.8% were obtained, indicating that the cryogel could be an interesting and promising adsorbent in bioseparation areas. [ABSTRACT FROM AUTHOR]

Abstract: Counter-current chromatography (CCC) was applied for preparative enantioseparation of three β-blocker drugs, including propranolol, pindolol and alprenolol. The two-phase solvent system was composed of chloroform–0.05molL−1 acetate buffer containing 0.10molL−1 boric acid (1:1, v/v), in which 0.10molL−1 di-n-hexyl l-tartrate was added in the organic phase as chiral selector. Influence factors in the enantioseparation of propranolol were investigated. The chromatographic retention mechanism based on borate coordination complex was proposed. 116mg of racemic propranolol was completely enantioseparated using conventional high speed CCC in a single run, yielding 48mg of (+)-propranolol with HPLC purity of 98.9% and 47mg of (−)-propranolol with HPLC purity of 96.3%. Recovery for propranolol enantiomers from CCC fractions was in the range of 75–82%. pH-zone-refining CCC was also successfully applied in enantioseparation of propanolol and it was found that 356mg of racemic propranolol could be completely enantioseparated. 145mg of (+)-enantiomer with HPLC purity of 95.6% and 148mg of (−)-enantiomer with HPLC purity of 98.2% were recovered from pH-zone-refining mode. Separation mechanism about chiral separation by pH-zone-refining CCC was discussed. [Copyright &y& Elsevier]